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Electrical (Hazardous Area) Classification
Establish a Basis of Safety with an Electrical Classification Assessment
By identifying the areas susceptible to fire or explosion, electrical classification (also known as hazardous area classification (HAC)) assists in reducing their chances of experiencing an incident resulting in damage to property and potential injury or loss of life. Though HAC was originally used primarily for choosing electrical equipment to prevent ignition in hazardous atmospheres, now HAC is being applied in risk assessments to areas that can contain flammable vapors, gases, combustible dust, or fibers. For this reason, HAC is needed not only in chemical plants but in a variety of other industries from food processing to power generation. Both OSHA and the NFPA reference HAC in their safety regulations / model consensus standards, as do the ATEX/DSEAR directives in Europe.
DEKRA can help you with new and existing regulations and in identifying those areas in a plant where flammable atmospheres and combustible dusts can be found. We are uniquely suited to provide HAC support and our international experts have the know-how and experience to guide you through the complexities of the classification process.
A Comprehensive Approach to Hazardous Area Classification
Implementing a hazardous area classification exercise requires a thorough knowledge of the relevant industrial processes and equipment. The DEKRA approach uses a disciplined eight step process from assembling the right team, through testing and data gathering, scenario evaluation, and documenting the area class and division (or zone) rating.
Along the way, DEKRA can support the process with specialized laboratory services and testing that might include: explosibility (dust deflagration constant (Kst)) and ignitability (minimum ignition energy of a dust cloud (MIE)), minimum ignition temperature of both a dust cloud and layer (MITc and MITl), minimum explosible concentration (MEC) tests, and conductivity properties, flammability limits (LFL and UFL), flashpoints (liquids), gas or vapor density, auto ignition temperature (AIT), minimum igniting current (MIC) and maximum experimental safe gap (MESG).
Hazardous area classification is the process of identifying and classifying locations where flammable gases, vapors, combustible dusts, or ignitable fibers may be present. Also known as electrical area classification or hazardous location classification, this process helps determine where specially designed electrical equipment and safeguards are needed to reduce ignition risks.
Hazardous area classification helps organizations reduce the risk of fires and explosions by ensuring electrical equipment, systems, and operating practices are suitable for areas where flammable atmospheres may develop. A thorough hazardous location assessment is an important part of process safety, equipment selection, explosion prevention, and ongoing risk management.
Hazardous area classification may be required wherever flammable gases, vapors, mists, combustible dusts, or ignitable fibers could create a hazardous atmosphere. Facilities that handle chemicals, fuels, solvents, powders, grain products, pharmaceuticals, or other combustible materials may need an electrical classification study to identify and document these risks.
Hazardous location classification separates areas according to the type of hazardous material that may be present:
- Class I locations involve flammable gases or vapors.
- Class II locations involve combustible dusts.
- Class III locations involve ignitable fibers or flyings.
These classifications help determine which electrical equipment and protection methods are suitable for safe operation.
Division 1 locations are areas where ignitable concentrations of hazardous materials may be present during normal operations. Division 2 locations are areas where those materials are not normally present at ignitable concentrations but could appear under abnormal conditions, such as a leak or equipment failure. These designations are documented during the electrical area classification process.
A hazardous area classification study typically includes a facility review, process evaluation, identification of potential release sources, and assessment of ventilation and operating conditions. A hazardous area consultant may also prepare classification drawings, review equipment suitability, document findings, and recommend practical measures for reducing ignition and explosion risks.
Hazardous area classification services can benefit chemical manufacturing, oil and gas, food processing, pharmaceutical production, battery manufacturing, specialty chemical, agricultural, and other industrial facilities. These services are especially relevant when operations involve flammable gases, vapors, combustible dusts, ignitable fibers, or other materials capable of creating a hazardous atmosphere.
Hazardous area classifications should be reviewed after significant process changes, equipment modifications, facility expansions, material changes, or updates to applicable codes and standards. Periodic hazardous area classification consulting can also help confirm that existing classifications, drawings, and equipment requirements remain accurate as facility conditions evolve.
Hazardous area classification supports compliance by helping organizations identify hazardous locations and specify electrical equipment designed for those environments. A documented hazardous location assessment also provides information that can support electrical safety, fire protection, process safety, engineering, maintenance, and equipment selection activities.
After an electrical classification study is completed, the organization typically receives classification drawings, supporting documentation, findings, and recommendations. These deliverables identify hazardous locations, address equipment suitability, and highlight risk reduction opportunities that can guide future engineering, maintenance, operational, and compliance activities.
