Fire alarm 2_d_radiant energy detectors

1. Initiating Devices
17.8 Radiant Energy-Sensing Fire Detectors
17.9 Combination, Multi-Criteria, and Multi-
Sensor Detectors
17.10 Gas Detection
17.11 Other Fire Detectors
17.12 Sprinkler Waterflow Alarm-Initiating
Devices
17.13* Detection of the Operation of Other
Automatic Extinguishing Systems
NFPA 72 Chapter 17

2. Initiating Devices
17.8.1.1 GENERAL
– 17.8 describe the standards to install these dev
17.8.2 FIRE CHARACTERISTICS and DETECTOR
SELECTION
17.8.2.1 Type and quantity of devices --> analysis
17.8.2.2 Selection based upon match and minimize
17.8.3 SPACING CONSIDERATIONS
17.8 Radiant Energy-Sensing Fire Detectors

3. Initiating Devices
17.8.3.1 GENERAL RULES
17.8.3.1.1 Follow listing and inverse square law
17.8.3.1.2 Quantity based upon non-obstruction
17.8 Radiant Energy-Sensing Fire Detectors

4. Initiating Devices
17.8 Radiant Energy-Sensing Fire Detectors
17.8.3.2.1 Location and spacing based on:
(1) Size of fire to be detected
(2) Fuel involved
(3) Detector sensitivity
(4) Detector field-of-view
(5) Distance between fire and detector
(6) Radiant energy absorption of the atmosphere
(7) Presence of extraneous sources of emissions
(8) Purpose of the detection system
(9) Response time required
17.8.3.2 SPACING CONSIDERATIONS for FLAME
DETECTORS

5. Initiating Devices
17.8.3.2 SPACING CONSIDERATIONS for FLAME
DETECTORS
17.8.3.2.2 System design shall specify size of fire
17.8.3.2.3 Reduce distance if not on axis
17.8.3.2.4 Reduce distance if application & test
differ
17.8.3.2.5 Do not obstruct the detector field of view
17.8.3.2.6 Keep detector window clean and clear
17.8 Radiant Energy-Sensing Fire Detectors

6. Initiating Devices
17.8.3.3 SPACING CONSIDERATIONS for
SPARK/EMBER DETECTORS
17.8.3.3.1 Location and spacing based upon:
(1) Size of the spark or ember to be detected
(2) Fuel involved
(3) Detector sensitivity
(4) Detector field-of-view
(5) Distance between fire and detector
(6) Radiant energy absorption of the atmosphere
(7) Presence of extraneous sources of emissions
(8) Purpose of the detection system
(9) Response time required
17.8 Radiant Energy-Sensing Fire Detectors

7. Initiating Devices
17.8.3.3 SPACING CONSIDERATIONS for
SPARK/EMBER DETECTORS
17.8.3.3.2 Design shall specify size of spark
17.8.3.3.3 All detection points shall be in field of view
17.8.3.3.4 Location/spacing based on inv. square law
17.8.3.3.5 Reduce distance if not in optical axis
17.8.3.3.6 Keep detector window clean and clear
17.8 Radiant Energy-Sensing Fire Detectors

8. Initiating Devices
17.8.4 OTHER CONSIDERATIONS
17.8.4.1 Protect detectors by design or
installation
17.8.4.2 Shield detectors if necessary
17.8.4.3 Protect detectors against outdoor
conditions
17.8.4.4 Do not install outside of listings
17.8 Radiant Energy-Sensing Fire Detectors