Air ducts are a major part of heating, ventilating and air-conditioning (HVAC) systems.
Firing may be entirely dispensed with, though care must still be exercised in ventilating.
Begin by opening windows and fully ventilating the room where you will be waxing your cross country skis.
They are now usually of special design, and may be divided into three classes - indirect radiators, direct radiators and direct ventilating radiators.
The Stortz ventilating bronchoscope is the most commonly used rigid bronchoscope in most centers.
