Fire sprinklers are essentially a valve that is activated by heat. It consists mainly of a small glass bulb that holds a liquid that reacts to heat. Using color-coding, they indicate the temperature they will explode, releasing the water.
The liquid inside the glass will expand when the ceiling temperature reaches a certain level, causing the glass to break.
Industrial environments can operate at higher temperatures than usual, so some fire sprinkler heads must resist these temperatures without exploding.
Sprinkler Head Operating Temperatures
Automatic fire sprinklers have glass bulbs or fusible links calibrated to operate at a designated temperature. The type, location, and typical ambient temperature are considered when selecting and installing sprinkler heads.
Following Standard AS 2118.1, the lowest temperature rating shall be not less than 30oC higher than the highest anticipated temperature condition except in certain circumstances;
- During summer, installing sprinklers with a temperature rating between 79°C and 100°C in nonventilated enclosed spaces, unventilated metal roofs, and in other locations exposed to direct sunlight may be necessary.
- The listing, manufacturer data sheets, codes, and standards referenced herein recommend sprinklers with a nominal temperature rating of 141°C for high piled storage, except when special sprinklers can be used with an alternative temperature rating.
- A sprinkler at the ceiling or roof immediately above and to a distance of three meters beyond the perimeter of drying ovens or hoods over papermaking machines and the like (see Clauses 5.6.14 and 5.7.6) must have an equivalent temperature rating, limited to a maximum of 141°C.