What's the coverage area for smoke and heat detectors according to NFPA 72?

it help to detect heat and also poisonous gases such as carbon monoxide, nitrogen and also oxygen level. it also detect fire in initial stage

deepens on hazards area 3 to 4 Mtrs

keep clear and clean the smoke detectors avoid dust.

 SMOKE 9 METER

HEAT 7 METER

mostly that covers 200 Sq meter

the first smoke alarm in the immediate area of the bedrooms. ... smoke alarms to protect any stairway as stairways act like chimneys for smoke and heat. ....  .

According to NFPA 72 edition 2013 Section 17.6.3.1.1 # Detector spacing.

All points on the ceiling shall have a detector within a distance equal to or less than 0.7 S (S is the listed Spacing). Equal to S = 9.1 Mtr. For Smoke detector , S= 15.2 Mtr. For Heat detector and the spacing between the detector must not be less than 0.4 S.

·         For Heat detector.

Heat detector spacing distance effective by the Ceiling height so we have another factor depend on the ceiling heat you can find this Factors on NFPA 72 edition 2013 Table 17.6.3.5.1 # Table heat detector spacing reduction based on ceiling height.  

·         For Smoke detector.

Smoke detector spacing distance effective by the air movement speed, so we have another factor depend on the Air movement you can find this Factors on NFPA 72 edition 2013 Table 17.7.6.3.3.2 # Table Smoke Detector Spacing Based on Air Movement.

and the spacing between detector and wall equal to .5 S , and corner .75 S.

All above for Smooth Ceiling 

For general area coverage with smoke detectors will be  65 m2.

Chapter 5 of NFPA 72 requires that spacing be based on manufacturer’s recommendations. Chapter 5 also recommends an installed spacing of 30 ft (9 m) between detectors. This recommendation applies to smooth, flat ceilings, and is also in agreement with the recommendation of most manufacturers