OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

May 17, 1976

[Name Withheld]

Dear [Name Withheld]:

In response to your question as to whether liquified flammable gases are considered as included under the requirements of Section 1910.106, Flammable and Combustible Liquids, the following references should provide guidance.

1. 1910.106(a)(17) defines a liquid as any material with a fluidity greater than that of 300 penetration asphalt when tested in accordance with ASTM D-5. The D-5 test method stipulates that when a test temperature is not given, the material shall be tested at 77 degrees F. Obviously, the LP gases would not be liquid at this temperature.

2. The other way to approach this definition is to consider whether the liquified gases are defined as gases. 1910.101(b) references CGA Phamplet P-1. P-1 in turn references the ICC, now DOT, regulations. DOT, in 49 CFR 173.300(a), defines a gas as having, in the container, an absolute pressure exceeding 40 PSI at 70 degrees F. A liquified gas is further defined, in 173.300(d), as a gas, which under the charged pressure, is partially liquid at a temperature of 70 degrees F.

We agree with you that both of these methods of reaching a conclusion presuppose a great amount of technical knowledge of a number of private and federal standards and regulations. We are considering, in our drafting of revision to 1910.106, the use of a simple statement of exemption as far as inclusion of liquified flammable gases would be concerned, with a reference to the appropriate requirements elsewhere.

Your concern in bringing this to our attention is appreciated. A copy of this letter is being directed to the OSHA Institute, so that they may be apprised of the information you will be imparting to their students.


Abraham M. Koolman, CSP, P.E.
Safety Specialist