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AREA CLASSIFICATION – ZONING. EN / IP Zone 0: The part of a hazardous area in which a flammable atmosphere is continuously present or. Figure Hazardous area zone classification shading convention. .. referred to as IP15) is a well-established Model Code for area classification in the. Level Definition In Hazardous Area Classification Ip15 – posted in Industrial Professionals: Hello, All For those who are familiar with hazardous.

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Model Code of practice in the Petroleum Industry’ Part 15 is recommended. The two parts are: The most commonly used standard in the UK for determining area extent and classification is BS EN part 10 1which classifixation broad applicability. Area classification may be carried out by direct analogy with typical installations described in established codes, or by more quantitative methods that require a more detailed knowledge of the plant.

Factors that could be considered during an on site inspection If there are any hszardous areas of zone 1 on the drawings, is there evidence that by design and operation controls, the sources of release and consequently the location and extent of hazardous areas have been minimised?

Where specialist vehicles e. Equipment built to such a harmonised standard may assume automatic conformity with those essential safety requirements of relevant directives that are covered by the standard. These should now be seen as rather conservative. Consequently, many employers are likely to try and justify not zoning storage compounds, where lift trucks handle flammable liquids or gases in containers.

The different parts of this standard set out requirements for construction of equipment for use in atmospheres containing explosive dusts; information about selection and maintenance; and BS EN DSEAR requires that hazardous area classification for flammable dusts should be undertaken hazadrous the same manner as that for flammable gases and vapours.

A hazardous area extent and classification study involves due consideration and documentation of the following:.

Level Definition In Hazardous Area Classification Ip15

The most common values used are:. The issues about representative samples of dust, and other factors that might cause the results to vary are also discussed in this guidance.

Status of Guidance Existing codes of practice provide information with respect to good practice for hazardous area classification. Measures to prevent major accidents should address all potential initiators. Typically these will involve written instructions, as specified in DSEAR schedule 1, or a formal permit to work system.


API versus IP15 – IET Engineering Communities

Do any zone 2 areas extend to places where the occupier has inadequate control over activities that could create an ignition source, or is there any suggestion that the zone boundaries have been arbitrarily adjusted to avoid this? Other processes such as hot oil heating circuits may handle products above their auto-ignition temperature. The main purpose is to facilitate the proper selection and installation of apparatus to be used safely in that environment, taking into account the properties of the flammable materials that will be present.

The Dangerous Substances and Explosive Atmospheres Regulations DSEAR provide for the first time a specific legal requirement to carry out a hazardous area study, and document the conclusions, in the form of zones. It contains much useful advice about limiting pumping speeds, electrostatic risks from clothing, and many detailed operations.

Hazardous Area Classification and Control of Ignition Sources

The flammable materials that may be present; The physical properties and characteristics of each of the flammable materials; The source of potential releases and how they can form explosive atmospheres; Prevailing operating temperatures and pressures; Presence, degree and availability of ventilation forced and natural ; Dispersion of released vapours to below flammable limits; The probability of each release scenario.

A – switch to normal size A – switch to large size A – switch to larger size. At present these are sold without any claim for ATEX compliance, but with the suggestion they may be useful in cases of remote risk. The consequences of a loss of power to the system should be included in any section looking at other consequences of power loss. New mechanical equipment will need to be selected in the same way. Hazardous areas may be considered to exist during the transfer operation, but should not be present once the transfer is complete.

Section 23 provides guidance on lightning protection. Dust Explosion Prevention and Protection: Hazardous areas are defined in DSEAR as “any place in which an explosive atmosphere may occur in quantities such as to require special precautions to protect the safety of workers”.


It tabulates values for an LPG mixture, gasoline, natural gas, and refinery hydrogen for pressures areea to barg. Basic concepts and methodology, British Standards Institution. European equipment standards may become ‘harmonised’ when a reference to them is published in the Official Journal of the European Community. The results of this work should be documented in Hazardous Area Classification data sheets, supported by appropriate reference drawings showing the extent of the zones around including above and below where appropriate the plant item.

Hazardous Area Classification and Control of Ignition Sources

Discussions are also ongoing, about vehicles with gas detection systems, designed to shut the engine and isolate other sources of flassification in the event of a gas release. The most recent general source of advice was drafted by a European standards working group, but was published in the UK as BS PD R and not as a full standard.

These will include electrical circuits; the inlet and exhaust of any internal combustion engine; electrostatic build up; overheating brakes, and other moving parts. This Technical Measures Document refers hazardkus the classification of plant into hazardous areas, and the systematic identification and control of ignition sources.

These are currently under revision, and will specify hazardous areas, that in most cases will be smaller than the separation distance. Area classification is a method of analysing and classifying the environment where explosive gas atmospheres may occur. HS G 2 Formula for hazarsous and safety: DSEAR sets out the link between zones, and the equipment that may be installed in that zone.

Similarly the IGE code gives a methodology for natural gas, relating the leak rate to the hole-size and the operating pressure. In this context, ‘special precautions’ is best taken as relating to the construction, installation and use of apparatus, as given in BS EN 1.

Using electrical equipment and instrumentation classified for the zone in which it is located.

Catastrophic failures, such as vessel or line rupture are not considered by an area classification study.