chapter 12 systems and equipment for fire protection
TRANSCRIPT
Chapter 12
Systems and Equipment for Fire Protection
Introduction
• Water is the most common extinguishing agent used for combating fires
• Automatic firefighting devices have been developed to aid in the application of water and other firefighting agents
• In occupancies or applications where water may cause damage or be ineffective, other extinguishing agents have been developed
WATER SUPPLY SYSTEM
• All systems must have storage capability
• Capacity and adequacy
• Adequacy gauged in several areas Average daily consumption Maximum daily consumption Peak hourly consumption
Learning Objective 1
Components of a Water Supply System
DISTRIBUTION SYSTEM
• Underground piping called water mains
• Largest are primary feeders
• Intermediate are secondary feeders
• Distributor piping
• Common sizes are 8, 12, and 16 inch
Learning Objective 1
Components of a Water Supply System
TYPES OF HYDRANTS IN USE TODAY
• Wet barrel hydrant
• Dry barrel hydrant
• Dry hydrant
• Hydrant installation
Cont.
Learning Objective 1
Components of a Water Supply System
TYPES OF HYDRANTS IN USE TODAY
• Airport or special property
• Complete prefire program
• Flushing hydrants
• Hydrant testing
• Hydrant painting
Learning Objective 1
Components of a Water Supply System
Learning Objective 2
Importance of Dependable Water Supply System
PUBLIC WATER COMPANIES
• Set up under public utility laws
• Provide for everyday needs of customers
• Usually have elected officials to administrate
PRIVATE WATER COMPANIES
• Maintain their own distribution and storage equipment
WATER SYSTEMS PROGRAM
• Letter of working agreement
• Grid map
• Hydrant survey and
service records
• PreplanningCont.
Learning Objective 3
Components of Water Supply Program
WATER SYSTEMS PROGRAM
• Auxiliary sources of water supply Reservoirs Cisterns Swimming pools Canals Rivers
Learning Objective 3
Components of Water Supply Program
PRIVATE FIRE PROTECTION SYSTEMS
• Designed to protect individual occupancies from fire
• Private homes, businesses, manufacturing plants, or public buildings
• Main purpose is to alert occupants
• Some systems alert and extinguish
Learning Objective 4
Fire Detection Systems and Their Components
DETECTION SERVICES
• Smoke detector
• Ionization chamber detector
• Flame or light detector
• Visible smoke detector
Cont.
Learning Objective 4
Fire Detection Systems and Their Components
DETECTION SERVICES
• Rate of rise detector
• Fixed temperature detector
• Carbon monoxide (CO) detector
• Manual pull alarm
• Water flow switch or excess flow alarm
Learning Objective 4
Fire Detection Systems and Their Components
MONITORED ALARMS
• Combination of alarms
• Must be monitored at some level
• Transmits to fire department
• Sometimes plagued with frequent false alarms
Learning Objective 4
Fire Detection Systems and Their Components
SPRINKLER SYSTEMS
• Residential sprinklers
• Commercial and industrial
• Wet pipe system
• Dry pipe system
• Deluge systemCont.
Learning Objective 5
Extinguishing Systems and Their Components
SPRINKLER SYSTEMS
• Preaction sprinkler system
• Sprinkler heads
• Standpipe systems
• Foam systems
• Carbon dioxide
Cont.
Learning Objective 5
Extinguishing Systems and Their Components
SPRINKLER SYSTEMS
• Dry chemical systems
• Wet chemical extinguishing systems (Class K)
• Fire extinguishers
• Obsolete agents
• Fire pumps
• Pressure-reducing devices
Learning Objective 5
Extinguishing Systems and Their Components
WATER
• Most common fire extinguishing agent in use today
• Extinguished through cooling and smothering
• Highest specific heat of any known substance
• Latent heat of vaporization
• Numerous delivery systems available
Learning Objectives 6 and 7
Different Types of Extinguishing AgentsHow Various Extinguishing Agents Work
FOAM PROPERTIES
• Its effectiveness over plain water is becoming popular
• Properties of extinguishing fires
• Components are water and foam concentrate
• Traditional purpose is to
extinguish flammable liquids
Learning Objectives 6 and 7
Different Types of Extinguishing AgentsHow Various Extinguishing Agents Work
CLASS B FOAM
• Forms a layer above the surface of the liquid
• Chemical foams
• Mechanical foams
• Protein foam
• Fluoroprotein foamCont.
Learning Objectives 6 and 7
Different Types of Extinguishing AgentsHow Various Extinguishing Agents Work
CLASS B FOAM
• Alcohol-type protein foams
• Aqueous film-forming foam (AFFF) Most popular type of synthetic foam
• High-expansion foams Will reduce visibility to nearly zero
Learning Objectives 6 and 7
Different Types of Extinguishing AgentsHow Various Extinguishing Agents Work
CLASS A FOAM
• Much lower concentration than class B
• Can stick to vertical surfaces
• Can pre-treat areas in advance
• Blocking gel
• Wetting agents
• Fire retardant
Learning Objectives 6 and 7
Different Types of Extinguishing AgentsHow Various Extinguishing Agents Work
CARBON DIOXIDE
• Extinguishes by smothering
• Installed where water is not the agent of choice
HALOGENATED AGENTS
• Break the chemical chain reaction
• Concern about their effect on the ozone layer
Learning Objectives 6 and 7
Different Types of Extinguishing AgentsHow Various Extinguishing Agents Work
CLEAN AGENTS
• Do not deplete the Earth’s ozone layer
DRY CHEMICAL
• Mixture of finely divided powders
DRY POWDER
• Used on combustible metals (Class D)
Learning Objectives 6 and 7
Different Types of Extinguishing AgentsHow Various Extinguishing Agents Work
Summary
• The fire department should have a close working relationship with the local water company
• A thorough knowledge of the strengths and weaknesses of the water system is necessary for decision-making purposes at the fire scene
• Firefighting agents are all applied through some type of system
• Pre-plan what is necessary to support these systems in case of fire