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.
PUBLISHED
SRPS EN ISO 21904-4:2020
PROJECT
prSRPS EN ISO 21904-4:2025
10.99
New project approved
Oct 9, 2025