Hazloc certification

TRaC can provide equipment test and certification for the US and Canadian market through partnership arrangements with NRTL and SCC facilities in North America. Wherever possible, testing and assessment is conducted in the UK and usually alongside the procedures for ATEX product certification.

The hazloc certification process includes two elements:

• Product test and assessment
• Factory inspection

"Hazloc" in the USA

The US National Electrical Code (NEC) is the primary source of reference for hazardous locations in the USA. Whilst the definitions of terms are US driven there is much common ground with the EU and IEC requirements. US participation in IECEx procedures and IEC standards writing has also meant that US standards are slowly moving towards harmonisation with the IEC (and EN) standards. However, for the present, significant differences remains between equipment standards and definitions of hazardous areas.

Hazardous locations are classified in three ways by the US NEC: Type, condition, and nature.

• Type - There are three types of hazardous conditions: Class I - gas and vapour, Class II - dust, and Class III - fibres

• Condition - There are two kinds of hazardous conditions: Division 1 - normal, and Division 2 - abnormal

• Nature - The nature of the hazardous substance or material (specified as Groups A, B, C, and D in Class I locations, and, in Class II locations: Groups E, F, and G)

Only special classified equipment may be used in a hazardous location. This equipment is classified using the same criteria as the hazardous location and carries clear marking to this effect. All hazardous location equipment must be certified by a third party NRTL or SCC body.

Hazardous location types

A Class I Hazardous Location is one in which flammable gases or vapours may be present in the air in sufficient quantities to be explosive or ignitable. This would be equivalent to an ATEX zone 1 (or in some cases a zone 0). Some typical Class I locations are:

• Petroleum refineries, and gasoline storage and dispensing areas
• Dry cleaning plants where vapors from cleaning fluids can be present
• Spray finishing areas
• Aircraft hangars and fuel servicing areas
• Utility gas plants, and operations involving storage and handling of liquified petroleum gas or natural gas

A Class II Hazardous Location is an area made hazardous by the presence of combustible dust suspended in the air. Some typical Class II locations are:

• Grain elevators;
• Flour and feed mills;
• Plants that manufacture, use or store magnesium or aluminum powders;
• Producers of plastics, medicines and fireworks;
• Producers of starch or candies;
• Spice-grinding plants, sugar plants and cocoa plants; and
• Coal preparation plants and other carbon handling or processing areas.

A Class III hazardous location is an areas where there fibres and flyings, which although not likely to be suspended in the air, can collect around machinery or on lighting fixtures and where heat, a spark or hot metal can ignite them. Some typical Class III locations are:

• Textile mills, cotton gins
• Cotton seed mills, flax processing plants
• Plants that shape, pulverize or cut wood and create sawdust or flyings

Hazardous location conditions

There are two kinds of hazardous conditions: Division 1 - normal and Division 2 – abnormal. In the Division 1 (normal) condition, the hazard would be expected to be present in everyday production operations or during frequent repair and maintenance activity. The situation could be called "abnormal” (and classified Division 2) when the hazardous material is expected to be confined within closed containers or closed systems and will be present only through accidental rupture, breakage or unusual faulty operation.

Hazardous location nature

The gases and vapours of Class I locations are broken into four groups by the Code: A, B, C, and D. These materials are grouped according to the ignition temperature, its explosion pressure and other flammable characteristics.

• Group A - The only substance in Group A is acetylene (a gas with extremely high explosion pressure)

• Group B - Includes hydrogen and other materials with similar characteristics

• Group C and Group D are by far the most usual Class I groups. Group D includes many of the most common flammable substances such as butane, petrol, natural gas and propane

In dust locations (Class II) are the hazardous materials in Groups E, F, and G. These groups are classified according to the ignition temperature and the conductivity of the hazardous substance. Conductivity is an important consideration in Class II locations, especially with metal dusts.

• Group E - This group includes metal dusts (including aluminium and magnesium dusts)

• Group F - This group contains such materials as carbon black, charcoal dust, coal and coke dust

• Group G - This group comprises grain dusts, flour, starch, cocoa and similar types of materials