Irish factories Act in 1955 position on explosions:
“In the case of a process giving rise to dust of such a character and to such an extent as to be liable to explode on ignition, then, unless the plant is so constructed as to withstand the pressure likely to be produced by any such explosion, all practical steps shall be taken to restrict the spread of the effects of such an explosion by the provision, in connection with the plant, of chokes, baffles, and vents, or other effective appliances”.
This is a very simple statement of fact which is still true today but now we have a dearth of legislation which attempts to harmonise the activities of EU member states and specify the minimum EHSR (essential health and safety requirements) of the process, its equipment and protective measures employed in it.
The ATEX directive consists of two EU Directives.
- The responsibility of the User: the ATEX 153 workplace directive 99/92/EC, Minimum requirements for improving the safety and health protection of workers potentially at risk from explosive atmospheres.
- Harmonised requirements for the Manufacturer to sell to the User: the ATEX 114 equipment directive 2014/34/EC, Equipment and protective systems intended for use in potentially explosive atmospheres, these are supported by EN standards.
Employers must classify areas where hazardous explosive atmospheres may occur into zones. The classification given to a particular zone, and its size and location, depends on the likelihood of an explosive atmosphere occurring and its persistence if it does.
Areas classified into zones (0, 1, 2 for gas-vapour-mist and (by placing a digit 2 in front for dust) 20, 21, 22 for dust) must be protected from effective sources of ignition. Equipment and protective systems intended to be used in zoned areas must meet the requirements of the directive. Certification ensures that the equipment or protective system is fit for its intended purpose and that adequate information is supplied with it to ensure that it can be used safely.
Manufacturers who apply its provisions and affix the CE Mark and the Ex marking are able to sell their equipment anywhere within the European union without any further requirements being applied with respect to the risks covered being applied. The directive covers a large range of equipment, potentially including equipment used on fixed offshore platforms, in petrochemical plants, mines, flour mills and other areas where a potentially explosive atmosphere may be present.
The directive also covers components essential for the safe use and safety devices directly contributing to the safe use of the equipment in scope. These latter devices may be outside the potentially explosive environment. Manufacturers/suppliers (or importers, if the manufacturers are outside the EU) must ensure that their products meet essential health and safety requirements and undergo appropriate conformity procedures.
When considering your hazard, you should carry out some simple steps. Do you have a hazard at all; check generic data or industry sources. If you cannot find the appropriate data then a classification test is required. If your product already is a proven hazard then you need to quantify the characteristics of the hazard and if protection systems are necessary, you need the extent of the explosion Pmax and KST. All of these parameters have to be relative to the process and condition of your equipment.
The Position in UK and Ireland
All businesses are required no matter what size to comply with the above. The ATEX 153 has been brought into legislation in the UK by the Dangerous Substances and Explosives Atmospheres Regulations (DSEAR) 2002 No. 2776, DSEAR
To comply you must:
- carry out a risk assessment of any work activities involving dangerous substances
- provide measures to eliminate or reduce risks as far as is reasonably possible
- provide equipment and procedures to deal with accidents and emergencies
- provide information and training to employees
- Classify places where explosive atmospheres may occur into zones and mark the zones where necessary.
- Many of the standards and guidance documents for ATEX are still on the drawing board. There are now further work being done on special conditions like bucket elevators, Flame diverters, and small and large vessels.
My last comment on this new challenge is that more than 2000 incidents of gas, mist and dust/air atmospheres occur annually in Europe, causing injuries, loss in production, plant damage and even death. This is not acceptable and the introduction of the ATEX and DSEAR regulations should be welcomed.
There are many organisations suddenly offering products and services which can help you through this, but make sure they are reputable with a history in explosion prevention and protection.
The ATEX exercise should be programmed and carried out by the employers with their employees to make our industry a safer and more profitable experience.