By Gregory Havel
Most construction job sites have power tools and equipment that use liquid or gaseous fuels. This article will discuss the storage of flammable and combustible liquids in small quantities. Future articles will discuss the storage of flammable and combustible liquids in larger quantities as well as the use of natural gas and liquefied propane gas.
The requirements for the storage and dispensing of flammable and combustible liquids may be found in National Fire Protection Association (NFPA) 30, Flammable and Combustible Liquids Code, 2015 edition. This code—or an earlier edition—is incorporated by reference into many state and municipal building and fire codes.
The U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA) regulations on the storage and dispensing of flammable and combustible liquids, in 29 CFR 1910.106 and 1926.152, incorporate much of the language from an early edition of NFPA 30. Although the details may not be identical when comparing present NFPA codes with OSHA regulations, the principles and definitions are the same.
According to the NFPA codes and OSHA regulations, safety cans are required for storage and dispensing of small quantities of combustible and flammable liquids on construction job sites. The definitions below are quoted from NFPA 30 Flammable and Combustible Liquids Code, 2015 edition:
- 184.108.40.206 Combustible Liquid. Any liquid that has a closed-cup flash point at or above 100°F (37.8°C) as determined by the test procedures and apparatus set forth in Section 4.4. Combustible liquids are classified according to Section 4.3.
- 220.127.116.11* Flammable Liquid. Any liquid that has a closed-cup flash point below 100°F (37.8°C), as determined by the test procedures and apparatus set forth in Section 4.4, and a Reid vapor pressure that does not exceed an absolute pressure of 40 psi (276 kPa) at 100°F (37.8°C), as determined by ASTM [American Society for Testing and Materials] D 323, Standard Test Method for Vapor Pressure of Petroleum Products (Reid Method). Flammable liquids are classified according to Section 4.3.
- 3.3.48* Safety Can. A listed container of not more than 5.3 gal (20 L) capacity having a screen or strainer (flame arrester) in each fill-and-pour opening and having a spring-closing lid and spout cover designed to safely relieve internal pressure when exposed to fire.
Metal safety cans (photo 1) are manufactured to comply with the standard American National Standards Institute/Underwriters Laboratories 30, Metal Safety Cans.
(1) Photos by author.
Safety cans are also made of high-density polyethylene with metal fill caps, pour spouts, and flame arresters. However, in larger sizes, these may not meet the OSHA and NFPA regulations for some flammable or combustible liquids. These plastic safety cans look like metal safety cans, except that the shell is plastic rather than painted metal. These must not be confused with the low-priced plastic Department of Transportation containers for flammable and combustible liquids that are sold for household use by hardware and home improvement stores, which have no flame arrester, no self-closing lids, and no pressure relief features; these are never acceptable for use on construction job sites or in manufacturing facilities or other commercial occupancies.
Any safety can must incorporate a flame arrester (photo 2) in both the fill opening and the pour spout. A flame arrester is usually a tubular metal screen with a metal bottom that is permanently attached to the safety can. Flame arresters may also be a flat metal screen in the opening in some types of safety cans. The purpose of a flame arrester is to reduce the possibility of a spark igniting the vapors in the top of the safety can while it is open for filling or dispensing liquid. A safety can from which the flame arrester has been removed is no longer a safety can.
Safety cans are constructed to reduce the chance of leaks and container failures, and to eliminate vapor release from the container under normal conditions by using self-closing lids and pressure-relief devices in case the cans are heated.
Safety cans are also color-coded for certain common products by their classification as flammable or combustible liquids.
Flammable liquids (Class I) and combustible liquids (Class II and Class III) are classified according to NFPA 30, Chapters 4.3.1 and 4.3.2:
- Class IA (flammable) liquids are those with a flash point below 73°F (22.8°C) and a boiling point below 100°F (37.8°C); including ethers and other volatile solvents.
- Class IB (flammable) liquids are those with a flash point below 73°F (22.8°C) and a boiling point at or above 100°F (37.8°C), including acetone and gasoline.
- Class IC (flammable) liquids are those with a flash point at or above 73°F (22.8°C), but below 100°F (37.8°C), including turpentine, and paint thinners.
- Class II (combustible) liquids are those with a flash point at or above 100°F (37.8°C) and below 140°F (60°C), including diesel fuel, naphtha, fuel oils, and Stoddard solvent.
- Class IIIA (combustible) liquids are those with a flash point at or above 140°F (60°C), but below 200°F (93°C), including kerosene, some fuel oils, and nitrobenzene.
- Class IIIB (combustible) liquids are those with a flash point at or above 200°F (93°C), including formalin, motor oils, and some fuel oils.
The common color coding of safety cans includes:
- Red: Class I flammable liquids, including gasoline and paint thinners.
- Yellow: Diesel fuel (see photos 1, 2, and 3).
- Blue: Kerosene and light fuel oils.
- Green: heavy oils and heavy fuel oils.
Safety cans must also be labeled with the name of their contents (photos 3 and 4) according to OSHA’s Hazard Communication regulations, 29 CFR 1910.1200.
The key points in the storage of flammable and combustible liquids on construction job sites and in commercial occupancies:
- Safety cans must be used, except for smaller quantities in manufacturer’s original shipping containers (five-gallon, gallon, quart, pint).
- Safety cans must be metal unless the product is compatible with the material used in plastic safety cans, and within the quantity limits listed in NFPA 30 for that product.
- Safety cans must incorporate flame arresters, self-closing lids, and pressure relief valves or pressure relief lids.
- Safety cans must be properly color-coded for their contents.
- Safety cans must be labeled with the name of and other information on their contents.
Since the same safety rules apply to fire stations and fire department operations as apply to construction job sites and commercial occupancies, you should ensure that the motor fuels and other flammable liquids at your station and on your apparatus are stored as our fire inspectors expect that they should be.
NFPA codes and standards are available by subscription in both print and online editions. Check with your fire prevention bureau or with your local technical college or regional fire training center library for access to these documents.
OSHA regulations are available online at no cost: www.osha.gov
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Gregory Havel is a member of the Town of Burlington (WI) Fire Department; retired deputy chief and training officer; and a 35-year veteran of the fire service. He is a Wisconsin-certified fire instructor II, fire officer II, and fire inspector; an adjunct instructor in fire service programs at Gateway Technical College; and safety director for Scherrer Construction Co., Inc. Havel has a bachelor’s degree from St. Norbert College; has more than 35 years of experience in facilities management and building construction; and has presented classes at FDIC.
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