What temp does bleach turn to a gas?

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Created on Friday, 03 September 2004 01:19

Written by Rich Fitzmorris

Question:  At what temperature does bleach start turning to gas? Should you use bleach in cooler water?

Answer: Liquid Chlorine Bleach at any strength constantly gives off some chlorine gas, and proper use-temperature depends on the specific application. If one is washing white cotton or cotton polyester textiles and the intent is to remove stains and maintain whiteness of the fabric, the following are guidelines for institutional laundering use:

Bleaching temperature is ideally between 145 and 155 degrees, with bath water pH between 10.2 and 10.8 on the pH scale. The duration of bleaching generally ranges from 7-10 minutes. In a good bleach cycle, time and chlorine-use are measured where roughly 85-90% of the available chlorine is used before the bath water is dumped to sewer.

Temperatures in excess of 155 degrees should not normally be used, as the chlorine will gas-off too quickly, creating the potential for textile damage. Cotton fibers can be weakened resulting in shorter textile life.

Lower temperatures are surely acceptable, but understand that the time for stain removal and brightening of the white cotton will take longer. However, if the exposure is too long, fiber damage is possible. As a general rule, as bleaching temperature is decreased, so is the bath water pH. This lowering of the pH in the bath allows the chlorine to gas as it should in order to do its job.

In home wash applications water is generally not exceedingly hot, and consumer-grade detergents are not high pH products. This combination allows the chlorine bleach to work properly in such applications..