Our inquiry is regarding Table A.6, in which the material and environmental limits for instrumentation and control devices are described. The note b in Table A.6 only provides an indication of possible components that fall in this category (diaphragms, pressure measuring device and pressure seals). However, we do not fully understand if the following instruments also fall in this category. – pressure gauges (with bourdon tube or diaphragms) – diaphragm seals/chemical seals – electronic pressure transmitters – electric and mechanical temperature measuring devices – Accessories o Restrictor Overpressure protector o Thermowell (solid machined, fabricated) o Syphon o Cooling tower Do you agree that the above mentioned instruments fall in the category as noted in Table A.6. ?
Table A.6 includes instrumentation and control devices that have been used so far without known failures in sour service. It is up to the Manufacturer to assess if the use of austenitic stainless steel instrumentation and control devices used for compressors are included in Table A.6. The Maintenance Panel cannot give advice on specific design issues. The applicability of Table A.6 to specific components must be agreed between the user and manufacturer. You are encouraged to submit a ballot to revise/clarify Table A.6. This ballot should include field history as prescribed in 15156-1 clause 8.2.
This question is in relation to NACE MR0175/ISO 15156-3 Table A.6
Reference: ISO 15156 Maintenance Panel Inquiry #2011-02
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