ATEX and Safety Showers
By their very nature safety showers and eye baths need to be located close to hazards. In many cases the hazardous materials the safety showers are in place to protect workers from may pose an explosion risk. As such the showers often need to be deployed in potentially explosive environments.
For a basic, un heated shower with no electrical components and no moving parts ATEX compliance is not a consideration. As long as the shower is made of a conductive material that remains earthed it will not need to be ATEX certified. However as soon as one starts adding any electrical components such as heating element, alarms or position lights then these components and the whole shower assembly must be ATEX certified.
ATEX compliant assemblies
Many components such as heating elements are available from the manufacturer as ATEX compliant models. Clearly each electrical or moving component that makes up a shower assembly must be ATEX certified but further to this the ATEX directive is quite clear that even assemblies of compliant parts may not be compliant themselves. Thinking about this a little it makes absolute sense a completely ATEX compliant motor attached to as a conductive ATEX compliant metal part could still create sparks if that part were hitting another hard surface. Each component in isolation would never represent an explosion risk but assembled they do.
For this reason it is not good enough to simply have ATEX complaint electrical components in a shower. The whole shower assembly needs to be certified if it is to be compliant.
The ATEX certification will designate which zones a piece of equipment can be safely deployed in. There are 3 classes of zone: 0,1 and 2. These classes exist for both gas/vapour and dust explosion hazards. The dust explosion risk zones are prefixed with the number 2. So a class 0 dust explosion risk zone would designated as zone 20 and a class 2 dust explosion would be ATEX zone 22. Gas explosion zones are simply 0,1 and 2 with no prefix.
Zone 0 environments have a permanent or near permanent explosion risk present. Unsurprisingly this is the toughest zone to get certified for. Equipment for use in such zone must have double redundant safety features meaning that even if one safety feature fails another will be in place to ensure the explosion risk is mitigated.
Zone 1 environments have and explosion risk that is likely to occur during normal operations. As the explosion risk is not permanent then the safety features required are less onerous.
Zone 2 environments have an explosion risk that is unlikely to occur during normal operations. In such zone the explosion risk may occur by accident of by some other atypical operation so safety features are still required on equipment but again the design of such features is less strenuous.
Further to the zone type a pieced of equipment will also be given an ATEX temperature rating. The ATEX temperature rating have 6 classes.
T1 = 450o
T2 = 300o
T3 = 200o
T4 = 135o
T5 = 100o
T6 = 85o
If a piece of equipment is approved for use in a T class then it means that the atmosphere in which it will be deployed will not be exposed to any temperatures above that. So a T3 rated piece of kit will never have any external part hotter than 200o
C. The T classes are designed to be below the flash point (self ignition point) of various types of gaseous and dust explosive environments. Any piece of equipment rated for a higher T class will be suitable for sue in all lower classes as well.
FSP Tech, our supplier, are one of the very few safety shower manufacturers that have true ATEX compliant and certified shower assemblies. Not only are ATEX certified components available for most electrical components but just as importantly the complete assembly is certified also. Further to this ATEX certification also requires a regular inspection of the manufacturing plant as well as an audit of quality control and test procedures to ensure the manufacturing process itself is delivering a completely compliant shower every time. After all compliant, safe design is utterly pointless if a shoddy manufacturing process results in products that are not built exactly to spec.
Our showers are certified to operate in ZONE 1 (dust and gas) and will come with either T4,5 or 6 ratings depending on which features are required. The important thing is that the whole assembly and manufacturing process has been certified, giving peace of mind that ATEX compliant kit is being installed.