Answer 1: An EC Type Examination Certificate is needed to demonstrate that equipment can be safely operated in a potentially explosive atmosphere created by the presence of flammable gas, vapour, mist or clouds of combustibe dust. EC Type Examination Certificates are issued only by European Notified Certification Bodies, such as PTB in Germany, CESI in Italy, BASEEFA in the UK and many others. The EC Type Examination Certificate is issued following the examination of the equipment Technical File and testing, according to the relevant standards that are applicable for each specific type of explosion protection applied to the equipment, such as flameproof or dust proof containers, intrinsically safe devices, etc. Once the EC Type Examination Certificate is obtained the manufacturer must also get from a Notified Body a certification of the production: it is a control of the manufacturing activities based on ISO 9001 and focused on the ATEX requirements of the product. The basis of EC Type Examination Certification is the European Directive 94/9/EC.

Answer 2: Many types of flame-resistant cable exhibit "cold flow" of the inner sheath bedding, which could have adverse effects on the protection of the apparatus. Where such cable is used, it is a requirement of I.S.EN 60079-14 clause 9-1-3 to employ a suitable cable entry device. The code of practice clearly states that "a cable gland employing a compression (displacement) seal should not be used on cable exhibiting cold flow characteristics". "Cold flow" can be more fully described as thermoplastic materials which flow when subjected to pressure at ambient temperature, i.e. the inner sheath bedding material will flow away from any pressure applied to it, including that of a cable gland inner seal of the compression or displacement type, the effect being that there may no longer be an effective seal on the inner sheath of the cable.

Answer 3: The entry thread does form part of the flame path between the enclosure and the cable gland and must, when installed with parrallel threads, provide at least five full threads engaged between the box and gland.

Answer 4: With regard to an Exe application there is nothing that prevents the use of two adapters. It is not good practice as cable glands and adapters are normally tested and certified with only one adapter or reducer fitted from an impact point of view, therefore if you have two you are increasing the effects of the impact and the number of sealing faces. If the application was flameproof this would not be acceptable.

Answer 5: Earth tags are used where equipotential bonding or earthing of equipment needs to be conducted at a common earth point outside the enclosure. The way they are used is that they are generally fitted to the front entry thread of a Cable Gland between the Enclosure and Cable Gland. The tag then has a hole in it into which a earth screw can be fitted and an earth wire attached, this can then be taken to a common earth point to enable equipotential bonding. The standard covering earthing in hazardous areas is I.S.EN 60079 – 14. If a Sealing Washer is required in addition to the Earth tag this is normally placed between the Enclosure and the Earth tag.

Answer 6: The arrangement of using a flameproof "Exd" cable gland in place of an increased safety "Exe" cable gland is usually acceptable. You must refer to I.S.EN 60079-14. It is therefore advisable to obtain clearance from the project/site inspecting authority in advance.

Answer 7: I.P. washers can be used in Exd applications providing it does not result in the length/number of threads being less than the standard requirements i.e. 5 full metric threads and 8mm of thread length. Refer to I.S.EN IEC 60079–14.

Answer 8: Modifications are not permitted on EExd enclosures, i.e. No additional entries, or changes to the flamepaths etc. If lid screws are lost or damaged, the enclosure manufacturer should be consulted to ensure the correct screw is sourced as a replacement.

Answer 9: Serrated washers are used to prevent rotation of the earth tag and any loosening of the gland, locknut/box assembly due to vibration. They are often used on increased safety plastic boxes containing earth plates which have been site drilled. The washer can also be used to replace the earth plate anti-rotation pips which are often removed during the machining process.

Answer 10:

• Gas group IIC – Minimum of 40mm
• Gas group IIB – Minimum of 30mm
• Gas group IIA – Minimum of 10mm

Answer 11: Some products carry a suffix ‘X’ after the certificate number. This denotes "special certification conditions". These are given on the certificate and on the installation leaflet. The conditions usually relate to cable entry, operation, lamps, installation position and location or maintenance, and must be observed by the user.

Answer 12: Some products carry a suffix ‘U’ after the certificate number. This denotes "that this is a component and has a schedule of limitations". These are given on the certificate and on the installation leaflet. The schedule of limitations must be observed by the user.

Answer 13: Manufacturers/suppliers of ATEX equipment are obliged to deliver a copy of the Declaration of Conformity, a set of instructions for safe use relating to the product and an "EC Type Examination Certificate". Manufacturers are not obliged to provide a copy of the Technical File. If you don’t receive these things then the manufacturer/supplier is not fulfilling his responsibilities under the ATEX directive.

Answer 14: If you have pre-ATEX equipment then you can supply spare parts for those products in accordance with the original design. This is repair of equipment and is handled under ATEX 137. The supply of parts for repair of existing equipment is not covered under ATEX 94/9/EC. If equipment is modified, (i.e. it is changed to operate or achieve it's purpose differently than the manufacturer had originally intended) whether it is pre-ATEX or not, may cause it to require re-assessment, depending on whether the modifications are 'substantial'. This would be the case if the modifications affect a principle part of the explosion protection. For example, modifying a shaft on a rotating machine may not be a problem, but modifying an endshield to give different flamepaths would require re-assessment. If an item of pre-ATEX equipment is to be replaced (because it is no longer able to function or is beyond repair) then it can be replaced with an equivalent ATEX compliant product. Alternatively it could be replaced with an identical pre-ATEX certified product, provided that product had been placed on the EU market for use in hazardous areas before 30 June 2003. Fore more information, please see clause 3.1 of the ATEX Directive (the term 'placed on the market' is defined in the guidelines).