How do I Connect a Tamper Switch?
-- When connecting sprinkler tamper switches or sprinkler waterflow switches, I have found that the best way to make sure the system is going to work correctly is to not use the labels on the switch inside the tamer switch assembly. Half of the time those labels are wrong. Those labels are for any system, sort of, and not just for fire alarm systems. Instead, use the Ohmmeter to figure out which screw terminals to use...Read More
What Voltage Should Be at the EOL of a NAC?
-- The goal, when measuring the voltage on the Notification Appliance Circuit -NAC-, is to make sure that there is enough voltage to turn on all the horns and strobes when there is a fire. The power may be off to the building during a power blackout, but the voltage still has to be there for the horns and strobes to warn people of fire...Read More
What is Causing a Network Fault?
-- A Network Fault is a problem (Trouble) with the fire alarm system. The fault has to be fixed before it can be cleared from the panel. To clear the trouble from the display, there's also a trouble memory that requires the troubles to be acknowledged and cleared after fixing the trouble...Read More
How is the Sensitivity of a Smoke Detector Determined?
-- To determine how much smoke it takes to set a smoke detector into alarm, sensitivity testing uses a calibrated, portable cloud chamber. It uses a photo-reader, kind of like the smoke sensing chamber inside a photo smoke detector, to sense the amount of smoke in the cloud chamber. The cloud chamber, or testing tool, completely encloses the smoke detector and starts out with clean air. For the measurement, artificial calibrated smoke is slowly introduced into the chamber...Read More
How do I Fix an Open Fault?
-- The fire alarm system is supposed to consist of the wiring in the building, all of the input devices -smoke detectors, pull stations, waterflow switches, etc.- and all of the output devices -fire horns and strobes, etc.- Between all of the input zones and output zones is a control panel. There should be an end-of-line resistor at the end of each loop -the pair of wires connected to a zone and connected to all of the devices on the zone-...Read More
What does Open Zone Alert Mean?
-- An Open Zone Alert on a fire alarm panel shows that the wire is not continuous. The fire alarm system, being a life safety system, is always checking the wires to make sure the devices like smoke detectors or pull stations are connected at all times...Read More
Is This an Addressable 4 Wire Speaker/Strobe?
-- A speaker and a strobe are always separate devices. Many times, as with the speaker/strobe that you show, the speaker and the strobe my be in the same box, but they are still separate devices, they aren't connected together inside. In this case, this is not an addressable device. On the back of the speaker / strobe, there are 4 terminals: 2 of the terminals are for the speaker and two of the terminals are for the strobe. In other words, the terminals aren't for a single 4 wire addressable circuit, but the terminals are for two completely separate 2 wire circuits: 2 of the wires are for powering the strobe and 2 of the wires are for powering the speaker...Read More
How do you Troubleshoot an Addressable System?
-- No matter what the panel says, or what a multimeter says, all faults are either an open or a short. Both causes could be in the building wide fire alarm system at once, and there may be more than one problem to contend with. Shorts could be inside a device, in the building wiring, or in the panel- opens could be inside a device, in the building wiring, or in the panel. A ground fault is a short, and ground faults require two shorts in order for a ground fault to affect the fire alarm system. At all times when troubleshooting, keep an open mind. Never assume that you know what the problem is until the problem is fixed...Read More
How do Pathways Affect Ground Faults?
-- Ground Faults are a big issue. Almost anytime there is a ground fault on a fire alarm system, the panel displays a trouble. Then, no matter what caused the trouble, the trouble has to be fixed. However, the NFPA has an exception to the rules regarding the displaying of ground fault troubles. For all types of pathways for signal or power in building wide fire alarm systems, the rule of thumb for displaying a ground fault trouble goes something like this, -Whenever there is a ground fault, the panel will display a trouble.- There is an exception to this rule ...Read More
Horns and Strobes for Handicap Apartments
-- Multifamily dwellings like apartments, condominiums, hotel rooms, etc., actually have two fire alarm systems: each individual residence's fire alarm system and the building's common fire alarm system. A fire alarm system, any fire alarm system, detects ... Read More
Why Do We Inspect Fire Alarm Systems?
-- 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 ... Read More
Troubleshooting Addressable Ins and Outs
-- A fire alarm system's main purpose is to detect fire and then tell people about the fire. A conventional fire alarm system does this detection-telling, and so does an addressable fire alarm system. Besides a better display on the addressable fire alarm system and the extension of the ... Read More
Quadruple Use of the Initiating Device Circuit (IDC)
-- In a fire alarm system, the Initiating Device Circuit (IDC) is an input circuit or detection circuit: it carries the alarms detected by devices like flow switches, pull stations, heat detectors, tamper switches, etc. A second use of the Initiating Device Circuit is to monitor itself, it supervises its own wires... Read More
I'm Having Trouble With a Door Release
-- While trying to trouble shoot why the door release for the front door is not working, one of the conductors grounded out against the fire alarm panel chases. This caused the door release to activate. Any thoughts? Read More
What Causes an Open NAC?
-- I am going to a job site where on the service call ticket states that a NAC is reading open circuit. What can cause an open circuit on the NAC line? Read More
How many T-Taps are Allowed on an SLC?
-- The answer to the question of how many T-Taps is allowed --- is It Depends. It depends on the manufacturer and it depends on how easy the installer wants to make the system for the technician... Read More
What is an As-Built Plan?
-- The owner of the building project is the beginning of the planning process and the end of the planning process. Conception Plans - How the building ... Read More
What is a Ground Fault?
-- With the exception of the ground fault circuitry inside the fire alarm control panel (FACP) itself, the wiring for fire alarm systems has... Read More
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