Protecting electrical equipment from daily wash downs while maintaining hygienic standards can prove to be a ‘hygienic headache’. Common problems include solution pooling, the possibility of trapped contaminants between walls and mounted enclosures as well as the unreachable areas created by floor standing enclosures. Hygiene checks have also revealed that the use of pressure washes harbours the risk of organic contaminants entering niches and tiny recesses in standard enclosure designs such as the two-bit lock, hinges, seals and glands. However, these problems can be easily overcome if during the design phase the enclosure is properly specified.
To prevent pooling, for example, an enclosure that incorporates a 30 degree sloped overhang allows cleaning fluids to completely drain away. An increased gap between the door and the roof will offer easier cleaning and a bezzled door return will ensure that fluids do not run back and take residence in the door seal. As this seal takes some punishment, it will need replacing on a regular basis, so one-piece replaceable unit is ideal, as it is quick and easy to install as well as being gap free.
Where two-bit locking mechanisms are concerned, it can be difficult to tell if the recessed hole is cleaned out completely. The solution is a hygienic lock that protrudes from the door surface and which contains no recesses. Hinges also provide a haven for bacterial colonisation. However, if they are mounted inside the seal they are effectively removed from the external environment thus eliminating any potential contamination hazard.
Enclosure mounting, seals, gaskets, and gland plates can affect the IP rating and can often make the difference between the success and failure of an enclosure. Typically, the more hostile the environment, the higher the IP rating. When there is no likelihood of the enclosure being washed down, the IP rating could be as low as IP43. However, when subjected to a daily wash down, the internal equipment will need full protection and that requires an IP rating of IP69K.
Established in 1993, the IP69K protection rating which is currently the highest available, was originally designed to address the high pressure, high temperature wash downs of road vehicles. When high velocity jets of cleaning fluid are directed at machinery and their controls to remove debris from a previous batch run, IP66 is far from adequate.
IP69K enclosures are subjected to a rigorous test before they receive their certified rating. The test involves 14-16 litre/minute jets of water at pressures of up to 100bar and temperatures as high as 80°C, aimed at the enclosure from a distance of no less than 100mm and no more than 150mm. The duration of the test calls for four directions and test jet times of 30 seconds each, at angles of 0, 30, 60 and 90 degrees.
So, how is IP69K different from UL Type 4? IP69K and UL Type 4 standards both require the enclosure to protect against the entry of water, but the Type 4 test is mainly concerned with hose down conditions involving lower pressure water at a greater distance (10-12ft) and with a greater volume of water (65gallons/minute). IP69K is therefore an important standard for enclosure systems used within any environment where the equipment is subjected to high pressure cleaning.
- With acknowledgement to Rittal for the information contained in this article. Rittal’s Premium Line KL series enclosures offer the highest environmental protection to IP69K and come in a range of sizes.