The following article has been authored by Brad Guy of Bluefield Compliance
Hazardous areas can sometimes appear to be an area of ambiguity and mystery for some.
This article is aimed at removing the mystery and explaining the basics of hazardous areas by giving some examples of where hazardous areas may be found along with the basic individual requirements.
Hazardous Areas are centred around electrical installations that may be surrounded by a flammable or combustible atmospheres where precautions need to be taken to prevent that electrical equipment becoming an ignition source and causing an explosion.
➡ Hazardous Areas Explained: Part 2 – Managing Hazardous Areas
Bluefield is passionate about equipment that operates reliably, at the lowest cost per tonne, and at reduced risk for clients in the mining, gas and transport industries.
The Bluefield specialists assist our clients to overcome the following:
Stress that comes from un-reliable equipment
Unwanted phone calls from site at night and on the weekend due to unscheduled events
Meetings to review maintenance budgets or production targets that are not on target
Asset replacement decisions that are not optimal for the business bottom line
Risk or uncertainty over asset integrity that could lead to catastrophic equipment failures
Requirements for hazardous areas are found in the IEC 60079 suite of standards.
The main standards used for classification, design, installation and inspection are:
IEC 60079.10.1 – Explosive Atmospheres Classification of Areas – Explosive Gas Atmospheres
IEC 60079.14 – Explosive Atmospheres Design Selection, Erection and Initial Inspection
IEC 60079.17 – Explosive Atmospheres Electrical Installations Inspection and Maintenance
WHAT IS A HAZARDOUS AREA?
According to IEC 60079.14 Edition 5 2013-11, a Hazardous Area is defined as an:
Area in which an explosive atmosphere is present, or maybe expected to be present, in quantities such as to require special precautions for the construction, installation and use of equipment.
An explosive atmosphere can be considered as a space that may at some stage through any means, may contain a flammable mixture of gas and air or a combustible mixture of dust and air – also referred to as potentially explosive atmospheres.
This does not consider what is called “catastrophic failure” in the standards, in this context, an example would be the rupture of a process vessel or pipeline and events that are not predictable. It would also apply to failures that cause a release of flammable or combustible material due to lack of, or incorrect maintenance.
EXAMPLES OF HAZARDOUS AREAS
Such hazardous areas can be found in many places throughout the industry in both large and small quantities, some examples are shown below:
Food manufacturing, where, in this case, it is the powdered milk that is combustible and when mixed with air if disturbed will ignite if an ignition source is available.
Coal handling prep plants are also considered as hazardous areas due to the concentrations of combustible coal dust clouds that can develop from spillage.
Gas wells, gas processing plants and gas-fired generators are common areas that contain hazardous areas due to the natural gas that is released in different sections of the plant in concentrations that can be considered as a flammable mixture.
Coal mines use MIBC which is flammable in certain concentrations requiring the surrounding area to be classified as a hazardous area.
Coal-fired power stations have hazardous areas where the coal dust can build up and form a combustible dust cloud.
The process of making paper utilises dust ingredients that can form a combustible mixture.
Ship fuel loading and unloading facilities have hazardous areas where fumes from the fuel can gather in flammable mixtures.
LPG bullets and fittings may have hazardous areas around possible sources of release.
On and offshore drilling rigs have many hazardous areas throughout the process area and extending further where the possibility of a flammable atmosphere may exist.
Food processing where organic dusts such as flour and other organic dusts are utilised in the food-making process to produce pastries, breads, cakes and biscuits etc.
In some cases, copper mining utilises chemicals that can be extremely flammable.
Hydrogen is another extremely volatile gas that can be used in power generation.
Fuel farms are an obvious source of flammable liquids and vapours.
Pet food manufacturers can use flammable gasses throughout the process.
3D printing is a relatively new industry that during the process may create a combustible dust atmosphere.
Gas compressors will create a hazardous area where the gas can congregate in flammable mixtures.
Mining and processing copper, lead, silver and gold use processes that have flammable gases and vapours including tanker loading and unloading.
Fume cupboards in laboratories will be considered as a hazardous area when flammable gasses and vapours are involved.
Biogas is a by-product of sewage and landfill that is treated as a hazardous area.
Methanol is a flammable liquid that gives off a flammable vapour and is used in some the processes at sewage treatment plants.
All the examples shown above are only a small cross-section of the industry that may have areas that can create a flammable atmosphere and where electrical equipment may need to be installed such as lighting, motors for pumps, heat tracing, solenoid valves, limit switches, process instrumentation and ventilation fans.
➡ Part 2 – Managing Hazardous Areas
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Thorne & Derrick International, based in the UK, are Approved Vendors to most Oil & Gas exploration and production companies and international EPC contractors including Bechtel, Petrofac, Saipem and Lamprell – our key sectors are the mining, process, pharmaceutical, chemical, utility, food/beverage, renewable and oil/gas industries.
We contribute strategic and added-value to the supply chains of the global chemical processing and energy sectors via our memberships of North East of England Process Industry Cluster (NEPIC) and NOF.
We are the Explosive Atmosphere Experts to COMAH-site operators providing innovative and often customised Ex solutions engineered to improve site safety and reliability.
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