Chemical Process Safety (PSM/RMP)

Properly applying NFPA 496 Pressurized Enclosures in a HAZLOC

NFPA 496 (Standard for Purged and Pressurized Enclosures for Electrical Equipment) is one of the most powerful engineering tools available for hazardous locations, but it is also one of the most abused standards for HAZLOCs. Like the Combustible Gas Detection System (CGDS) provisions in NFPA 70, NFPA 496 allows a facility to install ordinary, non-classified […]

Understanding the LIMITATIONS of NFPA 70, Article 500.7(k) Combustible Gas Detection System (CGDS)

In NFPA 70 (National Electrical Code / NEC), the use of a Combustible Gas Detection System (CGDS) is a highly specialized engineering provision. It essentially acts as a “get out of jail free” card—or more accurately, a reclassification tool—for specific industrial locations. When you install a qualified CGDS, the NEC allows you to lower the

The history of “weak seam welded roof” as a means of emergency venting atmospheric storage tanks

The concept of the weak seam welded roof—officially referred to in modern engineering standards as a frangible roof joint—has been a foundational safety mechanism for atmospheric storage tanks for over 90 years. NOTE: In 2015, NFPA 30 Section 22.7 was amended to eliminate the use of a weak roof-to-shell seam as an allowed means of

Failing to CLOSE a PRCS Entry Permit properly can have Process Safety implications months after the entry

As most of you know, PRCS Entry is one of the specific SWPs called out in the PSM and RMP standards. But many programs fail to meet 1910.146(f)(4), and a recent CSB accident report tied the requirement for canceling a permit to a catastrophic explosion event. 1910.119(f)(4) The employer shall develop and implement safe work

Pipeline Safety & Potential Impact Radius (PIR) Re-evaluations

NTSB’s historical investigations into major gas and hazardous liquid pipeline ruptures continue to shape current rulemaking tracking. PHMSA has been actively reviewing the established Potential Impact Radius (PIR) calculation methodologies used in integrity management programs. The review aims to determine whether current mathematical models accurately account for human response data, rapid-ignition variables, and modern accident

FRC must be the outer layer – NYLON Hi-Vis vest are a problem

In today’s workplaces, it’s hard to find a large business that does not require Hi-Vis Vest/Workwear. What is not hard to find is a business with HAZLOCs where workers are required to wear FRC but are wearing nylon Hi-Vis vests OVER their FRC. I am all for making workers more visible to powered industrial trucks

When you see it… Flange Jumpers for Flammable Liquid & Combustible Dusts Piping

Many may be familiar with “flange jumpers,” or some may call them “bonding jumpers,” that are used to ensure a continuity to ground across a flange with gaskets that act as “insulators”, such as PTFE gaskets. During a recent walkdown of a flammable liquids process, I came across this “jumper”. Design called for “jumpers” on

Chemical hoses aren’t the only hoses needing annual inspection and pressure testing!

I have written over a dozen posts explaining the code requirements for annual inspection/testing of our chemical hoses. But in the world of PSM/RMP, there is another hose that requires annual inspection and testing… The primary standard requiring fire hose to be service-tested annually is NFPA 1962, Standard for the Care, Use, Inspection, Service Testing,

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