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Hughes ... specialist equipment supplier

Hughes ... specialist equipment supplier

Safety showers: making right choices can be a life saver

The types of materials being handled will affect the choice of safety equipment as will extreme ambient temperatures. But, there are some fundamental points to consider that apply to the choice of emergency safety showers

THE contamination of workers’ clothing and bodies with dangerous substances after an accident, requires prompt action to avoid serious injury. Emergency safety showers suitably located in the work place can provide a quick and effective way to wash off contamination.

The types of materials being handled and processes involved will affect the choice of safety equipment as will extreme ambient temperatures. But, there are some fundamental points to consider that apply to the choice of emergency safety showers irrespective of the industry or the location.

It is always wise to consult a specialist equipment supplier as early as possible. On new build projects, for example, they can offer advice that may affect plant layout and ultimately save one having to make costly changes later to accommodate safety equipment.

Compliance with recognised standards is also important and may be mandatory on some sites. The American National ANSI Z 358.1 2009 standard is widely recognised and identifies four essential requirements for safe and effective use of emergency safety showers and eye wash units.

Adequate water flow: Emergency Safety Showers with manual, not self-closing, valves should deliver a minimum of 76 litres a minute from a water pressure of 2.1 Bar. Eye/facewash fountains should deliver 11.5 litres a minute with a flow rate of 1.5 litres a minute required for auxiliary aerated Eyebath diffusers on a flexible hose.

Ease of operation: Equipment must be both accessible and easy to operate, even if the victim has impaired vision. Hand-pull levers, panic bars or walk-on foot controls can be used to operate a stay-open ball valve to deliver a continuous drench for 15 minutes. The victim must be able to remove contaminated clothing without having to hold on to a spring return valve.

Instant and positive operation: Speed is essential and the water supply valve must open quickly and simply as maximum flushing must be provided within one second.

Reliability: This type of equipment may only be used occasionally and must, therefore, be able to give its rated performance after standing idle for long periods. Valves with robust and corrosion resistant actuating devices are essential for reliable operation.

At Hughes, for example, it designed its own control valve when it could not find a suitable product to meet our requirements. When casualties are in distress, they often use excessive force to activate a shower. This inevitably leads to stress on the valve and the risk of premature failure if it is not designed to withstand such abuse.

Tank shower

Showers can be floor standing or where space is restricted, mounted on walls or in the ceiling.

Galvanised, stainless steel or plastic pipe work eliminates the risk of corrosion. Stay open valves on the water supply ensure that casualties can remove clothing without having to hang on to the actuator bar or pull rod. It’s the same if a foot plate is fitted. Step on, and the shower starts ... step off and the shower still continues until manually turned off.

Alarms, lighting and a choice of devices to activate the Shower, such as pull rods, panic bars, chains and foot plates, can make showers easier to use and can alert co-workers.

Where the mains supply is unreliable or perhaps non-existent, emergency tank showers offer an effective alternative. They can also be fitted with heaters or chillers, depending on the climate, to provide tepid water between 16 deg C and 38 deg C as specified in the ANSI standard.

Maintaining a safe water temperature is essential to ensure emergency safety showers are used properly.

In hot climates, the water temperature in a tank shower can easily rise making it unusable.

Insulation alone is rarely sufficient so manufacturers invariably supply some form of mechanical cooling system.

A high efficiency chiller attached to the side of the tank will constantly circulate water and when the temperature starts to rise it will switch on to keep the water within the safe limits. This type of unit can be supplied as part of a new shower or retrofitted to existing units.

Flameproof versions are also available for Zone 1 Hazardous Areas. But where several showers are involved it is more cost effective to install a ring main system connected to a centralised chiller outside the Zone 1 area.

Where high temperatures during the day are followed by cold nights it may also be necessary to fit an immersion heater in the tank. In hot climates, an alternative to emergency tank showers is the self-draining shower. When these showers are not in use, the water automatically drains from the standpipe to prevent it from being heated by solar radiation.

Regular testing is essential and operating a shower every week is important to make sure it is working properly. Draining water from the tank during testing will also help to reduce the risk of legionnaires disease which is caused by a bacterium that can grow in static water between 20 deg C and 45 deg C.

Further protection can be achieved by applying an anti-microbial coating to the inside of the tank – something Hughes does routinely on all new tank showers by spraying with our long-life EndStat formulation.

The ANSI standard suggests that no one should have to walk for more than 10 seconds to reach an emergency shower. Clear markings and high visibility signs will help to guide casualties to the shower which should be on the same level as the hazard and free of any obstructions and easily accessible.

And finally, don’t forget servicing. It’s not an option but a necessity to protect your investment in safety. Daily inspection for mechanical damage and any obstructions should be followed by weekly checks of the water flow. This not only tests for correct operation but flushes the line and confirms that the water supply has not been inadvertently turned off.

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