FIRE PREVENTION AND
PROTECTION FOR THE HOUSE OWNER |
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| Chapter
Seven: Sprinkler Systems |
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| General |
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As mentioned earlier, smoke detectors equipped
in every home will reduce the loss of life due to fire. But a detector can only give a
warning so that occupants can evacuate and call the Fire Department. These warnings may be
short, because fires can develop rapidly and flashover may occur before evacuation can
take place. Delays are possible when persons are infirm, confused or perhaps inebriated.
The very young and the very old are especially vulnerable. It has been noted by the Office
of the Fire Commissioner of Canada that a quick-response residential sprinkler system,
when used in conjunction with smoke detectors, can contribute significantly in reducing
property and life losses. The testimonial given in Appendix C supports this finding.
Residential sprinkler systems are also recommended by The Wood Council of Canada and the
National Research Council of Canada. In fact, some Canadian municipalities are currently
considering making residential sprinkler systems ˙mandatory in single-family houses. |
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| Residential Sprinkler Systems |
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Sprinkler systems have long been used very
successfully in commercial buildings to control fires, minimize damage and save lives.
During the last few years there has been a significant breakthrough in sprinkler
technology, which now makes possible a degree of home fire safety much greater than
previously known and at a much lower cost. To make residential sprinklers systems
˙affordable, regulations now permit connection to domestic water ˙supplies. In addition,
the new sprinkler technology has provided extended coverage sprinkler heads (providing a
discharge that will not only cover a large area, but also provide wetting of the walls to
a greater height) and quicker-acting sprinkler heads specifically designed for residential
installations. Residential sprinkler systems are intended to suppress and contain the fire
in the room or area of origin, thereby preventing the spread of fire and affording
occupants, elsewhere in the building, additional time to react. Many supporters of the
home fire sprinkler system call it the "instant firefighter". |
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| Falacies and costs |
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A popular falacy is that a sprinkler could be
accidentally activated causing severe, unecessary water damage. However, records, which
have been compiled for well over 50 years, prove the likelihood of this occuring is very
remote. Furthermore, sprinklers have specific designs and rigorous tests to minimize such
accidents. It has been feared that water damage from a sprinkler system will be more
extensive than fire damage but, once activated, the sprinkler system will greatly limit
the fire's growth. Therefore, damage from a sprinkler system will be much less severe than
the fire and smoke damage if the fire had gone on unabated. Also, damage caused by water
from firefighting hoses can be far greater than water problems caused by sprinklers.
Regarding cost, current estimates suggest that, if installed during construction of the
house, a sprinkler system will cost about 1% of the total building price, and can often be
amortized with the mortgage. If installed after construction, this cost will just about
double. |
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| The wet-pipe
sprinkler system |
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The type of system most often used in
residential properties is the "wet-pipe sprinkler system". This employs
automatic sprinkler heads attached to a piping system containing water and connected to a
domestic residential water ˙supply. Water discharges immediately from sprinkler heads
opened by a fire. Only those sprinkler heads which have been operated by heat over the
fire will discharge water. They have a large area of coverage so that, under normal
circumstances, only one head is required in each room or hallway. Once a sprinkler has
been ˙activated, the passage of water through the pipes and over a flow-switch may
operate an alarm bell. |
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| Sprinkler heads |
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Quick-response residential sprinkler heads
contain a fusable link or heat-sensing element that allows water to be discharged when the
temperature at the head reaches about 71 degrees Centigrade (160 degrees Fahrenheit). The
water hits a deflector, resulting in a wide-area spray. They are usually low-profile, have
a flush-style design and are aesthetically pleasing. They are available in a pendant-style
for mounting on a ceiling (where the water is discharged in a hemispherical pattern below
the deflector) and a horizontal sidewall-style for mounting on a wall just beneath the
ceiling. Sprinkler heads must be ULC-approved. |
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| Control equipment |
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The sprinkler control equipment will usually
be located near the water mains entrance to the house. It will include a pressure guage,
an easily-operated shutoff valve, and may have a water-flow switch which can be connected
to an alarm located elsewhere in the house. |
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| Installation |
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The National Building Code of Canada states
that, where a water supply serves both a sprinkler system and a system serving other
equipment, control valves shall be provided so that either system can be shut off
independently. The sprinkler heads may be connected to each other and to the household
water supply by either copper or steel piping. The piping is concealed behind the walls
with the control equipment usually located in the basement or utility room. All
residential sprinkler systems should be installed professionally and in accordance with
NFPA Standard 13D and any applicable local codes. The installation has to be inspected
upon completion. |
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| Operation |
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During the early stages of a fire one or more
smoke detectors should operate to alert the occupants. When the temperature at any
sprinkler head reaches about 71 degrees Centigrade, the head releases the water. The water
hits a metal deflector plate causing a wide-area spray over the fire, which smothers the
flame. As soon as water begins to flow in the pipes a flow-switch may operate, sounding an
alarm bell. ˙Only the head activated by the extreme temperature releases water. No matter
what the conditions of the fire, the occupants should leave the building immediately and
call the Fire Department. When the fire fighters have determined that the fire is
extinguished they will either turn off the sprinkler valve ˙or ask the owner of the
building to do it. Once a sprinkler head has been activated, all the water must be drained
from the pipes and the head replaced. |
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| Maintenance |
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Once installed, residential sprinkler systems
require very little maintenance. The pressure guage should be checked regularly to
˙ensure that the water pressure is maintained in the system. However, as explained
earlier, once a sprinkler head has been activated, all the water must be drained from the
pipes and the head replaced. |
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Please read Disclaimer |
