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Hazardous Area Classification (HAC)

Hazardous Area Classification (HAC) study is done to evaluate and assess the different areas of plant based on the presence of Flammable material within the facilities. HAC study provides the details of Hazardous and Non-hazardous areas in the facility. It clears where the possibility of risk such as Fire and Explosion will occur in the facilities. Two systems are used to carry out the study. One is Class or Division system and other is Zone system.

Significance of Hazardous Area Classification study

There are five main objective of HAC in the process plant,

  • To eliminate the fatality and likelihood due to fire and explosion in the Flammable material atmosphere occurring around the source of ignition.
  • To eliminate the presence of ignition source around the Hazardous area.
  • To identify the Hazardous area in the facilities.
  • To reduce the Overall risk associated with the facility during design and installation itself.
  • To prepare operating and safety procedure for safe operation of plant and persons.

Why Hazardous Area Classification

Essential purpose to carry out Hazardous Area Classification study is to avoid the presence of Ignition sources such as Electrical apparatus in the Hazardous areas. If an electrical equipment is present in the area where the possibility of continuous or intermittent presence of Flammable material liquid/vapour, Combustible dust will lead to fire and Explosion. Those areas are easily identified and categorized by this study.

To ensure the Safe operation of plant and personnel during the design and commissioning stage itself.

Where to do Hazardous Area Classification

  • Oil and Gas drilling in Onshore and Offshore
  • Oil and Gas Production and Processing plants
  • Refineries
  • Petrochemical and Fertilizer industries
  • Gas pipelines and Centers
  • Terminals, Re-fuelling and Petrol stations

Steps involved in Hazardous Area Classification

Hazardous area classification has four major steps. They are,

  • Determination of type of hazard such as combustible gas, combustible dust and fibers that is present in the Facility
  • Identification of specific group for the hazardous substance involved.
  • Determination of degree of the classification.
  • Determination of the extent of the classified zones and locations in the facility.

Report Output

Hazardous Area Classification Study report helps to identify potentially hazardous and explosive area, determination of extent of hazardous zone and recommends the places need for special equipment within different zones. The report provides design requirements and guidelines for the selection and to identifying location of electrical equipment's in oil & gas / petrochemical / other industries


  • International - IEC 60 079 series
  • European     - CENELEC 60 079 series
  •  National      - USA : ANSI/API RP 505 (zone system)
  • Russia : Gost R 51330-X-99 series


  • Model CODE of safe practice Part IP 15 (UK)
  • “Non binding guide of good practice for implementing Directive n” 1999/92/EC”
  • API RP 505 Classification of locations for at Petroleum facilities
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