The header tank on our GFTS15 and GFTS25 ANSI-compliant, gravity-fed, self-contained safety shower and eyewash units are provided with an overflow. This overflow is especially useful when the tank is being filled by use of a potable water truck. In the case where these units are not connected to a potable water line for ease in filling the tank, the dual ball float valves do not come into play. Instead, an operator must control the flow of water from the water truck hose. The flow from some water trucks can be high and sometimes the header tank on the shower can be inadvertently overfilled. To minimize the likelihood of this occurrence, the overflow allows excess water to be vacated from the tank.
The Overflow
This overflow would provide access to the tank for foreign objects, such as dust and small debris to enter the tank and contaminate the tank in various potential ways, were nothing done to prevent it from happening. In order to prevent most unwanted contaminants from entering the tank through the necessary overflow, the overflow is screened. The screen will prevent most non-bacterial contaminants from entering, except for the smallest of dust and dirt particles. Because it is possible, especially in windy areas, for some small dust and dirt particles to enter through the screen, it is recommended that the tank be flushed once per year so that sludge cannot build up in the header tank over time. Built up sludge could interfere with the proper functioning of the safety shower/eyewash.
ANSI Z358.1 2014 Requires Potable Water
ANSI Z358.1 2014, which is the ANSI standard for safety showers and eyewashes, and which is the most-commonly-enforced standard for safety showers and eyewashes, requires that all flushing fluid used in safety showers and eyewashes be potable. Therefore, the water used in the header tank of gravity-fed safety showers and eyewashes must be potable to start with and must either be replaced every month or two, depending on ambient conditions, or it must be treated with an effective bacteriacide. We recommend use of our HClenz slow-release silver nitrate canister to treat the potable water and keep it in safe and compliant condition to be used in the self-contained safety shower and eyewash products.