Fire Protection and Prevention

Construction sites present numerous fire hazards including flammable liquids, hot work, temporary heating devices, electrical equipment, and combustible materials.

**Fire classes:** | Class | Fuel Type | Extinguisher | |-------|-----------|-------------| | A | Ordinary combustibles (wood, paper) | Water, foam, dry chemical | | B | Flammable liquids (gas, oil, paint) | Foam, CO2, dry chemical | | C | Electrical | CO2, dry chemical (non-conductive) | | D | Combustible metals | Specialized powder | | K | Cooking oils | Wet chemical | **PASS technique for fire extinguishers:** - **P**ull the pin - **A**im at the base of the fire - **S**queeze the handle - **S**weep side to side **Flammable liquid storage on construction sites:**

Flammable liquids must be stored in approved safety cans (not open containers or repurposed containers). Safety cans have spring-loaded self-closing lids and flame arrestors in the spout to prevent ignition of vapors inside the can.

Temporary heating equipment is a major fire cause on winter construction sites. Requirements include:

• Clearance of at least 18 inches to combustibles on all sides
• Never leave portable heaters unattended when workers leave
• Ensure adequate ventilation - combustion heaters consume oxygen and produce CO
• LP gas heaters must have the cylinder outside the building

Fire extinguisher inspection and maintenance:

Construction site fire extinguishers must be:

• Inspected monthly by a designated person (check pin, gauge, hose, condition)
• Serviced annually by a qualified fire extinguisher service company
• Hydrostatically tested at intervals specified by the manufacturer (typically every 5-12 years depending on type)
• Replaced or recharged immediately after any use, even partial discharge

The monthly inspection is a visual check - the inspector signs and dates a tag attached to the extinguisher. If the gauge reads in the red zone, the extinguisher must be removed from service for recharging.

Combustible dust explosion hazard:

Certain construction activities create combustible dust:

• Wood cutting (fine sawdust)
• Drywall sanding (gypsum dust mixed with paper fibers)
• Metal grinding (aluminum and magnesium dust)
• Grain handling on agricultural construction projects

A combustible dust explosion requires three elements: fuel (dust), oxygen, and ignition. When dust is suspended in air at the right concentration, a single spark can cause a catastrophic explosion. Control measures include local exhaust ventilation, wet suppression, and eliminating ignition sources in dusty areas.