Readings stored in this browser · Required airflow from current calculator inputs · Qactual = Vreturn × Afree
Interactive comparison of minimum airflow criteria · Tunnel area 25–120 m² · Airflow in m³/min
IS 4756:1978, Cl. 7.4.1 (Reaffirmed 2022) — Fresh air per person & diesel airflow | BS 6164:2019 — Return-air velocity for dust/fumes & methane risk | DGMS recommendations — Required ventilation air supply in gassy tunnels