Intrinsically Safe Pneumatic Equipment 1

[sjohnr]

I used to be up on this but since moving to the US I'm a bit behind. I recently stumbled on an air driven motor, perfect for an application we're working on, but the manufacturer (I won't mention the name) claims that it is intrinsically safe! And quotes all sorts of convincing ATEX type letters and numbers. What??!! Since when did pneumatic equipment need hazardous area certification? Does anyone know what the potential ignition source is here?

 

[davsy]

If you are supplying to Europe an air driven motor will need to be ATEX approved.

The manufacturers who supply into Europe have had to revise their equipment and have them certified ATEX. below is an excert from En 13463 (None electrical equipment for hazardous areas) specific to pneumatic and hydraulic items.

I think the main focus is that it must not be possible to create a temperature which is greater than the specified maximum surface temperature of the unit. this could be due to hot oils, clearances being too small or friction caused by a premature failure.

Choosing an air motor for a hazardous area over an explosion proof motor is not the simple option it used to be, over here in Europe anyway.


7.5 Hydrostatic/Hydrokinetic/Pneumatic – equipment
7.5.1 Hydrostatic/hydrokinetic and pneumatic power transmission equipment shall be constructed of pipes,
enclosures and/or other external parts, which do not produce hot surfaces exceeding the maximum surface
temperature, even when operating continuously at maximum normal rating.
7.5.2 Hydrostatic/hydrokinetic equipment shall comply with the requirements of EN 982.
7.5.3 Pneumatic equipment shall comply with the requirements of EN 983.
7.5.4 The maximum temperature of any power transmission fluid which can be released shall not exceed the
maximum surface temperature of the equipment, if this can create an ignition risk.
NOTE A suitable over-temperature protection device, can be a fusible plug in a fluid coupling which melts to release the
power transmission fluid from the coupling during overload/over-temperature (see prEN 13463-6).
7.5.5 To prevent ignition of the explosive atmosphere by burning liquid the power transmission fluid shall have a
suitable fire resistance rating.
NOTE 1 For Group I equipment this can be achieved by using a liquid with a fire resistance rating of at least "2", when tested
in accordance with the 'Community of Six Spray ignition Test' and a persistence of flame not exceeding 30 s, when tested in
accordance with the 'Wick test', as described in 3.1.1 and 3.2 of the European Safety and Health Commission for Mining and Other Extractive Industries (SHCMOEI) document - "Specifications and Testing Conditions Relating to Fire Resistant Fluids
Used for Power Transmission (Hydrostatic and Hydrokinetic)"
NOTE 2 National legislation in member states can require the use of different fire resistant fluids in certain hydraulic systems.
7.5.6 Air compressors used for pneumatic equipment shall:
¾ incorporate a filter on the intake system to prevent the ingress of dust or similar foreign material into the parts
where compression takes place;
¾ contain only lubricants which are resistant to carbonisation;
NOTE 1 Carbonisation of compressor lubricant (caused by exposure to elevated temperatures) results in the formation of oily
carbon deposits in the compressor delivery which can cause it to overheat and explode.
NOTE 2 For fluids operating at high pressure (e.g. inside compressors) allowance should be made for the fact that the
ignition temperature is lowered by increased operating pressure.