ISO 21904-4:2020

Health and safety in welding and allied processes - Equipment for capture and separation of welding fume - Part 4: Determination of the minimum air volume flow rate of capture devices

This document specifies two methods for establishing the minimum air volume flow rate. One method is dedicated for use with captor hoods, nozzles and slot nozzles with a ratio of slot length to hose diameter of 8:1 or less. The other method is dedicated for use with on-gun extraction devices.

These methods are not applicable to down draught tables.

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