SIST HD 138 S2:2002

SLOVENSKI SIST HD 138 S2:2002
prva izdaja
STANDARD
september 2002
Sealing test for pressurized waveguide tibing and assemblies
ICS 33.120.10 Referenčna številka
SIST HD 138 S2:2002(en)
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

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NORME
CEI
INTERNATIONALE
IEC
60261
INTERNATIONAL
Deuxième édition
STANDARD
Second edition
1989-01
Essai d'étanchéité applicable aux guides
d'ondes soumis à la pression et à leurs
dispositifs d'assemblage
Sealing test for pressurized waveguide
tubing and assemblies
© IEC 1989 Droits de reproduction réservés — Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun any form or by any means, electronic or mechanical,
procédé, électronique ou mécanique : y compris la photo- including photocopying and microfilm, without permission in
copie et les microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
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Pour prix, voir catalogue en vigueur
• • For price, see current catalogue

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261 ©IEC — 3 —
CONTENTS
Page
FOREWORD 5
5
PREFACE
Clause
7
1. Scope
2. Units 7
Test method A: Pressure drop during elapsed time (quantity test) 7
3.
3.1 Definitions of terms and symbols 7
9
3.2 Test procedure
11
3.3 Preferred test conditions
11
3.4 Summary of details which may need to be specified in the relevant specification
4. Test method B: Leak rate 11
4.1 Definition, units of terms and symbols 11
11
4.2 Test apparatus
13
4.3 Test procedure
4.4 Summary of details which may need to be specified in the relevant specification 13
4.5 Preferred test conditions 13
5. Test method C: Bubble test (quality test) 13
13
5.1 Test procedure
15
5.2 Preferred test conditions
Summary of details which may need to be specified in the relevant specification 15
5.3
6. Test method D: Halogen leakage test (quality test) 15
17
7. Test method E': Helium leakage test (quantity and quality test)
18
FIGURE

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261©IEC — 5 —
INTERNATIONAL ELECTROTECHNICAL COMMISSION
SEALING TEST FOR PRESSURIZED WAVEGUIDE TUBING
AND ASSEMBLIES
FOREWORD
1)
The formal decisions or agreements of the I EC on technical matters, prepared by Technical Committees on which all the National
Committees having a special interest therein are represented, express, as nearly as possible, an inte
rnational consensus of opinion
on the subjects dealt with.
2)
They have the form of recommendations for inte rn
ational use and they are accepted by the National Committees in that
sense.
3) In order to promote intern
ational unification, the I EC expresses the wish that all National Committees should adopt the text of
the I EC recommendation for their national rules in so far as national conditions will permit. Any divergence between the I E C
recommendation and the corresponding national rules should, as far as possible, be clearly indicated in the latter.
PREFACE
This standard has been prepared by Sub-Committee 46B: Waveguides and their accessories, of I EC
Technical Committee No. 46: Cables, wires, and waveguides for telecommunication equipment.
This second edition of IEC Publication 261 replaces the first edition issued in 1968.
The text of this standard is based on the following documents:
Six Months' Rule
Report on Voting
46B(CO)104 46B(CO)107
Full information on the voting for the approval of this standard can be found in the Voting Repo
rt
indicated in the above table.
The following /EC publications are quoted in this standard:
Publications Nos. 68-1 (1988): Environmental testing, Pa rt 1: General and Guidance.
68-2-17 (1978): Pa rt 2: Tests — Test Q: Sealing.

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— 7 —
261®IEC
SEALING TEST FOR PRESSURIZED WAVEGUIDE TUBING
AND ASSEMBLIES
1. Scope
This standard specifies uniform measuring methods for sealing tests for pressurized waveguide
components and assemblies. These measuring methods are carried out with regard to quantity and
quality.
2. Unit of pressure
The following SI unit of pressure is used in this standard: pascal (Pa).
Notes I. — 1 bar = 105 Pa.
2. — SI unit kilopascal (kPa) be used.
For ease in mathematical calculations it is recommended that the
3. - [1 psi Ibf/in 2] = 6.895 X 10; Pa.
3. Test method A: Pressure drop during elapsed time (quantity test)
The leak rate and the rate of pressure loss from a sealed assembly are determined by measuring
the change in the internal pressure during a test time inte rval.
Cautionary note. — Safety precautions shall be taken when using test methods that require a positive pressure for testing
components.
3.1 Definitions of terms and symbols
Leak rate
The quantity of a dry gas at a given temperature that flows through a leak per unit of time and for
a known difference of pressure across the leak (see I EC Publication 68-2-17).
Unit
The basic SI unit for leak rate is "pascal cubic metre per second (Pa  m 3/s)". The derived unit
"Pa  cm 3/s" is used in this standard:
1 Pa X m 3/s = 10 6 Pa X cm3/s
cm3
= 10 bar X /s.
During the test period, the pressure inside the component may decrease and the ambient pressure outside the
Note. —
waveguide may fluctuate. In all of these tests, any error due to va riations in the pressure differential arising from the
above effects during the testing period has been neglected.
Gauge pressure
The pressure as shown by a pressure gauge, that is the amount by which the pressure exceeds
atmospheric pressure.
Standard atmospheric conditions
A temperature of 293 K (that corresponds to 20 °C), and a pressure of 101.3 kPa. (These condi-
tions are described in IEC Publication 68-1.)

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261 © IEC — 9 —
Symbols
P0 = standard pressure (101.3 kPa)
P 1 = initial atmospheric pressure
P, = final atmospheric pressure
Pet = initial gauge préssure
Pe2 = final gauge pressure
initial absolute pressure within the assembly, corrected to standard temperature of 293 K
P1.o =
P,_0 = final absolute pressure within the assembly, corrected to standard temperature of 293 K
P1.2 = pressure drop during test time interval, corrected to standard temperature of 293 K
initial waveguide gas temperature (K)
T 1 =
T, = final waveguide gas temperature (K)
V combined volume of the assembly and the pressure-measuring apparatus
LR^ = leak rate, corrected to standard temperature
t = testing time interval.
3.2 Test procedure
a) Pressurize the assembly with air to the specified gauge pressure and disconnect the source of
air.
Allow sufficient time for the internal pressure to become stable and then record the gauge
b)
pressure Pei , the ambient pressure P1 and the waveguide gas temperature T1.
P2 and
c) At the end of the test time interval, record the gauge pressure P e2, the ambient préssure
the waveguide gas temperature T2.
d) Convert Pei and Pe2 to the corresponding absolute values according to the formulae:
23
(Pl + Pei)
P1.0 =
and
P2.0 = (P2 + )Pe2 T3
T2
e) Calculate the temperature-corrected pressure drop P 1.2 during the test time interval from the
relation:
P1.2 = P1.0 — P2.0
To convert pressure loss to volume of leak, use the formula:
J)
P I ,X V (10
LR^ = 5 PaX dm' Xh-'or105 PaXcm3Xs-')
t
Example: The combined volume of a waveguide assembly and its pressure-measuring apparatus
is 8.195 dm 3. It is pressurized with air and the initial gauge reading is 3.44 10 5 Pa. This reading is
taken when the atmospheric pressure is 93 kPa and the temperature of the waveguide is 293 K.
After 24 h, the gauge pressure has dropped to 3.29 10 5 Pa, the atmospheric pressure is 96 kPa and
the temperature of the waveguide is 298 K. Calculate the leak rate in 10 5 Pa X dm3/h.
(3.44 X 10 5 Pa + 0.93 X10 5 Pa) X 293 K
_
4.37 X 105 Pa
P10 =
293 K
(3.29 X 10 Pa + 0.96 X 10
5 5 Pa) X 293 K_
o=
P,
4. 1 8 X 105 Pa
298 K
4.37 X 10 Pa — 4.18 X 10 5 Pa = 0.19 X 10 5 Pa
P 1 . 2 = 5
8.195 dm 3 20.19  X 10
5 Pa —
=
LR^ 6.49 X 10 -2 X 10 5 Pa X dm3/h

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261©IEC — 11 —
3.3 Preferred test conditions
Unless otherwise specified:
shall be 10 5 Pa;
— the test gauge pressure P
et
the test time interval shall be 24 h;
—
et within the waveguide;
— the pressure drop shall not exceed 5% of the test gauge pressure P
— the maximum permissible ratio of the measurement apparatus volume shall be 0.1 to that of the
waveguide assembly volume;
ation of the ambient temperature shall be ± 5 K.
— the ma
...