Haws Integrated® What is Tempered Water?

Understanding the ANSI Z358.1 Tepid Water Requirements

The original ANSI Z358.1 Standard for Emergency Showers and Eyewashes was first written in 1981 by the ISEA (International Safety Equipment Association) with additional modifications in 1990, 1998, 2009, 2009, and the current 2014 version. The 2009 revision addressed crucial points relating to temperature range for water delivery.

Temperature Range for Water Delivery

In the 2004 Standard, it was not clearly outlined what tepid water meant and instead just simply stated that tepid was defined as moderately warm; lukewarm. The 2009 revision specified an exact temperature range to guarantee proper flushing.

Tepid Water is defined as 60° F -100° F  (16° C - 38° C)

• Encourages use of safety equipment
• Encourages removal of contaminated clothing
• Encourages full 15-minute drench
• Cools chemical burns
• Prevents chemical absorption


Temperatures in the lower end of the tepid water range may cause:

  • cold shock, possibly leading to cardiac arrest
  • user to end flushing before the recommended time has passed


Legionella bacteria growth thrives between 95 and 115° F, a range that overlaps the current ANSI tepid water range.

While the ANSI standard does require a weekly flush to clear all piping sections that lead to emergency shower and eyewash station, avoiding temperatures that harbor bacteria is a valuable step in limiting potential exposure.

Haws Integrated provides many solutions to emergency equipment needs with our dedicated team of engineers and technicians designing safety solutions. The Haws Integrated team provides a complete line of custom engineered mixing valves, tempered water solutions, recirculation systems, air-charged systems and alarms designed around specific requirements and meeting all ANSI Z358.1-2014 prerequisites.

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