Turning Up the Heat in Emergency Fixtures
You have many options when installing emergency fixtures for outdoor applications.
IT is entirely possible employees will never need to use emergency drench showers and eyewashes in a facility. That is, if primary protection systems are used effectively and the procedures are well designed. Yet emergency fixtures are the absolutely essential, must-be-there backup equipment in the event that other protection fails. The situation is often critical when emergency showers and eyewashes are needed, so units must be readily available and prepared for immediate use.
Designing a safety system to meet the particular needs of any facility or application is important. It is critical for those exposed to a chemical or other eye and skin hazards to have quick access to a functional drench shower and eyewash unit capable of providing water at an appropriate temperature. Emergency fixtures for outdoor locations, with the wide range of temperature fluctuations involved, are an often-overlooked component in overall safety design. It is likely some, or maybe even all, of a facility?s high-risk processes are located outside; the safety of workers in these locations can not be ignored.
Outdoor applications require emergency fixtures that are specifically designed to function through a range of temperatures, particularly in northern climates. Cold temperatures pose the most significant challenge for fixtures because frozen water in the pipes and valves not only causes them to be inoperable when needed, but can also cause permanent damage. In some locations, it is necessary to protect the water from both freezing and overheating.
There are applications in which a potential hazard is located indoors but the building is unheated. Or environments are temperature controlled but at levels that are near or below freezing. In general, the solutions discussed here are applicable to these situations, as well as to outdoor applications.
Four Solutions for Outdoor Emergencies
According to the ANSI Z358.1 standard, any emergency fixture installed where the potential for freezing exists should be protected from freezing, or freeze-protected equipment should be installed. There are multiple solutions for outdoor applications, all of which comply with this standard.
The types of fixtures we will cover should meet the standard's recommended 0.4 gallons per minute (GPM) minimum flow for eyewash units and a minimum of 20 GPM flow from the showerhead, but it is important always to verify that a specific unit meets these requirements. Following are four different types of emergency fixtures that are designed to withstand Mother Nature's extreme temperatures.
Frost-Proof Units
Two types of products fall into the category of traditional frost-proof units: through-wall fixtures and fixtures with buried incoming supply pipes. As the name implies, through-wall fixtures protect pipes from outdoor temperatures by keeping them on the inside of the wall. Other frost-proof fixtures protect pipes containing water by placing them underground, below the frost line. The constraints of a particular application will determine which of these fixtures offers the best solution.
A through-wall fixture can be very practical for outdoor hazards located near a plumbed and temperature-controlled building. This fixture mounts through an external wall, allowing the water supply pipes to be located in an indoor location, while the drench shower and/or eyewash are mounted on the outside wall of a building. The through-wall design protects water in the pipes against both overheating and freezing by keeping the ball valve assemblies internal to the building. This process is augmented with weep valves inside the building that drain any excess water from the outdoor portion of the system after activation.
Some manufacturers offer a shower version and an eyewash version of this product, and combination shower and eyewash units are available. Typically, fixtures can be specified for a range of wall thicknesses. Overall, the through-wall drench shower and eyewash products are versatile fixtures that offer a cost-effective option when there is a plumbed building nearby with a suitable outside wall. When this is not the case, other alternatives must be considered.
Frost-proof units with buried pipes can be more flexible in their placement, although they do require an underground water supply and all pipes that feed the unit must be below the frost line. The fixtures usually can be ordered with a range of bury depths to ensure the supply to the unit is safely below the frost line. Typically, a concrete pad or gravel patch is required for drainage, and eyewash fixtures with bowls also require a system to drain them below the frost line. The ball valves are also underground to prevent water from remaining in the above-ground pipes.
This article originally appeared in the October 2004 issue of Occupational Health & Safety.