FT1 CH.8 // Fire Detection, Alarm, and Suppression Systems

What is the main purpose of a fire detection system?

Protect individual properties from fire

What are the four ways that detection systems may be transmitted?

1. Mechanically

2. Hydraulicallt

3. Pneumatically

4. Electrically

What causes a heat detector to activate an alarm?

When the ambient temperature near the detector reaches a predetermined level

Fixed-temperature

Operation: Senses temperature changes and sounds alarm

Advantage: Inexpensive and least prone to false activations

Disadvantage: Slowest to activate under fire conditions

Rate-of-rise

Operation: Send an alarm if the temperature rapidly increases 

Advantage: Activates based on situational setting, rather than fixed temp

Disadvantage: Will give off false alarm if falsely placed in home

Ionization

Particles and molecules enter radioactive chamber, sending signal to alarm

Growth or Fully Developed Stage

Photoelectric

Reciever sends light source and when obstructed by smoke, it alarms.

Smoldering Stage

Which type of smoke alarm is more prone to false activations due to its sensitivity to conditions such as steam or byproducts from cooking?

Ionization Smoke Alarms

Which type of smoke alarm is more prone to false activations due to foreign objects entering the detector, such as dust and spiders? 

Photoelectric Smoke Detector

What factors influence the number and placement of smoke alarms installed in a residential dwelling?

All floors of the house (except attic) and outside of sleeping areas

What is the dead air space and why is it an issue for smoke alarm placement?

Any space located within 4 inches from the corner where a ceiling and wall meet. Smoke may not reach 

What are flame detectors and where are they used?

Detect light/flames in UV or IR wave spectrum

Petroleum and Chemical Facilities

What are CO detectors and why are they installed in residential occupancies?

Detect presence of Carbon Monoxide 

Presence of CO can be deadly if gone unoticed 

What are some examples where two detection systems have been combined into a single detection device?

Smoke and CO detector 

Protected premises (local) alarm system

nitiated manually by pulling handle and doesn’t notify fire department

Schools and Public Properties 

Proprietary system

System that’s wired into common recieving point in seperate structure

College Campus or Industrial Complex

Central station system

System that connects multiple buildings together to which signal is sent to off site facility

Large industrial buildings

Remote receiving station

Monitors through contracted services

Homes and Businesses 

Auxiliary systems

Control alert functions of the building through remote access 

Buisinesses

Which of the alarm systems does not automatically notify the fire department?

Local Alarm System

Describe an automatic sprinkler system and its purpose?

A system of pipes, nozzles, and valves designed to automatically activate during a fire to provide suppression 

What are some common causes of sprinkler system failure or incomplete operation?

Closed water valve

Damaged sprinkler head

Frozen pipes

Failure of secondary water supply

List five examples of how sprinkler systems enhance the life safety of building occupants. 

1. Prevent fire spread upwards

2. Confine fire to area of origin 

3. Protects means of egress

4. Extinguish fire in some cases

5. Protect Building and PropertyHow is water flow actuated in a wet-pipe sprinkler system? 

How is water flow actuated in a wet-pipe sprinkler system? 

From a public or private water supply 

How does the fire department augment the pressure and water supply of the sprinkler system? 

They connect hoseline into the sprinkler system from the fire engine 

What are the three most common release mechanisms for sprinklers? 

1. Fusible Link

2. Glass Bulb

3. Chemical Pellet

Ordinary

TR: 135 to170

CC: Uncolored or Black 

GBC: Orange or Red

Intermediate

TR: 175 to 225

CC: White

GBC: Yellow or Green

High

TR: 175 to 225

CC: White

GBC: Yellow or Green

High

TR: 175 to 225

CC: White

GBC: Yellow or Green

High

TR: 250 to 300

CC: Blue

GBC: Blue

Extra High

TR: 325 to 375

CC: Red

GBC: Purple

Very Extra High

TR: 400 to 475

CC: Green

GBC: Black 

Ultra High

TR: 500 to 575

CC: Orange

GBC: Black 

Very Ultra High

TR: 650

CC: Orange

GBC: Black 

What are the three basic mounting positions for sprinkler systems? 

Pendent

Upright

Sidewall 

OS&Y

Outside Screw and Yoke

Inside the building where the water pipe is.

Threaded stem out of yoke = Open

Threaded stem inside yoke = Closed

PIV

Post Indicator Valve

Located outside building

Will indicate marker saying “OPEN” or “SHUT” 

What are the two types of waterflow alarms and who is notified by each?

1. Hydraulic Alarm (Water Motor Gong)

• Operated by the movement of water 

• Alerts occupants and passersby 

2. Electric Waterflow Alarm

- Alerts the Fire Department 

Wet-pipe

Water goes all the way to sprinkler head

40 degree temp. and up

Under pressure at all times

Buildings  

Dry-pipe

Water that goes below 40 degrees

Air pressure used

Unheated warehouse

Deluge

Water flows from sprinklers in a designated area where system has been activated.

Can use a foaming agent in sprinklers

No hjeat detection

Aircraft Hangars

Preaction

Dry system that employs a deluge-type valve, fire detection devices, and closed sprinklers

Water damage prevention 

Water isn’t in pipes until heat or fire is detected

Residential

Protect lives and property in single or two-family homes

Wet and dry pipe systems

Which sprinkler system is the most commonly found automatic extinguishing system in use in the United States?

Wet Pipe System

Which sprinkler systems may be activated in conjunction with a detection device?

Deluge System

What is a standpipe system and why is it used?

Wet or dry pipes used in large single-story multistory buildings to provide water supply for fire fighting. Used to supply water or augment the pressure and volume of the system.

Class I

2.5 inch connection for fire department
no dedicated water supply

Manual dry standpipes

Trained personnel 

Class II

1.5 inch hose connection for occupant use

Dedicated water supply 

Occupants

Class III

2.5 inch and 1.5 inch connection for occupant and fire department use

Both parties use it

What is the most desirable classification of standpipe system?

Class 3

What is the purpose of a pressure-regulating device in a standpipe system?

When the pressure at the discharge opening of a standpipe connection exceeds 100 PSI

Why does the fire department connect a minimum of two 2 ½ - inch hose lines to the fire department connection of a standpipe or sprinkler system?

In case one of the other hoselines fail 

Foam systems

Use: Suppress class B fires such as gasoline, oil, and jet fuel

Operation: Foam blankets the fuel surface

Components: Foam concentrate tanks

Effectiveness: Highly Effective

Carbon dioxide systems

Use: Suppress Class B and C Fires such as flammable liquids and electrical fires

Operation: CO2 stored under pressure and displaces oxygen in area

Components: CO2 storage cylinders

Effectiveness: Very Effective in encolsed spaces

Halon systems

Use: Supress class A,B,C fires, espewcially where water damage must be avoided

Operation: Halon gas chemically interrupts chemical chain reaction

Compnents: Halon Sotrage Cylinders

Effectiveness: Highly effective/ no damage to equipment

Dry chemical systems

Use: Suppress Class A,B, and C fires in commercvial kitchens, fuel stations, and industrial settings
Operation: Dry powder isa discharged under pressure

Components: Agent Storage Tank

Effectiveness: Very effective

Wet chemical systems

Use: Class K Fires - high temperature cooking oils and fats

Operation: Wet chemical agent is sprayed causing soapy foam to smother fire

Compnents: Agent tank 

Effectiveness: Effective on deep fat fryer fires

What is the primary reason for the pre-action alarm in a carbon dioxide extinguishing system?

To evacuate occupants to prevent death 

Why isn’t foam effective on three-dimensional fires or flammable liquid processes?

Can’t form stable blanket needed to suffocate fire 

What is an industrial fire brigade and why is it important for the fire brigade to coordinate with the local fire department?

Facility workers trained in limited fire suppression and response procedures. It’s important to coordinater with local fire department in order to revieve assisting with additional on-scene incedent managment needs