What is Tepid Water?
Tepid water is temperature-controlled water that sits between 60°F and 100°F as defined by ANSI. When an emergency occurs where substances like harmful chemicals must be washed off, ANSI Z358.1-2014 requires a tepid water to be provided for 15 minutes to safety showers and eyewash stations. The temperature range ensures the water is not too hot or too cold, which may cause the worker to step out of the shower before a complete wash, reducing its effectiveness and increasing the chances of an injury from chemical burns.
Steam Heated Tepid Water Skid with Heat Exchanger
What Standards Apply to Tepid Water Skid Design?
OSHA does have a standard that states:
Where the eyes or body of any person may be exposed to injurious corrosive materials, suitable facilities for quick drenching or flushing of the eyes and body shall be provided within the work area for immediate emergency use.
ANSI standards help provide a better definition. The Z358.1-2014 Standard provides a more specific guideline and more detail into what is “suitable” when it comes to emergency showers and eyewash stations.
The standard states that emergency showers and eyewash stations must be located within 10 seconds (approximately 55 feet) from the hazard, with a clear, unobstructed path. It also states:
- The water must be tepid, at a temperature that falls between 60°F and 100°F
- The shower must be able to flow at a minimum of 20 gallons per minute for 15 minutes, while the eyewash station must be able to flow at a minimum of 0.4 gallons per minute (eye/facewash at 3 GPM) for 15 minutes (for units that combine both, each feature must meet these requirements simultaneously)
- If the local climate has the potential for freezing conditions, the equipment should be designed to protect against those conditions
Other codes that may have to be considered include the NSF (National Sanitation Foundation), UPC (United Plumbing Code), and the IPC (International Plumbing Code) based on your local requirements.
What Does a Typical Tepid Water Skid Package Include?
A typical package consists of stainless piping, a stainless tank that holds enough water to meet the ANSI standard with a flow of 20gpm for 15 minutes. The most common design criteria is to design the system to provide tepid water to any two safety shower/eyewash stations activated at the same time on a typical circuit. A recirculation pump and booster pump on VFD’s are used and sized based on the overall length of the safety shower/eyewash stations loop and elevation changes in the pipe routing. Systems are typically controlled by a PLC/HMI package providing both local and remote control and monitoring of the system.
Water can be heated electrically with an immersion heater inserted into the water tank or by utilizing sites steam source with an added heat exchanger package. Other components can include visual, audible and remote alarms, a temperature transmitter, a tank level transmitter used to activate an automated control valve to fill the tank with water as necessary, inlet water strainer, UV sterilizer system, freeze protection, full enclosures with HVAC and chiller packages.
Electric Heated Tepid Water Skid with UV Sterilization System & PLC Controls
What Tepid Water Skid System Testing and Annual Inspection Should I Consider?
ANSI recommends a detailed annual inspection of a facility to evaluate if any new hazards have been introduced in an area that may require the addition of a safety shower or eyewash and inspect for any safety shower system components that may need repair or replacement.
Safety showers/eyewashes should be tested weekly by activating the systems and an inspection tagging system with test date should be utilized.
Need help developing a tepid water skid system to meet ANSI Z358.1-2014, give S&S Technical a call to explore what packages and options make the most sense for you and your site.