Michael Mobley is certification project engineer at Oldham. Mobley can be reached at [email protected].
How does purchasing a product with a hazardous location certification benefit the purchaser? To answer that question, an overview of the certification process is required. This overview includes the steps necessary for a manufacturer to obtain a certification and what the certification can tell you about a product.
The certification process is broken into two parts—an evaluation of the technical aspects of the product being certified and a review of the quality systems of the facilities producing and controlling the design of the product. A product is not considered certified unless both aspects of the process are satisfied.
The technical evaluation of a product is what most people think of when they consider hazardous location certification. This is the process during which the product design is reviewed, samples are tested against national and international standards, product documentation and labeling are checked against requirements, design iterations are done to meet the requirements and, ultimately, the product meets the technical standards of the certification being pursued. This process can take months or even years to complete, depending upon many factors of the evaluation and design review. However, at the end of the process, the goal is to have a design that is fully compliant with all relevant standards and safe to use in hazardous locations.
While the above is nice, it ignores an important factor—a product needs to be not only designed, but also manufactured. As part of the manufacturing review of the device being certified, any location that has a direct impact upon the safety-critical features of the product must be operated under a quality system that meets the hazardous location requirements for the certification being sought. These requirements are met in addition to an ISO 9001 certification and are specific to hazardous location-approved products.
These requirements include supplier quality, design control processes, part inspections, purchasing department procedures, traceability of critical parts, traceability of final product and testing during manufacture. These aspects are checked via site audits by the certifying agency and must be approved prior to the issuance of a product’s final hazardous location certification.
The certification of a product indicates important characteristics of the product. These include the type of hazardous atmosphere in which the product can be used—gas, dust or fibers; the subtype of hazardous atmosphere via gas groups or dust groups—A, B, C, D, IIA, IIB, IIC for gas or E, F, G, IIIA, IIIB, IIIC for dust; the type of protection the product uses—for example, flameproof/explosionproof, intrinsically safe or non-incendive; the level of hazard for which it has been approved—Division 1 or 2 or Zone 0, 1 or 2; how warm the external surface of the product gets via the “T” code—T6 is the coolest and T1 is the hottest; and the approved operational ambient temperature range in which the product may be used and still remain safe. Examples of common codes are: Explosionproof Class 1 Division 1 Groups B, C, D, T4, -20°C ≤ Tamb ≤ 65°C for North America and (Flameproof) II 2G Ex d IIC T4 Gb -20°C ≤ Tamb ≤ 65°C for IECEx.
The benefit to the purchaser is in the proper usage of the product based upon the intent of the certification. Using a product approved for use in a hazardous location that is appropriate for the user’s needs reduces the chance of work-site accidents and can lower costs related to inspections and insurance. Using certified products is a piece of a system that creates and contributes to a safe work environment.