LEV capture basics
Local exhaust ventilation needs enough face velocity and capture velocity at the contaminant source. A common plain-opening approximation is:
V_face = Q ÷ A · V_x ≈ Q ÷ (10·X² + A)
LEV Capture Velocity Calculator
LEV · face & capture velocity
Estimate face velocity and approximate capture velocity at distance X from a plain opening.
Formula: V_face = Q ÷ A · V_capture ≈ Q ÷ (10 × X² + A) (plain opening approx.)
Frequently asked questions
Target capture speeds?
Depend on process — many dusts need ~0.5–1 m/s at the source; check ACGIH IV Manual / COSHH essentials.
Flanged hoods?
Flanges improve capture; the plain-opening formula is conservative/teaching only.
Does this replace thorough examination?
No. Statutory LEV testing and records remain mandatory where required.
Units?
Keep Q in m³/s and A in m² for V in m/s (or convert CFM/ft² carefully).
