The Water Based Fire Protection System and the Equipment | OSH 310, Study notes of Health sciences

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Chapter 9

Water-Based Fire Protection

Systems & Equipment

Part 2

Water as an Extinguishing Agent

• (^) The great majority of fires are extinguished using water.
• (^) Water is usually available at or near the fire scene and has special physical properties well suited for fire fighting.

Electrical Conductivity of Water

• (^) Water in its natural state contains impurities that make it conductive.
• (^) If water is applied to fires involving electricity, continuous circuit may be formed and shock applier.
• (^) Water-based foam agents are very conductive.

Using Water on Special Hazards

• (^) Chemicals
• (^) Combustible Metals
• (^) Radioactive Materials
• (^) Gases
• (^) Combustible & Flammable Liquids
  • (^) Cooling agent
  • (^) Mechanical tool
  • (^) Displacing medium

Types of Valves

Butterfly Post Indicator Gate Valve (Non-indicating) Outside Screw And Yoke (OS&Y)

Friction Loss

That part of the total pressure lost as water moves through a piping system or hose.

Types of Fire Hydrants

Dry Barrel Stem Nut Drain Hole Operating Stem Main Valve Wet Barrel Operating Stem Automatic Check Hose Outlet And Valve Seal

Dry-Barrel Fire Hydrants

• (^) Used in climates where freezing weather is expected.
• (^) Compression, gate, or knuckle-joint opens either with pressure or against pressure.
• (^) When hydrant is closed, the barrel is empty from the hydrant down to the main valve.
• (^) Any water remaining in hydrant should be drained.

Hydrant Flow & Location

• (^) Flow — Varies; coloring hydrants helps indicate range of water flow
• (^) Location
  • (^) Should not be spaced more than 300 feet apart in high-value districts
  • (^) Are usually placed near each street intersection, with intermediate hydrants where distances between intersections exceed 350 to 400 feet

Hydrant Inspection & Maintenance

• (^) Obstructions preventing pumper-to-hydrant connections
• (^) Outlets facing proper direction for pumper-to- hydrant connections
• (^) Sufficient clearance between the outlets and ground for hose connections
• (^) Damage
  • Rust or corrosion
  • Hydrant caps stuck in place with paint
  • Operable operating stem (easily turned)
  • Obstructions (bottles, cans, rocks) inside hydrant restricting water flow

Sprinkler System Advantages

• (^) Most reliable
• (^) Most effective
  • (^) (control 96% of fires in sprinkler-protected buildings)
• (^) Less business interruption
• (^) Less water damage
• (^) Enhance life safety
• (^) Reduce insurance costs

Parts of a Sprinkler Head

Frame Arms Lever Arms Valve Cap Deflector Release Mechanism (Fusible Link)

How the Bulb Works

1. Heat from fire heats liquid in bulb & breaks.
2. Releases cap.
3. Water is released onto diffuser.
4. Water puts out fire.

Sprinkler Head Temp Ratings

• (^) Sprinkler heads are designed with temperature ratings ranging from 135oF to as high as 500 o F.
• (^) Ratings of 165oF are common for use in buildings maintained at normal, constant temperatures.