Category: Halton Foodservice commercial kitchen ventilation kitchen
canopies ventilated ceilings
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Halton Foodservice
Ventilated Ceilings for Commercial Kitchens
Background
Over the past decade, or so, there has been a noticeable swing away
from conventional kitchen canopies towards the hi-tech appearance and
cleaner lines of the aesthetically-pleasing Ventilated Ceiling. This
applies, particularly, to those projects where the intention is more
towards making a feature of the kitchen rather than hide it away in the
sub-sub-basement.
Many Architects, Consultants and Interior Designers appreciate that a
well-designed, well-maintained Ventilated Ceiling can, not only enhance
the overall visual aspect of the entire area, but also contribute
significantly to the working environment for the kitchen staff…
potentially, a “win / win” situation.
Types of Ceiling
It is generally accepted that Ventilated Ceilings fall into two
separate and distinct categories;
- Modular cassette-type ceilings
- Plenum-type ceilings
In very basic terms, a modular cassette-type ceiling is engineered
around a square modular grid with nothing, apart from the
fire-suppression nozzles, protruding lower than the underside of the
ceiling cassettes themselves.
A plenum-type ceiling, on the other hand, has conventional grease
filters mounted in conventional sloping extract plenums suspended on the
underside of the ceiling…..”canopies” without sides and ends!
Design Considerations
As with the design for kitchen canopies, the level of extraction that
is required should be determined, as accurately as possible, from the
outset, ideally by utilising the HVCA DW/172 Specific Extract Flow Rate
calculation method. This is based on heat and effluent outputs from
identifiable items of cooking equipment and provides the most accurate
and reliable basis for design.
Again, as for conventionally-ventilated commercial kitchens, it would be
usual to provide fresh, filtered, tempered air back into the kitchen at
a rate equal to 85% of that being extracted, thereby maintaining the
kitchen at a healthy negative pressure of around 15%.
Typically, Ventilated Ceilings appear to offer optimum performance when
set at a height between 2400mm and 3500mm above finished floor level.
Too low and the kitchen will appear oppressive. Too high and the rising
thermal currents will have cooled and start to fall back before reaching
the ceiling.
The initial layout for the various ceiling components is determined, in
the main, by the layout of the cooking equipment and other heat and
steam-emitting appliances in the kitchen. Once the correct number of
grease-extracting cassettes have been selected and located, it is
relatively simple to arrange the supply-air cassettes, luminaries and
passive tiles in such a way that they support and complement the
requirement to provide a well-lit, properly-ventilated kitchen.
The Big Issue
As can be seen from this typical section through one of our ceilings,
a feature of the design of a Halton Cyclocell Ventilated Ceiling is that
both the extract and supply-air is totally ducted in the ceiling void.
Typical Elevation through Halton Ventilated Ceiling
Unfortunately, and for reasons we have been unable to explain, this
basic design principle does not appear to have been adopted by many of
the other key players in this field.
The vast majority of Ventilated Ceilings are designed and installed with
the ceiling void being used as part of the ductwork system.
No baffle-type grease filters are even close to being 100% efficient
and, therefore, by definition this means that whatever grease and oil
gets through the filters is bound to condense out on the building fabric
and pipework / electrical services passing through the ceiling void.
To say the very least, this is a major fire risk. It is alright to say
that it is the operator’s responsibility to keep the void clean, but as
can be seen from these photographs, taken recently in the void above a
Ventilated Ceiling in one of London’s top-class hotels, regular cleaning
would entail totally dismantling the entire kitchen ceiling.
One day, Environmental Health Officers will understand and appreciate
the magnitude of the Health and Safety risk that exists in these “open
voids”, and insist upon the use of cleanable, containable plenums and
ductwork…..An affordable solution to an ongoing problem.
Information associated with: Halton Foodservice - Commercial Kitchen
Ventilation & Canopies
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Halton Foodservice Ltd
11 Laker Road
Airport Industrial Estate
Rochester
Kent
ME1 3QX
Tel: +44 (0) 1634 666111
Fax: +44 (0) 1634 666333
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