Hello everyone, I was hoping to get some help on a question that has been going around my office. (if some how NFPA could tell me even better.)
We our trying to understand if in high air movement areas we are require a spacing adjustment for air sampling detectors. We are not all in agreement on, as per section 17.7.3.6.1 the sampling holes are treated like spot smokes. however in section 17.7.3.3.3 it says to fallow the manufactures instruction for high air movement area. this some to what contradicts 17.7.3.6.1.
please let me know what you think and if you need more information.
NFPA 72 2016:
17.7.3.6.1 "Each sampling point of an air sampling-type smoke detector shall be treated as a spot-type detector for location and spacing."
17.7.6.3.3.2 "Where spacing must be adjusted for air flow, spot-type detector spacing shall be adjusted with table 17.7.6.3.3.2 or figure 17.7.6.3.3.2 before making any other spacing adjustments required by code.
17.7.6.3.3.3 " Air sampling or projected beam smoke detectors shall be installed in accordance with the manufactures published instruction."
The recommended sample hole spacing for high airflow environments are:
Unlike traditional smoke detectors, Air Sampling Smoke Detectors systems effectively detect diluted smoke in high airflow environments by using very sensitive sensing chamber and cumulative sampling, the aggregation of smoke drawn through multiple sampling holes. In addition, Air Sampling Smoke Detectors systems actively draw air through the sampling holes to provide consistent and predictable detection performance in high airflow environments.