Image 1: Symbol for ATEX certified electrical equipment for explosive atmospheres
In the European Union, organisations must follow directives which ensure that employees are protected from explosion risk in areas with an explosive atmosphere. The ATEX Directive, which was first implemented in 2003, and updated in 2014, was created for this reason and consists of two EU directives that describe what equipment and work space is permitted in an environment with an explosive atmosphere.
The ATEX Directive
The ATEX Directive is in place due to the risk that the accidental ignition of an atmosphere containing a large quantity of gas, vapour, mists or dust may cause an explosion which could cause material damage or even loss of life.
A potentially explosive atmosphere occurs when 3 elements are combined to trigger an explosion: oxygen in the surrounding air, a flammable substance and a source of ignition. This is a particular risk for the chemical and petrochemical industries where such hazardous atmospheres are at risk of being developed during the production, transformation, transport and storage of flammable products.
The Directive specifically covers:
- Equipment intended for use in potentially explosive atmospheres and which can cause an explosion through their own potential sources of ignition.
- Protective systems (units intended to halt incipient explosions immediately and/or to limit the effective range of explosion flames and pressures) intended for use in potentially explosive atmospheres.
- Components or any item essential to the safe functioning of equipment and protective systems but with no autonomous function.
ATEX Approved ESD Control Plastics
Antistatic (ESD/Static Dissipative) plastics are required for use in potentially explosive atmospheres. This is because contact or continuous rubbing of two insulative materials can produce potentially dangerous arcing and electric discharge. As most plastics are insulators, they are prone to this problem which can be caused when static build up is insulated against finding a path to discharge from the mating contact surfaces
SciCron Technologies have developed antistatic acrylic and polycarbonate products which are ATEX approved. Their acrylic and polycarbonate plastic sheets are coated with a proprietary, clear, static dissipative coating which is a unique technology that prevents charge generation on the sheet surfaces, and thereby controls particulate attraction and prevents electrostatic discharge (ESD) events.
SciCron’s acrylic AC-300™ and polycarbonate PC-350™ resist tribocharging under all circumstances and cannot generate a charge when properly grounded. This is crucial in potentially explosive environments and makes them ideal for use in manufacturing and assembly operations for charge sensitive electronic components, where they can help prevent both immediate and latent ESD caused defects.
AC-300™ and PC-350™ are registered trademarks of SciCron Technologies.
In addition to SciCron’s antistatics, Quadrant EPP also manufacture ATEX approved ESD control products including Tivar® CleanStat White and Ertacetal® C ELS.
TIVAR® CleanStat White is an ATEX tested thermoplastic with permanent antistatic performance for pharmaceutical and food applications. Ultra-high-molecular weight polyethylene (UHMW-PE) TIVAR® CleanStat White is unique in combining good electrostatic dissipation (ESd), excellent wear resistance and food contact compliancy in a neutral / white coloured material.
Ertacetal® C ELS is Quadrant's copolymer conductive acetal grade. This grade is specifically developed for the use in applications where the characteristics of POM C are required, but with the added benefit of good electrical conductivity, such as in electrical applications and explosion sensitive areas where it complies with the ATEX Directive.
TIVAR® and Ertacetal® are registered trademarks of the Quadrant group of companies.
Applications for ATEX Approved Plastics
Static dissipative plastics have many general industrial uses, including protection for static charge sensitive manufacturing devices and control of spark discharge in explosive environments. Typical applications include; covers, windows, doors, and access panels for electronic equipment, machines and instruments; fabricated desiccators, cabinets, and boxes; transparent room partitions and pass-thru modules; process equipment enclosures; and mini-environment glazing panels.
Image 2: A PC-350 protection shield which is fixed onto specialist lighting equipment that is ATEX approved and used in hazardous areas within Oil & Gas and Mining sectors.