Depending on where you live and your insurance requirements,
residential smoke detectors and in some cases sprinkler systems, are rapidly
becoming a requirement in all new construction. Aside from the regulations, it
is important to remember that smoke alarms do save lives. For that reason, you
should consider carefully the technology behind the various detectors out there
and how best to install them in your home.
The starting point is to understand fire and how it works.
There are four basic stages to a fire, understanding how a fire progresses and
how you can protect yourself in each stage is critical in designing an effective
fire detection system.
I - During the first, incipient stage,
which may last for seconds to days, there is no noticeable smoke, heat or flame.
During this stage, flammable gasses, or “products of combustion” are emitted
II - Next, is the smoldering stage, during
which there still is no substantial flame or heat, but the combustion increases
enough to create visible smoke.
III - The flame stage usually involves
less smoke, but flames break out generating substantial heat.
IV - The fourth stage of a fire is often referred to as the high
heat stage. At this point, the fire has spread rapidly throughout the
home, producing extensive flames, extreme heat and many toxic gases.
The next important factor in effectively detecting the threat
of fire is to look at the various types of smoke detectors on the market. Smoke
detectors are abundant and are found in almost every hardware and grocery store
in town. As with anything that costs money, not all smoke detectors are created
equal. From the basic technologies involved to the testing procedures, it is
important to know what you are buying. U.L.C. (Underwriters Laboratories of
Canada) does test and rates fire devices, however you should still examine the
technologies as well as how their limitations may apply to the area in which
they are installed.
There are two basic types of smoke detectors available today.
Yes, at the end of the day, both detect fires but the differences lie in
reliability and detection technology.
I – Ionization detectors are the most common and
often least expensive detectors available. This detectors' smoke chamber
contains a radioactive source that emits radiation, resulting in a weak flow of
electric current. When particles such as those produced by fire enter the smoke
chamber, they reduce the current and trigger the alarm. This type of detector is
generally most effective in detecting the “products of combustion” produced
during the incipient stage of a fire.
Although early detection is always desirable, there are several
inherent flaws with this technology. For example, some ionization detectors are
not as effective in detecting the smoke produced during the smoldering stage.
Another downfall is their general susceptibility to false alarms that have a
tendency to become more than a minor nuisance, once the fire department is
II – Photoelectric detectors, although not
effective in detecting the invisible gases created during the incipient stage,
are generally more stable and reliable when it comes to false alarm immunity.
Further to that, good quality photoelectric detectors are far superior at
detecting visible smoke that may not contain the invisible gases required to set
off an ionization detector.
There are two types of detection methods within the
photoelectric realm; obscuration and light
scattering. Obscuration involves a the interruption of a beam of light
while light scattering utilizes the light diffusing properties of smoke to
redirect a beam of light to a light sensor. Both are effective, however the
obscuration type detector requires more smoke to activate than the light
Smoke detectors can be either battery operated, wired in or a
combination of the two. Traditionally, wired in detectors were powered by the
standard house wiring and installed by the electrician during construction;
however, there is a better option available. Many security alarm companies offer
low voltage smoke detectors that obtain their power directly from your security
panel. Not only does this simplify integration, the security systems' back up
battery will provide power to the detector, even in the event of a power failure
or electrical fire.
In addition to smoke detectors are Heat detectors, rather
simple in their design; these detectors utilize the heat produced during the
flame and high heat stages of a fire to physically activate a switch. The two
basic types of heat detectors on the market are “Fixed
temperature” and “Rate of Rise”.
Fixed temperature detectors utilize either thermostat technology or a
fusible link that will melt at a preset temperature. Rate of Rise detectors, on
the other hand, often use an air chamber with a small hole that allows a
measurable amount of air to escape during expansion. A rapid increase in
temperature will cause the pressure in the chamber to expand faster than the
small hole will release, resulting in the expansion of the air chamber and
activation of a switch. The most common heat detector utilizes both
technologies, however certain applications may not be suited for rate of rise
Sprinkler systems also utilize the principles of heat
detectors. Some sprinklers rely on a small glass tube that will break once a
certain temperature is reached - resulting in the activation of a mechanical
switch, while others rely on the fusible link technology.
Finally, there is the aspect of remote monitoring. It is great
to have a buzzer sound when your home is on fire, however, what about the times
you may be overcome with smoke or out of town. Who will notify the authorities?
Fortunately, most of the better quality detectors are able to connect to your
security system. Even a sprinkler system has the ability to connect a “flow
switch” to your existing security alarm. If you have any questions, or would
like to know about enabling fire protection on your security system, please feel
free to contact KeepSafe Systems at (604) 874-8772
The KeepSafe Systems service area includes but is not
limited to North Vancouver, West Vancouver, Richmond, Delta, Tsawassen, Ladner,
Surrey, Cloverdale, Abbotsford, Mission, Aldergrove, Maple Ridge, Haney, Port
Coquitlam, Coquitlam, Port Moody, Burnaby, New Westminster, Kamloops, Kelowna,
Courtney, Comox, Nanaimo, Lions Bay, Squamish and pretty much everywhere in