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What does UL-Recognized Mean?
What are the mounting requirements for pull stations and horn/strobes as per ADA? What is the relationship between NFPA 72 and NFPA 101 (PDF) as they apply to fire alarm systems?
What does EIA mean?
What does UL-Recognized Mean?
It means that the component meets most, but not all of the requirements for UL listing as a fire alarm device for a particular function, but the listing has certain "Conditions of Acceptability" which must be met at the time of installation to be acceptable and conform to the listing standard. For example, a relay may be sold without an enclosure, but an enclosure is required to obtain a UL listing. The manufacturer of the relay may apply for the "Recognized" listing, based on the relay being installed in a UL listed enclosure (the condition of acceptability). The enclosure manufacturer would have to get the relay tested by UL to obtain a listing for the relay in the enclosure and publish documentation showing the proper installation/application of the relay.
Refer to The world of difference between UL 'Listed' and UL 'Recognized'.
What are the mounting requirements for pull stations and horn/strobes as per ADA?
NFPA 72 sets the guidelines for installation. Basically, the highest operable part of the pull station must be no more than 48 inches above the floor if only a forward reach is possible or no more than 54 inches if the clear floor space allows a parallel approach by a person in a wheelchair. A strobe must be 80 inches above the highest floor level, or 6 inches below the ceiling, whichever is lower.
What is the relationship between NFPA 72 and NFPA 101 as they apply to fire alarm systems?
NFPA 72 is an installation standard for fire alarm systems. It defines how a system is to be installed, how it is to function and how it is to be maintained.
NFPA 101, the Life Safety Code, has the function of defining when a fire alarm system is required in a building of a particular occupancy and what functions are necessary for that occupancy.
What does EIA mean?
The Electronics Industry Alliance (EIA) defines standards are used to define what protocol certain classes of circuits should follow. For instance, many Fire-Lite panels have a serial communication circuit for interfacing with a serial printer or personal computer. This circuit follows the conventions set forth in the EIA-232 standard (formerly the RS-232 standard). Some Fire-Lite annunciators follow the EIA-485 standard.
How to Troubleshoot Ground Faults
A ground fault detected on a fire panel means that there is another reference to ground coming into the system other than the system ground. This is usually caused by a wire making electrical contact with something it shouldn't (such as conduit).
The best way to troubleshoot a ground fault would be to remove all field wiring from the panel, along with any option modules, phone lines and batteries, leaving only AC connected to the panel. The ground fault detection on the panel is immediate, so any ground coming in from the bell circuits, zone wiring, annunciators, or communicators will disappear once the wiring is disconnected. That will allow you to track the circuit bringing in the ground fault. Then you can check that particular circuit to see where the fault is coming from. If everything is off the panel except AC, and the ground fault is still present, the panel is possibly damaged.
Ground faults are very often caused by pulling wiring through conduit during installation, which can strip off the insulation and cause the bare wire to come in contact with the grounded conduit.
Examples of what can cause a ground fault:
. Wire "grounding out" to conduit.
. Moisture or water in a back box
. Water in an underground conduit
. Ground on a phone line.
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