It’s always amazing to me how often people can make a great initial decision on a direction that needs to be taken and then blow it with a bad downstream call. So it is with tempered water systems for emergency equipment.
With the 2004 revision to ANSI’s Z358.1, the specific requirement for tempering emergency equipment outlet water temperatures to be between 60ºF and below 100ºF was clearly established. The requirement applies to all outlet water for the full 15-minute drench or irrigation cycle. Nowhere in the requirement does ANSI state that the temperature range does not have to be met if there is a water supply interruption or failure.