Storing & Handling Flammables
May 1, 2008
The primary hazard associated with petroleum-based chemicals is, of course, flammability. Attention must be paid and special precautions taken for their storage, handling and use. Those precautions have been pretty effectively laid out by OSHA in their legislated standards for the General (29 CFR 1910.106), Construction (29 CFR 1926.152) and Shipyard industries (29 CFR 1915.36); as well as in voluntary standards from the National Fire Protection Agency (NFPA 30: A Guide to Flammable and Combustible Liquids) and the International Fire Code Institute (IFCI).
Which standard applies and when?An important distinction has been made within the standards that can make a significant difference in the costs of controlling hazards and providing appropriate protection, and that distinction is whether the material is flammable or combustible.
Are you holding on?
Because we're about to take a little roller coaster ride of definitions, classifications and exceptions:
A flammable liquid is any liquid having a flashpoint below 100° F (37.8° C) (except any mixture having components with flashpoints of 100° F (37.8° C) or higher, the total of which make up 99 percent or more of the mixture). Flammable liquids are categorized into three groups, as follows:
q Class IA - Liquids having flashpoints below 73° F (22.8° C) and having boiling points below 100°F (37.8°C).
Examples: Acetaldehyde, ethyl ether and cyclohexane.
q Class IB - Liquids having flashpoints below 73° F (22.8° C) and having boiling points at or above 100° F (37.8°C).
Examples: Acetone, benzene and toluene.
q Class IC - Liquids having flashpoints at or above 73° F (22.8° C) and having boiling points below 100° F (37.8°C).
Examples: Hydrazine, styrene and turpentine.
A combustible liquid is any liquid having a flashpoint at or above 100° F (37.8° C). Combustible liquids are divided into two classes:
u Class II - Liquids having flashpoints at or above 100° F (37.8° C) and below 140° F (60° C), except any mixture having components with flashpoints of 200°F (93.3°C) or higher, the volume of which make up 99 percent or more of the total volume of the mixture.
Examples: Acetic acid, naptha and Stoddard solvent.
u Class III - Liquids having flashpoints at or above 140°F (60°C). Class III liquids are subdivided into two subclasses:
u Class IIIA - Liquids having flashpoints at or above 140°F (60°C) and below 200°F, except any mixture having components with flashpoints of 200°F (93.3°C) or higher, the total volume of which make up 99 percent or more of the total volume of the mixture.
Examples: Cyclohexanol, formic acid and nitrobenzene.
u Class IIIB - Liquids having flashpoints at or above 200°F (93.3°C).
Examples: Formalin and picric acid.
Per 1910.106(a)(18)(ii)(b) "Class IIIB liquids" shall include those with flashpoints at or above 200°F (93.3°C). This section does not cover Class IIIB liquids. Where the term "Class III liquids" is used in the section, it shall mean only Class IIIA liquids.
Note: When a combustible liquid is heated for use to within 30°F (16.7°C) of its flashpoint, it shall be handled in accordance with the requirements for the next lower class of liquids.
Methods of complianceWhile most of you might be involved in production-level operations I am fortunate enough not to be, so my considerations are limited to what I will go into here rather than spin your head with another 83 pages of roller coaster-like requirements.
ContainersApproved containers are your first line of defense against the hazards associated with flammable and combustible liquids. And an approved container (1910.106(a)(29)) is defined as:
- not more than five-gallons capacity,
- having a spring-closing lid and spout cover,
- designed to safely relieve internal pressure when subjected to fire exposure.
Going back, for a moment, to the financial considerations I strongly recommend that you not waste your money on polyethylene-type (that, by the way, do not have self-closing lids or pressure relief) and go for the more expensive but "worth it in the long run" containers made of steel.
CabinetsYour second line of defense is a cabinet; combustibles- or flammables-approved (do yourself a favor and restrict items stored to combustibles/flammables only, thereby avoiding compatibility issues). Approved cabinets are designed and constructed to specific requirements; OSHA's 1910.106(d)(3)(ii)(a) states that metal cabinet shall be constructed in the following manner:
- Bottom, top and sides of cabinet shall be at least No. 18 gauge sheet steel,
- Cabinet must be doubled walled with 1_" airspace,
- Joints shall be riveted, welded or made tight by some equally effective means,
- Door shall have a three point latch,
- Door sill shall be raised at least 2" above the cabinet bottom to retain spilled liquid within the cabinet,
- Cabinet shall have a "FLAMMABLEâ€”KEEP FIRE AWAY" legend,