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Parent Category: Safety Info Posts

Category: Hazardous Materials

Published: 30 April 2019

The NFPA 704 Diamond still reigns supreme as the labeling system for bulk tanks in the chemical industry and recently I posted an article about a Category 1 Flammable Gas and it's "Degree of Hazard".  It is my professional opinion that a CAT 1 Flammable Gas is a "4" in the NFPA Flammability Hazard; however, based on texts/e-mails/phone calls I can say we are not in short supply of safety professionals who disagree with me.  And almost all of those who disagree with the "black and white" view of assigning the "Degree of Hazard" to a CAT 1 Flammable Gas point to two (2) sections in NFPA 704. 

(NOTE:  those who are not members of SAFTENG can click on the link to access the standard for free)

In this article, I will discuss three (3) examples of how/when the NFPA 704 "Degree of Hazard" could be represented differently than when the hazardous material is stored at ambient conditions or in different locations.  The three examples are:

1. 1. Flammable Liquids stored in a refrigerated/chilled state
   2. Flammable Liquids processed at temperatures above their flash points and approaching their auto-ignition temp(s)
   3. Anhydrous Ammonia stored outside vs. inside

Here is what NFPA says about increasing or decreasing the "Degree of Hazard" for a material:

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