System Sensor A05-1003-002 manuale d’uso

APPLICA TIONS GUIDE System Smoke Detectors[...]

1 Foreword Studies hav e shown that in the United States the use of early w arning fire and smok e detection sy stems has resulted in a significant r eduction ov erall in fire deaths . The sooner a fire is detected, the better the chances ar e for survival. A potential problem with smok e detectors is un wanted alarms that often r esult in people b[...]

NFP A Codes and Standards NFP A publishes standards for the proper application, instal- lation, and maintenance of automatic smoke detector s. The principal codes and standards that should be r evie wed before specifying or installing automatic smok e detectors are listed belo w: National Fire Pr otection Association (NFP A) Batterymarch P ark, Qui[...]

Manufacturer’ s Publications The manufacturer of the smok e detectors being used should be contacted for any published information on their products . SYSTEM SENSOR 3 Industry Publications NEMA Guide for Proper Use of Smok e Detectors in Duct Applications NEMA T raining Manual on Fire Alarm Sy stems NEMA Guide to Code R equirements for Fir e Prot[...]

APPLICA TIONS GUIDE: SYSTEM SMOKE DETECTORS 4 Photoelectric Smoke Detector Operation Smoke pr oduced by a fir e affects the intensity of a light beam passing through air . The smoke can block or obscure the beam. It can also cause the light to scatter due to reflec- tion off the smoke particles . Photoelectric smoke detector s are designed to sense[...]

Wiring Supervision The initiating circuits that con- nect smoke detector s to a con- trol panel should be super- vised so that a fault (trouble) condition that could interfer e with the proper oper ation of the circuit will be detected and annunciated. Smoke detector s are gener ally categorized as either 2-wire or 4-wire detector s. T w o-wire det[...]

APPLICA TIONS GUIDE: SYSTEM SMOKE DETECTORS 6 Class A Circuits Class A circuits also differ entiate between short cir cuits across the loop and opens on the loop. Supervision is accomplished by monitoring the le vel of curr ent passing through the installation wiring and the end-of-line r esistor , which in a Class A circuit is an integr al part of[...]

SYSTEM SENSOR 7 A manufacturer’ s installation wiring dra wing routes wir es and show s connections in a certain manner to accommo- date supervision requir ements. An y variance fr om the manufacturer’ s dra wings might cause a portion of a circuit to be unsupervised and, if an open or short circuit fault occurred, it could pr ev ent the circui[...]

After all detectors ha ve been installed, test the complete sy stem to ensure that no wiring faults exist, and that all parts of the sy stem operate as intended. A complete sy stem checkout consists of testing each detector at its installed location and following the panel manufactur er’s instruc- tions for sy stem checkout. Also, r efer to NFP A[...]

SYSTEM SENSOR be mounted on the wall. W all-mounted detectors should be located not less than 4 inches nor more than 12 inches from the ceiling to the top of the detector , and at least 4 inches (1 0 cm) from any corner w all junction. (See Figure 18.) When air supply and/or air return ducts ar e present in a r oom or space , the detector(s) should[...]

APPLICA TIONS GUIDE: SYSTEM SMOKE DETECTORS Special Application Detectors The guidelines in this document generally apply to stan- dard open-ar ea smoke detector s. S ystem Sensor has a num- ber of advanced technology detector s that are optimized for specific environments and should be consider ed. Pinnacle ™ Laser technology smoke detector is d[...]

SYSTEM SENSOR In other wor ds, if a diagonal thr ough the center of the room is no greater than the diameter of the cir cle , or 42.4 feet (12.8 meters), one detector can be used under ideal condi- tions. Figur e 2 1 shows how a length of hallw ay can be pr o- tected by only tw o detectors under ideal conditions . Special Spacing Problems The ideal[...]

APPLICA TIONS GUIDE: SYSTEM SMOKE DETECTORS 12 • Alternate Detector Mounting. Mounting alternate detectors up to 3 feet (1 m) belo w the ceiling can increase detection of small or smoldering fir es when the possibility of air stratification e xists. Figur e 23 illustrates such an installation. Specific designs for such an alternate detection shou[...]

SYSTEM SENSOR 13 Smoke detector s are designed to be as maintenance free as possible . How ev er , dust, dirt, and other foreign matter can accumulate inside a detector’s sensing elements and change its sensitivity . They can become either more sensitiv e , which may cause un wanted alarms, or less sensitiv e , which could reduce the amount of w [...]

14 APPLICA TIONS GUIDE: SYSTEM SMOKE DETECTORS What to Do About Unwanted Alarms No detection sy stem is imper- vious to unw anted alarms. Statistically , as the system size and the total number of detectors incr eases, the total number of nuisance alarms per year tends to incr ease . Historical experience in a giv en installation or data on similar[...]

SYSTEM SENSOR 15 NFP A standards requir e and smoke detector manufactur ers r ecommend that all detector s be visually inspected twice a year . Clean the detectors at least once a y ear , or more frequent- ly if environmental conditions w arrant it. See the section on Detector T esting and Maintenance in this guide for more details. In cases where [...]

APPLICA TIONS GUIDE: SYSTEM SMOKE DETECTORS 16 If assistance must be sought from the installer or man- ufacturer , there will be an indication of the tests that hav e already been done b y the owner’ s personnel. These services can be pro vided by qualified outside organizations . The installers of smok e detector equipped alarm sy stems are r es[...]

SYSTEM SENSOR Addressable System Smoke Detector Sy stem smoke detector s, which, in addition to pro viding alarm and trouble indica- tions to a control unit, ar e capable of communicating a unique identification (address). Air Sampling-type Detector A sampling-type detector consists of piping or tubing distri- bution from the detector unit to the a[...]

APPLICA TIONS GUIDE: SYSTEM SMOKE DETECTORS 18 product e valuation, that maintains periodic inspection of listed equipment or materials and whose listing states either that the equipment or material meets appropriate standards or has been tested and found suitable for use in a specified manner . Note: The means for identifying listed equipment may [...]

SYSTEM SENSOR 19 Customer Name: Installation Date: Installing Contractor: Inspection and T est Date: Inspection and T est Performed By: Check one Location Action T aken By Date T ime Recorded By Fire T rouble (Bldg, Zone, Det #) Probable Cause Action T aken Name and Date Appendix 2 Fire Alarm Log[...]

©2002 System Sensor . The company reserves the right to change specifications at any time. A05-1003-002[...]