Why Do We Inspect Fire Alarm Systems?
People depend on fire alarm systems to keep vigilant. When the system fails, the only way to find out that it failed is to either regularly inspect it, or wait for a fire to find out the system failed. Regularly inspecting the fire alarm system is better than waiting for a fire.
The question isn't whether the system works, the question is whether the system detects fire and let people know about the fire.
By Douglas Krantz
A long time ago, before regular testing of fire alarm systems was required, the NFPA and other fire protection professionals discovered that large numbers of fire alarm systems just weren't working... at all.
Originally, when they were installed, these systems worked properly. Over time, though, slow deterioration of the originally working system would cause a small portion of a system not to function. More time expired and another portion of the system wouldn't function. Eventually, given enough time, the whole system wouldn't work.
At that point, the building owner would think everything was working, when in reality, nothing was working.
The regulators decided that the systems had to be tested on a regular basis by someone who knew fire alarm systems, and any deficiencies that were found had to be repaired.
- To make sure they can actually detect smoke AND notify the occupants of the building, the smoke detectors had to be tested
- To make sure they can actually detect heat AND notify the occupants of the building, the heat detectors had to be tested
- To make sure they can be actually pulled AND notify the occupants of the building, the manual pull stations had to be tested
- To make sure they can actually detect water is flowing AND notify the occupants of the building, the waterflow switches had to be tested
- To make sure they can actually sound off AND notify the occupants of the building, the fire horns and Strobes had to be tested
Basically, the testing is to make sure the devices detect fire and notify the occupants of the fire.
Shortcuts in Testing
Sometimes, the temptation is to take shortcuts because economically, full testing doesn't seem practical. But shortcuts don't always show that the devices actually work.
- Activating with a magnet doesn't show if the smoke detector or heat detector will detect smoke or heat
- Using a key to open a pull station doesn't show if someone can actually pull it
- Opening a flow switch and pushing the lever doesn't show if the paddle inside the waterpipe isn't broken or isn't sticking
- Using the internal microphones inside horns and speakers or photo detectors inside strobes doesn't show that the horn or strobe isn't blocked, taped up, or otherwise prevented from notifying anyone
Bottom Line Testing
To test to see if something works, use the real thing.
- To test a smoke detector, use smoke (whatever is recommended by the manufacturer)
- To test a heat detector, if it doesn't destroy the heat detector, use heat
- To test a manual pull station, use the hand to pull it
- To test a waterflow switch, flow water
- To test each notification device, go around and listen and look
Testing the detection devices with what the devices detect, and testing the notification devices with eyes and ears (that's what the occupants of the building are going to use) is the only true way of seeing if the devices actually work.
Magnets, Keys, Levers, Photocells, Microphones
Yes, magnets are easier to use for checking smoke and heat detectors. Yes, opening up the pull station first with the key and activating it while it's open saves time in testing. Yes, pushing the lever on the flow switch allows testing without making a mess with water. Yes, using microphones inside the sounders and photocells inside the strobes to check the notification appliances make it so someone doesn't have to go everywhere in a building.
But while all of these methods save time, none of these methods show if the devices really detect and notify.
To keep the system working so it doesn't deteriorate over time, the complete system - all the detection devices, one by one, and all the horns and strobes, one by one - need to be regularly tested.
Only with full testing can the problems be found and fixed.
Based on his electronics training, and his understanding of Life Safety, Douglas Krantz has compiled his knowledge of Conventional Fire Alarm Systems into the book Make It Work - Conventional Fire Alarms
. The book covers the basics of the Conventional Fire Alarm System, and shows how Life Safety and internal supervision affects the fire alarm system.
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