Appendix C – Functional Testing Using Gas
Senscient ELDS™
Rev 15
147
GB
12. Appendix C – Functional Testing Using Gas
12.1. Introduction
Senscient’s ELDS 1000 / 2000 Series OPGDs are factory-calibrated with their specified gases
using special equipment and procedures that are operated in a closely controlled environment.
ELDS™ Transmitters use their retained sample of target gas(es) to achieve and maintain
Harmonic Fingerprint lock. Provided that Harmonic Fingerprint lock is maintained, there are no
physical mechanisms that will cause the gas calibration of an ELDS OPGD to change during
operational service, so once an ELDS OPGD has been factory-calibrated it is calibrated-for-life.
A Safety Instrumented System employing ELDS OPGDs will meet the requirements of SIL2 per
IEC 61508-1 by proof tests being performed upon the ELDS OPGDs at an interval of one to two
years. The recommended proof test for an ELDS OPGD is an operator witnessed SimuGas Auto
or SimuGas Live test. (See “Exida – ELDS FMEDA & SimuGas Proof Test.pdf”). Senscient
advises that witnessed SimuGas tests are all that are needed to verify the correct functionality of
ELDS OPGDs in field service conditions.
Testing OPGDs with target gas(es) in field-service conditions is difficult, potentially hazardous and
prone to the significant sources of error that are associated with uncontrolled, outdoor
environments. Consequently, Senscient does not recommend testing ELDS OPGDs with target
gas(es) in field-service conditions and recommends the use of SimuGas wherever possible.
In circumstances where operators are mandated to perform testing of gas detectors using a
sample of gas, Senscient can supply a Gassing Cell or Gas Challenge Cell for use with our ELDS
products. The procedures for correct use of a Gassing Cell or Gas Challenge Cell are detailed in
the following sections along with applicable limitations.
12.2. Testing with the Gassing Cell
Where operators are mandated to test ELDS OPGDs with gas in field-service conditions, these
tests can be performed using the Gassing Cell, but operators are advised that such tests will be
subject to much greater margins of error than the original factory calibration.
The compact design of the Gassing Cell only allows gas response checking to be
performed using relatively high concentration test gases. Gases which can be satisfactorily
used inside the Gassing Cell include methane, propane, butane, hydrogen sulphide and
carbon-dioxide.
WARNING
Operators must follow the applicable safe handling procedures when using flammable or toxic
gases in conjunction with the Gassing Cell. Operators are advised to consult with the responsible
Health & Safety Officer (or equivalent) to establish the applicable safe handling procedures.
Содержание Senscient ELDS 1000 series
Страница 1: ...Operating Manual Senscient ELDS 1000 2000 Series Open Path Cross Duct Gas Detectors A 5170 0 Rev 15 ...
Страница 58: ...Installation Commissioning 58 Senscient ELDS Rev 15 GB 2 x Mounting Brackets ...
Страница 140: ...Certification 140 Senscient ELDS Rev 15 GB 9 1 2 Control Drawing CENELEC ATEX ...
Страница 142: ...Certification 142 Senscient ELDS Rev 15 GB 9 1 4 Control Drawing CSA US Canada ...
Страница 158: ...Appendix D Manufacturer s EC Declarations 158 Senscient ELDS Rev 15 GB 13 Appendix D Manufacturer s EC Declarations ...
Страница 159: ...Appendix D Manufacturer s EC Declarations Senscient ELDS Rev 15 159 GB ...
Страница 160: ...Appendix D Manufacturer s EC Declarations 160 Senscient ELDS Rev 15 GB ...
Страница 184: ...For local MSA contacts please visit us at MSAsafety com Because every life has a purpose ...