• Standards

The ISA76 standards committee, Composition Analyzers, has undertaken a first step in the process of creating a possible new standard or modifying an existing industry standard for the safe design of sample probes. The committee is investigating the mechanical design of sample probes and injection quills in response to concerns by industry users about a possible gap in current best practices. Several industry standards are currently used, including ASME PTC 19.3, Thermowells, and IEC/TR 61831, On-line Analyzer Systems - Guide to Design and Installation. However, current practices either specifically exclude sample probes or do not reflect the most recent practices and industry knowledge.

As a first step in the process of creating a new standard or proposing changes to an existing standard, ISA76 is seeking input from the wider industry, including manufacturers, EPCs, and end user companies. ASME PTC 19.3 is believed to be the most comprehensive standard in terms of understanding the static and dynamic stresses on a probe (with the current restriction that the thermowell standard specifically eliminates probes from its applicability).

ISA76 is seeking to determine if any users have designed a sample probe according to ASME PTC 19.3 2010 and/or 2016 and have experienced probe failure due to static or dynamic loads. It is expected that this information will enable ISA76 to understand the extent that the nuances between a probe and a thermowell impact the overall structural performance on a practical level. At this time, ISA76 is asking users to indicate, anonymously if desired:

Do you design, or have you ever designed, a sample probe according to ASME PTC 19.3?

Have you ever had a mechanical failure of the probe designed to ASME PTC19.3 (which could not be disregarded due to an engineering error such as material choice or corrosion)? If your answer to the second question is yes, would you allow ISA76 leaders to follow up to understand the application and failure?

Any additional information on quantities, current company design practices, and other related information and any questions that could be considered by ISA76 will also be greatly appreciated.

Please send your responses to Charley Robinson, ISA Standards, crobinson@isa.org, with the subject line "Sample Probe Survey," and indicate clearly if (a) you would like to remain anonymous, and (b) if ISA76 leaders may follow up with you to better understand your experience. 

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