Protective clothing for welding and allied processes in accordance with EN ISO 11611 protects the wearer from small molten metal splashes, brief contact with flames, and radiant heat from the electrical arc. The clothing can be suitable for persons during welding and allied processes where the same type and similar hazards occur. The protective effect is achieved with flame retardant fabric in conjunction with specific processing properties, which are defined in EN ISO 11611. One criterion for classification as protective clothing for use in welding is limited flame spread. Testing this criterion involves analysing how the fabric burns after being exposed to a small vertical flame.
The test is based on EN ISO 15025 (formerly DIN EN 532), which specifies that:
- no sample may continue to burn to the upper or side edges
- no sample may exhibit hole formation greater than 5x5 mm²
- no sample may give off flaming or melting debris
- the mean afterflame time may not exceed 2 seconds
- the mean afterglow time may not exceed 2 seconds
Classification of the protective clothing into two classes
Class 1 (lower): Protection against less hazardous welding techniques and situations with a lower number of welding splashes and radiant heat; at least 15 drops of molten metal and radiant heat transfer index (RHTI) 24 ≥ 7 s
Class 2 (higher): Protection against more hazardous welding techniques and situations with many welding splashes and high radiant heat; at least 25 drops of molten metal and radiant heat transfer index (RHTI) 24 ≥ 16 s
The flame spread tests may be carried out according to two different procedures – it is also possible to test using both methods (A1+A2).
Method A – surface ignition: The flame is applied to the centre of the sample.
Method B – bottom edge ignition: The flame is applied to the bottom edge of the sample.