Requirements for drawings and documentation for intrinsically  safe “d” electrical equipment  during certification as per IECEx OD 017

The following dimensions/details should be shown in the drawings/documents of intrinsically safe “d” electrical equipment:

1. The maximum structural tolerance for each joint/interface and the flame path length and maximum flame path gap;
2. The length, dimensions, and minimum yield strength or grade of fasteners. The data and characteristics of fasteners can be included in a table that is cross-referenced with applicable drawings;

3. Space the bolt holes evenly;
4. The size and tolerances of the through holes for fasteners. This can be included in a table cross-referenced with applicable drawings;
5. The depth of drilling and tapping. This can be included in a table cross-referenced with applicable drawings;
6. Minimum thickness of material around the hole. This can be included in a table cross-referenced with applicable drawings;
7. The maximum and minimum diameters of the shaft and hole, as well as the maximum radial clearance “m” and minimum radial clearance “k” of rotating parts.
8. The threaded joint surfaces, including the introduction device, shall include the size range and maximum number, pitch, thread fit grade, and the length of the thread on the housing (taking into account chamfers and grooves).
9. It should show the areas where cable entry devices, switch actuators, viewing ports, and outlets may be installed.
10. Methods for fixing non-threaded fittings, such as those with a flange joint face;
11. The size and location of holes on the enclosure surface for mounting certified components;
12. The overall dimensions of the case, including the minimum wall thickness;
13. The type and size of the weld;
14. The minimum thickness, material, and installation method of the window;
15. Normally, internal component layout diagrams and thermal dissipation diagrams showing the positions and approximate sizes of the components, including the gap between the component and the nearest wall, are used to control:
    the location of heat sources for temperature classification; the tolerance temperature of plastic components, windows adhesives, other potting materials, cable entry devices, etc.; to confirm the local environment of some components such as intrinsically safe barriers.
    Dimensions related to pressure overlapping effect
    If the certificate is to cover changes in content: there must be sufficient detail in the scope so that the design limitations for each change are absolutely clear.
16. Surface roughness of the flame path;
17. For bonded joints: technical specifications of the adhesive, manufacturer’s data sheets, and the minimum distance through the bonded joint surface; type and thickness of gaskets.
18. Technical specifications and data sheets for sealing packing used in applications such as packing boxes;
19. The complete specifications for the sintered metal components that constitute the shell or flammable sensor part, including: material, maximum bubble diameter, minimum density, size, etc.
20. The insulating materials that are subjected to electrical stresses related to the explosion-proof type, such as the CTI (Creepage and Tracking Index) of the insulating material through the insulating sleeve;
21. The total internal volume and the net internal volume (if the general dimensions are not clearly visible);
22. The length and dimensions of interference fit or pressed parts;
23. If lubricating grease is used on the joint surfaces, it should be identified and a detailed specification data sheet should be provided to detail the aging process, solvent evaporation, corrosion, and flash point.
24. The thickness of the electroplated flame path;
25. Detailed information on the installation of batteries and cells, as well as safety devices to prevent the battery from overheating, being connected incorrectly, and exceeding the manufacturer’s charging specifications. Any information on internal thermal protection devices and their location.

Reference: IECEx OD 017 Edition 7.0 2024-04 IECEx OPERATIONAL DOCUMENT IEC System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres (IECEx System) IECEx Certified equipment scheme –Drawing and documentation guidance for IECEx certification – for use by manufacturers and ExTLS “[S].