Bsi bs en 00752 2008 (2013)

BRITISH STANDARD

BS EN
EN
752:2008
752:2008

Incorporating
Incorporating
Corrigenda
Corrigendum
October
October 2009
2009 and
November 2013

Drain and sewer
systems outside
buildings

ICS 93.030







BS EN
BS
EN 752:2008

752:2008

National foreword
This British Standard is the UK implementation of EN 752:2008. It supersedes
BS EN 752, Parts 1 to 7, which have been withdrawn.
The UK participation in its preparation was entrusted to Technical Committee
B/505, Wastewater engineering.
A list of organizations represented on this committee can be obtained on
request to its secretary.
The British Standard contains both the text of the European Standard together
with a National Annex, which gives further UK-specific guidance on the
application of the European text. The European Standard should therefore be
read in conjunction with the National Annex and, to assist in this, cross
references to the clauses in the European text are included in the headings in
the National Annex.
This revision of EN 752 includes some important and timely changes. It takes
a more integrated view of sewer system management in the context of the
wider urban drainage system and the wider water environment. This both
supports the current initiative on integrated urban drainage management in
the UK and is essential for the proper implementation of the Water Framework
Directive. In response to climate change, the European text introduces the
concept of exceedence flood risk assessment and further UK guidance on this
is given in the National Annex.
This publication does not purport to include all the necessary provisions of a
contract. Users are responsible for its correct application.
Compliance with a British Standard cannot confer immunity from
legal obligations.

This British Standard was
published under the authority

of theBritish
Standards
Policywas
and
This
Standard
Strategy
Committee
published under the authority
onthe
30 April
2008 Policy and
of
Standards

Strategy Committee
on 30 April 2008
© The British Standards
Institution 2013.
Published by BSI Standards
Limited
2013
9
©
BSI 200

ISBN
ISBN 978
978 00 580
580 69252

84887 92

Amendments/corrigenda issued since publication
Date
Comments
Amendments/corrigenda
issued since publication

31 October 2009
Date

Correction to N.A 5.8, value b
Comments

31 October 2009

Correction to N.A 5.8, value b

30 November 2013

National Annex NA revised


EN 752

EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM

January 2008

ICS 93.030

Supersedes EN 752-1:1995, EN 752-2:1996, EN 7523:1996, EN 752-4:1997, EN 752-5:1997, EN 752-6:1998,
EN 752-7:1998

English Version

Drain and sewer systems outside buildings
Réseaux d'évacuation et d'assainissement à l'extérieur des
bâtiments

Entwässerungssysteme außerhalb von Gebäuden

This European Standard was approved by CEN on 24 November 2007.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: rue de Stassart, 36

© 2008 CEN

All rights of exploitation in any form and by any means reserved
worldwide for CEN national Members.

B-1050 Brussels

Ref. No. EN 752:2008: E


BS EN 752:2008
EN 752:2008 (E)

Foreword
Contents

BS EN 752:2008
EN 752:2008 (E)

Page

This document (EN 752:2008) has been prepared by Technical Committee CEN/TC 165 “Wastewater
Foreword..............................................................................................................................................................7
Engineering”, the secretariat of which is held by DIN.
1
Scope ....................................................................................................................................................10
This European Standard shall be given the status of a national standard, either by publication of an identical
2
Normative references ..........................................................................................................................10

text or by endorsement, at the latest by July 2008, and conflicting national standards shall be withdrawn at the
latest
byTerms
July 2008.
3
and definitions .........................................................................................................................11
4
Objectives.............................................................................................................................................19
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
4.1
General..................................................................................................................................................19
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
4.2
Public Health and Safety.....................................................................................................................20
4.3
Occupational Health and Safety.........................................................................................................20
This document supersedes EN 752-1:1995, EN 752-2:1996, EN 752-3:1996, EN 752-4:1997, EN 752-5:1997,
4.4
Environmental Protection ...................................................................................................................20
EN 752-6:1998, EN 752-7:1998.
4.5
Sustainable Development ...................................................................................................................20
5
Requirements
.......................................................................................................................................21
According
to the CEN/CENELEC
Internal Regulations, the national standards organizations of the following
5.1
Functional

Requirements....................................................................................................................21
countries
are bound
to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
5.1.1 Introduction
..........................................................................................................................................21
Republic,
Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
5.1.2 Protection
fromMalta,
flooding
.....................................................................................................................22
Lithuania,
Luxembourg,
Netherlands,
Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
5.1.3 Maintainability
......................................................................................................................................22
Sweden,
Switzerland and
the United Kingdom.
5.1.4 Protection of surface receiving waters .............................................................................................22
5.1.5 Protection of groundwater..................................................................................................................22
5.1.6 Prevention of odours and toxic, explosive and corrosive gases ...................................................23
5.1.7 Prevention of noise and vibration......................................................................................................23
5.1.8 Sustainable use of products and materials ......................................................................................23
5.1.9 Sustainable use of energy ..................................................................................................................23
5.1.10 Structural integrity and design life ....................................................................................................23
5.1.11 Maintaining the flow ............................................................................................................................23

5.1.12 Watertightness .....................................................................................................................................23
5.1.13 Not endangering adjacent structures and utility services ..............................................................23
5.1.14 Inputs quality........................................................................................................................................23
5.2
Determination of performance requirements for the drain and sewer system .............................23
6
6.1
6.2
6.2.1
6.2.2
6.2.3
6.2.4
6.2.5
6.2.6
6.2.7
6.2.8
6.2.9
6.2.10
6.3
6.3.1
6.3.2
6.3.3
6.3.4
6.3.5
6.3.6
6.3.7
6.3.8

2

Integrated Sewer System Management .............................................................................................26
Introduction ..........................................................................................................................................26
Investigation.........................................................................................................................................27
Introduction ..........................................................................................................................................27
Purpose of investigation .....................................................................................................................28
Review of performance information ..................................................................................................28
Determine the scope of the investigation .........................................................................................30
Review existing information ...............................................................................................................30
Inventory update ..................................................................................................................................31
Hydraulic investigation .......................................................................................................................31
Environmental investigation...............................................................................................................31
Structural investigation.......................................................................................................................32
Operational Investigation....................................................................................................................32
Assessment..........................................................................................................................................33
Introduction ..........................................................................................................................................33
Assessment of the hydraulic performance.......................................................................................33
Assessment of environmental impact ...............................................................................................33
Assess structural condition ...............................................................................................................34
Assess operational performance .......................................................................................................34
Compare with performance requirements ........................................................................................34
Identify unacceptable impacts ...........................................................................................................34
Identify causes of performance deficiencies....................................................................................34

7


BS EN 752:2008
EN 752:2008
(E)
BS

EN 752:2008
EN 752:2008 (E)

BS EN 752:2008
EN 752:2008 (E)

6.4
Developing the Plan ............................................................................................................................34
6.4.1 Introduction..........................................................................................................................................34
6.4.2 Develop integrated solutions .............................................................................................................35
6.4.3 Assess Solutions.................................................................................................................................38
Contents
Page
6.4.4 Prepare action plan .............................................................................................................................39
Contents
Page
6.5
Implementation ....................................................................................................................................40
Foreword..............................................................................................................................................................7
6.5.1 Introduction..........................................................................................................................................40
6.5.2 Carry out work .....................................................................................................................................40
Foreword..............................................................................................................................................................7
1
Scope ....................................................................................................................................................10
6.5.3 Monitoring performance .....................................................................................................................41
1
6.5.4 Scope
Review....................................................................................................................................................10
performance
and update plan.......................................................................41

2
Normative
referencesrequirements
..........................................................................................................................10
2
7
3

Normative
..........................................................................................................................10
Health and references
Safety Principles
..............................................................................................................41
Terms
definitions
.........................................................................................................................11

3
8
4
8.1
4.1
4
8.2
4.2
4.1
8.3
4.3
4.2
8.4

4.4
4.3
8.4.1
4.5
4.4
8.4.2
4.5
5
8.4.3
5.1
5
8.4.4
5.1.1
5.1
8.5
5.1.2
5.1.1
8.5.1
5.1.3
5.1.2
8.5.2
5.1.4
5.1.3
8.5.3
5.1.5
5.1.4
8.5.4
5.1.6
5.1.5
8.5.5

5.1.7
5.1.6
8.5.6
5.1.8
5.1.7
8.6
5.1.9
5.1.8
8.6.1
5.1.10
5.1.9
8.6.2
5.1.11
5.1.10
8.6.3
5.1.12
5.1.11
8.6.4
5.1.13
5.1.12
8.7
5.1.14
5.1.13
8.7.1
5.2
5.1.14
8.7.2
5.2
8.7.3
6

8.7.4
6.1
6
6.2
6.1
9
6.2.1
6.2
9.1
6.2.2
6.2.1
9.2
6.2.3
6.2.2
9.2.1
6.2.4
6.2.3
9.2.2
6.2.5
6.2.4
9.2.3
6.2.6
6.2.5
9.2.4
6.2.7
6.2.6
9.2.5
6.2.8
6.2.7
9.2.6

6.2.9
6.2.8
9.3
6.2.10
6.2.9
9.3.1
6.3
6.2.10
9.3.2
6.3.1
6.3
9.3.3
6.3.2
6.3.1
9.3.4
6.3.3
6.3.2
9.3.5
6.3.4
6.3.3
9.3.6
6.3.5
6.3.4
9.3.7
6.3.6
6.3.5
9.4
6.3.7
6.3.6
9.4.1

6.3.8
6.3.7
9.4.2
6.3.8
9.4.3

Terms
definitions
.........................................................................................................................11
Designand
Principles
................................................................................................................................42
Objectives.............................................................................................................................................19
General .................................................................................................................................................42
General..................................................................................................................................................19
Objectives.............................................................................................................................................19
Types of
systems
................................................................................................................................42
Public
Health
and Safety.....................................................................................................................20
General..................................................................................................................................................19
Layout
and
profile
...............................................................................................................................43
Occupational
Health
and Safety.........................................................................................................20

Public Health and Safety.....................................................................................................................20
Hydraulic Design
.................................................................................................................................44
Environmental
Protection
...................................................................................................................20
Occupational Health and Safety.........................................................................................................20
General .................................................................................................................................................44
Sustainable
Development
...................................................................................................................20
Environmental Protection ...................................................................................................................20
Foul drains and sewers.......................................................................................................................44
Sustainable
Development
...................................................................................................................20
Requirements
.......................................................................................................................................21
Surface water drains and sewers ......................................................................................................45
Functional Requirements....................................................................................................................21
Requirements
.......................................................................................................................................21
Combined drains
and sewers ............................................................................................................47
IntroductionRequirements....................................................................................................................21
..........................................................................................................................................21
Functional
Environmental Considerations ..........................................................................................................47
Protection
from

flooding .....................................................................................................................22
Introduction
..........................................................................................................................................21
General .................................................................................................................................................47
Maintainability
......................................................................................................................................22
Protection of
from
flooding
.....................................................................................................................22
surface
receiving
waters .............................................................................................49
Protection
of surface
receiving waters .............................................................................................22
Maintainability
......................................................................................................................................22
Protection of Groundwater
.................................................................................................................49
Protection of
of groundwater..................................................................................................................22
Protection
waters .............................................................................................22
Prevention of surface
septicityreceiving
........................................................................................................................49
Prevention
of groundwater..................................................................................................................22
odours and toxic, explosive and corrosive gases ...................................................23

Protection
of
Combined sewer
overflows and surface water treatment...............................................................50
Prevention of
of odours
noise and
vibration......................................................................................................23
Prevention
and
toxic, explosive and corrosive gases ...................................................23
Emergency overflows
.........................................................................................................................50
Sustainable
use
of
products
and materials ......................................................................................23
Prevention
of noise and vibration......................................................................................................23
Structural Design.................................................................................................................................50
Sustainable
use
of
energy
..................................................................................................................23
Sustainable
use of products and materials ......................................................................................23
Introduction..........................................................................................................................................50
Structural

integrity
and design
life ....................................................................................................23
Sustainable
use ofofenergy
..................................................................................................................23
Structural design
pipelines
............................................................................................................51
Maintaining
the
flow
............................................................................................................................23
Structural integrity
design
life ....................................................................................................23
design ofand
other
components
............................................................................................51
Watertightness
Maintaining
the.....................................................................................................................................23
flow..............................................................................................................................51
............................................................................................................................23
Materials selection
Not endangering
adjacent structures and utility services ..............................................................23
Watertightness
.....................................................................................................................................23

Operational Considerations
...............................................................................................................52
Inputs
quality........................................................................................................................................23
Not
endangering
adjacent structures and utility services ..............................................................23
General
.................................................................................................................................................52
Determination
of performance requirements for the drain and sewer system .............................23
Inputs
quality........................................................................................................................................23
Separators
............................................................................................................................................52
Determination
of
performance
requirements for the drain and sewer system .............................23
Self-cleansing
conditions
...................................................................................................................52
Integrated
Sewer
System Management.............................................................................................26
Access to drains
and sewers .............................................................................................................53
Introduction
..........................................................................................................................................26
Integrated Sewer System Management.............................................................................................26

Investigation.........................................................................................................................................27
Introduction
..........................................................................................................................................26
Detailed Design....................................................................................................................................53
Introduction ..........................................................................................................................................27
Investigation.........................................................................................................................................27
Introduction..........................................................................................................................................53
Purpose
of investigation
.....................................................................................................................28
Introduction
..........................................................................................................................................27
Layout and profile
...............................................................................................................................53
Review
of
performance
information
..................................................................................................28
Purpose
of investigation .....................................................................................................................28
Introduction..........................................................................................................................................53
Determine
the
scope
of
the
investigation
.........................................................................................30
Review

of performance information ..................................................................................................28
Layout ...................................................................................................................................................53
Review
existing
information
...............................................................................................................30
Determine
the scope of the investigation .........................................................................................30
Accessibility.........................................................................................................................................54
Inventory
updateinformation
..................................................................................................................................31
Review
existing
...............................................................................................................30
Depth.....................................................................................................................................................54
Hydraulic
investigation
.......................................................................................................................31
Inventory
update ..................................................................................................................................31
Need for pumping................................................................................................................................55
Environmental
investigation...............................................................................................................31
Hydraulic
investigation
.......................................................................................................................31
Pumping Installations
.........................................................................................................................55
Structural

investigation.......................................................................................................................32
Environmental
investigation...............................................................................................................31
Preliminary Investigations..................................................................................................................56
Operational
Investigation....................................................................................................................32
Structural
investigation.......................................................................................................................32
General .................................................................................................................................................56
Assessment..........................................................................................................................................33
Operational
Investigation....................................................................................................................32
Topography..........................................................................................................................................56
Introduction ..........................................................................................................................................33
Assessment..........................................................................................................................................33
Geotechnical Survey ...........................................................................................................................56
Assessment
of the hydraulic performance.......................................................................................33
Introduction
Groundwater..........................................................................................................................................33
........................................................................................................................................57
Assessment
of
impact ...............................................................................................33
Assessment
of environmental
theservices
hydraulic
performance.......................................................................................33
Existing drainage

.................................................................................................................57
Assess
structural
condition
...............................................................................................................34
Assessment
ofutility
environmental
impact ...............................................................................................33
Other existing
services ............................................................................................................57
Assess
operational
performance
.......................................................................................................34
Assess
structural
condition
...............................................................................................................34
Extraneous
water.................................................................................................................................57
Compare
with
performance
requirements
........................................................................................34
Assess
operational
performance .......................................................................................................34
Hydraulic

Design .................................................................................................................................57
Identify
unacceptable
impacts
...........................................................................................................34
Compare
with performance requirements ........................................................................................34
Introduction..........................................................................................................................................57
Identify causes
of performance
deficiencies....................................................................................34
Identify
unacceptable
impacts ...........................................................................................................34
Foul drains
and sewers.......................................................................................................................57
Identify
of performance
deficiencies....................................................................................34
Surface causes
water drains
and sewers
......................................................................................................58

2
2

3

BS EN 752:2008
EN 752:2008 (E)

6.4
9.4.4
6.4.1
9.4.5
6.4.2
9.4.6
6.4.3
9.4.7
6.4.4
9.5
6.5
9.5.1
6.5.1
9.5.2
6.5.2
9.5.3
6.5.3
9.5.4
6.5.4
9.6

BS EN 752:2008
EN 752:2008 (E)

Developing
the Plan
Combined drains

and............................................................................................................................34
sewers.............................................................................................................58
Introduction..........................................................................................................................................34
Capacity of pipelines ...........................................................................................................................59
Develop
integrated
solutions..............................................................................................................59
.............................................................................................................35
Sewers with
steep gradients
Assess
Solutions.................................................................................................................................38
Outfall Design Requirements .............................................................................................................60
Prepare
action plan
.............................................................................................................................39
Environmental
Considerations...........................................................................................................60
Implementation
....................................................................................................................................40
Introduction ..........................................................................................................................................60
Introduction..........................................................................................................................................40
Outfall Design Requirements .............................................................................................................60
Carry
out work
.....................................................................................................................................40
Prevention
of septicity
........................................................................................................................60
Monitoring

performance
.....................................................................................................................41
Drains and sewers near water
abstraction areas .............................................................................61
Review
performance
requirements
and update plan.......................................................................41
Operational Considerations................................................................................................................61

9.6.1 Health
Introduction
..........................................................................................................................................61
7
and Safety
Principles ..............................................................................................................41
9.6.2 Separators ............................................................................................................................................61
8
................................................................................................................................42
9.6.3 Design
Design Principles
for self-cleansing
....................................................................................................................61
8.1
General
.................................................................................................................................................42
9.6.4 Access to drains and sewers .............................................................................................................62
8.2
Types of systems ................................................................................................................................42
10

Construction
Principles
......................................................................................................................63
8.3
Layout
and profile
...............................................................................................................................43
10.1
General..................................................................................................................................................63
8.4
Hydraulic
Design .................................................................................................................................44
10.2
Pipelines.................................................................................................................................................44
...............................................................................................................................................63
8.4.1
General
10.3
Ancillaries.............................................................................................................................................63
8.4.2
Foul
drains and sewers.......................................................................................................................44
8.4.3
Surface
water
drains
and sewers ......................................................................................................45
11
Operations
and

Maintenance..............................................................................................................64
8.4.4
Combined
drains
and
sewers ............................................................................................................47
11.1
Introduction ..........................................................................................................................................64
8.5
Environmental
Considerations
..........................................................................................................47
11.2
Objectives.............................................................................................................................................65
8.5.1
General
.................................................................................................................................................47
11.3
Data requirements ...............................................................................................................................65
8.5.2
Protection
of surface
receiving
waters .............................................................................................49
11.4
Investigation
and analysis
of operational
problems........................................................................66
8.5.3 Protection of Groundwater .................................................................................................................49

12
Performance
............................................................................................................................67
8.5.4
Prevention
oftesting
septicity
........................................................................................................................49
8.5.5 Combined sewer overflows and surface water treatment...............................................................50
13
Qualifications and Training ................................................................................................................67
8.5.6 Emergency overflows .........................................................................................................................50
14
Sources ofDesign.................................................................................................................................50
Additional Information.....................................................................................................68
8.6
Structural
8.6.1 Introduction..........................................................................................................................................50
Annex A (informative) Relevant EU Directives ...............................................................................................69
8.6.2 Structural design of pipelines ............................................................................................................51
A.1
Introduction ..........................................................................................................................................69
8.6.3 Structural design of other components ............................................................................................51
A.2
Relevant Directives..............................................................................................................................69
8.6.4 Materials selection ..............................................................................................................................51
8.7
...............................................................................................................52
Annex BOperational
(informative)Considerations

Sources of Additional
Information ............................................................................70
8.7.1
General
B.1
National.................................................................................................................................................52
Standards Bodies .................................................................................................................70
8.7.2
Separators
............................................................................................................................................52
B.2
Austria...................................................................................................................................................70
8.7.3
conditions
...................................................................................................................52
B.2.1 Self-cleansing
Regulatory Bodies
...............................................................................................................................70
8.7.4
to drains and sewers .............................................................................................................53
B.2.2 Access
Other organisations.............................................................................................................................70
B.3
Denmark................................................................................................................................................71
9
Detailed Design....................................................................................................................................53
B.3.1 Regulatory Bodies ...............................................................................................................................71
9.1
Introduction..........................................................................................................................................53
B.3.2 Other organisations.............................................................................................................................71

9.2
Layout and profile ...............................................................................................................................53
B.4
France ...................................................................................................................................................72
9.2.1 Introduction..........................................................................................................................................53
B.4.1 Regulatory Bodies ...............................................................................................................................72
9.2.2 Layout ...................................................................................................................................................53
B.4.2 Other organisations.............................................................................................................................72
9.2.3 Accessibility.........................................................................................................................................54
B.5
Germany ...............................................................................................................................................72
9.2.4 Depth.....................................................................................................................................................54
B.5.1 Regulatory Bodies ...............................................................................................................................72
9.2.5 Need for pumping................................................................................................................................55
B.5.2 Other organisations.............................................................................................................................73
9.2.6 Pumping Installations .........................................................................................................................55
B.6
Ireland ...................................................................................................................................................73
9.3
Preliminary Investigations..................................................................................................................56
B.7
Italy........................................................................................................................................................73
9.3.1 General .................................................................................................................................................56
B.7.1 Regulatory Bodies ...............................................................................................................................73
9.3.2 Topography..........................................................................................................................................56
B.7.2 Other organisations.............................................................................................................................73
9.3.3 Geotechnical Survey ...........................................................................................................................56
B.8
The Netherlands...................................................................................................................................74
9.3.4 Groundwater ........................................................................................................................................57

B.8.1 Regulatory Bodies ...............................................................................................................................74
9.3.5 Existing drainage services .................................................................................................................57
B.8.2 Other organisations.............................................................................................................................74
9.3.6 Other existing utility services ............................................................................................................57
B.9
Norway ..................................................................................................................................................75
9.3.7 Extraneous water.................................................................................................................................57
B.9.1 Regulatory Bodies ...............................................................................................................................75
9.4
Hydraulic Design .................................................................................................................................57
B.9.2 Other organisations.............................................................................................................................75
9.4.1 Introduction..........................................................................................................................................57
B.10
Portugal ................................................................................................................................................75
9.4.2 Foul drains and sewers.......................................................................................................................57
B.10.1 Regulatory Bodies ...............................................................................................................................75
9.4.3 Surface water drains and sewers ......................................................................................................58
B.10.2 Other organisations.............................................................................................................................76

4

3


BS EN 752:2008
EN 752:2008 (E)

BS EN 752:2008
EN 752:2008 (E)

9.4.4
B.11 Combined
Sweden .................................................................................................................................................76
drains and sewers.............................................................................................................58
9.4.5
B.11.1 Capacity
Regulatory
of Bodies...............................................................................................................................76
pipelines ...........................................................................................................................59
9.4.6
B.11.2 Sewers
Other organisations
with steep gradients
............................................................................................................................76
..............................................................................................................59
9.4.7
B.12
Outfall
Switzerland...........................................................................................................................................76
Design Requirements .............................................................................................................60
9.5
B.12.1 Environmental
Regulatory Bodies...............................................................................................................................76
Considerations...........................................................................................................60
9.5.1
B.12.2 Introduction
Other organisations
..........................................................................................................................................60
............................................................................................................................77
9.5.2

B.13 Outfall
United Kingdom...................................................................................................................................77
Design Requirements .............................................................................................................60
9.5.3
B.13.1 Prevention
Regulatory of
Bodies...............................................................................................................................77
septicity ........................................................................................................................60
9.5.4
B.13.2 Drains
Other organisations
and sewers near
............................................................................................................................79
water abstraction areas .............................................................................61
9.6
Operational Considerations................................................................................................................61
Annex C (normative) Operations and maintenance ......................................................................................80
9.6.1 Introduction ..........................................................................................................................................61
C.1
Introduction..........................................................................................................................................80
9.6.2 Separators ............................................................................................................................................61
C.2
Operations planning............................................................................................................................80
9.6.3 Design for self-cleansing ....................................................................................................................61
C.2.1 Inspection routines .............................................................................................................................80
9.6.4 Access to drains and sewers .............................................................................................................62
C.2.2 Operations procedures .......................................................................................................................80
10
C.2.3 Construction
Contingency Planning.........................................................................................................................80

Principles ......................................................................................................................63
10.1
C.3
General..................................................................................................................................................63
Pipelines ...............................................................................................................................................81
10.2
C.3.1 Pipelines
General .................................................................................................................................................81
...............................................................................................................................................63
10.3
C.3.2 Ancillaries.............................................................................................................................................63
Functional problems ...........................................................................................................................81
C.3.3 Structural problems ............................................................................................................................82
11
Operations and Maintenance..............................................................................................................64
C.4
Manholes and Inspection Chambers.................................................................................................83
11.1
Introduction ..........................................................................................................................................64
C.5
Combined sewer overflows................................................................................................................83
11.2
Objectives.............................................................................................................................................65
C.6
Detention tanks....................................................................................................................................84
11.3
Data requirements ...............................................................................................................................65
C.7
Separators, settling chambers and gullies .......................................................................................84
11.4

Investigation and analysis of operational problems........................................................................66
C.8
Pumping installations .........................................................................................................................85
C.9
Inverted siphons..................................................................................................................................85
12
Performance
testing ............................................................................................................................67
C.10
Pest control ..........................................................................................................................................86
13
Qualifications and Training ................................................................................................................67
C.11
Making connections to existing drains and sewers ........................................................................86
C.12 Sources
Control of
drains
and sewers ..............................................................................................87
14
ofdisused
Additional
Information.....................................................................................................68
C.13
Control of building over or adjacent to sewers................................................................................87
Annex A (informative) Relevant EU Directives ...............................................................................................69
Annex DIntroduction
(normative) ..........................................................................................................................................69
Health and Safety .........................................................................................................88
A.1
D.1

Safe systems
of work..........................................................................................................................88
A.2
Relevant
Directives..............................................................................................................................69
D.2
Training and supervision....................................................................................................................88
Annex
BHazardous
(informative)
Sources of Additional Information ............................................................................70
D.3
atmospheres.....................................................................................................................88
B.1
National
Standards
Bodies
D.3.1 Oxygen deficient and
toxic .................................................................................................................70
atmospheres .........................................................................................88
B.2
Austria...................................................................................................................................................70
D.3.2 Potentially explosive atmospheres ...................................................................................................88
B.2.1
Regulatory
Bodies
...............................................................................................................................70
D.4
Traffic control
......................................................................................................................................89

B.2.2
Other
organisations.............................................................................................................................70
D.5
Protective equipment and welfare facilities......................................................................................89
B.3
Denmark................................................................................................................................................71
D.6
Emergency procedures.......................................................................................................................89
B.3.1
Regulatory
Bodies ...............................................................................................................................71
D.7
Temporary works.................................................................................................................................89
B.3.2
Other
organisations.............................................................................................................................71
D.8
Excavation work ..................................................................................................................................89
B.4
France
...................................................................................................................................................72
D.9
Hazardous
materials ...........................................................................................................................90
B.4.1
Regulatory
Bodies
...............................................................................................................................72
D.10

Vaccinations
........................................................................................................................................90
B.4.2 Other organisations.............................................................................................................................72
Annex EGermany
(normative)
Hydraulic Design ..........................................................................................................91
B.5
...............................................................................................................................................72
E.1
General .................................................................................................................................................91
B.5.1
Regulatory
Bodies ...............................................................................................................................72
E.1.1 Other
Introduction..........................................................................................................................................91
B.5.2
organisations.............................................................................................................................73
E.1.2 Ireland
Selection
of Flow Simulation Method................................................................................................91
B.6
...................................................................................................................................................73
E.2
Hydraulic calculations ........................................................................................................................92
B.7
Italy........................................................................................................................................................73
E.2.1 Regulatory
Velocity equations...............................................................................................................................92
B.7.1
Bodies ...............................................................................................................................73

E.2.2 Other
The Saint
Venant equations ...............................................................................................................94
B.7.2
organisations.............................................................................................................................73
E.3
Methods
of calculating runoff from small development schemes .................................................96
B.8
The
Netherlands...................................................................................................................................74
E.4
Calculation Bodies
of foul wastewater
flows for drain systems .................................................................97
B.8.1
Regulatory
...............................................................................................................................74
E.5
Calculation
of foul wastewater flows for sewer system..................................................................97
B.8.2
Other
organisations.............................................................................................................................74
E.6
Combined
sewer overflows................................................................................................................98
B.9
Norway
..................................................................................................................................................75

B.9.1 Regulatory Bodies ...............................................................................................................................75
Annex F (normative) Pumping Installations...................................................................................................99
B.9.2 Other organisations.............................................................................................................................75
F.1
General .................................................................................................................................................99
B.10
Portugal ................................................................................................................................................75
F.2
Planning of pumping installations.....................................................................................................99
B.10.1 Regulatory Bodies ...............................................................................................................................75
F.2.1 Preliminary Considerations................................................................................................................99
B.10.2 Other organisations.............................................................................................................................76

4

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BS EN 752:2008
EN 752:2008 (E)

BS EN 752:2008
EN 752:2008 (E)

B.11
F.2.2 Sweden
Planning..............................................................................................................................................100
.................................................................................................................................................76
B.11.1
F.3

Regulatory
Design of pumping
Bodies...............................................................................................................................76
stations .............................................................................................................101
B.11.2
F.3.1 Other
Layoutorganisations
.................................................................................................................................................101
............................................................................................................................76
B.12
F.3.2 Switzerland...........................................................................................................................................76
Wet well design ..................................................................................................................................102
B.12.1
F.3.3 Regulatory
External layout
Bodies...............................................................................................................................76
and access...............................................................................................................103
B.12.2
F.3.4 Other
Environmental
organisations
impact
............................................................................................................................77
.......................................................................................................................103
B.13
F.3.5 United
Structural
Kingdom...................................................................................................................................77
design ...............................................................................................................................103
B.13.1

F.3.6 Regulatory
Maintenance
Bodies...............................................................................................................................77
considerations ............................................................................................................103
B.13.2
F.4
Other
Designorganisations
of rising mains
............................................................................................................................79
......................................................................................................................104
F.4.1 Principal considerations ...................................................................................................................104
Annex C (normative) Operations and maintenance ......................................................................................80
F.4.2 Choice of route...................................................................................................................................104
C.1
Introduction..........................................................................................................................................80
F.4.3 Choice of diameter.............................................................................................................................104
C.2
Operations planning............................................................................................................................80
F.4.4 Pressures and external loads...........................................................................................................104
C.2.1 Inspection routines .............................................................................................................................80
F.4.5 Choice of materials............................................................................................................................105
C.2.2 Operations procedures .......................................................................................................................80
F.4.6 Thrust..................................................................................................................................................105
C.2.3 Contingency Planning.........................................................................................................................80
F.4.7 Discharge points................................................................................................................................105
C.3
Pipelines ...............................................................................................................................................81
F.4.8 Control of Septicity............................................................................................................................105
C.3.1 General .................................................................................................................................................81

F.4.9 Valve chambers..................................................................................................................................105
C.3.2 Functional problems ...........................................................................................................................81
F.5
Components and appliances............................................................................................................106
C.3.3 Structural problems ............................................................................................................................82
F.5.1 Pumps .................................................................................................................................................106
C.4
Manholes and Inspection Chambers.................................................................................................83
F.5.2 Prime Movers and Drives..................................................................................................................106
C.5
Combined sewer overflows................................................................................................................83
F.5.3 Valves..................................................................................................................................................107
C.6
Detention tanks....................................................................................................................................84
F.5.4 Controls and electrical equipment...................................................................................................107
C.7
Separators, settling chambers and gullies .......................................................................................84
F.5.5 Instrumentation..................................................................................................................................108
C.8
Pumping installations .........................................................................................................................85
F.5.6 Alarms.................................................................................................................................................108
C.9
Inverted siphons..................................................................................................................................85
F.6
Health and Safety...............................................................................................................................108
C.10
Pest control ..........................................................................................................................................86
C.11
Bibliography
Making

....................................................................................................................................................110
connections to existing drains and sewers ........................................................................86
C.12
Control of disused drains and sewers ..............................................................................................87
C.13
Control of building over or adjacent to sewers................................................................................87
Annex D (normative) Health and Safety .........................................................................................................88
D.1
Safe systems of work..........................................................................................................................88
D.2
Training and supervision....................................................................................................................88
D.3
Hazardous atmospheres.....................................................................................................................88
D.3.1 Oxygen deficient and toxic atmospheres .........................................................................................88
D.3.2 Potentially explosive atmospheres ...................................................................................................88
D.4
Traffic control ......................................................................................................................................89
D.5
Protective equipment and welfare facilities......................................................................................89
D.6
Emergency procedures.......................................................................................................................89
D.7
Temporary works.................................................................................................................................89
D.8
Excavation work ..................................................................................................................................89
D.9
Hazardous materials ...........................................................................................................................90
D.10
Vaccinations ........................................................................................................................................90
Annex E (normative) Hydraulic Design ..........................................................................................................91

E.1
General .................................................................................................................................................91
E.1.1 Introduction..........................................................................................................................................91
E.1.2 Selection of Flow Simulation Method................................................................................................91
E.2
Hydraulic calculations ........................................................................................................................92
E.2.1 Velocity equations...............................................................................................................................92
E.2.2 The Saint Venant equations ...............................................................................................................94
E.3
Methods of calculating runoff from small development schemes .................................................96
E.4
Calculation of foul wastewater flows for drain systems .................................................................97
E.5
Calculation of foul wastewater flows for sewer system..................................................................97
E.6
Combined sewer overflows................................................................................................................98
Annex F (normative) Pumping Installations...................................................................................................99
F.1
General .................................................................................................................................................99
F.2
Planning of pumping installations.....................................................................................................99
F.2.1 Preliminary Considerations................................................................................................................99

6

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BS EN 752:2008
EN 752:2008 (E)

BS EN 752:2008
EN 752:2008 (E)

F.2.2 Planning..............................................................................................................................................100
F.3
Design of pumping stations .............................................................................................................101
F.3.1 Layout .................................................................................................................................................101
F.3.2 Wet well design ..................................................................................................................................102
F.3.3 External layout and access...............................................................................................................103
Foreword
F.3.4 Environmental impact .......................................................................................................................103
F.3.5 Structural design ...............................................................................................................................103
This document
(EN 752:2008)
has ............................................................................................................103
been prepared by Technical Committee CEN/TC 165 “Wastewater
F.3.6
Maintenance
considerations
Engineering”,
theofsecretariat
of which
is held by DIN.
F.4
Design
rising mains
......................................................................................................................104
F.4.1 Principal considerations ...................................................................................................................104
This European

shall be given the status of a national standard, either by publication of an identical
F.4.2
ChoiceStandard
of route...................................................................................................................................104
text or by
endorsement,
at the latest by July 2008, and conflicting national standards shall be withdrawn at the
F.4.3
Choice
of diameter.............................................................................................................................104
latest byPressures
July 2008. and external loads...........................................................................................................104
F.4.4
F.4.5 Choice of materials............................................................................................................................105
AttentionThrust..................................................................................................................................................105
is drawn to the possibility that some of the elements of this document may be the subject of patent
F.4.6
rights. CEN
[and/or points................................................................................................................................105
CENELEC] shall not be held responsible for identifying any or all such patent rights.
F.4.7
Discharge
F.4.8 Control of Septicity............................................................................................................................105
F.4.9
Valve chambers..................................................................................................................................105
This document
supersedes EN 752-1:1995, EN 752-2:1996, EN 752-3:1996, EN 752-4:1997, EN 752-5:1997,
F.5
Components
and appliances............................................................................................................106

EN 752-6:1998,
EN 752-7:1998.
F.5.1 Pumps .................................................................................................................................................106
F.5.2
Prime
Movers
and Drives..................................................................................................................106
According
to the
CEN/CENELEC
Internal Regulations, the national standards organizations of the following
F.5.3
countriesValves..................................................................................................................................................107
are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
F.5.4
Controls
andEstonia,
electrical
equipment...................................................................................................107
Republic,
Denmark,
Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
F.5.5
Instrumentation..................................................................................................................................108
Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
F.5.6
Sweden,Alarms.................................................................................................................................................108
Switzerland and the United Kingdom.

F.6
Health and Safety...............................................................................................................................108
Bibliography ....................................................................................................................................................110

6

7


BS EN 752:2008
EN 752:2008 (E)

Introduction
Drain and sewer systems are part of the overall wastewater system that provides a service to the community.
This can be briefly described as:


removal of wastewater from premises for public health and hygienic reasons;



prevention of flooding in urbanised areas;



protection of the environment.

The overall wastewater system has four successive functions:


Collection;



Transport;



Treatment;



Discharge.

Drain and sewer systems provide for the collection and transport of wastewater.
Historically, drain and sewer systems were installed because there was a need to remove the polluted water
to prevent diseases.
Traditionally, drain and sewer systems were constructed to collect and transport all types of wastewater
together irrespective of the initial source. This led to difficulties in handling the peak flows in times of heavy
rainfall and to the introduction of combined sewer overflows, which discharged polluted water to surface
receiving waters.
It was later recognised that separate systems, where foul wastewater was kept separate from runoff derived
from surface water, would be an improvement over such combined systems.
Although many drain and sewer systems started out as combined systems there are strong arguments for
considering the separation of foul wastewater and surface water. The pollutant effects are not the same and
the separation of effluents allows for the different treatment for each element of wastewater, providing more
environmentally friendly solutions.
This concept is included in the approach of integrated sewer management.
EN 752 provides a framework for the design, construction, rehabilitation, maintenance and operation of drain
and sewer systems outside buildings. This is illustrated in the upper part of the diagram below. EN 752 is

supported by more detailed standards for the investigation, design, construction, organisation and control of
drain and sewer systems such as those listed in the lower part of the diagram. To support these detailed
standards information will come from specifications produced by individual organisations for their own use.
Product standards should also take into account the functional requirements in EN 752 through EN 476,
EN 773, EN 1293, EN 13380 and EN 14457.

8


BS EN 752:2008
EN 752:2008 (E)

Figure 1 — Pyramid Diagram

9


BS EN 752:2008
EN 752:2008 (E)

1

Scope

This European Standard sets out the objectives for drain and sewer systems outside buildings. It specifies the
functional requirements for achieving these objectives and the principles for strategic and policy activities
relating to planning, design, installation, operation, maintenance and rehabilitation.
It is applicable to drain and sewer systems, which operate essentially under gravity, from the point where
wastewater leaves a building, roof drainage system, or paved area, to the point where it is discharged into a
wastewater treatment plant or receiving water.

Drains and sewers below buildings are included provided that they do not form part of the drainage system for
the building.

2

Normative references

The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 476:1997, General requirements for components used in discharge pipes, drains and sewers for gravity
systems
EN 858-1, Separator systems for light liquids (e.g. oil and petrol) — Part 1: Principles of product design,
performance and testing, marking and quality control
EN 858-2, Separator systems for light liquids (e.g. oil and petrol) — Part 2: Selection of nominal size,
installation, operation and maintenance
EN 1295-1, Structural design of buried pipelines under various conditions of loading — Part 1: General
requirements
EN 1610, Construction and testing of drains and sewers
EN 1825-1, Grease separators — Part 1: Principles of design, performance and testing, marking and quality
control
EN 1825-2, Grease separators — Part 2: Selection of nominal size, installation, operation and maintenance
EN 1990, Eurocode — Basis of structural design
EN 1991-1-1, Eurocode 1 — Actions on structures — Part 1-1: General actions Densities — self-weight,
imposed loads for buildings
EN 1991-1-2, Eurocode 1 — Actions on structures — Part 1-2: General actions — Actions on structures
exposed to fire
EN 1991-1-3, Eurocode 1 — Actions on structures — Part 1-3: General actions — Snow loads
EN 1991-1-5, Eurocode 1 — Actions on structures — Part 1-5: General actions — Thermal actions
EN 1991-2, Eurocode 1 — Actions on structures — Part 2: Traffic loads on bridges

EN 1991-4, Eurocode 1 — Actions on structures — Part 4: Silos and tanks

10


BS EN 752:2008
EN 752:2008 (E)

EN 1992-1-1, Eurocode 2 — Design of concrete structures — Part 1-1: General rules and rules for buildings
EN 1992-1-2, Eurocode 2 — Design of concrete structures — Part 1-2: General rules - Structural fire design
EN 1992-3, Eurocode 2 — Design of concrete structures — Part 3: Liquid retaining and containment
structures
ENV 1993-1-1, Eurocode 3 — Design of steel structures — Part 1-1: General rules and rules for buildings
EN 1994-1-1, Eurocode 4 — Design of composite steel and concrete structures — Part 1-1: General rules and
rules for buildings
EN 1996-1-1, Eurocode 6: Design of masonry structures — Part 1-1: General rules for reinforced and
unreinforced masonry structures
EN 1997-1, Eurocode 7: Geotechnical design — Part 1: General rulesEN 1998-1, Eurocode 8: Design of
structures for earthquake resistance — Part 1: General rules, seismic actions and rules for buildings
EN 1998-3, Eurocode 8: Design of structures for earthquake resistance — Part 3: Assessment and retrofitting
of buildings
EN 1998-1, Eurocode 8: Design of structures for earthquake resistance — Part 1: General rules, seismic
actions and rules for buildings
EN 1999-1-1, Eurocode 9: Design of aluminium structures — Part 1-1: General structural rules
EN 12889, Trenchless construction and testing of drains and sewers
EN 13508-2, Condition of drain and sewer systems outside buildings — Part 2: Visual inspection coding
system
EN 14654-1, Management and control of cleaning operations in drains and sewers — Part 1: Sewer cleaning

3

Terms and definitions

For the purposes of this document, the following terms and definitions apply.
3.1
aerobic
dissolved oxygen is present
[EN 1085:2007, definition 4100]
3.2
aesthetic
<of pollution> aspects sensed by sight or smell, e.g. floating solids, oil films or bank-side litter
3.3
air valve
valve used to allow air to escape from or enter into a rising main
3.4
anaerobic
dissolved oxygen, nitrate, nitrite and sulfate is absent
[EN 1085:2007, definition 4120]

11


BS EN 752:2008
EN 752:2008 (E)

3.5
backdrop manhole
manhole with a connection, by means of a vertical pipe, at or just above invert, from a drain or sewer at a
higher level
3.6

backwater level
elevation of the surface of the wastewater predicted or occurring in a drain or sewer system due to the
hydraulic conditions downstream
3.7
biochemical oxygen demand (BOD)
concentration of dissolved oxygen consumed under specific conditions (t days at 20 °C with or without
nitrification inhibition) by the biological oxidation of organic and/or inorganic matter in water
[EN 1085:2007, definition 3110]
3.8
catchment area
area draining to a drain, sewer or watercourse
[EN 1085:2007, definition 1270]
3.9
cleaning ball
spherical device, having an indented surface, designed to be carried through a drain or sewer by the flow to
facilitate removal of sediments
3.10
confined space
space in which the ventilation is restricted to the extent that special safety precautions need to be taken
3.11
combined sewer overflow
device, on a combined system that relieves the system of excess flow
[EN 1085:2007, definition 2130]
3.12
combined system
drain and sewer system designed to carry both foul wastewater and surface water in the same pipeline(s)
[EN 1085:2007, definition 2110]
3.13
common trench
trench in which more than one pipe is located

3.14
dam board
removable plank or section placed across a sewer or drain to divert or hold back the flow
3.15
depression storage
precipitation retained in surface hollows that does not contribute to runoff
3.16
design life
notional lifetime of an asset used for the purposes of design

12


BS EN 752:2008
EN 752:2008 (E)

3.17
detention tank
tank or reservoir for the temporary storage of wastewater
[EN 1085:2007, definition 2240]
3.18
domestic wastewater
water discharged from kitchens, laundry rooms, lavatories, bathrooms, toilets and similar facilities
[EN 1085:2007, definition 2030]
3.19
drain
pipeline, usually underground, designed to carry wastewater from a source to a sewer
[EN 1085:2007, definition 2250]
3.20
drainage service

natural or artificial system for the draining of a catchment area
3.21
dry weather flow
flow not affected by rainfall or snow melt
[EN 1085:2007, definition 3050]
3.22
dry well
dry chamber forming part of a pumping station and containing pumping equipment, normally used in
conjunction with a wet well
3.23
duty point
rate of flow and the corresponding total head for which a pump is designed or selected
3.24
exfiltration
escape of wastewater from a drain or sewer system into surrounding ground
[EN 1085:2007, definition 2230]
3.25
extraneous water
unwanted flow in a drain or sewer system
3.26
explosion proof
protected from causing ignition of flammable gases
3.27
flooding
condition where wastewater and/or surface water escapes from or cannot enter a drain or sewer system and
either lies on the surface or enters buildings (see also surface flooding)
3.28
flow balancing
reduction in peak discharge by means of temporary storage of flow

13


BS EN 752:2008
EN 752:2008 (E)

3.29
flushing
use of a temporary substantially increased flow to facilitate removal of obstructions or sediments from drains
or sewers
3.30
gravity system
drain or sewer system where flow is caused by the force of gravity and where the pipeline is designed usually
to operate partially full
[EN1085:2007, definition 2260]
3.31
hydro-biological stress
detrimental impact on aquatic flora and fauna, caused by high flow velocity and scour
3.32
infiltration
〈into the ground〉 the movement of surface water or treated effluent into the ground
[EN 1085:2007, definition 2210]
3.33
infiltration
〈into the drain or sewer system〉 unwanted flow resulting from an ingress of groundwater into a drain or sewer
system (see Figure 2)
[EN 1085:2007, definition 2220]
3.34
inspection chamber
chamber with a removable cover constructed on a drain or sewer that permits the introduction of cleaning and

inspection equipment from surface level, but does not provide access for personnel
3.35
integrated sewer system management
co-ordinated management of the planning, design, construction, rehabilitation, operation and maintenance of
all drain and sewer systems in a catchment area taking into account all aspects of their performance
3.36
integrated urban drainage management
co-ordinated management of the planning, design, construction, rehabilitation, operation and maintenance of
all urban drainage systems in a catchment area taking into account all aspects of their performance
3.37
integrated water policies
co-ordinated policies for the management of all bodies of water within a river basin including urban drainage
systems within it
3.38
inverted siphon
length of gravity drain or sewer that is lower than upstream or downstream lengths to allow the pipeline to
pass below an obstacle, and which consequently operates under pressure
3.39
jetting
use of high-pressure water jetting equipment to facilitate removal of obstructions or sediments from drains or
sewers

14


BS EN 752:2008
EN 752:2008 (E)

3.40
maintenance

routine work undertaken to ensure the continuing performance of drain and sewer systems
3.41
manhole
chamber with a removable cover constructed on a drain or sewer to permit entry by personnel
3.42
outfall
structure or point from which wastewater is discharged to a wastewater treatment plant or receiving water
[EN 1085:2007, definition 1280]
3.43
operations
actions taken in the course of normal functioning of drain and sewer systems (e.g. monitoring and regulation
or diversion of wastewater)
3.44
pumping installation
pumping station together with any associated rising main(s)
3.45
pumping station
building, structures and equipment used to transfer wastewater through a rising main or otherwise to raise the
wastewater
3.46
rainfall intensity
depth of rain falling in unit time, or volume of rain falling in unit time per unit area
3.47
ramp manhole
manhole with a steeply inclined pipe or channel from a drain or sewer at a higher level
3.48
rain water
water arising from atmospheric precipitation, which has not yet collected matter from the surface (see
Figure 2)
[EN 1085:2007, definition 2060]

3.49
receiving water
any type of water body where water or wastewater is discharged
[EN 1085:2007, definition 1100]
3.50
rehabilitation
measures for restoring or upgrading the performance of existing drain and sewer systems
3.51
relevant authority
organisation with appropriate statutory powers of control

15


BS EN 752:2008
EN 752:2008 (E)

3.52
renovation
work incorporating all or part of the original fabric of the drain or sewer by means of which its current
performance is improved
3.53
repair
rectification of local damage
3.54
replacement
construction of a new drain or sewer, on or off the line of an existing drain or sewer, the function of the new
drain or sewer incorporating that of the old
3.55
retention time

time during which wastewater is held within the pumping installation
3.56
rising main
pipe through which wastewater is pumped
[EN 1085:2007, definition 2170]
3.57
rodding
use of appropriate device on the end of flexible rods to facilitate removal of obstructions (or sediments) from
drains or sewers
3.58
rodding point
small diameter non-man access connection to a drain or sewer that facilitates cleaning or inspection
3.59
runoff
water from precipitation which flows off a surface to reach a drain, sewer or receiving water (see Figure 2)
3.60
runoff coefficient
factor dependent on the ground catchment, and by which the rain water quantity per unit of time must be
multiplied in order to indicate the flow expected to be carried to the drain or sewer system
3.61
self-cleansing
ability of the flow in a drain or sewer to carry away solid particles, which would otherwise be deposited in the
pipe
3.62
self-purifying capacity
ability of receiving waters to recover from pollution by natural processes
3.63
separate system
drain and sewer system, usually of two pipelines, one carrying foul wastewater and the other surface water
[EN 1085:2007, definition 2120]

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EN 752:2008 (E)

3.64
septic wastewater
anaerobic wastewater which usually contains hydrogen sulphide
[EN 1085:2007, definition 2020]
3.65
sewer
pipeline or other construction, usually underground, designed to carry wastewater from more than one source
[EN 1085:2007, definition 2270]
3.66
sewer system
network of pipelines and ancillary works which conveys wastewater from drains to a treatment plant or other
place of disposal
[EN 1085:2007, definition 2270]
3.67
structural condition
state of a drain or sewer in matters relating to the integrity of its fabric
3.68
sub-critical flow
state of flow when the water velocity is less than the velocity of the small surface wave with water levels
tending to be stable
3.69
super-critical flow
state of flow when the water velocity is greater than the velocity of the small surface wave with violent

fluctuations in water level being possible
3.70
surcharge
condition in which wastewater and/or surface water is held under pressure within a gravity drain or sewer
system, but does not escape to the surface to cause flooding
3.71
surface flooding
condition where wastewater and/or surface water escapes from, or cannot enter, a drain or sewer system and
either lies on the surface or enters buildings from the surface (see also flooding)
3.72
surface receiving water
receiving water body that is on the surface of the ground (e.g. river, lake or sea) (see Figure 2)
3.73
surface water
water from precipitation, which has not seeped into the ground and which is discharged to the drain or sewer
system directly from the ground or from exterior building surfaces (see Figure 2)
[EN 1085:2007, definition 2070]
3.74
time of concentration
time taken for runoff to travel from the hydraulically most distant point of the catchment area to a defined point
in the drain or sewer

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BS EN 752:2008
EN 752:2008 (E)

3.75
tank sewer

section of sewer which acts as a detention tank
3.76
trade effluent
wastewater discharge resulting from any industrial or commercial activity
[EN 1085:2007, definition 2040]
3.77
urban drainage system
systems used for the collection and transport of wastewater and other rain water runoff in an urban area

Key
1

Rain Water (see 3.48)

2

Runoff (see 3.59)

3

Surface Water (see 3.73)

4

Infiltration (see 3.32)

5

Surface Receiving Water (see 3.72)
Figure 2 — Terminology for flows derived from rain water

3.78
utility services
services provided to customers and industry such as gas, electricity, telephone, cable TV and water

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EN 752:2008 (E)

3.79
vortex manhole
circular manhole within which a large difference in level is accommodated by the wastewater entering
tangentially and descending helically
3.80
wastewater
water composed of any combination of water discharged from domestic, industrial or commercial premises,
surface run-off and accidentally any sewer infiltration water
[EN 1085:2007, definition 1010]
3.81
wastewater treatment plant
facility for the physical, biological and/or chemical treatment of wastewater
[EN 1085:2007, definition 4500]
3.82
wet well
chamber forming a part of a wastewater pumping station into which wastewater discharges prior to pumping. It
can include submersible pumping equipment and pipework
3.83
whole life cost

aggregate cost of a scheme over its design life, being the sum of the construction, operating and maintenance
costs all calculated at the same time base
3.84
winching
use of a bucket or other device pulled through a drain or sewer to facilitate removal of sediments (or
obstructions)

4

Objectives

4.1 General
The four objectives of drain and sewer systems are:


Public health and safety;



Occupational health and safety;



Environmental protection;



Sustainable development.

A number of European Union Directives (e.g. the Urban Wastewater Treatment Directive (91/271/EEC)) make

requirements for drain and sewer systems which relate to these objectives. For further information see Annex
A (informative).
Drain and sewer systems are part of the urban drainage system (see Figure 3). Urban drainage systems
comprise all infrastructures for the management of wastewater and rain water in the built environment. The
extent and role of the drain and sewer system within the urban drainage system will depend on local
circumstances for each system.

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BS EN 752:2008
EN 752:2008 (E)

Urban drainage systems are part of a wider system of water management (see Figure 3). The Water
Framework Directive (2000/60/EC) provides the basis for integrated management of the whole water
management system through the river basin management plan.
Integrated sewer system management includes a consideration of the interactions of the drain and sewer
system with the urban drainage system as a whole, and the wider water environment.

4.2 Public Health and Safety
Drain and Sewer systems are provided in order to:


prevent spread of disease by contact with faecal and other waterborne waste;



protect drinking water sources from contamination by waterborne waste;



carry runoff and surface water away while minimising hazards to the public.

Poorly designed, constructed or maintained systems can cause health or safety hazards to the public.
The objective is to design, construct, operate, maintain and rehabilitate the system in order to minimise the
health and safety risks associated with the conveyance of wastewater.

4.3 Occupational Health and Safety
All work associated with the installation, operation, maintenance and rehabilitation of drain and sewer systems
presents a range of occupational health and safety hazards.
The objective is to minimise the occupational health and safety risks likely to arise during installation,
operation, maintenance, and rehabilitation.

4.4 Environmental Protection
The objective is to design, construct, operate and maintain the system to minimise the impact on the
environment.
The impact of drain and sewer systems on the receiving waters shall meet the requirements of any national or
local regulations or the relevant authority. Other environmental requirements specified by any national or local
regulations or the relevant authority shall also be met.

4.5 Sustainable Development
The objective is to design, construct, operate, maintain and rehabilitate the system at the best environmental,
social and economical costs so that it:
a) uses materials that minimise the depletion of finite resources;
b) can be operated with the minimum practicable use of energy; and,
c) can be constructed, operated and, at the end of their life, decommissioned with the minimum practicable
impact on the environment.

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BS EN 752:2008
EN 752:2008 (E)

5

Requirements

5.1 Functional Requirements
5.1.1

Introduction

Functional requirements cover the drain and sewer systems, together with combined sewer overflows,
pumping installations and other components, including the effects of their discharges on receiving waters and
the receiving wastewater treatment plant. The requirements shall be considered in respect of the whole
system to ensure that additions or modifications to the system do not result in failure to meet the target
standards.
Requirements shall be established that, whilst taking into account sustainable development and whole life
costs including indirect costs (e.g. cost of social disruption), ensure that drain and sewer systems convey and
discharge their contents without causing unacceptable environmental nuisance, risk to public health, or risk to
personnel working therein.
Each functional requirement can relate to more than one objective. An indication of the relevance of each of
the functional requirements to achieving the objectives is shown in Table 1.
Table 1 — Relationship between objectives and functional requirements
Clause No

Public Health
and Safety

Occupational
Health and
Safety

Environmental
Protection

Sustainable
development

5.1.2 Protection from flooding

XXX

XX

XXX

–

5.1.3 Maintainability

XX

XXX

XX

XX

XXX

X

XXX

XX

5.1.5 Protection of groundwater

XXX

–

XXX

XXX

5.1.6 Prevention of odours and
toxic, explosive and corrosive
gases

XXX

XXX

XXX

XXX

5.1.7 Prevention of noise and
vibration

XX

XXX

X

X

–

–

XX

XXX

5.1.9 Sustainable use of energy

–

–

XX

XXX

5.1.10 Structural integrity and

design life

XXX

XXX

XXX

XXX

5.1.11 Maintaining the flow

XXX

–

XXX

X

5.1.12 Watertightness

XXX

X

XXX

XX

5.1.13 Not endangering adjacent
structures and utility services

XXX

XXX

X

XX

XX

XXX

XXX

XX

5.1.4 Protection
receiving waters

of

surface

5.1.8
Sustainable
use
products and materials

5.1.14 Inputs quality
NOTE

of

XXX is High;
X is Low and;
– is not related.

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BS EN 752:2008
EN 752:2008 (E)

5.1.2

Protection from flooding

Flooding from drains and sewers can have a major impact on the health of people affected. The economic
impact can be high and depends on the type of location flooded.
Flooding shall be limited to nationally or locally prescribed frequencies taking into account the:


health and safety effects of the flooding;



costs of the flooding;



extent to which any surface flooding can be controlled without causing damage;



whether surcharge is likely to lead to flooding of basements.

NOTE
In some jurisdictions it is the responsibility of the property owner to provide protection to prevent flooding of
basements due to surcharge.

The hydraulic capacity shall limit flooding to nationally or locally prescribed levels and frequencies taking into
account backwater levels. The hydraulic capacity shall allow for foreseeable increases in flow over the design
life of the system. The effects of flows discharged into downstream sewers or receiving waters shall be
considered. Further details are included in clause 8.
Where there are components in the system, which have a high risk of failure, measures should be taken to
avoid or minimise the risk of flooding in the event of failure of those components.
5.1.3

Maintainability

The system shall be planned, designed, constructed and rehabilitated to allow appropriate maintenance
activities to be carried out safely and without risks to the health of personnel.
Adequate access and working space shall be provided for maintenance purposes.
5.1.4

Protection of surface receiving waters

Surface receiving waters shall be protected from pollution within nationally or locally prescribed limits.
The impact of drain and sewer systems on the surface receiving waters shall meet the requirements of any
national or local regulations or the relevant authority. Other environmental requirements specified by any
national or local regulations or the relevant authority shall also be met.
The measures to achieve the standards required under Water Framework Directive (2000/60/EC) will be
summarised in the Water Framework River Basin Plan.
5.1.5

Protection of groundwater

Groundwater shall be protected from pollution within nationally or locally prescribed limits. The effect of the
drain and sewer system on the local recharge of aquifers shall be considered.
The impact of drain and sewer systems on the receiving groundwater shall meet the requirements of any
national or local regulations or the relevant authority. Other environmental requirements specified by any
national or local regulations or the relevant authority shall also be met.
The measures to achieve the standards required under Water Framework Directive will be summarised in the
Water Framework River Basin Plan.

22