Bsi bs en 00472 1995 (2000)

BRITISH STANDARD

Pressure gauges —
Vocabulary

The European Standard EN 472:1994 has the status of a
British Standard

BS EN
472:1995


BS EN 472:1995

Committees responsible for this
British Standard
The preparation of this British Standard was entrusted to Technical
Committee GEL/65, Measurement and control, upon which the following
bodies were represented:
British Coal Corporation
British Gas plc
British Nuclear Fuels plc
Electrical Contractors’ Association
Electricity Association
Energy Industries Council
GAMBICA (BEAMA Ltd.)
Health and Safety Executive
Institution of Gas Engineers
The following bodies were also represented in the drafting of the standard,
through subcommittees and panels:
British Compressed Air Society

British Compressed Gases Association
British Fluid Power Association
British Pressure Gauge Manufacturers’ Association
Department of Trade and Industry (National Engineering Laboratory)

This British Standard, having
been prepared under the
direction of the Electrotechnical
Sector Board, was published
under the authority of the
Standards Board and
comes into effect on
15 September 1995
© BSI 01-2000
The following BSI references
relate to the work on this
standard:
Committee reference GEL/65
Draft for comment 91/24810 DC
ISBN 0 580 24628 0

Amendments issued since publication
Amd. No.

Date

Comments


BS EN 472:1995

Contents
Committees responsible
National foreword
Foreword
Text of EN 472

© BSI 01-2000

Page
Inside front cover
ii
2
3

i


BS EN 472:1995

National foreword
This British Standard has been prepared by Technical Committee GEL/65 and is
the English language version of EN 472:1994, Pressure gauges — Vocabulary
published by the European Committee for Standardization (CEN).
No British Standard is superseded.
A British Standard does not purport to include all the necessary provisions of a
contract. Users of British Standards are responsible for their correct application.
Compliance with a British Standard does not of itself confer immunity
from legal obligations.

Summary of pages
This document comprises a front cover, an inside front cover, pages i and ii,
the EN title page, pages 2 to 7 and a back cover.
This standard has been updated (see copyright date) and may have had
amendments incorporated. This will be indicated in the amendment table on the
inside front cover.
ii

© BSI 01-2000


EUROPEAN STANDARD

EN 472

NORME EUROPÉENNE
October 1994

EUROPÄISCHE NORM
UDC 681.2.084.83:001.4
Descriptors: Measuring instruments, manometers, vocabulary

English version

Pressure gauges — Vocabulary

Manomètres — Vocabulaire

Druckmeßgeräte — Begriffe

This European Standard was approved by CEN on 1994-10-19. 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 Central Secretariat 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
Central Secretariat has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium,
Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,
Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and
United Kingdom.

CEN
European Committee for Standardization
Comité Européen de Normalisation
Europäisches Komitee für Normung
Central Secretariat: rue de Stassart 36, B-1050 Brussels
© 1994 Copyright reserved to CEN members

Ref. No. EN 472:1994 E


EN 472:1994

Foreword

Contents

This European Standard has been prepared by
Technical Committee CEN/TC 141, Pressure
gauges, of which the secretariat is held by AFNOR.
This European Standard shall be given the status of
a national standard, either by publication of an
identical text or by endorsement, at the latest by
April 1995, and conflicting national standards shall
be withdrawn at the latest by April 1995.
In accordance with the CEN/CENELEC Internal
Regulations, the following countries are bound to
implement this European Standard: Austria,
Belgium, Denmark, Finland, France, Germany,
Greece, Iceland, Ireland, Italy, Luxembourg,
Netherlands, Norway, Portugal, Spain, Sweden,
Switzerland and United Kingdom.

Page
Foreword
2
0
Introduction
3
1
Scope
3
2
Definitions relating to pressure gauges
3

3
Definitions relating to pressure gauge
components
3
4
Definitions relating to the characteristics
5
Index
7

2

© BSI 01-2000


EN 472:1994

0 Introduction
In the preparation of this International Standard,
the following two principles have been followed as
far as possible:
— to standardize suitable terms without
perpetuating unsuitable terms merely because
they have been used in the past;
— to discard any term which is used with
different meanings and to replace it by a term
which has an unequivocal meaning.

2.7
differential pressure gauge

a pressure gauge used to measure the difference
between two applied pressure and/or vacuum
values, the metallic pressure-responsive element(s)
of which drive(s) one pointer
2.8
duplex pressure gauge

1 Scope

a pressure gauge used to measure two applied
pressure and/or vacuum values, by means of two
separate pressure-responsive elements in one case,
each of which drives its own pointer

This European Standard defines the fundamental
and general terms to be used for pressure gauges.

2.9
control pressure gauge

2 Definitions relating to pressure
gauges

a pressure gauge fitted with one or more switches
which open or close one or more control circuits
depending on the pointer position

2.1
indicating pressure gauge

2.10
edgewise pressure gauge

a measuring instrument which displays the value of
the applied pressure by means of a pointer relative
to a scale

a pressure gauge with a rectangular dial for flush
mounting in a panel or a control board, where the
pivotal axis of the pointer lies in a plane parallel to
the plane of the panel or control board

2.2
indicating pressure gauges with an elastic
measuring element

2.11
liquid filled pressure gauge

instrument in which the mechanical measuring
sequence directly transmits the elastic deformation
of the sensing element to the indicating device,
consisting of a pointer and a graduated scale

a pressure gauge, the case of which is filled with a
liquid

2.3
pressure gauge

a gauge incorporating safety features and
particularly suitable for use with high pressure
gases and steam

an indicator of the applied (gauge) pressure with
respect to the atmospheric pressure
2.4
vacuum gauge
an indicator of the applied (gauge) vacuum with
respect to the atmospheric pressure
2.5
combined pressure and vacuum gauge
a combined indicator of the applied (gauge) pressure
or vacuum with respect to the atmospheric pressure
2.6
absolute pressure gauge
an indicator of absolute pressure, i.e. pressure
relative to a complete vacuum
NOTE This description therefore does not apply to pressure
gauges graduated in absolute pressure units, the indications of
which are influenced by variations of atmospheric pressure.

© BSI 01-2000

2.12
safety pattern gauge

3 Definitions relating to pressure
gauge components
3.1 pressure-responsive element

An elastic element which undergoes deformations
under the effect of pressure variations. It may be a
Bourdon tube, diaphragm, diaphragm capsule,
bellows or other type of element.
3.1.1
bourdon tube
a type of spiral pressure-responsive element where
a tube with a non-circular cross-section is bent into
a circular or coiled shape. Under the effect of the
internally applied pressure the tube tends to
straighten. The deflection induced is proportional to
the pressure applied

3


EN 472:1994

3.1.2
diaphragm

3.5.2
maximum pointer

a type of pressure-responsive element usually in the
form of a concentrically corrugated membrane
where the pressure applied causes the diaphragm to
deflect in proportion to the pressure

a secondary pointer driven by the pointer which

stays at the maximum value reached by the latter

3.1.3
capsule

a screw, stud, or other projection, fitted to limit the
travel of the pointer

a type of pressure-responsive element comprising of
two diaphragms suitably shaped and joint
pressure-tight around their circumference. The
pressure commonly acts on the interior of the
capsule and the expansion generated thus is
proportional to the pressure
3.1.4
bellows
a type of pressure-responsive element in the form of
a thin-walled convoluted tube. The change in its
length is proportional to the pressure
3.2
movement
an assembly by means of which the deformations of
the pressure-responsive element are transformed
and enlarged into an angular variation
3.3
pressure element assembly
the assembly of all the pieces coming into contact
with the fluid whose pressure is measured
3.4 connection
The part by which the pressure gauge can be

coupled to the pressure tapping of the plant,
pipework or equipment.
3.4.1
shank

3.5.3
pointer stop

NOTE It is not the function of a pointer stop to act as an
overload stop.

3.6
adjustable mark
a moving index operated from the outside and not
driven by the indicating pointer, used to place a
reference mark on the dial
3.7
case
the casing which contains the pressure-responsive
element, parts of the pressure element assembly
and the movement. It may also include a safety
device. The front face of the case may be circular,
square or rectangular
3.8 blow-out device
A safety device incorporated in the case or back
plate to permit the rapid and safe dissipation of
internal pressure in the event of a leakage or burst
in the pressure responsive element.
3.8.1
blow-out back

a safety device incorporating the greater part of the
back of the case
3.8.2
baffle wall

the part of the gauge that includes the screwed
connection, the spanner flats, square or hexagon,
the spigot, and the inlet orifice

a barrier between the pressure responsive element
and the dial, so disposed that, in the event of a
leakage or burst in the pressure responsive element,
the blast would be dissipated away from the front

3.4.2
screwed connection

3.8.3
removable back plate

the threaded portion of the shank

a plate at the back of the case, that is removable for
the purpose of giving access to the interior

3.5 pointer
The index, the position of which, in relation to the
scale, indicates the value of the measured pressure.
3.5.1
adjustable pointer

a pointer with an adjustable device for zero
correction

3.9
flange
the circular, square or rectangular part, removable
or fixed, projecting from the case, on which the
latter is mounted
3.10
window
the transparent front intended for protection of the
pointer, dial and control devices, if any

4

© BSI 01-2000


EN 472:1994

3.11
bezel ring

3.16
adjustment

the part which retains the window on the case

operation of bringing a pressure gauge into a state
of performance suitable for its use

3.12
clamp
the part used for mounting clamp fixing pressure
gauges on panel boards
3.13
spacer
the distance piece, ring, or collar separating the
window from the dial
3.14
dial
that part of an indicating device, fixed or moving,
which carries the scale or scales

3.17
user adjustment
the operation intended to bring a pressure gauge
into a state of performance and freedom from bias
suitable for its use, employing only the means at the
disposal of the user

4 Definitions relating to the
characteristics
4.1
nominal size

3.15 scale (of an indicating device)

a conventional alpha-numerical designation
relating to the size of the pressure gauge

An ordered set of scale marks, together with any
associated numbering, forming a part of an
indicating device.

4.2
nominal range

3.15.1
scale length

for each scale range, the set of indicated values of
the applied pressure for which a pressure gauge
gives values within that scale range

for a given scale, the length of the line between the
first and the last scale marks and passing through
the centres of all the shortest scale marks

NOTE The nominal range is expressed in units of the applied
pressure regardless of the units marked on the scale, and is
normally stated in terms of its lower and upper limits,
for example – 200 mbar to + 400 mbar.

NOTE

The line may be real or imaginary, curved or straight.

3.15.2
scale range

for a given scale, the set of scale values between the
extreme scale marks
NOTE The scale range is expressed in the units marked on the
scale, regardless of the units of the applied pressure and is
normally stated in terms of its lower and upper limits,
for example 0 bar to 100 bar.

3.15.3
scale division

4.3
span
the modulus of the difference between the two limits
of a nominal range of a pressure gauge
EXAMPLE
Nominal range – 200 mbar to + 400 mbar:
span 600 mbar.
4.4
specified measuring range

the part of a scale between any two successive scale
marks

the set of values of an applied pressure for which the
error of a pressure gauge is intended to lie within
specified limits

3.15.4
scale spacing

4.5
accuracy class

the distance between any two successive scale
marks measured along the same line as the scale
length

a class of pressure gauge which meets certain
metrological requirements that are intended to keep
errors within specified limits

NOTE Scale spacing is expressed in units of length, regardless
of the units of the applied pressure or the units marked on the
scale.

3.15.5
scale numbering
the set of numbers, associated with scale marks,
which correspond to the set of values of the applied
pressure defined by the scale marks

© BSI 01-2000

NOTE An accuracy class is usually denoted by a number
adopted by convention and called the class index.

4.6
limits of permissible error
the extreme values of an error permitted by
specifications, regulations etc. for a given pressure

gauge

5


EN 472:1994

4.7
error (of indication) of a pressure gauge

4.9
hysteresis

the indication of a pressure gauge minus the true
value of the applied pressure

the property of a pressure gauge whereby its
response to a given stimulus depends on the
sequence of preceding stimuli

4.8
repeatability of a pressure gauge
the ability of a pressure gauge to give, under defined
conditions of use, closely similar responses for
repeated applications of the same stimulus

NOTE Although hysteresis is normally considered in relation to
the applied pressure, it may also be considered in relation to
influence quantities.

NOTE The defined conditions of use are usually as follows:
— repetition over a short period of time;
— use at the same location under constant ambient
conditions;
— reduction to a minimum of the variations due to the
observer.

6

© BSI 01-2000


EN 472:1994

Index
A

E

pointer stop 3.5.3

absolute pressure gauge 2.6
accuracy class 4.6
adjustable mark 3.6
adjustable pointer 3.5.1
adjustment 3.16

edgewise pressure gauge 2.10
error (of indication) of a pressure
gauge 4.7

pressure element assembly 3.3
pressure gauge 2.3
pressure-responsive element 3.1

F

R

flange 3.9

removable back plate 3.8.2
repeatability of a pressure gauge 4.8

B
baffle wall 3.8.2
bellows 3.1.4
bezel ring 3.11
blow-out back 3.2.1
blow-out device 3.8
Bourdon tube 3.1.1
C
capsule 3.1.3
case 3.7
clamp 3.12
combined pressure and vacuum gauge 3.5
connection 3.4
control pressure gauge 2.9
D
dial 3.14

diaphragm 3.1.2
differential pressure gauge 2.7
duplex pressure gauge

H
hysteresis 4.9

S

M

safety pattern gauge 2.12
scale (of an indicating device) 3.15
scale division 3.15.3
scale length 3.15.1
scale numbering 3.15.5
scale range 3.15.2
scale spacing 3.15.4
screwed connection 3.4.2
shank 3.4.1
spacer 3.13
specified measuring range 4.4

maximum pointer 3.5.2
movement 3.2

U

I
indicating pressure gauge 2.1

indicating pressure gauges with an elastic
measuring element 2.2
L
limits of permissible error 4.6
liquid filled pressure gauge 2.11

N

user adjustment 3.17

nominal range 4.2
nominal size 4.1
nominal span 4.3

V

P

window 3.10

vacuum gauge 2.4
W

pointer 3.5

© BSI 01-2000

7

BS EN
472:1995

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