Systems approach to first response
Urban legend has it that the first emergency eyewash was designed by a concerned plant supervisor who fashioned an eyewash out of spare drinking fountain bubblers. In my mind, thatâ€™s closely akin to trying to halt a four-alarm blaze with a garden hose. But everything has to start somewhere.
Today, between ANSI and OSHA, we have a fundamental safety net that requires compliance to very specific standards of safe operations, preparations in the event of an accident and appropriate response mechanisms.
Traditional logicTraditionally, we have had a logical plant safety progression of:
This reasonably straightforward approach (see Figure 1) still works well, although the scope of each of the three areas continues to broaden dramatically. For instance, a single industrial spill/splash threat from a caustic agent used in manufacturing still carries appropriate precautions and responses if an accident occurs. But now the threat might be broader due to the potential for intentional spills/splashes (terror, worker violence, etc.) and through a deeper understanding that the traditional responses to an accident may carry their own negative consequences. For example, a caustic splash victim might encounter evaporative cooling during a 15-minute drench shower cycle, possibly leading to hypothermia. So while our logical progression still applies, the diagram might look like whatâ€™s pictured in Figure 2.
Evolving and more complex hazards complicate the specification of emergency response systems. What used to be a relatively simple task of defining risks, applying the needed precautions and preparing for accidents â€” by linking together â€œappropriateâ€ emergency equipment components â€” has become a science. Selecting and matching complimentary components that work together within the limitations of space, water pressures and potential simultaneous use of multiple showers, with appropriate redundancies and integrated safeguards, is more than can be ascertained by looking through catalogs.
Turnkey safetyThe driving force behind the acceleration into turnkey safety thinking â€” custom-engineered installations â€” has primarily been the need for tempered water. That, along with ever-tougher ANSI standards, has forced specifiers into treating their complete installation as a â€œsystemâ€.
If youâ€™re considering an emergency shower apparatus as an individual component, thatâ€™s one thing. But think about that same shower as part of a plant-wide fully engineered system that has to deliver tempered water at a specific pressure, for a specific use cycle â€” with the possibility that multiple showers may be in use simultaneously. You start to get the idea here.
First, a tempered water blending system valve must compensate for input water temperature changes and provide for cold water bypass in the event of hot water failure.
Next, consider the maximum load requirements of simultaneous use on both the total water supply and the tempering system. Also, take into account the geography covered by the linked system. Do you have sufficient water â€” both volume and pressure â€” for maximum load use? Do you need a booster pump? Are the volume and recovery time of your tempering system sufficient to maintain â€œtepidâ€ conditions with maximum load use?
Finally, consider the showers, eyewashes or combination units in your system. Do they individually have the capability to compensate for pressure changes, due to line pressure fluctuations and/or simultaneous use situations and still attain the minimum operating flow heights and patterns?
Other issues: the cost penalties of over-speccing a single piece of the total system versus the other components; the impact of remote operations where water and/or power may be issues; or the need for reverse tempering. Reverse tempering is appropriate in areas where the ambient temperatures heat the water in emergency equipment piping to a point where it is too hot to be used without cooling. This can happen due to either operation in a warm climate or proximity to hot manufacturing and/or processing operations.
Simple solutionsTurnkey safety can be as simple as specifying an engineered valve system to control your tempering operation or matching a single combination shower/eyewash to assure that using both the shower and eyewash simultaneously wonâ€™t diminish the flow of either to below prescribed levels. Forget even one variable if you try to piece a tempering valve system together and you create a possibly worse situation than youâ€™re trying to address. And youâ€™d be surprised at the combination shower/eyewash products on the market that donâ€™t offer flow controls in them.
Beyond single product â€œsystemsâ€, the next consideration might be a skid-mounted system that provides matched components for tempered water heating, blending and circulation. That basic platform can be built to feed a single shower or multiple units over a prescribed plant geography. It can also be built to incorporate a shower or combination unit right into the skid, with or without the ability to tap into the tempering system for other nearby showers.
Finally, that same basic platform, with or without additional componentry, can be encased in a booth, making it a fully self-contained turnkey system. When these booths are configured with showers, we refer to them as Enclosed Emergency Environments (E3). They are highly visible, private safe-havens for the injured â€” and the future of safety and first response.