unit 3 fire suppression section 1 detection and alarm systems

Unit 3 Fire Suppression

Section 1 Detection and Alarm Systems

1. Importance of Fire Detection and Alarm Systems

1.1. Time Element

1.2. Notification

a. Type A Manual Alarm

b. Type B Automatic Alarm

1.3. Activation

Note: Studies with children and notification!

2. Types of Detectors

2.1. There are three broad classifications

of fire detection: Heat, Smoke & Flame Detectors.

2.2. Fire Detectors are used in a variety of fire prevention and suppression systems.

3. Classification of Heat Detectors

3.1. Heat Detectors respond to the excess heat generated in a fire

3.2. Two subclassifications based on operation

3.2.1. Fixed Temperature which operate at predetermined temperature

3.2.2. Rate of Rise operate based on a specified rate of temperature rise (degrees/min.)

4. Smoke Detectors

4.1. Smoke detectors respond to the presence of smoke

4.2. General Information

4.3. Classifications of Smoke Detectors

4.3. Two Classifications

4.3.1. Photoelectric smoke detectors

4.3.2. Ionization smoke detectors


4.3.1. Photoelectric smoke detectors


4.3.2. Ionization smoke detectors

PROPER LOCATION OF SMOKE DETECTORS

VS 19-2

Outside Sleeping Areas

On Each Level of House

Dining Kitchen

EntryLiving Room

Bath

BRBR

Master Bedroom

Dining

Room

Living

Room

Basement

Bedroom No. 1

Bedroom No. 2

Ha

llw

ay

PROPER MOUNTING OF SMOKE DETECTORS

VS 19-3

3 Feet(1m)

Horizontal Distance from Peak

Mount on Wallat least 4 inches(102 mm)

from ceiling

No Closerthan

4 inches(102 mm)

FromSide Wall

Best inCenter ofCeiling

Dead AirSpace

No more than 12 inches(305 mm)

from ceiling

Best LocationAcceptable Location

5. Flame Detectors

5.1. Flame detectors respond to the presence of a flame

5.2. General Information

5.3. Principle of Operation

http://www.protectowire.com/products/flame_detectors.htm

6.0 Placement of Fire Detectors

6.1. In general, fire detectors are normally placed on the ceiling or within 12" of ceiling

6.2. Where possible the detectors should be located throughout entire building

6.0 Placement of Fire Detectors Cont’d

6.3. Spacing of detectors will vary based on several factors

6.4. Connection to Remote Locations

6.5. Testing & Maintenance of fire detectors

7.0 Components to a Fire Alarm

System

7.1. Power supply

7.2. Detectors & manual pull boxes

7.3. Signal supervisors

7.0 Components to a Fire Alarm

System Cont’d

7.4. Local Alarms

7.5. Indicator Boards

7.6. Reference for Alarm Systems

Unit 3 Fire Suppression

Section 2 “Fixed Extinguishment Systems”

1. Introduction to Sprinkler Systems

1.1. Effectiveness of Sprinkler Systems

1.2. Function of Sprinklers

1.3. Advantages of Sprinklers

1.4. Cost of Sprinklers

2. Types of sprinkler systems

2.1. There are four major classifications of sprinkler systems


2.2. Wet-pipe Systems

2.2.1. Operation of system


2.3. Dry Pipe System


Air

Water

Dry Pipe System

Two question to ask:

• activation / trip pressure for valve

• is air pressure greater than activation/trip pressure (should be 10 – 15 psi greater)

Activation/Trip pressure set by the manufacture

70 psi

Activation/Trip pressure = 40 psi

Air pressure should be 50 – 55 psi


2.4. Pre-action Systems 2.4.1. Operation of System

2.4.2. Advantages over dry- pipe system

2.4.3. Disadvantage--two systems must both function properly


2.5. Deluge sprinkler system


2.5.2. Uses of Deluge System

3. Basic Sprinkler System Components

3.1. Water Supplies

3.1.1. Types of water supplies

· Public Water

· Pressure Tanks

Basic Sprinkler System Components


• Gravity feed from tank

Easier for water to flow down than up



· Fire pumps

· Fire Department

Connections


3.1.2. Amount of water supply

a. Hazard of Occupancy—most important

· Light hazard class

· Ordinary hazard class

Group 1

Group 2

· Extra hazard class

Group 1

Group 2

Basic Sprinkler System Components

a. Hazard of occupancy

Hazard Class Combustibility of Content

Amount of Combustibles

Heat Liberation Heads Open

Light Low Low Low Few

Ordinary Group 1 Low Moderate Moderate Moderate

Ordinary Group 2 Moderate Moderate -

HighModerate -

High Moderate

Extra Hazard Group 1 Very High Very High Very High Many

Extra Hazard Group 2 Very High Very High Very High Many


3.1.2. Amount of water supply

b. Obstructions to water delivery

c. High ceilings

d. Unprotected vertical openings

between floors

e. Division of spaces


3.1.3. Calculating water supply

Q = k √P

Where:

Q = supply (GPM)

k = coefficient of orifice (inside pipe size)

P = pressure (PSI)


3.2. Sprinkler Piping

3.2.1. The piping and type of valve will vary depending on type of system

3.2.2. Types of piping

3.2.3. Hydraulic design

of systems

SPRINKLER PIPING

tank (or natural water supply

public water supply - 8” – 12”

yard main6” – 8”always below freeze line

cross main

branch lines feed mainsprinkler head

post indicator valve

“open” or “closed”

should be “open”

pad lock

unlock to close valve

riser(alarms, water flow valve, sprinkler valve)


3.3. Sprinkler Valves

3.3.1. The purpose of a sprinkler valve is to retain & control flow of water and to isolate individual risers.

CONTROL VALVE LOCATIONVS 15-4

Main Control Valve

(OS&Y)

Every system will have two valves: a main water control valve and a sprinkler valve.

The main control valve should always be in the OPEN position.

TYPES OF CONTROL VALVESVS 15-5

OS&Y (Outside Screw and

Yoke)

PIV (Post Indicator Valve)

WPIV (Wall Post Indicator Valve)


3.4. Alarms on Sprinkler Systems

3.4.1. Every sprinkler system should

have an alarm that sounds when water flows through the

system.

3.4.2. Types of Alarms

3.4.3. Supervisory signals


3.5. Test Connections

3.5.1. Two Inch Drain Test

3.5.2. Inspectors Test Connection

3.6. Sprinkler Heads

3.6.1. Operating Principle

Frame Arms

Lever Arms

Valve Cap

Deflector

Release Mechanism

(Fusible Link)



3.6.2. Type based on position

SPRINKLER DESIGNSVS 15-3

Pendant

Sidewall

Upright



3.6.3. Type based on activation

a. Solder-link

b. Frangible bulb

c. Fusible pellet

RELEASING MECHANISMSVS 15-2

Fusible Link

(Standard)

Chemical Pellet

Frangible Bulb

Fusible Link (Quick

Response)



3.6.4. Deflectors

3.6.5. Flow rates

SPRINKLER DESIGNSVS 15-3

Pendant

Sidewall

Upright



3.6.6. Temperature rating of sprinkler heads

Non-Colored Ordinary 135-1700F

White Intermediate 175-2250F

Blue High 250-3000F

Red Extra High 325-3750F

Green Very High 400-4750F

Orange Ultra High 500-6500F



3.6.7. Special service sprinkler heads

4. Location and Spacing of Sprinklers

4.1. Fundamental rule

4.2. Reference on location and spacing: NFPA code 13, Sprinkler Standards

4. Location and spacing of sprinklers

4.3. Spacing depends on the class of hazard of occupancy and the type of ceiling construction

4.3.1. Light hazard - 15' maximum between sprinklers

4.3.2. Ordinary hazard - 12-15' ft. depending on use of area

4.3.3. Extra hazard - 12' maximum


4.4. Sprinklers must also be spaced so that each sprinkler does not protect more than a specified area:

4.4.1. Light hazard occupancy—floor area/sprinkler maximum of 130-200 square feet, depending on type of ceiling

4.4.2. Ordinary hazard occupancy--max. area per sprinkler 100-130 square feet, depending on use of

space

4.4.3. Extra hazard occupancy--90 square feet sprinkler maximum

Extra High Hazard 90 ft2


4.5. Determine protection area for sprinkler heads using the following formula:

As = S X L

Where “S” is the distance between heads on the lines and “L” is the distance between

branch lines.

4. Location and spacing of sprinklers 4.5. Protection area of sprinklers along “walls”

As = S X L

S is the larger of either twice the distance to the wall or the distance to the next sprinkler head

L is the larger of either twice the distance to the wall or the distance to the next branch line.

10 ft

3 ft

9 ft

4 ft

AS = S x LS = 3 x 2 = 6 or 10L = 4 x 2 = 8 or 9

AS = S x L

AS = 90 ft


4.6. Other location specifications that may influence spacing

5. Carbon Dioxide Extinguishing Systems

5.1. Application

5.2. Advantages

5.3. Disadvantage


5.4. Storage of CO2

5.5. Delivery Mechanism


5.6. Types of fixed systems

5.6.1. Total flooding

5.6.2. Local application

5.7. Inspection of Systems

6. Dry Chemical Fire Extinguishing Systems

6.1. Application

6.2. Operation of system

Carbon Dioxide Extinguishing Systems

6.3. Types of fixed systems– Total flooding

• apply to an entire room or confined area

– Local application• applying CO2 over the surface of the tank

local application

Acid Pickling Tank

6. Dry Chemical Fire Extinguishing Systems

6.4. Quantity and rate of application is determined by a qualified professional

6.5. Inspection and maintenance must be completed at least once each year (NFPA Code #17)

7. Foam Fire Extinguishing System

7.1. Application

7.2. Inspection and maintenance

7.3. Fire code for foam systems is NFPA #11 and NFPA #16 for foam-H2 combination systems

Foam Fire Extinguishing System

7.4. Types of systems

– fixed• activate with detector head • high hazard areas

– portable• fire departments

7.5 Video on Foam

liquid

air

mechanical agitation

http://www.myfoxchicago.com/myfox/MyFox/pages/sidebar_video.jsp?contentId=3012858&version=1&locale=EN-US

Unit 3 Fire Extinguishment

Section 3 “Explosion Prevention”

1. Introduction

1.1. Principles of Explosion Prevention

a) Venting to relieve the pressure

b) Suppression to extinguish or retard the deflagration

c) Purging to eliminate the combustible

mixture

2. Fundamentals of explosion venting

2.1. Location of hazardous operations

2.2. Design of the vent

2.2.1. Location of vent is important

2.2.2. Size of vent

2.2.3. Design variables for vents


2.3. Design of vent closures

2.3.1. Most effective vent for release of explosion pressure is an unobstructed vent opening

2.3.2. Several small vents may be as effective as one large opening

as long as total area is the same


2.3. Design of vent closures

2.3.3. The nearer a vent is located to the point of explosion the more effective it will be

2.3.4. If diaphragms (of the same size and thickness) are made thicker then more pressure will be required to rupture them


2.4. Maintenance of vents

3. Explosion Suppression

3.1. Elements in the system

3.1.1. Pressure Detector

3.1.2. Suppressors

3.1.3. Suppressant Material

unit 3 fire suppression section 1 detection and alarm systems

Documents

smoke flame detectors

ionization smoke detectors

photoelectric smoke

types of detectors

presence of smoke

hallway slide

general information

principle of operation