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NFPA 72 Questions and Answers with
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What does PFLA stand for? ✔✔Power Limited Fire Alarm.
What does NPFLA stand for? ✔✔Non-Power Limited Fire Alarm.
What material must NPFLA circuit conductors be made from? ✔✔Only solid or stranded copper is permitted.
What is a single station detector? ✔✔Battery powered smoke detectors that do not communicate off premises.
What is a multiple station detector? ✔✔Mains powered smoke detectors with battery backup that are linked together, so that if one unit initiates, alarms in all detectors will sound. They do not communicate off premises.
How frequently must household single and multiple station detectors be inspected and tested? ✔✔In accordance with the manufacturers recommendations, at least monthly.
How frequently must household fire alarm systems be inspected and tested? ✔✔At least every 3 years, by a qualified service technician.
How frequently must heat detectors be tested? ✔✔Two or more annually different detectors must be tested each year though and within 5 years all detectors must have been tested.
What does "restorable" mean? ✔✔The detector can be "restored" or "reused" after it has initiated an alarm.
What does "non-restorable" mean? ✔✔The detector cannot be "reused" after it has initiated an alarm. (Think of a heat detector, which self-destructs upon initiating.)
What size conductors are permitted? ✔✔Size 18 A.W.G and 16 A.W.G are permitted, provided they do not exceed certain rated ampacities.
What is used to protect transformers or other devices supplied from power-supply conductors? ✔✔An over-current device not rated over 20 Amperes.
It is capable of preventing fire from rising floor-to-floor.
What is General Purpose cable? What are it's characteristics? ✔✔Cable for general purpose fire alarm use. Not to be used where Plenum or Riser cable is required.
It is resistant to the spread of fire.
What "type" shall plenum cable be? What substitutions are allowed? ✔✔Power Limited Fire Alarm Plenum (FPLP) CMP can be substituted.
What "type" shall riser wire be? What substitutions are permitted? ✔✔Power Limited Fire Alarm Riser (FPLR) CMP, FPLP, CMR can be substituted.
What "type" shall general purpose wire be? What substitutions are permitted? ✔✔Power Limited Fire Alarm (FPL) CMP, FPLP, CMR, FPLR, CMG and CM can be substituted.
(All types)
What is the maximum voltage permitted through multi-conductor NPFLA cables? ✔✔150 Volts.
What is the voltage rating of PFLA cables? ✔✔Not less than 300 Volts.
Shall the voltage be marked on PLFA cables? ✔✔No, because they may be misinterpreted and used for electrical applications.
What is "Rate Compensation Detector"? ✔✔A device that responds when the temperature reaches a pre-determined level.
What is "Rate of Rise Detector"? ✔✔A device that responds when the temperature rises at a rate exceeding a pre-determined value.
What is "Smoke Detector"? ✔✔A device that detects both Visible and Invisible combustion particles.
Which sensor is best at detecting "invisible" smoke particles? ✔✔Ionization.
Which sensor is best at detecting thick "visible" smoke particles? ✔✔Photoelectric.
What is a Supervisory signal? ✔✔A signal that indicates the need for action in connection with the SUPERVISION of fire equipment.
What is a Trouble signal? ✔✔A signal that indicates a fault with the fire equipment. It must have an audible signal, distinctive from alarm signals.
Does an exterior horn for a sprinkler system need to be supervised? ✔✔Yes.
Does a Fire Hood system need to be supervised? ✔✔Yes.
What is "Cloud Chamber Detection"? ✔✔A detector that draws an air sample into a high- humidity, low pressure chamber. The conditions in the chamber cause the moisture in the air to condense on the smoke particles, forming a cloud. The density of this cloud is measured by a photoelectric principle, if it meets a certain criteria, an Alarm is generated.
What is "Ionization Detection"? ✔✔A detector that used a small amount of radioactive material to "Ionize" the air between two differently charged electrodes. When smoke is present between these electrodes, it causes the conductance of the air to decrease, and this causes the alarm to trip.
What is "Photoelectric Light-Scattering Smoke Detection"? ✔✔A detector that uses a light source and a photosensitive sensor, arranged so that light will only fall on the sensor when smoke particles are present. The particles reflect and retract light towards the sensor, tripping the alarm.
What is important about the Way trouble signals sound? ✔✔They must be distinctive from alarm signals
What three procedures must be in place before it is permitted to install a means to silence trouble/supervisory/alarm signals? ✔✔1. The means shall be key operated and contained within a locked enclosure.
- The means shall transfer its audible warning to a visual warning. (i.e. flashing lamp)
- The audible trouble signal shall sound when the system is set to this "silent" mode and no trouble or supervisory exist.
Fire/Supervisory signals shall be __________ in sound from other signals and shall not be used for any other purpose. ✔✔Distinctive.
What code shall all wiring, cable and equipment be in accordance with? ✔✔NFPA 70 and the National electrical code. Specifically articles 760, 770 and 800.
When more than one detector is used on a ceiling, what spacing measurement shall be used? ✔✔All points shall have a detector equal to 0.7 (70%) times the listed spacing.
Can a detector be installed during construction? ✔✔No, unless they are replaced after all construction is complete.
Why must a smoke detector not be placed above 25ft? ✔✔Because of the effects of stratification, smoke will often not rise above this point
As the mounting location of smokes and heats gets higher, the listed spacing must be reduced. True or False? ✔✔False. The higher a heat is positioned, the smaller the spacing. The higher a smoke is positioned, the wider the spacing.
Detectors and appliances shall be protected from damage by a mechanical guard as long as...? ✔✔It is listed for the purpose and does not interfere with the operation of the device.
What is a water flow device? ✔✔An attachment to the sprinkler system that can detect a predetermined rate of water flow, and is able to initiate the fire alarm.
When water flow occurs that is equal or greater than the flow of a single sprinkler, how quickly shall the alarm signal initiate? ✔✔Within 90 seconds.
Can detectors be installed within an air duct system? Can they be used as a substitute for open area protection? ✔✔Yes. And no.
Detectors shall be _________ for the purpose for which they are being used. ✔✔Listed (i.e. UL Listed)
Which signals must take priority over all other signals? ✔✔Fire. Even if a non fire signal is generated first.
All extinguishment systems with automatic detection equipment for activation shall also have...? ✔✔Means for manual activation. (pull station)
How many fire alarm boxes (pull stations) are required in systems employing automatic fire or water flow detectors? ✔✔At least one, located where required by the authority having jurisdiction
- The alarm verification feature is not used.
The number of water flow switches connected to a single initiating device circuit shall not exceed...? ✔✔5.
The number of supervisory devices connected to a single initiating device circuit shall not exceed...? ✔✔20.
Detectors and appliances can be mounted using wires behind them. True or False? ✔✔False. All detectors and appliances must be secured independently of their wiring.
Fire alarm pull boxes (pull station) shall be located where? ✔✔Throughout the protected area, in conspicuous locations. They must be within 5 feet of the exit doorway on each floor.
Partitions shall cause spaces to be considered separate rooms when they extend to within ___% of the ceiling height. ✔✔15%
Non fire alarm equipment is permitted to be integrated with the fire alarm system so long as...? ✔✔... any grounds or short circuits in this equipment do not cause interference with the fire alarm equipment.
What is the purpose of an end of line resistor? ✔✔To supervise the current flowing through appliance and detector circuits, so that grounds and faults can be detected.
What MUST be monitored for integrity? ✔✔The installation wiring between the fire alarm control unit and the relay or other appliance (Horn, Strobe, etc)
EACH elevator lobby, elevator hoist way and elevator machine room detector MUST be capable of what? ✔✔Initiating elevator recall when all other devices are in alarm condition
Must the fire alarm devices within the elevator hoist way be integrated with the fire alarm? ✔✔Yes.
Wall mounted appliances must be located between which two distances above a finished floor? ✔✔Not less than 80 inches and not greater than 96 inches above the finished floor.
In areas in which more than two visual notification appliances can be seen, they shall be _________. ✔✔Synchronized.
This is to avoid triggering epileptic seizures.
How should visible notification appliances be mounted when ceiling height exceeds 30 feet? ✔✔The appliances should be suspended at or below 30 feet. If this is not possible, wall mounted appliances must be used.
The installation of fire devices shall comply with which 9 rules? ✔✔1. Equipment shall not be located where ambient condition are outside of manufacturer's recommendations.
- Equipment shall not be located within spaces where temperatures fall below 40f and above 100f.
- Equipment shall not be located on any mounting surface that will become considerably warmer or cooler than the room.
- Equipment within a 20ft path of a cooking appliance must be of the photo-electric type or have a means of alarm silencing.
- Equipment shall not be installed within a 36in horizontal path of a bathroom containing a shower or tub.
- Equipment shall not be installed within a 36in horizontal path of the supply registers heating/cooling systems.
- Equipment shall not be installed within a 36in horizontal path from the tip of a ceiling fan blade.
- Smoke rising up a stairway must not be blocked by a door or obstruction.
- For stairways up from a basement, equipment shall he placed on the basement ceiling near to the entry to the stairs.
