1926.155: Fire Protection Definitions
This section defines terms used in the construction fire protection and prevention subpart, such as approved, closed container, combustion, fire brigade, fire resistance, flammable and flammable liquid. A flammable liquid has a flashpoint at or below 199.4 °F (93 °C), and flammable liquids are divided into four categories.
Key takeaways
- 1926.155 is part of OSHA's construction standards (29 CFR Part 1926, Subpart F).
- OSHA cited it 2 times in the last 3 years, in 2 inspections, with $3,255 in current penalties.
- Most-cited part: 1926.155(l) Safety can (2 citations).
- Free 5-minute toolbox talk for your crew below.
In this article
What this rule covers
29 CFR 1926.155, "Definitions applicable to this subpart", is an OSHA construction standard (Part 1926, Subpart F). It has 19 numbered paragraphs. The official text below is copied word for word from the Electronic Code of Federal Regulations (eCFR). The numbers, injury cases and training on this page show how OSHA enforces it on real job sites.
Official text
Show the full text of 1926.155 (19 paragraphs)
(a) Approved, for the purpose of this subpart, means equipment that has been listed or approved by a nationally recognized testing laboratory such as Factory Mutual Engineering Corp., or Underwriters' Laboratories, Inc., or Federal agencies such as Bureau of Mines, or U.S. Coast Guard, which issue approvals for such equipment. Open (a)
(b) Closed container means a container so sealed by means of a lid or other device that neither liquid nor vapor will escape from it at ordinary temperatures.
(c) [Reserved] Open (c)
(d) Combustion means any chemical process that involves oxidation sufficient to produce light or heat.
(e) Fire brigade means an organized group of employees that are knowledgeable, trained, and skilled in the safe evacuation of employees during emergency situations and in assisting in fire fighting operations.
(f) Fire resistance means so resistant to fire that, for specified time and under conditions of a standard heat intensity, it will not fail structurally and will not permit the side away from the fire to become hotter than a specified temperature. For purposes of this part, fire resistance shall be determined by the Standard Methods of Fire Tests of Building Construction and Materials, NFPA 251-1969.
(g) Flammable means capable of being easily ignited, burning intensely, or having a rapid rate of flame spread.
(h) Flammable liquid means any liquid having a vapor pressure not exceeding 40 pounds per square inch (absolute) at 100 °F (37.8 °C) and having a flashpoint at or below 199.4 °F (93 °C). Flammable liquids are divided into four categories as follows: Open (h)
(1) Category 1 shall include liquids having flashpoints below 73.4 °F (23 °C) and having a boiling point at or below 95 °F (35 °C).
(2) Category 2 shall include liquids having flashpoints below 73.4 °F (23 °C) and having a boiling point above 95 °F (35 °C).
(3) Category 3 shall include liquids having flashpoints at or above 73.4 °F (23 °C) and at or below 140 °F (60 °C).
(4) Category 4 shall include liquids having flashpoints above 140 °F (60 °C) and at or below 199.4 °F (93 °C).
(i) Flash point of the liquid means the temperature at which it gives off vapor sufficient to form an ignitable mixture with the air near the surface of the liquid or within the vessel used as determined by appropriate test procedure and apparatus as specified below.
(1) The flashpoint of liquids having a viscosity less than 45 Saybolt Universal Second(s) at 100 °F (37.8 °C) and a flashpoint below 175 °F (79.4 °C) shall be determined in accordance with the Standard Method of Test for Flash Point by the Tag Closed Tester, ASTM D-56-69 (incorporated by reference; See § 1926.6), or an equivalent method as defined by § 1910.1200 appendix B.
(2) The flashpoints of liquids having a viscosity of 45 Saybolt Universal Second(s) or more at 175 °F (79.4 °C) or higher shall be determined in accordance with the Standard Method of Test for Flash Point by the Pensky Martens Closed Tester, ASTM D-93-69 (incorporated by reference; See § 1926.6), or an equivalent method as defined by § 1910.1200 appendix B.
(j) Liquefied petroleum gases, LPG and LP Gas mean and include any material which is composed predominantly of any of the following hydrocarbons, or mixtures of them, such as propane, propylene, butane (normal butane or iso-butane), and butylenes. Open (j)
(k) Portable tank means a closed container having a liquid capacity more than 60 U.S. gallons, and not intended for fixed installation.
(l) Safety can means an approved closed container, of not more than 5 gallons capacity, having a flash-arresting screen, spring-closing lid and spout cover and so designed that it will safely relieve internal pressure when subjected to fire exposure. Open (l) 2 citations
(m) Vapor pressure means the pressure, measured in pounds per square inch (absolute), exerted by a volatile liquid as determined by the “Standard Method of Test for Vapor Pressure of Petroleum Products (Reid Method).” (ASTM D-323-58).
[44 FR 8577, Feb. 9, 1979; 44 FR 20940, Apr. 6, 1979, as amended at 77 FR 17894, Mar. 26, 2012]
Source: eCFR, text current as of 2026-10-15.
Where and how often it was cited
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OSHA interpretation letters
- The definitions of combustible and flammable liquids under 29 CFR 1926 and 29 CFR 1910. (2010-07-14)
- Requirements for storage and handling of gasoline on a construction site. (2004-01-29)
- Clarification of requirements for 1000 gallon diesel storage tank. (2000-06-09)
- Storage of diesel fuel and kerosene at construction sites. (1994-08-17)
- Definition of liquid as applicable to 1926.152. (1977-09-06)
- Use of Mapp gas, oxygen, and acetylene in a tunnel. (1976-04-19)
- The handling, Storing and Use of MAPP Gas in Underground Construction Work. (1976-04-15)
- Underwriters Laboratories and Factory Mutual Research Corp. test and list approved containers. (1976-03-29)
- Applicable Standards for Dispensing Flammable or Combustible Liquids. (1974-12-26)
Most-cited parts of this rule
- 1926.155(l) Safety can 2 citations
- 1926.155(a) Approved,
- 1926.155(c)
- 1926.155(h) Flammable liquid
- 1926.155(j) Liquefied petroleum gases, LPG
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Frequently asked questions
What does approved mean in this subpart?
Equipment listed or approved by a nationally recognized testing laboratory or a Federal agency that issues approvals for such equipment.
What is a closed container?
A container sealed by a lid or other device so that neither liquid nor vapor will escape at ordinary temperatures.
What is a flammable liquid?
Any liquid having a vapor pressure not exceeding 40 pounds per square inch (absolute) at 100 °F (37.8 °C) and a flashpoint at or below 199.4 °F (93 °C).
About this page
Sources
- 29 CFR 1926.155 (eCFR), text current as of 2026-10-15
- U.S. Department of Labor enforcement data: OSHA inspections, citations and accident records, copied nightly; data as of 2026-10-20
3-year window. Federal OSHA only; state-plan rules are not counted. Plain-language text is a summary, not legal advice; the official text controls. Black Belt Safety is not part of OSHA or the Department of Labor.