Fire Protection and Prevention in Construction: Understanding OSHA Subpart F

November 17, 2025

Fire safety is one of the most critical responsibilities on a construction site. With the combination of flammable materials, active ignition sources, and ongoing high-risk activities such as welding and cutting, the potential for fire is always present. The Occupational Safety and Health Administration (OSHA) addresses this risk in Subpart F of 29 CFR 1926, which outlines mandatory fire protection and prevention requirements for construction and demolition work.

This article provides an overview of the key requirements of Subpart F, along with best practices based on the fire prevention program used by Century Contractors, Inc.

Employer Responsibilities

Under OSHA 1926.150, employers are required to develop and implement a fire protection program that applies to all phases of the project. This program must ensure:

  • The availability of appropriate firefighting equipment.
  • Immediate response to emerging fire hazards.
  • Ongoing inspection and maintenance of fire protection systems.

Fire protection must not be delayed. Equipment must be installed or provided as soon as fire hazards are identified.

Understanding Fire Classifications

One of the most important steps in preventing and fighting fires is knowing how to classify them. Fires are categorized based on the material that is burning:

  • Class A: Fires involving ordinary combustibles such as wood, cloth, paper, and plastics.
  • Class B: Fires fueled by flammable liquids and gases like gasoline, oil, grease, and paint.
  • Class C: Fires involving energized electrical equipment (panels, motors, wiring).
  • Class D: Fires involving combustible metals, including magnesium, sodium, aluminum, and potassium.
  • Special: Certain chemicals may fall outside these classifications and require special extinguishing agents or methods.

Each fire class requires specific extinguishing agents and methods to effectively and safely control the fire.

Fire Extinguisher Requirements and Placement

Proper fire extinguisher selection, placement, and maintenance are key to a successful fire protection strategy. OSHA and Century Contractors offer the following guidance: OSHA Standards (1926.150):

  • A 2A-rated extinguisher must be provided for every 3,000 square feet of protected building area.
  • The maximum travel distance to reach an extinguisher must not exceed 100 feet.
  • For multi-story buildings, at least one extinguisher must be placed on every floor and positioned near stairways.
  • In areas where more than five gallons of flammable or combustible liquids or five pounds of flammable gas are used, a 10B-rated extinguisher must be available within 50 feet.
  • OSHA also allows substitutions for 2A-rated extinguishers, such as:
    • A 55-gallon open drum of water with two fire pails.
    • A 1⁄2-inch diameter hose (max 100 feet) capable of discharging at least five gallons per minute.

Century Contractors Additional Requirements:

  • Requires 5A-rated extinguishers instead of 2A in both indoor and yard storage areas.
  • Travel distance must not exceed 75 feet, a stricter standard than OSHA’s.
  • All extinguishers must be mounted, clearly marked, and easily accessible.
  • Carbon tetrachloride extinguishers are prohibited due to the toxicity of the vapors they produce.

Types of Fire Extinguishers

  • 2A: Contains water, soda acid, or foam; must discharge at least two gallons per minute.
  • 10B: Contains CO2, foam, or dry chemical agents; must discharge at least 17 gallons or 30 pounds.
  • Halogenated agents (e.g., Freon FE 1301): Often used in confined spaces such as computer rooms but should be used with caution as they release hazardous gases when heated.

All fire extinguishers should be used according to the fire class they are designed for. Using the wrong type can be ineffective—or dangerous.

Using a Fire Extinguisher: The PASS Method

Proper use of fire extinguishers is critical during an emergency. OSHA recommends training all employees on the PASS method:

  • Pull the pin to unlock the extinguisher.
  • Aim low, pointing the nozzle at the base of the fire.
  • Squeeze the handle to discharge the agent.
  • Sweep from side to side until the fire is extinguished.

Inspection and Maintenance

Fire extinguishers must be inspected monthly to ensure they are in working condition and have not been discharged or damaged. Each extinguisher should have an inspection tag, and inspection records must be retained for at least one year.

Testing intervals (as per NFPA standards) include:

  • Cartridge, soda acid, pressure, foam, and CO2 types: every 5 years
  • Dry chemical extinguishers: every 12 years

These inspections should include visual checks for pressure, hose condition, and proper mounting.

Fire Prevention Practices

Century Contractors outlines several preventive practices that go beyond compliance and contribute to a safer work environment:

  • Maintain clean work areas. Flammable materials should not be allowed to accumulate.
  • Do not block access to extinguishers, hydrants, hose reels, or fire lanes.
  • Use only approved safety containers for flammable or combustible liquids.
  • Store flammable liquids and gases in designated cabinets or cages.

Smoking is allowed only in clearly marked designated areas, and the use of “strike anywhere” matches is prohibited.

Hot Work and Fire Watch

Welding, cutting, and similar operations require added precautions:

  • A fire watch must monitor all hot work activities during and for at least 10 minutes afterward.
  • Fire blankets should be used to catch sparks and slag.
  • Fire extinguishers must be on hand and checked out from the site tool trailer before starting work.
  • In enclosed spaces, torches and hoses must be removed when not in use to prevent gas buildup.

Fire watch personnel must:

  • Wear a visible orange vest.
  • Be trained in alarm systems and emergency response.
  • Be ready with a 20 lb. ABC extinguisher during operations.

Final Thoughts

Fire prevention on construction sites is not just about meeting OSHA requirements—it’s about protecting lives, equipment, and the integrity of the job site. The combination of proper planning, clear procedures, trained personnel, and well-maintained equipment forms the foundation of an effective fire protection program.

By aligning with OSHA 1926 Subpart F and following internal best practices like those from Century Contractors, companies can significantly reduce the risk of fire-related incidents and improve overall site safety. For safety managers, project supervisors, and crew leaders, fire prevention must remain a daily priority—one that starts with awareness and ends with accountability.