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MODULE 2
Water-Based Suppression System Basics
Based on the Ohio Building Code (OBC)
National Fire Protection Association (NFPA) &
Ohio Fire Code (OFC)
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WATER-BASED SUPPRESSION SYSTEM BASICS-PART ONE
This module covers:
• Water supply sources
• Components of fire suppression such as piping, valves, sprinkler
heads, tests, foam system
• Different types of automatic sprinkler systems
• Standpipe systems
• Foam and water mist suppression system
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Water Supplies
• The typical water supply for a water-based suppression
system is a connection to a public waterworks system.
However, other sources of water supply are acceptable.
• Sources:
• NFPA 13: 23.2 Water supply types
• NFPA 13D: 6.2 Water supply sources
• NFPA 13R: 9.3 Water supply sources
• NFPA 20: 7.2 Water supplies
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Water Supplies: Sources
• A public waterworks system
• An elevated tank
• A pressure tank designed to American
Society of Mechanical Engineers
(ASME) standards for a pressure vessel
with a reliable pressure source
• A stored water source with an
automatically operated pump
• A well with a pump of sufficient
capacity and pressure to meet the
sprinkler system demand
Example of a water supply source:
An elevated tank
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Fire Department Connections
• NFPA states: The purpose of the Fire Department Connection is to
supplement the water supply, but not necessarily provide the entire
sprinkler system demand. Fire Department Connections are not intended to
deliver a specific volume of water.
• FDCs are required for most NFPA 13 and 13R automatic sprinkler systems
and standpipe systems
• NFPA 13 requires the fire department connection to be located on the street
side of buildings
• OBC 912.1 Installation. Fire
department connections shall be
installed in accordance with the
NFPA standard applicable to the
system design and shall comply with
Section 912.2 through 912.5
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Piping
• In a wet pipe-sprinkler system water is constantly maintained within the piping
• Dry pipe-sprinkler systems prevent the water from entering the sprinkler system
piping
Materials
• Above ground piping material examples found in NFPA 13: 6.3 - steel, copper,
and chlorinated polyvinyl chloride (CPVC).
• Below ground material examples found in NFPA 13: 10.1 - ductile iron, steel,
concrete, plastic, copper
Location
• NFPA 13: 10.6.1 Pipe shall not be run under buildings
• NFPA 13: 10.6.2 Where pipe must be run under buildings, special precautions
shall be taken.
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Valves
• A control valve controls the
water to the sprinkler system
and should be open at all
times
• A check valve has two-port
valves, one for fluid to enter
and the other for fluid to
leave.
• Pressure Requirements: NFPA
13: 6.7.1.1 When water
exceed 175 psi, valves shall
be used in accordance with
their pressure rating
Automatic Sprinkler Systems Handbook , Eighth Edition
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Backflow Preventers
•
A device with check valves, air inlets, and/or relief valves installed on water piping designed to
prevent the flow of water or other liquids, mixtures, or substances into the distributing pipes of a
potable supply of water from any source or sources other than its intended source
•
Means of backflow prevention
•
air gap
•
atmospheric vacuum breaker (AVB)
•
reduced pressure valve assembly (RP)
•
double check valve assembly (DC)
•
NFPA 13: 7.2.6.5.4 A check valve or other positive backflow prevention device shall be installed in
the air supply to each system to prevent airflow or water flow from one system to another.
•
NFPA 13: 10.10.2.5.1 The back flow prevention assembly shall be forward flow tested to ensure
proper operation.
•
NFPA 13: 10.10.2.5.2 The minimum flow rate shall be the system demand, including hose stream
demand where applicable
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NFPA 13: Automatic Sprinkler Systems Handbook, 2013 Edition
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SPRINKLER Definition
•
The component of a fire sprinkler system that discharges water after a fire has been detected
•
NFPA 13: 3.6.1 The following are characteristics of a sprinkler that define its ability to control or
extinguish a fire:
• Thermal sensitivity
• Temperature rating
• Specific orifice size
• Installation orientation
• Example: sidewall or pendent sprinklers
• Water distribution characteristics
• Special service conditions
• Example: Corrosion-Resistant or Decorative Sprinklers
Nozzle Definition
•
NFPA 13: 3.6.4.4 a device for use in applications requiring special water discharge patterns,
directional spray, or other unusual discharge characteristics.
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University of Toronto
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Initiating Devices
• A system component that originates transmission of a changeof-state condition
• Includes smoke detectors, water flow alarm, fixed temperature
detectors, rate of rise detectors, and heat detector
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Test connections
• Verify proper operation of equipment
• Example: NFPA 13: 8.17.4.1 Main drain test connections shall be
provided at locations that will permit flow tests of water supplies and
connections
• For inspection of sprinkler systems:
• Alarm test connections can be located anywhere downstream of the
main control valve on a wet pipe system per NFPA 13: 8.17.4.2.4
• Trip test connections must be located on the highest, most remote
branch line of a dry pipe system per NFPA 13: 8.17.4.3.2
• NFPA 13: 26.1 A sprinkler system installed in accordance with this
standard shall be properly inspected, tested, and maintained in
accordance with NFPA 25.
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Alarm attachments
• NFPA 13: 8.17 System Attachments
• NFPA 13: A.8.17.1 Central station, auxiliary, remote station, or propriety
protective signaling systems are a highly desirable supplement to local
alarms, especially from a safety to life standpoint.
• NFPA 13: 8.17.1.1 Local Waterflow Alarms. A local waterflow alarm shall
be provided on every sprinkler system having more than 20 sprinklers.
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Automatic Sprinkler Systems: Wet Pipe
• Definition NFPA 13: 3.4.10 Employs
automatic sprinklers attached to a
piping system containing water and
connected to a water supply
• NFPA 13: 7.7.1.3.2 Must be maintained
at or above 40 °F (4 °C).
• The water discharges immediately from
sprinklers opened by heat from a fire
Fire Systems, Inc
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Automatic Sprinkler System: Dry-Pipe
• Definition per NFPA 13: 3.4.5
Employs automatic sprinklers that
are attached to a piping stream
containing air or nitrogen under
pressure
• Are used when there is danger of
some or all of the piping freezing.
• The release of pressure permits the
water pressure to open a dry pipe
valve, and the water then flows
into the piping system and out the
opened sprinklers
Fire Systems, Inc
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Automatic Sprinkler System: Deluge
• Definition per NFPA 13: 3.4.4 Employs
open sprinklers that are attached to a
piping system that is connected to a
water supply through a valve
• Valve is opened by the operation of a
detection system installed in the same
area
• When valve opens, water flows into
the piping system and discharges from
all sprinklers
Fire Systems, Inc
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Automatic Sprinkler System: Pre-Action
• Definition per NFPA 13: 3.4.9 A system that employs
automatic sprinklers that are attached to a piping system that
contains air (under or not under pressure)
• Has a supplemental detection system installed in the same
area as the sprinklers
• Per NFPA 13: 7.3.2.1 Three basic types: single interlock, noninterlock, and double inter-lock
• typically used in areas containing high value equipment or
contents and spaces which are highly sensitive to the effects
of accidental sprinkler water discharge.
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Automatic Sprinkler System: Other
• Anti-freeze
• Circulating Closed Loop
• Combined Dry Pipe-Preaction
• Gridded
• Looped
• Multi-Cycle
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Standpipe Systems and Classes: Automatic
•
A standpipe system that is attached to a water supply capable of supplying the system demand
and that requires no action other than opening a hose valve to provide water at hose
connections.
•
Standpipe systems are classified by their usage: Class I for heavy stream applications, Class II as
first aid fire appliances, and Class III which has the features of both Class I and Class II
•
Wet: contains water at all times that is attached to a water supply capable of supplying the
system demand at all times and that requires no action other than opening a hose valve to
provide water at hose connections.
•
Dry: permanently attached to a water supply capable of supplying the system demand at all
times, containing air or nitrogen under pressure, the release of which (as from opening a hose
valve) opens a dry pipe valve to allow water to flow into the piping system and out of the opened
hose valve.
•
Semi-automatic Dry: permanently attached to a water supply that is capable of supplying the
system demand at all times arranged through the use of a device such as a deluge valve and that
requires activation of a remote control device to provide water at hose connections.
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Standpipe Systems and Classes: Manual
• Standpipe systems are classified by their usage: Class I for heavy
stream applications, Class II as first aid fire appliances, and Class
III which has the features of both Class I and Class II
• Wet: contains water at all times that relies exclusively on the
fire department connection to supply the system demand.
• Dry: has no permanently attached water supply that relies
exclusively on the fire department connection to supply the
system demand.
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Foam Proportioning Systems
• NFPA 11: 3.3.23 Proportioning. The continuous introduction of foam
concentrate at the recommended ratio into the water stream to form foam
solution.
• Foam concentrate shall be introduced into the water flow by a concentrate
controller utilizing balanced-pressure injection.
• Types of Foam Proportioning System (NFPA 11: 3.3.23)
• Balance Pressure Pump-Type Proportioning
• In-Line Balanced Pressure Proportioning
• Direct Injection Variable Pump Output Proportioning
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Foam Concentrate
• NPFA 11.3.3.12 Foam Concentrate. A concentrated liquid
foaming agent as received from the manufacturer.
• Types of Foam Concentrate (NFPA 11: 3.3.12)
• Alcohol-Resistant Foam Concentrate
• Aqueous Film-Forming Foam Concentrate (AFFF)
• Fluoroprotein Foam Concentrate
• Film-Forming Fluoroprotein Foam Concentrate (FFFP)
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Foam Generators
• Foam Generator Types (NFPA 11: 3.3.14)
• Aspirator Type
Jet streams of foam solutions aspirate sufficient amounts of air
that is then entrained on the screens to produce foam
• Blower Type
Foam solution is discharged as a spray onto screens through
which an airstream developed by a fan or blower is passing
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NFPA 11 Standard for Low-, Medium-, and High-Expansion Foam 2005 Edition
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Foam-Water Suppression Systems
• Foam-water sprinkler system or foam-water spray systems are outlined in
NFPA 16.
• Foam-water sprinkler:
• A special system that is pipe-connected to a source of foam concentrate
and to a water supply. The system is equipped with appropriate discharge
devices for extinguishing agent discharge and for distribution over the area
to be protected.
• Foam-water spray:
• A special system that is pipe-connected to a source of foam concentrate
and to a water supply. The system is equipped with foam-water spray
nozzles for extinguishing agent discharge (foam followed by water or in
reverse order) and for distribution over the area to be protected.
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Foam-Water Suppression Systems
• (NFPA 11: 5.1) Low-expansion foam to protect outdoor storage
tanks, interior flammable liquid hazards, loading racks, diked
areas, and non diked spill areas
• (NFPA 11: 6.3) Medium and high-expansion foam shall be
permuted to protect: (1) ordinary combustibles, (2) flammable
and combustible liquids, combinations of (1) and (2), and
liquefied natural gas (high-expansion only)
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http://www.moody.af.mil/news/story.asp?id=123132709
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Foam-Water Suppression Systems: Dry
• Employs automatic sprinklers or nozzles that are attached to a
piping system that contains air or nitrogen under pressure
• The release of the pipe permits the water pressure to open a valve
known as a dry pipe valve.
• The water then flows into the piping system and out the opened
sprinklers.
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In Control Fire Protection
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Foam-Water Suppression Systems: Preaction
• Employs automatic sprinklers or nozzles attached to a piping
system containing air that might or might not be under pressure,
with a supplemental detection system installed in the same area
as the sprinklers.
• Actuation of the detection system opens a valve that permits
water to flow into the sprinkler piping system and to be
discharged from any sprinklers that have activated.
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In Control Fire Protection
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Foam-Water Suppression Systems: Deluge
• Employs open discharge devices, which are attached to a piping
system that is connected to a water supply through a valve that is
opened by the operation of a detection system, which is installed
in the same areas as the discharge devices.
• When the valve opens, water flows into the piping system and
discharges from all discharge devices attached thereto
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In Control Fire Protection
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Water Mist Suppression Systems
• A distribution system connected to
a water supply or water and
atomizing media supplies
• Is equipped with one or more
nozzles capable of delivering water
mist intended to control, suppress,
or extinguish fires
• NFPA 750 is the appropriate
standard for the installation of
water mist systems
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Lessons Learned from Module 2
• There are many types of water supplies for water-based
suppression systems, such as elevated tanks and water
transported from a lake or spring.
• A wet pipe automatic sprinkler system should not be installed in
an area that goes below freezing and must be maintained at or
about 40 degrees Fahrenheit.
• Foam concentrate is a foam fire-fighting agent that must be
diluted with water
• There are two types of foam generators, blower and aspirator.
• It is important to be familiar with the OBC, NFPA, OFC, and OPC.
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