Citation

Khan MM, Chaffee JL. Fire Mater. 2006; 30(4): 271-283.

Affiliation

FM Global, 1151 Boston-Providence Turnpike, Norwood, MA 02062, U.S.A

Copyright

(Copyright © 2006, John Wiley and Sons)

DOI

10.1002/fam.909

PMID

unavailable

Abstract

A thermal liquid bath was used to determine the activation temperature of a wide range of temperature rated (57-182 deg C) glass bulb (3 and 5 mm diameters) sprinklers using water and glycerine. An optical switch and a thermocouple were installed adjacent to each sprinkler (within 10 mm) to record the activation of each glass bulb in the liquid bath having a uniform temperature distribution (+/-0.5°C). All the tests for determining the activation temperatures of glass bulb sprinklers were conducted in the liquid bath using a 0.277 deg C/min rate of temperature rise. Based on a heat transfer analysis, this rate is within the maximum allowable rate of rise of water and glycerine temperatures, which allows the glass bulb temperature to closely follow the liquid temperature. The sprinkler activation temperature was evaluated in terms of percentage rating, which is expressed as the percent variation of the average activation temperature, as measured in the liquid bath, from the nominal rated temperature. Sprinklers (93 deg C rated or lower) activation temperatures in water were consistently within +/-3.5% of rating. In glycerine, the activation temperatures of sprinklers rated between 93 and 182 deg C performed within 3.5% of their rating.