IIAR 6 Appendix B Pressure Vessels Checklist | Part 3

Part 3: This is a continuation of our blog series explaining how to perform an IIAR 6 Appendix B inspection of an ammonia pressure vessel.


The final information required on the first page of the checklist pertains to the vessel relief valves. The manufacturer, model, pressure setting, and capacity can be obtained from the relief valve nameplate. If your facility reprints the same completed first page for each checklist, this is one data point on the first page that can change. Be sure to check if the relief valve installed matches what is listed on the form. The ‘year installed’ can be determined by inspecting the installation date tag attached to the relief valve.


In the example below, the vessel is protected by a dual relief valve assembly consisting of two relief valves and a three-way relief isolation valve.


The relief valves are external to the equipment and terminate to the atmosphere, so this configuration is categorized as ‘External’.

The previous blogs in this series are available in the following links. You can watch our free video of how to perform an IIAR 6 Appendix B Pressure Vessel inspection here.

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