Pyropress has recently supplied hundreds of explosion proof switches including flow, level and pressure switches to a leading safety shower manufacturer for units that will be used in hazardous areas in the middle east.
“An integral part of safety showers that are installed in countries that experience high ambient temperatures is a chiller unit. This ensures the safety shower and eye wash provides cool water when actuated,” explains Paul Maddern from Pyropress. “It’s these chiller units that require explosion proof switches when operating in hazardous areas.”
Safety showers are an essential component for any emergency response plan in industrial settings, globally. The “emergency showers” provide a high volume of water to rinse the full body in case of an accidental exposure to hazardous materials.
These safety showers are required in refineries and other installations that contain or are processing liquids or chemicals that will cause injury to personnel if they accidently come into contact with them. The aim is to provide on the spot decontamination, flushing away harmful substances like acid or chemicals quickly, to decrease the seriousness of any injury, before seeking further medical treatment.
Another first aid treatment includes the use of eyewash units which are designed to flush out contaminants from the eyes in case of a chemical splash or other eye irritants. Quite often, sites have combination showers which combine both an eyewash unit and a safety shower in one.
Safety showers for hazardous area zones
“The problem is that in many high risk industries, safety showers and eye wash units are typically installed near to, or inside, hazardous areas,” he says. “The idea is that a safety shower should be in accessible location that can be reached in seconds if needed, regardless of whether it’s a potentially explosive atmosphere. But it simply cannot be the source of an ignition, particularly if there is a spillage of flammable liquid.”
In hazardous areas that are classified as ATEX Zone 1 or Zone 2, all equipment operating in those areas must be ATEX-rated and should not be the source of an ignition. Safety showers are no exception and there are many sources of ignition found on standard safety showers, particularly those that need the water cooled.
A safety shower must supply a large amount of water for a specified amount of time, 15 minutes for example. The specific amount depends on the respective standards, but it could be between 30 to over 100 litres per minute.
Explosion proof (ATEX) flow switches for the safety showers
“The project that we worked on required a flow detection that did not rely on moving parts, such as a paddle, to actuate it,” says Paul. “The Pyropress flow switch is an unique in-line design working on the principle of differential pressure across an orifice.”
Flow calculations were conducted for the eyewash, the safety shower and both operating together, which led to Pyropress providing a customised 1.25” flow switch from its Perseus range.
“A custom orifice ratio ensured that the ATEX flow switch would activate on the low flow of the eyewash,” he adds. “Dual contacts were also provided for local and remote alarms.”
Perseus flameproof Ex d and intrinsically safe Ex ia flow switches for use in hazardous areas are suitable for 
hydraulics, water, sea water, chemicals, fuel oil and any other liquid.
With multiple switch configurations, robust housing and proven long-term reliability (SIL rating) in tough environments, these flow switches are ideal for OEMs on applications such as A/C units, chilling, heating and ventilation systems, radiator systems and more.
These ATEX compliant flow switches can be found in oil & gas and petrochemical facilities globally, in addition these are fitted to many desalination plants.
The temperature of the water delivered by emergency showers is also important and should be tepid, and not too warm or too cold. Water temperatures between 20 °C and 25 °C are considered ideal which is hard to achieve in the middle east without cooling the water.
Flameproof ATEX pressure switches used in HVACR
“For these units, the cooling is supplied by an HVACR manufacture who uses a range of Pyropress switches in its design and build,” he says. “A Perseus explosion proof pressure switch monitors the pressure levels of the system and turns it on when the pressure drops too low and off when it reaches the desired level. It also activates the maximum cooling fan speed and provides a safety cut-off if the pressure is outside of the safe range.”
Perseus ATEX pressure switches are available as flameproof Ex d or intrinsically safe options for use in 
hazardous areas for hydraulics, air, water, gases, chemicals, fuel oil, refrigerants and more.
With multiple switch configurations, robust housing and proven long-term reliability (SIL rating) in tough environments, these pressure switches are ideal for OEMs building pumps, compressors, gas turbines, diesel engines and more.
The flameproof Ex d and intrinsically safe pressure switches can be found in oil & gas and petrochemical facilities globally.
Explosion proof ATEX level switch
Pyropress also supplied an explosion proof level switch for the condensate. The explosion proof condensate safety switch is installed in the ATEX HVACR system and is designed to shut off the system if, for example, the drain line becomes clogged or the pump fails, preventing water damage.
Perseus ATEX level switches are available as flameproof Ex d or intrinsically safe ia options for use in hazardous 
areas for hydraulics, water, chemicals, fuel oil or any other liquid.
With multiple switch configurations, robust housing and proven long-term reliability (SIL rating) in tough environments, they are ideal for measuring levels in tanks and containers, either vertically or horizontally.
These flameproof level switches (ATEX / IECEx) can be found in oil & gas and petrochemical facilities globally.
In addition to the switches, the safety shower system incorporates audible and visual indication.
Pyropress’ sister company Ex-tech Signalling provides a wide range of explosion proof sounders and ATEX beacons that can be incorporated into safety showers and other related safety systems used in hazardous areas.
About the Author
Paul Maddern is an explosion protection instrumentation expert and has been part of the Pyropress team for 35 years.
