EN ISO 11611

What EN ISO 11611 is

EN ISO 11611 is the standard covering protective clothing worn during welding and allied processes — the welding-specific counterpart to EN ISO 11612’s general industrial heat/flame protection. It sets minimum requirements for garments protecting the wearer against the specific combination of hazards welders face: molten metal spatter, brief flame contact, radiant heat from the welding arc, and short-term accidental contact with live electrical conductors.

The current version is EN ISO 11611:2015, which superseded the earlier EN ISO 11611:2007 and, before that, EN 470-1:1995.

Scope: what it covers and what it doesn’t

EN ISO 11611 covers garments protecting the wearer’s body, and — specifically for welding — also extends to hoods (head) and gaiters (feet), which is broader than EN ISO 11612’s very limited head/foot scope. However:

• It does not cover hand protection (welding gloves fall under a separate standard).
• It does not cover face or eye protection (welding masks/visors are separately regulated).
• For full protection, the standard explicitly expects other certified PPE — for the head, face, hands, and feet — to be worn alongside an EN ISO 11611 garment, not instead of it.

The four hazards it addresses

1. Molten metal spatter — small splashes/droplets of molten metal generated during welding, cutting, or similar processes
2. Limited flame spread — brief contact with sparks or small flames
3. Radiant heat — heat radiated from the welding arc itself
4. Accidental electrical contact — minimizing shock risk from short-term, accidental contact with live conductors at voltages up to approximately 100V DC under normal welding conditions

On that last point, it’s worth being precise: this protection is specifically against low-voltage accidental contact during welding, not a substitute for dedicated electrical-hazard PPE like arc flash protective clothing. It also degrades with sweat, soiling, or contamination — a heavily soiled garment may no longer provide the tested level of electrical protection even if it still looks otherwise intact.

Class 1 vs Class 2

EN ISO 11611 divides protective performance into two classes based on how hazardous the welding process is:

	Class 1 (lower risk)	Class 2 (higher risk)
Suited to	Less hazardous techniques with lower spatter/radiant heat	More hazardous techniques with higher spatter/radiant heat
Molten metal drop resistance	Withstands at least 15 drops before burn-through	Withstands at least 25 drops before burn-through
Radiant heat transfer (RHTI 24)	≥ 7 seconds	≥ 16 seconds (commonly cited)
Typical processes	Gas welding, TIG welding, MIG welding, micro-plasma welding, brazing, spot welding, basic MMA (shielded electrode)	MMA welding (alkaline/cellulose electrodes), MAG welding (CO₂/mixed gas), high-voltage MIG, flux-cored arc welding, plasma cutting, gouging, oxygen cutting, thermal spraying
Typical situations	Open, well-ventilated work areas	Confined spaces, overhead or forced working positions, machine-operated cutting/welding processes

Fabric weight and construction generally scale with class — achieving Class 2 typically calls for heavier-weight fabrics or high-performance blends (aramid or similar) to provide a denser physical barrier against the higher spatter and heat exposure.

Key tests behind the classification

• Molten metal spatter resistance — the most critical test for this standard. Drops of molten metal are directed at a vertically oriented fabric sample, and the number of drops required to raise a temperature sensor behind the fabric by 40K determines the class achieved (15 drops for Class 1, 25 for Class 2).
• Radiant heat resistance (ISO 6942) — a fabric sample is exposed to radiant (infrared) heat, with a calorimeter on the reverse side measuring how long the sample can be exposed before the temperature rises by 24°C (the “RHTI 24” figure referenced above).
• Limited flame spread (ISO 15025) — the same core flame-spread test method used elsewhere in the EN/ISO heat-and-flame family, confirming the fabric doesn’t sustain or spread flame after brief contact.
• Electrostatic/antistatic performance (EN 1149-2) — relevant given the electrical contact risk welding presents.

Design requirements

Beyond fabric performance, EN ISO 11611 imposes specific garment construction rules aimed at stopping molten spatter from reaching the wearer through gaps or design features:

• All pockets must have covering flaps, so molten metal spatter can’t fall directly into them.
• Pocket flaps must be at least 2cm wider than the pocket opening on each side, so they can’t be pushed aside or into the pocket by spatter.
• Fasteners must not create folds or pockets where spatter could lodge and remain in contact with the fabric.
• Cuff width adjustment must be positioned on the underside of the sleeve, away from the area most exposed to falling spatter.
• Trouser pocket openings must not exceed a 10° angle, reducing the risk of spatter entering directly.
• The jacket collar must be able to fasten all the way to the top, protecting the neck area.
• No continuous/exposed metal parts (e.g. metal press studs) are permitted, since these could conduct heat and create thermal “bridges” against the skin.

Selection guidance (Annex A)

EN ISO 11611:2015 includes an informative Annex A, giving selection guidance matched to specific welding activities and working conditions — indicating, for example, which processes and situations call for Class 1 versus Class 2 protection. This is intended to guide procurement decisions based on the actual welding techniques and working environment involved, rather than defaulting to one class regardless of task.

Marking

A compliant garment’s pictogram/label will typically show:

• The EN ISO 11611 standard reference
• The Class achieved (1 or 2)
• The flame test result applied (A1 and/or A2, using the same flame-spread classification convention used in EN ISO 11612)

How it relates to EN ISO 11612

These two standards are often confused, since both address heat and flame using overlapping test methods:

• EN ISO 11611 is specific to welding and allied processes, and uniquely requires testing for molten metal spatter resistance and electrical contact protection — requirements EN ISO 11612 does not include.
• EN ISO 11612 applies more broadly to general industrial heat/flame protection outside welding.
• A garment certified only to EN ISO 11612 does not automatically comply with EN ISO 11611 — the welding standard’s spatter and electrical resistance requirements are mandatory and specific to it, so the two certifications are not interchangeable even where fabric performance looks similar on paper.

What EN ISO 11611 does NOT guarantee

• It does not protect against high-energy arc flash events from electrical switchgear — that requires dedicated arc flash PPE certified to IEC 61482 series standards, not EN ISO 11611.
• It does not cover hands, face, or eyes — separate certified PPE for these areas is required for complete protection.
• Electrical contact protection is only valid under normal, clean conditions — sweat, soiling, or contamination can reduce this protection even while the garment otherwise appears serviceable.
• Garments must be replaced once damaged (holes, open seams) or degraded (thinned/brittle fabric from UV exposure) — visibly worn garments can no longer be assumed to deliver their originally certified Class 1 or Class 2 performance.
• Synthetic undergarments (polyester, nylon, etc.) are strongly discouraged underneath EN ISO 11611 clothing — if the outer layer is breached in a severe incident, synthetic fabric can melt into the skin and cause additional burns; natural fibres (cotton, wool) are the recommended base layer choice instead.

Quick summary

Aspect	EN ISO 11611 detail
Current edition	EN ISO 11611:2015 (successor to EN ISO 11611:2007 / EN 470-1:1995)
Hazards covered	Molten metal spatter, limited flame spread, radiant heat, low-voltage (~100V DC) accidental electrical contact
Classes	Class 1 (lower risk, 15 drops, RHTI24 ≥7s) vs Class 2 (higher risk, 25 drops, RHTI24 ≥16s)
Key tests	Molten metal drop test, ISO 6942 (radiant heat), ISO 15025 (flame spread), EN 1149-2 (antistatic)
Design rules	Covered/oversized pocket flaps, no exposed metal fasteners, protected cuffs, high collar closure
Excludes	Hands, face, eyes — separate PPE required
Not a substitute for	Arc flash PPE (IEC 61482) for electrical switchgear hazards
Related but distinct from	EN ISO 11612 (general heat/flame) — not interchangeable certifications