1、NEMA Standards PublicationNational Electrical Manufacturers Association1(0$6%4XDOLW,QIRUPDWLRQDO*XLGHIRU$XWRPDWLF)LUHHWHFWLRQDQG$ODUP6VWHPVQuality Informational Guide for Automatic Fire Detection and Alarm SystemsPrepared for the professional Authority Having Jurisdiction (AHJ)Quality Information Gu
2、ide Page i FO REWO R D This information is intended to provide guidance to the local Authority Having Jurisdiction (AHJ) for establishing programs to ensure highly reliable fire detection and alarm systems in his or her community. A recommended model ordinance is included in this document to assist
3、the AHJ in improving the reliability of existing systems. This information was prepared by the Signaling Section of the National Electrical Manufacturers Association (NEMA, www.nema.org) and the Automatic Fire Alarm Association (AFAA, www.afaa.org). Portions of this material are reprinted with permi
4、ssion from NFPA 72-2013, National Fire Alarm and Signaling Code, Copyright 2012, National Fire Protection Association, Quincy, MA. This reprinted material is not the complete and official position of the NFPA on the referenced subject, which is represented only by the standard in its entirety. Comme
5、nts on this information and suggestions for changes should be forwarded to: Signaling Section, c/o NEMA, 1300 N. 17th Street, Suite 900, Rosslyn, VA 22209 Current Edition April 2014 Quality Information Guide Page ii Table of Contents FOREWORD i TABLE OF CONTENTS ii INTRODUCTION 1 ELEVATING THE QUALI
6、TY OF OLDER INSTALLATIONS 1 WHAT CAUSES UNWANTED ALARMS? . 1 ELIMINATING UNWANTED ALARMS . 2 BEGINNING THE ELIMINATION PROCESS 6 LONG TERM QUALITY ASSURANCE 6 NRTL CERTIFICATION PROGRAMS. 10 TRAINING PROGRAMS 10 APPENDIX A REFERENCED PUBLICATIONS . 12 APPENDIX B MODE ORDINANCE . 13 Quality Informati
7、on Guide Page 1 INTRODUCTION AUTOMATIC FIRE DETECTION AND ALARM SYSTEMS, when intelligently combined with the other elements of an overall fire protection plan, can significantly reduce property damage, personal injuries, and loss of life from fire in buildings. To be effective, fire detection and a
8、larm systems must be: PROPERLY DESIGNED PROPERLY INSTALLED PROPERLY MAINTAINED PROPERLY ENFORCED This information is intended to provide guidance to the local AHJ for establishing programs to ensure highly reliable fire detection and alarm systems in his or her community. DEFINITIONS An unwanted ala
9、rm encompasses false, nuisance, malicious, unintentional, and unknown alarms. The following definitions are from NFPA 72-2013, National Fire Alarm and Signaling Code (NFPA 72). National fire Alarm and Signaling Code and NFPA 72 are registered trademarks of the National Fire Protection Association, Q
10、uincy, MA. 3.3.307 Unwanted Alarm. Any alarm that occurs that is not the result of a potentially hazardous condition. 3.3.307.1 Malicious Alarm. An unwanted activation of an alarm-initiating device caused by a person acting with malice. 3.3.307.2 Nuisance Alarm. An unwanted activation of a signaling
11、 system or an alarm-initiating device in response to a stimulus or condition that is not the result of a potentially hazardous condition. 3.3.307.3 Unintentional Alarm. An unwanted activation of an alarm-initiating device caused by a person acting without malice. (SIG-FUN) 3.3.307.4 Unknown Alarm. A
12、n unwanted activation of an alarm-initiating device or system output function where the cause has not been identified. 3.3.268 Smoke Alarm. A single- or multiple-station alarm responsive to smoke. (SIG-HOU) 3.3.66.20 Smoke Detector. A device that detects visible or invisible particles of combustion.
13、 (SIG-IDS) ELEVATING THE QUALITY OF OLDER INSTALLATIONS Unwanted alarms are disruptive to building occupants. Over time, they can cause building occupants to ignore all alarms. Failure to respond to actual alarms can have disastrous consequences. Unwanted alarms are costly to the fire services, sinc
14、e they consume valuable fire department resources. Unwanted alarms are demoralizing and potentially dangerous to firefighters and the public. If you have an unwanted alarm problem, it can be remedied only by qualified technical personnel! WHAT CAUSES UNWANTED ALARMS Most unwanted alarms are initiate
15、d by cooking sources, such as toasters, cooking and frying fumes, steam from boiling water, and airborne grease. Most of these unwanted alarms can be eliminated by moving the smoke detector to the proper distance from the cooking source, as described in the “Eliminating Unwanted Alarms” section of t
16、his guide. Examples of unwanted or unnecessary alarms: THE MISCHIEVOUS OPERATION OF A MANUAL FIRE ALARM BOX SMOKE DETECTOR ACTIVATION FROM COOKING ELECTRICAL DISTURBANCES, TRANSIENTS, AND LIGHTNING EQUIPMENT MALFUNCTIONS Quality Information Guide Page 2 Lack of smoke detector maintenance allows for
17、the accumulation of dust and dirt, which will make smoke detectors more sensitive. Cooking sources that would not normally activate a clean detector might be sufficient to cause a dirty detector to alarm. Electrical disturbances from storms and nearby lightning strikes can cause surges on the utilit
18、y companys power lines that can affect older fire alarm panel and smoke detector operation. Another source of unwanted alarms can be mischief or vandalism by misguided individuals who falsely operate manual fire alarm boxes for amusement. ELIMINATING UNWANTED ALARMS Improper installation is a leadin
19、g cause of unwanted alarms. Where detectors are installed in improper locations, relocate them. Unwanted alarms can almost always be eliminated with the following actions: Smoke detectors should not be installed within 10 of a fixed kitchen cooking appliance. Photoelectric smoke detectors or ionizat
20、ion smoke detectors with a hush feature are allowed within 10-20 of fixed kitchen cooking appliances. Smoke detectors near bathrooms with tubs or showers, circulating fans, and/or air supply registers should not be placed within 36” of the door or vent. In attics, furnace rooms, garages, loading doc
21、ks, or rooms with fireplaces, consider ambient temperature that might be out of range of a smoke detector. Do not place a smoke detector anywhere that smoke or steam can be expected to occur under normal conditions. In most instances, misapplication of smoke detectors can cause problems from the ver
22、y first day a system is commissioned. The following references from NFPA 72, list conditions where the use of smoke detectors should be avoided: 17.7.1.7 The selection and placement of smoke detectors shall take into account both the performance characteristics of the detector and the areas into whi
23、ch the detectors are to be installed to prevent unwanted and unintentional alarms or improper operation after installation. 17.7.1.8 Unless specifically designed and listed for the expected conditions, smoke detectors shall not be installed if any of the following ambient conditions exist: (1) Tempe
24、rature below 32F (0C) (2) Temperature above 100F (38C) (3) Relative humidity above 93 percent (4) Air velocity greater than 300 ft/min (1.5 m/sec) 17.7.1.9 The location of smoke detectors shall be based on an evaluation of potential ambient sources of smoke, moisture, dust, or fumes, and electrical
25、or mechanical influences, to minimize unwanted alarms. 17.7.1.10 The effect of stratification below the ceiling shall be taken into account. The guidelines in NFPA 72 Annex B shall be permitted to be used. 21.3.6 Smoke detectors shall not be installed in unsprinklered elevator hoistways unless they
26、are installed to activate the elevator hoistway smoke relief equipment. NFPA 72 requires that smoke alarms, listed as complying with ANSI/UL 217, more than 10 years old be replaced. This requirement applies to smoke alarms installed in one- and two-family dwellings only. Although we understand that
27、this is difficult to enforce, when the dwelling is sold, an inspection is required. This can be enforced at that time. By adhering to these requirements, unwanted alarms caused by the following can be eliminated. NFPA 72 TABLE A.17.7.1.9 (a) and (b) COMMON SOURCES OF AEROSOLS, PARTICULATE MATTER AND
28、 MOISTURE Moisture - Live steam - Steam tables - Showers - Humidifiers - Slop sink - Humid outside air (condensing) - Water spray ENGINE EXHAUST - Gasoline forklift trucks - Diesel trucks and locomotives - Engines not vented to the outside HEATING ELEMENT WITH ABNORMAL CONDITIONS - Dust accumulation
29、 - Improper exhaust - Incomplete combustion Quality Information Guide Page 3 COMBUSTION PRODUCTS AND FUMES - Cooking equipment - Ovens - Dryers - Fireplaces - Exhaust hoods - Cutting, welding, and brazing - Machining - Paint spray - Drywall dust - Curing - Chemical fumes - Cleaning fluids - Excessiv
30、e tobacco smoke - Heat treating - Corrosive atmospheres - Dust or lint - Linen/bedding handling - Sawing, drilling, and grinding - Pneumatic transport - Textile and agricultural processing ATMOSPHERIC CONTAMINATION - Corrosive atmospheres - Dust or lint - Excessive tobacco smoke - Heat treating - Li
31、nen and bed handling - Pneumatic transport - Sawing, drilling, or grinding - Textile and agricultural processing - ELECTRICAL NOISES AND TRANSIENTS - Vibration or shock - Radiation - Radio frequency - Intense lighting - Lightning - Electrostatic discharge - Power fluctuations AIRFLOW - Gusts - Exces
32、sive velocity - Mounting near supply/exhaust vents In some instances, substituting a smoke detector that utilizes a different detection technology can eliminate an unwanted alarm problem. Photoelectric smoke detectors, for example, are less likely to alarm from rapid air changes or gusts. Therefore,
33、 replacing an ionization-type detector with a photoelectric-type detector might eliminate the unwanted alarms from an ionization detector. Dirty smoke detectors must be cleaned. Maintenance programs should be established to clean on a regularly scheduled basis detectors that are installed in dirty l
34、ocations. In normal environments, smoke detectors should be visually inspected annually and properly cleaned when sensitivity testing reveals an issue, as required by NFPA 72. Fire alarm system features have been effective in eliminating unwanted alarms from smoke detectors in many installations. In
35、 order to be accepted as a valid alarm-initiation signal, an actuated smoke detector with alarm verification is required to confirm alarm conditions within a given time period after being automatically reset. Alarm verification has proven to be an effective technique for filtering out unwanted smoke
36、 detector alarms from such transient conditions as cooking fumes, radio frequency interference, electrical disturbances, and random tobacco smoke. Alarm verification is a standard feature in most new fire alarm control units. NFPA 72 states: 23.8.5.4 Fire Alarm Signal Initiation Detection Devices. 2
37、3.8.5.4.1 Systems equipped with alarm verification features shall be permitted under the following conditions: (1) The alarm verification feature is not initially enabled, unless conditions or occupant activities that are expected to cause unwanted alarms are anticipated in the area that is protecte
38、d by the smoke detectors. Enabling of the alarm verification feature shall be protected by password or limited access. (2) A smoke detector that is continuously subjected to a smoke concentration above alarm threshold does not delay the system functions of Sections 10.7 through 10.16, 23.8.1.1, or 2
39、1.2.1 by more than 1 minute. (3) Actuation of an alarm-initiating device other than a smoke detector causes the system functions of Sections 10.7 through 10.16, 23.8.1.1, or 21.2.1 without additional delay. (4) The current status of the alarm verification feature is shown on the record of completion
40、. A multi-criteria fire detector is a device that Quality Information Guide Page 4 contains multiple sensors that separately respond to physical stimulus such as heat, smoke, or fire gases, or employs more than one sensor to sense the same stimulus. This sensor is capable of generating only one alar
41、m signal from the sensors employed in the design either independently or in combination. The sensor output signal is mathematically evaluated to determine when an alarm signal is warranted. The evaluation can be performed at the detector or at the control unit. This detector has a single listing tha
42、t establishes the primary function of the detector. How does a multi-criteria detector differ from a traditional single technology smoke detector, a combination detector or a multi-sensor detector? Multi-Criteria Detector: The detector has multiple sensors. Several examples are photoelectric, ioniza
43、tion, heat, gas or light Each sensor output is mathematically evaluated to determine when an alarm signal is warranted The detector has one listing and generates a single alarm signal Single Technology Detector: The detector has a single sensor, either photoelectric or ionization The detector has on
44、e listing and generates a single alarm signal Combination Detector: The detector has multiple sensors. Several examples are a combination of a heat sensor with a smoke sensor or a rate-of-rise with a fixed temperature heat sensor Each sensor output is not mathematically evaluated to determine when a
45、n alarm signal is warranted The detector has multiple listings and generates an individual alarm signal for each sensor Multi-Sensor: The detector has multiple sensors. Several examples are photoelectric, ionization, heat, gas or light Each sensor output is mathematically evaluated to determine when
46、 an alarm signal is warranted The detector will have multiple listings and has the capability of generating multiple alarm signals A multi-criteria fire detector is listed for the “Primary Function of the Device”. A single output will be generated from this sensing device. A multi-criteria fire dete
47、ctor will contain a combination of sensors as part of its overall detection package. Listed below are some of the sensors that might be included in the design. A typical make-up of a package of sensors that are part of a multi-criteria fire detector might include some of the following sensors but pr
48、obably not all: Photoelectric Smoke Sensor (PE) Ionization Smoke Sensor (ION) Fixed Temperature Heat Sensor Rate of Rise Heat Sensor Carbon Monoxide Sensor (Incipient Ignition Release) Carbon Monoxide Standard Sensor (Fossil Fuel Detection) Gas Sensor (not carbon monoxide but toxic gases) If a lightning strike is powerful enough and close enough, regardless of the available protection, it can cause an unwanted alarm. There are, however, techniques to significantly reduce this type of unwanted alarm. If c
