DOT CFR §393.95: Commercial Vehicle Requirements

Overview

49 CFR §393.95 establishes federal requirements for emergency equipment on all power units operating in interstate commerce. These regulations ensure commercial motor vehicles carry appropriate fire suppression equipment for emergency situations.

The regulation applies to all commercial motor vehicles including trucks, truck tractors, and buses, with specific requirements based on the type of cargo being transported. Compliance is enforced by the Federal Motor Carrier Safety Administration (FMCSA).

Vehicle Requirements

Standard commercial vehicles not transporting hazardous materials must carry:

• Option A: One fire extinguisher with an Underwriters' Laboratories rating of 5 B:C or more
• Option B: Two fire extinguishers, each with an Underwriters' Laboratories rating of 4 B:C or more
• Class A rating is not required but may be beneficial for cargo fires
• Dry chemical, carbon dioxide, or halogenated agent types are acceptable
• Water-based extinguishers are prohibited due to freezing concerns

Note: Many carriers require higher ratings or additional extinguishers based on their safety policies.

Hazmat Transport Requirements

Vehicles transporting hazardous materials in placardable quantities must carry:

• Minimum Rating: One extinguisher with UL rating of 10 B:C or more
• Division 1.1, 1.2, 1.3 Explosives: No open flame warning devices permitted
• Class 3 Flammable Liquids: Additional restrictions on ignition sources
• Division 2.1 Flammable Gases: Special mounting requirements away from relief valves
• Compressed Gas Fuel Vehicles: Extinguisher required regardless of cargo

Specifications & Mounting

DOT requirements for extinguisher installation:

• UL Rating Label: Must be clearly marked by manufacturer with UL rating
• Visual Indicator: Must permit visual determination of charge status
• Accessibility: Must be readily accessible for immediate use
• Secure Mounting: Must be mounted to prevent sliding, rolling, or vertical movement
• Weather Protection: Extinguishing agent must not require freeze protection
• Location: Typically mounted in cab, but may be outside if weather-protected
• EPA Compliance: Agents must meet SNAP regulations for environmental safety

Inspection & Maintenance

Required inspection and maintenance procedures:

• Monthly Visual Inspection:

  • Verify extinguisher is in designated location
  • Check for physical damage or corrosion
  • Confirm pressure gauge shows full charge
  • Ensure mounting bracket is secure

• Annual Service:

  • Professional inspection by certified technician
  • Weight check for agent loss
  • Verification of discharge components
  • Update of inspection tag
• Documentation: Maintain records of inspections and service
• Replacement: Immediate replacement if discharged or damaged
• Hydrostatic Testing: Required at intervals per manufacturer specifications