There are many manufacturers that make specialist equipment suitably for use in explosive environments. These specialist testers and equipment must be made with the utmost care and attention, with clearly marked ATEX certification that tells users exactly where the equipment is applicable for use in.
All manufacturers of explosive-protected equipment must completely with the requirements of the Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 1996. These are more commonly referred to as ATEX regulations.
All equipment intended for use in potentially explosive atmospheres, including machines, apparatus, fixed or mobile devices, control components and related instrumentation, detection or prevention systems, is governed over by these regulations. The equipment is defined as:
- intended for the generation, transfer, storage, measurement, control and conversion of energy or the processing of material and which are
- capable of causing an explosion through their own potential sources of ignition
Equipment Groups
Under the regulations, ATEX equipment is divided into two specific groups:
- Group 1 – Equipment intended for use in underground mining applications with dangers such as fire, damp and combustible dust
- Group II – all other places at risk of explosive atmospheres
These are also further divided up into subcategories to better understand the specific application for equipment usage.
| Equipment Sub-Group | Definition |
|---|---|
| Group I, Category M1 | The equipment within this category is designed to remain functional even in the event of rare incidents relating to equipment with an explosive atmosphere present |
| Group I, Category M2 | Specially designed to de-energise in the event of an explosive atmosphere developing |
| Group II, Category 1 | This equipment is used in continuous-risk explosive atmospheres where there is a realistic constant risk of ignition |
| Group II, Category 2 | Equipment designed to be used in areas in which explosive atmospheres caused by gases, vapours, mists or air/dust mixtures are likely to occur |
| Group II, Category 3 | Equipment designed to be used in areas in which there is a low risk of explosive atmospheres developing, and if they do, it will be only for a small period of time or infrequently |
Developing Explosive Prevention Equipment
This CordEx camera is designed to be used in environments where normal cameras might cause an ignition
It is the responsibility of any manufacturer planning to develop this type of equipment to prevent combustion of the atmosphere as best as possible using integrated explosion safety.
The equipment should prevent explosive atmospheres from forming by stopping elements that could cause combustion from forming and should take into full account electrical and non-electrical ignition sources to create an acceptable level of protection.
One of the most important aspects is using materials that will not trigger an explosion at any point over the foreseeable operating life of the equipment being developed. This is required to be adhered to by the ATEX Regulations 1996 which states that it “must not be possible for a reaction to take place between the materials used and the constituents of the potentially explosive atmosphere that could impair explosion detection”.
To do so, the manufacturer must consider the material’s ability to resist explosive reactions and determine the corrosion and wear resistance, electrical conductivity, impact strength and ageing resistance and the effects of temperature variations upon said material.
Potential Hazards in Potentially Explosive Atmospheres
As a manufacturer, it is the responsibility of the company to ensure their equipment prevents hazards from arising as a result of several factors.
| Type of Hazard | Definition |
|---|---|
| Ignition Sources | Every piece of explosion-proof equipment must prevent sparks, flames, electrical arcs, high surface temperature, acoustic energy, electromagnetic waves and all other errors that could cause an ignition. |
| Static Electricity | Electrostatic charges capable of resulting in dangerous discharges must be prevented by means of appropriate measures |
| Stray Electric and Leakage Currents | Conductive parts must be constructed in such a way that dangerous corrosion, overheating of surfaces and sparks cannot form and potentially ignite the atmosphere |
| Overheating | Friction and impact between parts in the equipment must be limited as far as possible to ensure regulated temperatures. |
| Pressure Compensation Operations | Any equipment that relies on pressure must be regulated to prevent pressure compensations from generating shock waves or compressions that could cause ignition |
| Power Failure | In the result of a power failure the equipment must be protected against ignition. It is best practice to allow the system to run independently from main power sources. |
| Connections | Equipment and protective systems must be fitted with suitable cable and conduit entries. When equipment and protective systems are intended for use in combination with other equipment and protective systems, the interface must be safe |
Equipment must also be designed to be capable of performing their intended function safely, even in changing environmental conditions, in the presence of voltage, humidity, vibration, contamination and other external effects.
It must also be protected against mechanical and thermal stress and capable of withstanding attack by existing or foreseeable aggressive substances.
