Fire Sprinkler system | Firefighting lesson 6

Summary

This script offers a comprehensive overview of sprinkler systems, emphasizing the fire triangle's role in fire sustenance. It explains the necessity of heat, fuel, and oxygen for fire and delves into various firefighting systems, particularly sprinkler systems. The video outlines different sprinkler head types, their activation temperatures, and system classifications like wet, dry, pre-action, and deluge. It also covers sprinkler system design considerations, including pipe scheduling, water demand, and layout requirements, ensuring compliance with NFPA standards.

Takeaways

• 🔥 The fire triangle consists of three key components: heat, fuel, and oxygen, all of which are necessary for a fire to ignite and sustain.
• 💧 Sprinkler systems are part of automatic firefighting systems, designed to activate and fight fires without human intervention.
• 🚿 Sprinkler heads come in various types, including upright, pendant, sidewall, and concealed, each serving different purposes and spaces.
• 🔧 Wet pipe sprinkler systems always contain water, allowing for immediate discharge when activated, whereas dry pipe systems hold water behind a valve until triggered by heat.
• 💡 Pre-action systems and deluge systems are advanced types of sprinkler systems, with the latter being used for high-hazard areas where all sprinkler heads activate simultaneously.
• 🏗️ Firefighting systems in buildings typically include a large water storage tank, a pumping system, and a network of pipes connected to sprinklers or hydrants.
• 🔍 The temperature at which a sprinkler head activates is determined by its rating, identified by the color of the liquid in the bulb (for glass bulb sprinklers).
• 📏 The design and layout of sprinkler systems depend on factors like hazard classification, with specific spacing requirements for sprinkler heads according to NFPA 13 standards.
• 💦 The minimum water supply for pipe schedule systems is determined based on factors such as water flow rate, residual pressure, and system duration, ensuring adequate firefighting capability.
• 🔧 Floor control riser assemblies in buildings may include various components like auxiliary drain valves, pressure-reducing valves, and water flow switches, all critical for efficient and safe system operation.

Q & A

What is the fire triangle and why is it important?

The fire triangle is a scientific principle representing the three components needed to ignite and sustain a fire: heat, fuel, and oxygen. It is important for understanding how fires sustain themselves and is essential background information for using fire safety equipment.

What is a flash point in the context of fire safety?

A flash point is the lowest temperature at which a material can ignite. Different materials have different flash points, and understanding them is crucial for fire prevention and safety.

How does a fire blanket work in relation to the fire triangle?

A fire blanket works by removing the oxygen side of the fire triangle. It either removes or displaces oxygen, causing the fire to suffocate and thereby ceasing the combustion reaction.

What are the two types of firefighting systems mentioned in the script?

The two types of firefighting systems mentioned are manual and automatic. Manual systems require physical intervention, while automatic systems fight fires without human intervention.

What are the three basic parts of a sprinkler system?

The three basic parts of a sprinkler system are a large store of water in fire storage tanks, a specialized pumping system, and a network of pipes ending in either hydrants or sprinklers.

What are the four most common styles of sprinkler heads?

The four most common styles of sprinkler heads are the standard spray upright, standard spray pendant, sidewall sprinkler, and concealed sprinkler head.

What is the purpose of the heat-sensitive element in a sprinkler head?

The heat-sensitive element in a sprinkler head allows water to flow at a given temperature, activating the sprinkler when the temperature reaches a certain threshold.

What are the four main types of fire sprinkler systems?

The four main types of fire sprinkler systems are wet pipe, dry pipe, pre-action, and deluge systems.

How does a dry pipe system differ from a wet pipe system?

A dry pipe system is not constantly filled with water; instead, water is held behind a dry pipe valve. When a sprinkler head activates due to heat, air is released, causing a pressure drop that opens the valve and allows water to fill the system.

What is unique about the operation of a pre-action system?

A pre-action system does not admit water into the system's piping until a pre-action valve is opened, which is triggered by one or two events: sprinkler activation and detection device activation, depending on the type of pre-action system installed.

What is the purpose of a deluge system in fire protection?

A deluge system uses open sprinklers or nozzles and is activated by a detection system such as smoke detection. Once activated, water fills the system and flows from every open sprinkler head, providing immediate and extensive water coverage.

Outlines

00:00

🔥 Fire Triangle and Firefighting Systems Overview

This paragraph introduces the concept of the fire triangle, which is a fundamental principle in firefighting, emphasizing the three essential components for fire ignition and sustenance: heat, fuel, and oxygen. It explains the role of flash points in ignition and discusses common fuel sources found in homes and businesses. The paragraph also covers the function of fire blankets and extinguishers in disrupting the fire triangle. It then transitions into an overview of firefighting systems, distinguishing between manual and automatic systems, with a focus on sprinkler systems. The components of a sprinkler system are outlined, including fire storage tanks, pumping systems, and pipe networks. The paragraph concludes with a mention of various sprinkler head types and their components, highlighting their temperature ratings and activation mechanisms.

05:02

💧 Sprinkler Head Types and Fire Sprinkler System Designs

This paragraph delves into the different types of sprinkler heads, including upright, pendant, sidewall, and concealed, detailing their specific functions and ideal applications. It further explains the four main types of fire sprinkler systems: wet pipe, dry pipe, pre-action, and deluge systems. Each system's unique components and operational mechanisms are described, such as the presence of water in the pipes for wet systems and the delayed water flow in dry pipe systems. The paragraph also touches on the pre-action system's reliance on detection device activation and the open sprinklers used in deluge systems. Lastly, it discusses the considerations for selecting an appropriate sprinkler system based on the level of hazard and the design layouts for fire sprinkler systems, including tree, grid, and looped systems.

10:02

🏢 Fire Sprinkler System Layout and Water Supply Requirements

The final paragraph focuses on the design and layout of fire sprinkler systems, particularly tree systems, and the calculations for water demand. It provides an example of designing a tree sprinkler system for a light hazard office area, explaining the maximum coverage area per sprinkler head, design spacing, and distance from walls. The paragraph outlines the methods for determining water supply requirements, such as the pipe schedule method and hydraulic calculation method. It also details the minimum water flow rate, residual pressure, and duration for pipe schedule systems, emphasizing the need for a sufficient water tank. The paragraph concludes with a discussion on the components and considerations for a floor control riser assembly, including pressure reducing valves, control valves, and water flow switches, as well as their specifications and requirements.

Keywords

💡Fire Triangle

The Fire Triangle is a fundamental scientific principle that describes the three elements necessary for a fire to start and continue: heat, fuel, and oxygen. In the video, it is emphasized as a crucial concept for understanding fire behavior and for the effective use of fire safety equipment. The script mentions that removing any one of these elements can extinguish a fire, which is a key principle behind the operation of fire suppression systems.

💡Flash Point

Flash point refers to the lowest temperature at which a material can vaporize to form an ignitable mixture in air. It is a critical parameter in fire safety, as it helps to determine the likelihood of a material catching fire. The video script uses the concept of flash point to illustrate the varying susceptibility of different materials to ignition, which is essential knowledge for designing effective fire protection strategies.

💡Firefighting Systems

Firefighting systems are mechanisms designed to detect and suppress or extinguish fires. The video distinguishes between manual and automatic systems, with the latter including sprinkler systems that operate without human intervention. The explanation of these systems is integral to understanding how buildings are protected from fire damage, highlighting the importance of both human and automated responses in fire safety.

💡Sprinkler System

A sprinkler system is a type of automatic firefighting system that controls fires by activating sprinklers when the heat of a fire is detected. The video script provides a detailed schematic of the components of a sprinkler system, including water storage tanks, pumps, and pipes, emphasizing the role of sprinklers in early fire detection and suppression, which is vital for minimizing damage and ensuring safety.

💡Standard Spray Upright

Standard Spray Upright is one of the four common styles of sprinkler heads mentioned in the video. It sprays water upward to a concave deflector, creating a dome-shaped pattern. The video explains that these sprinkler heads are efficient for dispersing water between obstructions and are often used in areas with open ceilings or where accessibility is limited, showcasing their practical application in fire protection design.

💡Pendant Fire Sprinkler Head

Pendant Fire Sprinkler Heads are the most common type of sprinkler head, hanging from the ceiling with a convex deflector plate. When activated, they disperse water widely in a conical pattern. The video script highlights their widespread use due to their effectiveness in covering large areas and their suitability for various room configurations.

💡Sidewall Sprinkler Heads

Sidewall Sprinkler Heads are designed to protrude horizontally from the wall, making them ideal for small spaces or areas with obstructions where ceiling piping is not feasible. The video script explains their utility in specific architectural contexts, emphasizing the importance of选择合适的 sprinkler heads based on the layout and requirements of the space being protected.

💡Concealed Sprinkler Head

Concealed Sprinkler Heads are designed to blend with the ceiling aesthetics, with a heat-sensitive plate that detaches at a lower temperature than the sprinkler head itself, activating the sprinkler. The video script discusses how these heads maintain the visual continuity of a ceiling while still providing necessary fire protection, highlighting the balance between form and function in fire safety design.

💡Wet Pipe System

A Wet Pipe System is a type of sprinkler system where the pipes are always filled with water, allowing for immediate water discharge upon sprinkler head activation. The video script describes the components and operation of wet pipe systems, emphasizing their quick response time as a critical feature for effective fire suppression in buildings.

💡Dry Pipe System

A Dry Pipe System is similar to a wet pipe system but differs in that the pipes are not constantly filled with water. Instead, water is held back by a dry pipe valve until needed. The video script explains that this system is useful for spaces where freezing could be a concern, as it prevents water from sitting in the pipes, illustrating the importance of environmental considerations in system selection.

💡Pre-Action System

A Pre-Action System combines features of both wet and dry pipe systems but introduces a delay in water flow until specific detection devices are activated. The video script details the operation of pre-action systems, emphasizing their use in high-value or high-hazard areas where false alarms could lead to significant water damage, highlighting the precision and control offered by this system.

💡Deluge System

A Deluge System is designed to activate all sprinklers simultaneously upon detection, using open sprinklers or nozzles. The video script describes how this system is used in high-hazard areas where a rapid, extensive response is necessary, such as aircraft hangars, illustrating the role of deluge systems in providing comprehensive fire suppression in critical environments.

Highlights

The fire triangle is a fundamental principle that explains how fires sustain themselves, consisting of three elements: heat, fuel, and oxygen.

Heat is required for ignition, with different materials having specific flash points—the lowest temperature at which they ignite.

Fuel sources in homes and businesses include paper, oil, wood, and fabrics, all of which can sustain a fire.

Oxygen, which makes up 21% of Earth's atmosphere, is essential for sustaining the combustion reaction.

Firefighting systems are classified into manual and automatic systems, with sprinkler systems being an example of automatic systems.

Sprinkler systems consist of three basic parts: fire storage tanks, a specialized pumping system, and a large network of pipes ending in either hydrants or sprinklers.

The four most common types of sprinkler heads are: upright, pendant, sidewall, and concealed.

Sprinkler systems are categorized into four main types: wet pipe, dry pipe, pre-action, and deluge systems.

Wet pipe sprinkler systems always contain water in the pipes, which is immediately discharged through the sprinkler heads when activated.

Dry pipe systems hold water behind a dry pipe valve and release it only when the sprinkler head is activated, making them suitable for unconditioned spaces.

Pre-action systems are similar to dry pipe systems, but water is admitted into the system only after specific detection events occur.

Deluge systems use open sprinklers or nozzles, allowing water to flow from all heads once the detection system is activated.

The layout of fire sprinkler systems can follow different designs, including tree, grid, and looped configurations.

The maximum area of coverage per sprinkler head depends on the hazard classification and mounting orientation, based on NFPA 13 standards.

Water demand for firefighting sprinkler systems is determined by either the pipe schedule method or the hydraulic calculation method, ensuring proper coverage and pressure.

Transcripts

[Music]

sprinkler systems

before diving in the sprinkler system

let us go through some basic information

related to firefighting

the fire triangle

the fire triangle is a scientific

principle that is important for all

people to be aware of understanding how

fires sustain themselves is essential

background information in situations

where you may have to use fire safety

equipment

the fire triangle or combustion triangle

is the three components needed to ignite

and sustain a fire

the three ingredients of a fire triangle

are

heat fuel and oxygen

first a source of heat is required for

ignition to occur and different

materials have different flash points

flash point is the lowest temperature at

which the material ignites

second a fire cannot begin if there is

no material to burn

homes and businesses are full of

flammable materials such as paper oil

wood and fabrics any of these can serve

as a fuel for a fire

third to sustain the combustion reaction

oxygen is needed as it reacts with the

burning fuel to release heat and co2

earth's atmosphere consists of 21 oxygen

so there is plenty available to trigger

a fire if the other two components are

present fire blankets and certain fire

extinguishers remove the oxygen side of

the triangle by removing it or

displacing it causing suffocation and

thereby ceasing the combustion reaction

so here are some facts about the fire

triangle that we should keep in mind

normal air contains 21 percent oxygen

fuel may also contain oxygen heat

sources include the sun hot surfaces

sparks friction and electrical energy

fuel sources can be a solid liquid or

gas

firefighting systems are classified

either manual or automatic

manual firefighting systems includes

extinguishers fire cabinets siamese

connection and fire hydrants

these requires the physical intervention

of manpower to fight the fire automatic

system as its name says fights the fire

automatically without the intervention

of human being and that what a sprinkler

system do

here is a schematic diagram of the

system components

usually both systems exist in all

buildings to form a competent

firefighting system matching the nfpa

standards

so in any building the system consists

of three basic parts a large store of

water in tanks either underground or on

top of the building called fire storage

tanks

a specialized pumping system this

usually includes three types of pumps

jockey pump electric pump and diesel

pump

you can refer to my video about fire

pumping system for more info

a large network of pipes ending in

either hydrants or sprinklers nearly all

buildings require both of these systems

sprinkler systems when it comes to the

sprinkler head itself the four most

common styles of sprinklers are

the standard spray upright standard

spray pendant

sidewall sprinkler concealed sprinkler

head

nearly all fire sprinklers are composed

of the same components

a ceiling assembly or plug that prevents

water from escaping a heat sensitive

element that allows water to flow at a

given temperature a deflector that

distributes water effectively in a frame

the sprinkler's temperature rating is

the temperature at which the sprinkler

will activate

options range from 135 to 650 degrees

fahrenheit

these ratings can be identified by the

color of the liquid inside the bulb in

the case of glass bulb sprinklers

the selection is taken from nfpa 13

table 7241 based on the hazard class for

the structure that the fire sprinkler

system is protecting

upright sprinkler head upright fire

sprinklers spray water upward to a

concave deflector like an umbrella

producing a dome-shaped spray pattern

rather than descending through the

ceiling these sprinkler heads are

usually mounted on pipes just below the

ceiling upright sprinkler heads are

efficient at dispersing water between

obstructions thus they are frequently

used for rooms that are inaccessible

such as mechanical rooms and in

warehouses and industrial spaces they

are also often applied in structures

with open ceilings

the pendant fire sprinkler head it is

the most common type that you will see

pendant sprinkler heads descend from the

ceiling with a convex circular gap

deflector plate on the bottom

when the sprinkler heads activate they

send a stream of water downward onto

their deflectors which then disperse the

water widely side to side throughout the

room in a conical pattern

sidewall sprinkler heads

protrude horizontally out of the wall

parallel to the floor rather than

descending from the ceiling or mounted

on a pipe pointing upward

sidewall sprinklers are ideal for small

spaces such as hallways spaces with

obstructions and where ceiling piping is

not available

concealed sprinkler head

this heat sensitive plate detaches at

temperatures roughly 20 degrees lower

than the fire sprinkler head allowing

the concealed sprinklers deflector to

drop in the head to activate

now we have covered the most common

sprinkler head types let's go ahead and

discover the fire sprinkler system types

there are four main types of systems

what pipe system

dry pipe system

pre-action system

and deluge system

wood pipe sprinkler systems here are the

components of a wet sprinkler system

in addition to the water supply piping

and sprinklers these systems have

backflow prevention device

control valve

main drain

fire department connection

water flow alarm

wet pipe sprinkler systems always

contain water in the riser and piping

as soon as a sprinkler head activates

due to the heat of a fire water is

immediately discharged through the open

head

dry pipe fire sprinkler systems

dry pipe systems are very similar to

what pipe systems with one major

difference

the pipe is not constantly filled with

water instead the water is held behind a

dry pipe valve usually some distance

away from where the sprinklers are

located

like a wet pipe system when the

temperature at the ceiling becomes hot

enough the glass bulb or fusible link of

the sprinkler breaks however in this

case water isn't immediately available

because the pipe is not water filled

instead air is released from the now

open sprinkler head

this creates a drop in pressure causing

the dry pipe valve to open in water to

fill the system

water will then flow from the open

sprinkler head

since there is a delay between sprinkler

operation and water flow the size of dry

pipe systems is limited

the size limitation is intended to

minimize the amount of time water

delivery is delayed

a dry pipe system is a great option for

unconditioned spaces or locations where

the temperature of the space cannot be

guaranteed to be high enough to prevent

water in the system from freezing

pre-action system

a pre-action type sprinkler system

employs the basic concept of a dry pipe

system and that the sprinklers are

closed in water is not normally

contained within the pipes

one difference however is how water is

admitted to the system

water introduction into the system's

piping is initiated by opening of a

normally closed mechanically latched

valve known as a pre-action valve

means of operating the pre-action valve

depends on which of the three types of

pre-action systems non-interlock single

interlock or double interlock is

installed

pre-action valve operation is dependent

upon one or two of the following events

occurring sprinkler activation and

detection device activation

a non-interlock system requires only one

of either event to occur before water is

admitted into the system

a single interlock system is activated

only upon the event of detection device

activation

however in a double interlock system the

two separate events must happen before

water is admitted into the system

sprinkler activation and detection

device activation

deluge systems

are similar to pre-action systems in

that they use another type of detection

for operation however the biggest

difference is that deluge systems use

open sprinklers or nozzles

instead of getting water flow from

individual heads that have operated once

water fills the system water will flow

from every sprinkler head

much like a pre-action system a deluge

valve will keep water from filling the

system until the operation of another

type of detection system such as smoke

detection

once the detection system is activated

water not only fills the system but

flows from the open sprinklers or

nozzles

an important consideration in the

selection of the type of sprinkler

system is the level of hazard being

protected if protecting an area of very

high hazard such as aircraft hangers a

deluge system may be the most suitable

automatic sprinkler system design

the layout of fire sprinkler systems is

usually one of the following

tree sprinkler system it is the normal

design system and it consists of main

pipeline with branches on both left side

and right side

grid sprinkler system a sprinkler system

in which parallel cross mains are

connected by multiple branch lines

looped sprinkler system a sprinkler

system in which multiple cross mains are

tied together so as to provide two paths

for water to flow to an operating

sprinkler and branch lines are not tied

together

the maximum area of coverage per

sprinkler head depends on hazard

classification and sprinkler mounting

orientation that is sidewall or overhead

sprinkler head spacing the table below

shows sprinkler spacing requirements

based on nfpa 13 for example in a light

hazard office area the maximum coverage

area per sprinkler head is 200 square

feet and the maximum design spacing

between sprinklers is 15 feet the

maximum distance of sprinkler head from

wall is half of the maximum distance

between sprinkler heads minimum distance

between sprinklers is typically six feet

let us take an example an office area of

ninety by sixty feet

assume we want to design a tree

sprinkler system let us go ahead and lay

out the piping system and sprinkler

heads being a light hazard the maximum

spacing between sprinklers is 15 feet

the distance between sprinklers and

walls is no more than half than the

distance between sprinklers

the water demand for firefighting

sprinkler systems shall be determined by

either the pipe schedule method or the

hydraulic calculation method

according to nfpa 13 pipe schedule

system is defined as sprinkler system in

which the pipe sizing is selected from a

schedule that is determined by the

occupancy classification and in which a

given number of sprinklers are allowed

to be supplied from specific sizes of

pipe since our space is considered light

hazard and having no more than two

sprinkler heads on each branch then the

size of all branches is one inch

for the main line always start from the

end this portion is feeding four

sprinkler heads then its size should be

one and half inches

this portion is feeding eight sprinkler

heads then its size should be two inches

and all the rest are two and a half

inches because the number of sprinkler

heads is more than ten and less than

thirty

what is the minimum water supply

requirements for pipe schedule systems

the table below summarizes the minimum

water flow rate residual pressure and

duration of pipe schedule systems

therefore 500 gpm multiplied by 30

minutes means a minimum of fifteen

thousand gallons water tank shall be

constructed

a breakout of a floor control riser

assembly the following is a full

arrangement for a combination standpipe

sprinkler riser where high pressures

necessitate a pressure reducing valve at

each level while every element in this

specific arrangement is certainly not a

necessity on every project here's some

considerations that go into the

requirements and considerations for a

layout like this auxiliary drain valve

permits faster draining of system as

opposed to only draining inspectors test

valve

check valve can help reduce false water

flow alarms on floor where sprinklers

have not activated drain pipe size three

quarter inch for two inch system pipe

one and quarter inch for two and half to

three in half system pipe or two inch

for four inch system pipe drain valve

minimum size three quarter inch for five

to fifty gallon system one inch for

above 50 gallon system drain riser

discharge must be to outside or drain

capable of handling the flow size must

be at least one pipe size larger than

the largest drain connection tying into

it

inspectors test must be accessible and

must discharge outside or to a drain

capable of handling flow must be

downstream of water flow alarm pressure

gauge required at each floor control

valve pressure reducing valve provided

to reduce the system pressure such that

the working pressure will not exceed a

standard 175 psi listed pressure of the

sprinklers piping and fittings prvs can

also be used to limit the system

pressure to higher amounts when

pressures are allowed to exceed 175 psi

control valve for entire riser is

required to permit isolating a riser

without interrupting other systems

size of minimum 4 inch unless

hydraulically calculated to permit

smaller size

sight glass enables easy verification of

water flow for inspectors test floor

control valve

must be accessible electrically

supervised or locked signage must be

provided and shall be tested annually

water flow switch is used in wet

sprinkler systems to detect the flow of

water and to send an alarm signal

[Music]