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Fire Sprinkler Systems Monitoring
A P P L I C A T I O N S G U I D E
Fire Sprinkler
Systems Monitoring 1
Preface
Before the first automatic sprinkler system was developed in the 1870s, a sprinkler system consisted of a perforated pipe, a valve, a person to open the
valve, and an elevated barrel or tank filled with water. A more dependable system was created in response to increased fire loads and increased values of
buildings and their contents. A more advanced sprinkler system became possible as technology became more sophisticated.
Sprinkler systems automatically detect and then control, suppress, or extinguish fires. Water supplies can come from city water mains, dedicated storage
tanks or ponds. Valves and alarm devices control and monitor the waters flow. Distribution pipes send water to the sprinkler heads using a municipal
water source to maintain and increase water pressure according to design criteria. Modern systems can detect a fire condition and discharge water quickly,
before a fire grows to a fatal or catastrophic size, reducing fire deaths by nearly 100 percent. Understanding your fire sprinkler system can be life saving.
After reading this guide, you will be more knowledgeable about the water flow detectors, supervisory switches, pressure switches, explosion proof prod-
ucts, and alarm bells within a fire sprinkler system.
This guide provides information for the proper application, installation and maintenance of System Sensor sprinkler and notification products. Installation
must comply with all code requirements such as NFPA and comply with directives from Authorities Having Jurisdiction (AHJ). AHJ directives always take
precedence over other codes and have final authority.
System Sensor was founded in 1984, and has become the largest manufacturer of fire detection and notification appliances in the world. More than 1,900
System Sensor associates collaborate to build quality products for conventional detection; intelligent detection; audible and visible (AV) notification; heat-
ing, ventilation, air conditioning (HVAC) monitoring; and sprinkler systems monitoring. High production standards and strong customer engagement
contribute to the solid demand for System Sensor products.
Every day we aim to develop advanced ideas that deliver advanced solutions.
A P P L I C A T I O N S G U I D E
Fire Sprinkler
Systems Monitoring
Contents
Preface
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Fire Sprinkler Systems
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Wet Pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Dry Pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Deluge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Pre-action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Standards
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
NFPA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Building and Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Testing Laboratories

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Fire Sprinkler Systems Monitoring
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Vane Type Water Flow Detectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Product Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Testing, Maintenance and Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Supervisory Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Principles of Operation/Product Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Maintenance and Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Pressure Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Principles of Operation/Product Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Maintenance and Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Explosion Proof Detectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Product Placement/Maintenance and Service . . . . . . . . . . . . . . . . . . . . . . . . .10
Alarm Bells and Horn/Strobes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Testing and Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Glossary
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 A P P L I C A T I O N S G U I D E : F I R E S P R I N K L E R S Y S T E M S M O N I T O R I N G
Section 1
Fire Sprinkler
Systems
There are four types of fire
sprinkler systems: wet pipe, dry
pipe, deluge, and pre-action.
These choices allow sprinkler
systems to provide an array of
of hazard and environmental protection, customized to each
individual situation.
Wet Pipe Sprinkler Systems
Wet pipe sprinkler systems are the most common systems.
They have the fewest number of components and require less
installation time than other systems. A wet pipe sprinkler
system has a series of piping systems connected to regularly
distributed sprinkler heads, fed by a main riser. Maintenance
is minimal, so financial savings are also realized.
Wet pipe sprinkler systems cannot be installed in an area
where distribution pipes are exposed to freezing tempera-
tures, such as parking garages, because they always contain
water.
The operation of a wet pipe sprinkler system depends on
the heat reactive sprinkler heads. When a fire starts, its heat
causes a fusible glass bulb or metallic heat sensor within the
sprinkler head to shatter or melt and separate. Either action
causes water to discharge from the distribution piping, strik-
ing the deflector on the open sprinkler head and spraying
water onto the fire in an engineered pattern or throw.

Wet pipe systems are fixed temperature installations, meaning
each sprinkler head is activated only if exposed to a predeter-
mined temperature as low as 155F or as high as 286F.
There are three types of wet pipe sprinkler systems: wet pipe
sprinkler system with an alarm check valve, wet pipe sprin-
kler system with maintained excess pressure, or wet pipe
sprinkler system with a straight pipe riser.
Wet Pipe Sprinkler System with an Alarm Check Valve
When water enters the fire sprinkler system piping, it
becomes non-potable and unsuitable for drinking. To keep
the non-potable water from leaking back into the city water
supply, an alarm check valve can be installed. The alarm
check valve is a small device consisting of a spring, valve
clapper and alarm port.
The spring holds the valve clapper closed, so that water will
flow only in one direction. Water will not flow out of the
sprinkler head until a predetermined temperature causes
the individual sprinkler head to activate. When a sprin-
kler head is activated, the clapper opens allowing water to
flow through the valve to feed the system. As the alarm port
becomes exposed to water pressure, it causes a water motor
gong, mechanical bell, or A/V device to sound. A water flow
switch or detector connected to an