Page 28 - Occupational Health & Safety, May 2018

EMERGENCY SHOWERS & EYEWASH
In sizing the tempered water system for any particular application, providing a source
for sufficient quantities of water is essential. Recent advancements in instantaneous hot water heaters have made these products practi- cal for use in emergency equipment applications, especially where space for traditional hot water heaters and hot water storage tanks is limited.
emergency equipment in the appropriate locations and that the comfort zone approach is being added to the existing emergency equipment assets.
Let’s consider the most appropriate steps to be taken:
1. Ascertain your actual inlet water temperature range and compare it to the desired range. This involves checking the ini- tial and sustained temperature readings at the various emergency equipment sites located throughout the facility. Since conditions can change from location to location, the chore of checking each shower and eyewash is the safest bet. Don’t forget the impact of seasonality on water temperatures. It may be necessary to check at several times during the year.
2. Determine the overall changes needed. If initial tempera- tures are either too hot or too cold, while sustained temperatures
are within the ANSI mandated temperature range or even the rec- ommended comfort zone, consideration of a re-circulation system is appropriate.
If sustained use temperatures fall outside of the temperature parameters, you may require warming technologies, cooling tech- nologies, or, in certain areas and circumstances, both. In most instances, these types of systems can be sized to handle multiple showers/eyewashes each. Specific applications should take into ac- count the volume of shower and eyewash locations to be included in each loop, the maximum distance between components, and the impact of exposure of warmed or cooled pipes to ambient air tem- peratures. It is highly recommended that specifiers work with eye- wash and shower manufacturers directly to determine the appro- priate system, given your specific geographic location, processes, temperatures, and layout/equipment locations.
It should also be noted that while tempered water—meaning warming cold water—has been a hot topic of late, just as many in- stallations need cooling of high-temperature supply water. Elevated temperatures can come from several sources, including high am- bient temperatures, exposure to process heat, or excessively high supply temperatures.
3. Identify the number, required location(s), and sizing of the thermostatic mixing valve(s). This applies only to tempering water or warming sustained-use cold input water prior to emergency equipment use. Temperature control for cooling operations is handled
24 Occupational Health & Safety | MAY 2018
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