As the saying goes, hindsight is 20/20.  Very often, when an ammonia release occurs, we find that the incident is not addressed in our “what-if” PHA studies.   We perform our incident investigation and realize that the root cause of the release was there all along and was something that could (or should) have been easy to foresee.  But why was it not so obvious when we were conducting our PHA? What did we miss?  Why do we not see the obvious? The following are some tips and suggestions for...

In this article, I will explain the basic principles of Postweld Heat Treatment (PWHT), why it is used in the fabrication of pressure vessels, and how to use this information in pressure vessel inspections.  The rules for PWHT are found in the ASME pressure vessel code, and I caution you that this article is basic information and in no way comprehensive .  If you have a question about a particular vessel, seek advice from the original manufacturer or a repair/alteration organization...

Are refrigeration materials of construction interchangeable?  Can you replace carbon steel that is installed in an area prone to...