Most state and local governments have adopted the 2003 or later International Plumbing Code (IPC) which requires the use of "tepid" (moderately lukewarm) water in emergency showers and eyewash stations. See page 4 of this chart for the list of 35 states where it has been adopted at the state/local level:
https://www.iccsafe.org/wp-content/uploads/Code_Adoption_Maps.pdfAmerican National Standards Institute (ANSI) Standard Z358.1-2014 at (Section 6.4.6; B6) states that water delivered by emergency equipment be "tepid" which is defined as between 60 =B0F (16 =B0C) and 100 =B0F (38 =B0C) except when this would accelerate an adverse chemical reaction. ANSI is an internationally respected body that fosters "best practices" standards in a variety of areas. Thus, even if your state/local government does not require tepid water, your insurance carrier or attorney may require or advise you to follow the ANSI recommendation. Further, as Z358.1 is incorporated by reference into the International Plumbing Code (IPC) this means that tempering valves are basically required under most state and local plumbing codes.
Tepid water delivery is achieved with a tempering unit (also called a thermostatic mixing valve or blending valve) that automatically mixes hot and cold water supplies to deliver water in the recommended temperature range. You can find examples of these on our company's web site at
http://www.safetyemporium.com/showers/tempering-valves/Plumbing into cold water only in regions where the temperature can reach freezing is bad in a different way. Victims run the potential of hypothermia trying to stay in extremely cold water for 15 minutes, and are likely to cut their treatment short because of the frigid temperature. Of course, hot only is worse, as the hot water supplies outside residential environments are likely scalding.
