by Lori Riddle

Tank builders and many others in our industry use potentially hazardous materials all the time. Fire safety is vital in our business. In our fabrication facilities, where we are using plasma arc cutting equipment, steel plate beveling equipment and other specailty equipment for turning carbon and stainless steel plate into field erected welded steel tanks, sparks are always flying and fire is a constant danger. On our tank construction sites, our work with welding equipment means there's an ever present fire danger. Knowing what materials are flammable, and to what degree, can make a life or death difference.

The NFPA HazCom Diamond

The National Fire Protection Association has developed a simple, easy-to-recognize rating system to identify and rank hazards of a material. This rating system complies with OSHA's HazCom 2012 system as well.

In the NFPA labeling sytem, the label is diamond-shaped, made up of four smaller diamonds, one each blue, red, yellow, and white. A number or special symbol is placed on the four diamonds.

CNX_Chem_01_03_HazDiamond wikicommons


Blue Diamond = Health Hazards

The blue diamond, on the left of the label, indicates the potential Health Hazards of the material.

0 – No hazard

1 – Can cause irritation if not treated

2 – Can cause injury. Requires prompt treatment.

3 – Can cause serious injury despite medical treatment.

4 – Can cause death or major injury despite medical treatment.


Red Diamond = Flammability Hazard

The red diamond, appearing at the top of the label, conveys Flammability Hazard information.

0 – Will not burn.

1 – Ignites after considerable preheating

2 – Ignites if moderately heated

3 – Can be ignited at all normal temperatures

4 – Very flammable gases or very volatile flammable liquids.


Yellow Diamond = Reactivity/Stability

The yellow diamond, appearing at the right side of the label conveys Reactivity (or Stability) information.

0 – Normally stable. Not reactive with water.

1 - Normally stable. Unstable at high temperature and pressure. Reacts with water.

2 – Normally unstable but will not detonate.

3 – Can detonate or explode but requires strong initiating force or heating under confinement.

4 – Readily detonates or explodes.


White Diamond = Special Hazard Info

The white diamond, appearing at the bottom of the label conveys Special Hazard information. This information is conveyed by use of symbols which represent the special hazard.

For example:

W means the material is water reactive.

W with a strike-through indicates do NOT use with water.

OX indicates an oxidizing agent.

Understanding the NFPA HazCom Diamond labeling system is important for job site safety. If you can assess at a glance the potential danger of a material stored in or around your work area, you will be better equipped to protect yourself and your fellow workers.

For information about how the NFPA HazCom Diamond relates to the OSHA HazCom 2012 labeling system, check out this comparison chart.

For more information about the NFPA codes, check out NFPA.

Storage Tank Construction Job Site Safety HazCom

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