EN 1149-5 standard: protective clothing - Electrostatic properties
A standard specific to the atex zone
EN 1149-5 lists the requirements for the materials used and the design of electrostatic dissipation protective clothing. Their mission is to prevent electrical discharges deemed incendiary in an ATEX zone. Protective clothing that meets this French standard is used in an activity in a potentially flammable or even explosive atmosphere (food industry, gas delivery, processing trades, refineries, service stations, etc.). The outer fabric of the garment must be antistatic (AST) to protect personnel.
Electrostatic discharges and the human body
The human body has a low enough electrical resistance to act as a conductor, but if it is isolated from earth. It can thus accumulate electrostatic discharges. This can occur by contact, by touching charged equipment or materials, by induction, due to a load on the garment or by the presence of nearby charged objects. Wearing workwear that complies with the EN 1149-5 standard then makes it possible to dissipate electrostatic charges through conductive fibres.
The ISO 1149-5 antistatic standard for protective clothing against electric shock
The ATEX directive 99/92/EC of Annex II, art.2.3 concerns the protection of workers who are likely to be exposed to a flammable atmosphere. To avoid the risk of explosion in a dangerous environment or sparks, the consequences of which can be serious, it is necessary to wear equipment designed with a specific textile material. It stipulates that workers must be provided with suitable work clothes which do not create electric shocks. The fabric of manufacture must flow the charges thanks to the addition of conductive fibers in linear form or in the form of a grid. The distance between conductive fibers in one direction should not exceed 10 mm. In order to ensure effective protection, PPE complying with the EN 1149-5 standard must imperatively be in contact with the skin and the wearer must be earthed.
The antistatic layer must permanently cover the other non-AST layers. This recovery must be guaranteed in all circumstances. Conductive accessories such as buttons and zippers are permitted, provided they are covered by AST fabric. Labels and retro-reflective strips, on the other hand, must be permanently attached.
Some standard precautions to take
The making of protective clothing for women and men belonging to standard EN 1149-5 must also respect several points. PPE must be put on and taken off in the ATEX environment. The wearer closes his garment completely, and ensures that he is grounded. The pictogram designating this standard describes the antistatic which is effective only if:
- The relative humidity is below 25%,
- The garment and its user benefit from appropriate grounding at all times.
Electrostatic dissipative protective clothing has electrostatic properties. These result from a treatment or the addition of conductive fibers in stainless steel or carbon. Indeed, this is not enough, hence the importance of wearing antistatic shoes EN ISO 20345: 2004 standard A and prohibited badges. It is imperative that PPE worn in such flammable atmospheres also provide thermal protection (standard EN14116 or EN11612).