Watertight solutions to decontamination regulations
October 1st 2008

Craig Yates looks at the recommended regulations governing the use of emergency decontamination shower units

In any working environment, where the eyes or body of an operative may be exposed to injurious materials, suitable decontamination facilities for quick drenching or flushing of the eyes and body must be provided for emergency use.

Where operatives are often working alone on unmanned sites or inhospitable environments there is always a possibility of being exposed to hazardous spills. Therefore, any plant works not providing suitable decontamination facilities is taking huge risks in the long run.

The current American National Standard (ANSI Z358.1- 2004) governs the worldwide design, manufacture and installation of emergency shower units and eyewashes – whether these are plumbed in, self-contained or mobile.

As the standards govern everything from location and installation through to spray pattern, visibility and operation, companies need to carefully consider the type of decontamination solution that meet the needs of the workers and environment in which they work.

Contrary to popular belief, an industrial safety shower isn't comparable to the immersion heated showers most people have in their bathrooms.

Under the ANSI standard the unit has to be capable of delivering 75 litres per minute of clean water – more than 15 times the average for a domestic shower. It is recommended the temperature of the water should be tepid – as a general guide this is a range of 15-37ºC – to avoid either shocking the body with freezing water or scalding with hot water.

In our tank showers where water is stored, the temperature is maintained at 20ºC to minimise risk of Legionella (the risk increases over 25ºC). We use a 250- watt heater blanket attached to the underside of the tank, which is sufficient to hold the tank water at a nominal 20º C with an outside temperature of minus 10º C. This is in preference to immersion heaters which, if fitted horizontally, can easily burn out when the shower is in use as the element is exposed to air. If fitted vertically in a water pocket, immersion heaters are prone to fill with scale which acts as an insulator causing the element to burn out. The scale also provides the perfect surface, when not energised, for Legionella to multiply.

The ANSI standard also states that installation of an emergency shower unit has to be within 10 seconds from the hazard. It must be on the same level as the hazard and the path of travel must be free of obstructions that inhibit the immediate use of the equipment.

The equipment must also be protected from freezing. This can be dealt with by using a heated shower. However, a shower specified as 'heated' doesn't, and won't, provide continuous warmed water. In fact you get less than 1 second of warmed water when in use – the initial warmth is just for frost protection.

Putting the need for heat to one side, it is more efficient to use a system that doesn't store water in the pipe work. We decided a number of years ago to supply, as standard, completely self-draining safety showers, so they don't hold any water at all. If there's no water, it can't ever freeze There are now a number of energy efficient models that avoid the wasteful dumping of huge volumes of water needed for the weekly testing stipulated by ANSI. For example, systems that use multi-nozzles create a fine spray. These units are used most effectively by positioning the nozzles to hit all parts of the body at close range. This also avoids the mist drifting before it meets the body should the unit not be enclosed.

For the smaller company, regulatory emergency showers don't have to be expensive since much of the equipment needed can be easily transported from site to site.

A portable emergency shower facility, or industrial eyebath, can be put into action wherever and whenever it is needed. The practicality of having something that can be folded down to the size of a small case and transported, rather than having to install one every time a new contract is started, is highly beneficial and cost effective.

Points to consider for specification Identify the hazard and the seriousness of the risk Will you need a shower facility or just an eye wash? Are you likely to be moving around a lot? If so portability will be an issue.

How big is the site and how many workers are employed? This will affect the number of facilities there will need to be provided If a unit needs to be sited outside, identify the extremes of temperature and wind chill effect in which the unit will have to function Can the unit drain onto the ground or will the water need to be contained? Where is the supply to the mains? Will the water supply be uninterrupted or intermittent? This is important to determine which shower you will need.

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