“Serious exhaust design flaw — the duct plenum is installed at the front internal apex of the commercial range hood, with the lateral duct running above it. This traps grease and prevents cleaning access. Without access panels, it becomes both a hygiene issue and a major fire hazard. Surprisingly, we still see this configuration in many new builds — a clear sign that design standards need more attention | J Commercial Services Commercial Exhaust Systems

What is a Plenum Box? (Purpose on FCUs and Diffusers) - aircondlounge