Electrostatic properties
When to use EN 1149-5 garments
Anti-static garments that comply with the EN 1149-5 standard are designed for professionals working in ATEX zones 1, 2, 20, 21 and 22 where the minimum ignition energy is not less than 0.016 mJ. They play a critical role in preventing accidental electrostatic discharges that could otherwise ignite an explosive atmosphere.
It is important to note that these garments must not be used in oxygen-enriched environments or in ATEX zone 0, unless explicitly authorised by the responsible safety engineer.
What is static electricity?
Static electricity is the build-up of electrical charges on a surface, such as clothing or the human body. It can arise in different ways:
through the movement of a person,
by friction between layers of clothing,
or by induction from nearby charged objects.
These charges remain until they discharge, often as a small spark. Materials like polyester are particularly prone to static build-up, and in explosive environments even a tiny spark can trigger ignition. Anti-static clothing prevents this by safely conducting charges away before they accumulate.
A single garment can accumulate up to 30,000 volts of static electricity just by moving
Did you know? A single garment can accumulate up to 30,000 volts of static electricity just by moving. Anti-static clothing prevents this build-up by continuously dissipating the charges, reducing the risk of sparks and explosions in ATEX environments.
How does EN 1149-5 work?
Electrostatic protective clothing prevents the build-up of static electricity on the body. The fabric contains conductive fibres that allow charges to dissipate safely into the ground, rather than discharging suddenly as a spark. In explosive atmospheres, even a very small spark can ignite gas, vapour or dust. By ensuring that the wearer is part of a fully earthed system, EN 1149-5 garments minimise the risk of accidental ignition and contribute to overall ATEX safety.
The effectiveness of EN 1149-5 garments depends on permanent earthing. The wearer must be in continuous conductive contact with the ground to dissipate electrostatic charges. This is typically achieved by combining conductive fabrics with footwear that complies with EN ISO 20344. The resistance between wearer and earth must remain below 10⁸ Ω.
ATEX zone classifications
EN 1149-5 garments are intended for ATEX zones 1, 2, 20, 21 and 22. These zones are defined by the likelihood and duration of explosive atmospheres.
Gas, mist and vapour zones:
Zone 0: Explosive atmosphere present continuously or for long periods.
Zone 1: Explosive atmosphere likely to occur occasionally during normal operation.
Zone 2: Explosive atmosphere unlikely in normal operation, and if it does occur, will only last a short time.
Dust zones:
Zone 20: Explosive dust clouds present continuously or for long periods.
Zone 21: Explosive dust clouds likely to occur occasionally during normal operation.
Zone 22: Explosive dust clouds unlikely in normal operation, and if they occur, will only last briefly.
Correct use of EN 1149-5 anti-static protective clothing
To ensure full protection, anti-static garments must be worn and handled correctly. Always follow these essential guidelines:
Dress before entering the ATEX zone. Put on garments before entering the hazardous area and keep them fastened at all times.
Fasten properly. Ensure all zips, cuffs and hook-and-loop fastenings are fully closed and overlapping for good contact with the skin or conductive underwear.
Never unfasten or remove garments inside the ATEX environment. Accessories such as name badges or pads must remain attached.
Wear as a complete system. Combine garments as part of a fully earthed outfit - either a single coverall or multiple overlapping items such as a jacket and trousers - and always wear conductive footwear to maintain grounding.
Maintain full coverage. All non-compliant underlayers must stay completely covered, even when bending or stretching. Ensure garments overlap sufficiently, for example the jacket over the trouser waistband.