Recent Blog Posts

Ammonia Week in Review | April 18, 2025

April 18th, 2025

Repeats and Fines in this week’s edition of the Ammonia Week in Review… Second Ammonia Leak in Six Years Forces Arena Shutdown in Port Alberni – This is the second time in six years that the chiller has suffered a “catastrophic failure,” according to city officials. […keep reading] Ammonia Leak Happens at Tyson Foods Poultry Plant – All workers […]

Relief Valve Replacement (Dual Assembly)

April 15th, 2025

This is an update to a blog that was originally posted on 3/10/15. You can read the original blog here. Question: Do both relief valves on a dual assembly have to be replaced every five (5) years, or just the relief valve that has been subject to system pressure? Answer: Most pressure vessels in an […]

Relief Valves Discharging Back into a Refrigeration System

March 18th, 2025

This is an update to a blog that was originally posted on 4/19/16. You can read the original blog here. ANSI/IIAR 2-2021 §15.3.10 outlines the requirements for providing Hydrostatic Overpressure Protection. In situations where thermal hydrostatic expansion of trapped liquid ammonia could occur, hydrostatic protection must be provided. Per ANSI/IIAR 2-2021 §15.3.10.1, Protection against overpressure […]

Condenser Relief Valves

January 7th, 2025

Question: Are pressure relief valves required to be installed on an evaporative condenser? This is an update to a blog that was originally posted on 9/10/13. You can read the original blog here. Answer: This is a very good question and one that gets asked frequently. Since an evaporative condenser is not a pressure vessel, […]

When Does a Relief Valve’s Clock Start?

April 2nd, 2019

While it is well known that good engineering practice requires that relief valves be replaced every five years, industry literature does not clearly state when the five-year timer starts its countdown. Is it when the valve is manufactured? Taken out of the box? Installed? Exposed to ammonia? Due to the lack of clarification on this […]