When flammable liquid tanks are equalized — meaning they are interconnected by piping that allows fluid levels to equalize between them — we MUST account for this in our secondary containment design. From a regulatory and engineering standpoint, the governing principle is to protect against the worst-case single-event release. If tanks are interconnected, a failure…...
A worker was standing on top of a tanker truck to transfer gasoline from a tanker trailer to the tanker truck. The tanker truck’s engine was running, and the pumping system was engaged. The worker opened access hole covers to a compartment in the truck that held diesel and to another that was empty. Some…...
OSHA, IFC, and NFPA have “separation distance” requirements for flammable liquid storage tanks. These requirements have been around longer than I have been dealing with hazardous materials and process safety, and yet we always come across some wildly out of “compliance” arrangements of these flammable liquid tanks. using OSHA’s Flammable Liquid Standard 1910.106 we can…...
NFPA has updated its NFPA 497, Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas, with a few minor revisions. Probably the most significant revision is NFPA’s position on “intentional releases and maintenance venting.” The most beneficial revision was NFPA officially…...
In the 2027 edition of NFPA 30, the standard now provides a NEW schematic illustrating the spatial layout of hazardous (classified) locations for indoor areas with process equipment containing ignitible (flammable or combustible) liquids at pressures of 100 psig or less. I am not sure why they included this in NFPA 30 (Chapter 7) or…...
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…...
