SLIDE 6 Custom Enclosures - Zone 1 (ATEX Cat 2)
- Pressurized Enclosures PE2
– Expo construct OR verify clients assembly
Schedule of Limitations GA drawings & Component List
– 3rd Party Certificate in Expo name:
IECEx: ITS 08.0044X ATEX: ITS10ATEX16944X
Ex px IIC T4 Gb Ex p IIIC T135°C
Expo-Intertek Schedule of Limitations 1
Maximum Size * 2100 mm (82.68”) H x 1800 mm (70.87”) W x 1000 mm (39.37”) D Maximum volume = 3780 Litres Purge Time Purge Time must reflect 10 volume changes and be between 10 and 30 minutes Layout * 30% minimum free space, in any cross section of any plane of the enclosure.
* Can be exceeded: requires witnessed purge test
Expo-Intertek Schedule of Limitations 2
Ventilation of Internal Items * Internal closed items require minimum ventilation holes of 1cm²/litre to avoid potential trapped gas. If necessary, increase existing holes to suit or make new/additional holes (min. size 28.2mm2 or 0.043in2) Closed items need ventilation distributed equally at the top and bottom surfaces. Permitted Closed Items Hermetically sealed or potted devices. Allowed if total volume of such sealed items < 1% of the internal free volume of the enclosure, and:
- the item does not contain any potential source of ignition, or
- the item is Ex d, Ex e (no batteries), Ex i, Ex m or Ex n
certified
* Can be exceeded: requires witnessed purge test
Expo-Intertek Schedule of Limitations 3
Heat Dissipation Two temperature limiting devices must be used (one can be used to initiate a cooling system). Batteries or Cells The following approved batteries are allowed: CR2032 (VARTA or Panasonic) CR½ AA (VARTA or Sonnenschein) SL-340 (Tadiran or Sonnenschein)
** Non-approved batteries require an Expo “Battery Test”
Fans Maximum airflow permitted: 400 litres/sec (14.125 ft3/sec) Inlet Position > 200 mm (7.78”) from air leakage points, e.g. door gaskets or access plate gaskets.
* Can be exceeded: requires witnessed purge test
Expo-Intertek Schedule of Limitations 4
* Can be exceeded: requires witnessed purge test
Optical Devices Low power communication devices are allowed. Permitted Thru-Wall Components Devices or components mounted through the enclosure wall must have a suitable IP rating for the enclosure and must either be metallic (or if non-metallic, must be Ex rated - demonstrates compliance with UV & Impact specification). Cable Glands, Conduits and Sealing Systems shall be Ex-certified and suitable for use with the cable type and in the required Hazardous Location.
Expo-Intertek Schedule of Limitations 5
Isolation of Electrical Inputs to the Enclosure ALL electrical supplies (power & signals) that enter the enclosure NOT individually protected by another explosion protection technique MUST be automatically isolated following the ALARM signal of the Expo Purge Control system. Hot Internal Components Internal devices with surface temperature above T4 (135 ºC) must be declared, and extra precautions identified and specified. Examples are: filament lamps, power semiconductors, thyristors, heaters, power resistors, etc.
