Recent Blog Posts

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 […]

Ammonia Week in Review | April 5, 2019

April 5th, 2019

An ammonia mini bar causes a hotel evacuation in this week’s edition of the Ammonia Week in Review… Chester Grosvenor Hotel Evacuated after Reports of Ammonia Smell – Firefighters were called to the hotel on Eastgate Street in Chester shortly before 5am today (Wednesday, April 3) and crews, two wearing breathing apparatus, investigated where the smell was coming […]

Manufacturer Instructions and Ammonia Three-Way Relief Isolation Valves

May 29th, 2018

It is common practice in the ammonia refrigeration industry to install a three-way isolation valve upstream of relief valves protecting an ammonia refrigeration pressure vessel. For vessels larger than 10 ft3, this is required by most model codes and standards. These three-way valves allow a relief valve to be replaced without the hassle of pumping […]

Comparing RAGAGEPs: Relief Valve Sizing

May 15th, 2018

It’s widely known that pressure vessels must be equipped with over-pressure protection (2015 ASME B&PVC UG-125), often in the form of a pressure relief valve. Properly sizing a relief valve requires engineering analysis which accounts for the type of over-pressure scenarios that might occur. In most cases, model codes and standards (RAGAGEPs) specify the relief […]

PSI Explained: Safety Systems

August 8th, 2017

Title 8 CCR §5189(d)(3)(A)(8) and Title 29 CFR §1910.119(d)(3)(i)(H) requires that “information pertaining to the equipment in the process shall include: Safety systems (e.g. interlocks, detection or suppression systems)”. At minimum, Safety Systems documentation must identify and summarize all Safety Systems associated with the chemical process. Once developed, this documentation will serve as a useful […]