Replacement air

Replacement air
The ventilation system design should take into account
the need to replace extracted air. Mechanical and/or
natural means can provide make-up air, but it should
be fresh and unadulterated from the outside.
In smaller kitchens, there may be sufficient
replacement air drawn in naturally via ventilation grilles
in walls, doors or windows.
Where air is drawn in naturally, some means of control
over pest entry is usually needed. A fine mesh grille
will restrict the ventilation, and a larger grille area
can compensate. However, for larger installations, a
mechanical system using a fan and filter is more suitable.
The ‘clean air’ should not be taken from ‘dirty’ areas,
eg waste storage, smoking areas etc. The make-up air
should not impair the performance of flues serving gas
appliances.