Area Classification Why ? Where ? How ? Who ? When ?

/ Industrial Knowledge / By

AREACLASSIFICATION Why?A brief history ofaccidents

Severe accidents in coal mines occurred through the world in the 19th and 20th century (thousands of casualties).

Causes : result of ignition of Fire damp by sparks (often generated by electrical apparatus) leading to those catastrophic accidents .


Oil & gas and chemical industries also generated many accidents (fire ,explosion).

Safety problems related to the design and use of electrical apparatus in hazardous areas have led the Authorities, at a very early stage to impose very strict rules.

AREA CLASSIFICATION Why? Fire , Explosionorigin

Ø In a situation in which there may be an explosive (flammable) atmosphere , the following steps should be taken:
  1. eliminate the likelihood of an explosive gas atmosphere occurring around the source of ignition, or
  2. eliminate the source of ignition.

Where this is not possible, protective measures, process equipment, systems and procedures should be selected and prepared so the likelihood of the coincidence of a) and b) is so small as to be acceptable.

  • Area classification : method of analysing and classifying the environment where explosive gas atmospheres may occur so as to facilitate the proper selection and installation of equipment to be used safely in that environment.
  • Allows preparation of safety procedures for plant operation and maintenance.
  • The area classification process reduces the overall installation risk level through design improvements.

AREA CLASSIFICATION Where ? Included as per IECEx

  • Oil & gas production and processing plants :

-onshore

-offshore : platforms, FPSO (Floating Production Storage Offloading vessels)

  • Oil and gas tankers, drilling ships
  • Oil refineries
  • Petrochemical and Chemical processing plants
  • Gas pipelines and distribution centers
  • Re-fuelling stations or petrol stations
  • Underground coal mines
  • Printing industries, paper and textiles
  • Hospital operating theatres
  • Surface coating industries
  • Sewerage treatment plants
  • Grain handling and storage and processing (flour-milling industry)
  • Sugar refineries
  • Light metal working, where metal dust and fine particles can appear
  • Woodworking areas

IEC 60079-10-1 Classification of areas – Explosive gas atmospheres

Standard intended to be applied where there may be an ignition hazard due to the presence of flammable gas or vapour, mixed with air under normal atmospheric conditions but does not apply to :

  • mines susceptible to firedamp, but IEC 60079 series apply to mines (gas group I)
  • processing and manufacture of explosives.
  • areas where a hazard may arise due to the presence of combustible dusts or fibers (refer to IEC 61241-10 / IEC 60079-10-2).
  • catastrophic failures which are beyond the concept of abnormality dealt with in this standard.
  • rooms used for medical purposes.
  • domestic premises.

AREACLASSIFICATION How?

We will cover how in our next post, welcome to subscribe.