Yes, we can absolutely max out the Maximum Allowable Quantities (MAQs) for multiple different hazard classes within a single control area and still avoid triggering a Group H (Hazardous) occupancy. However, there is also a major caveat regarding how those materials are categorized and whether they pose overlapping physical or health hazards. Here is how […]
5703.6.8 Piping supports have three (3) recognized methods to protect piping that may be exposed to a “pool fire”. First lets look at the code language: 5703.6.8 Piping supports. Piping systems shall be substantially supported and protected against physical damage and excessive stresses arising from settlement, vibration, expansion, contraction or exposure to fire. The supports
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
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 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
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
Tentative Interim Amendment (TIA) 27-1 refers to a significant update to the 2027 Edition of NFPA 30: Flammable and Combustible Liquids Code. Issued on April 15, 2026, with an effective date of May 5, 2026, this TIA (Log #1886) was processed by the Technical Committee on Flammable and Combustible Liquids to address safety gaps regarding
The 2027 edition of NFPA 30 introduces significant structural and technical updates designed to improve clarity, streamline protection requirements, and integrate emerging safety technologies. Here are the primary changes professionals need to know.
Low humidity makes most LEL (Lower Explosive Limit) detectors read lower than they should, because catalytic‑bead sensors depend on moisture for heat transfer and baseline stability. This can lead to under‑reporting of gas concentration, slower response, and—in extreme dryness—temporary sensor desensitization. Below is a clear, technically grounded explanation based on how LEL sensors work and
With this week’s event in Japan, where the roofs of the flammable liquid storage tanks were blown off, I shared OSHA’s “emergency venting” requirements to explain why the roofs were off the tanks, which sparked a lot of sidebar discussions. Sizing these emergency venting options is quite easy, as I explain in this article with
Yes, both terms essentially mean the same thing, but they refer to very different hazardous atmospheres. LEL, or Lower Explosive Limit, applies to gases and Vapors. MEC, which is Minimum Explosive Concentration, deals with Combustible Dusts. Here are some other differences:
This is a response to a client regarding their question… do we need to use non-sparking tools in our flammable and combustible dust areas? This is a GREAT practice, but many people may be surprised that OSHA has to use its GDC to cite this requirement, as it is NOT an OSHA/NFPA/IFC requirement. Of course,
