Canopies

Canopy types

A number of types and style of extract canopy have been developed and these can be broadly classified as follows:

  • Overhead wall type canopy - wall or island mounted
  • Overhead island type canopy
  • Low level wall type canopy
  • Passover type canopy
  • Counter type canopy
  • Eyebrow canopy
  • Condensation canopy

Most styles of canopy can be provided with an integral make-up air facility, and these can take the form of:

  • Front face perforated diffuser
  • Front face grille
  • Internal slot - Induction, compensating or short circuit
  • Vertical grille or louvres. compensating for spot cooling


Examples of the various types and combinations available are shown below:

BE: Bridge Extraction Sytems Ltd range of ventilation hoods and ancillary items.
WE:
Wall Type Extract Hood
WES:
Wall Type extract / supply air hood
IE:
Island type extract hood
IES:
Island type extract / supply air hood
CM:
Mechanical extract condense hood
CNM:
Non mechanical condese hood

 products

Optional extras:

RL: Recessed lighs add
SP: LED lights add
CAS: Capture air stream add
SP: Spot cooling add -
SDU:
Service Distribution Unit SR - Service riser
WL:
Stainless steel wall cladding
BE:
IES with recessed lights or LED spot lights
GI:
Gas interlock panel with emergency stop button and fan current monitoring

NOTE: All hoods are manufactured from 304 stainless DP1. Fully welded with any visible joints polised flat. Site joints are liquid tights with no visible mechanical fixings.

 

Extract canopies

Extract canopies are designed generally in accordance with DW/172.

Each canopy contains a full length stainless steel grease filter housing, which can contain either single or double sided filter banks. Canopies are constructed from 1.2mm thick, grade 304 satin finish stainless steel, and have an all welded construction with a 50mm x 25mm perimeter condense channel, complete with drain plug contained with the channel if required. The grease collection system channels can be removed by the kitchen staff for cleaning. All joints and seams are fully welded and liquid tight.

500mm x 400mm x 50mm or 500mm x 250mm x 50mm heavy duty washable stainless steel baffle type grease filters are provided, with a 45mm rolled section channel frame with safety edge, and drain holes punched in the bottom leading edge. Removable stainless steel grease collecting draws shall be provided within the apron of the filter housing. Stainless steel vapour-proof twin fluorescent recessed light units are provided or bulkhead type lighting can be supplied within the canopy.

Ventilation is required in both the kitchen and the adjoining areas because:

  • Considerable convective and radiant heat is given off by the cooking equipment.
  • The air becomes laden with odours, grease, fumes and products of combustion.
  • During meal preparation and washing up, humidity is increased over a wide area.
  • Air replacement and consistency of temperature are required in adjoining areas.
  • Air is required to dilute and replace products of combustion from gas fired appliances
  • Supply air is required to ensure complete combustion of the fuel


Extract only canopies are available in the following styles

  • Overhead wall type canopy - wall or island mounted
  • Overhead island type canopy
  • Low level wall type canopy
  • Passover type canopy
  • Condensation type canopy


The four main emissions that require removal are:

  • Smoke
  • Expanded air from the hot body radiant heat load surrounding the cooking device
  • Precipitation of moistures existing in the food into a vaporous state, primarily consisting of steam, grease and cooking odours
  • Exhaust fumes from direct fuelled appliances such as gas, charcoal or mesquite

 

Induction canopies

It is essential that an allowance is made for the provision of replacement of air, in order for the kitchen extract system to function correctly.

Where mechanical input is selected, the system should provide 85% of the total extracted volume, with the remaining 15% infiltrating naturally into the kitchen from the surrounding areas. The mechanical or "fan assisted" method ensures that the kitchen remains under negative pressure thus minimising the potential transfer of odours to areas outside the kitchen.

Make-up air can be introduced into the kitchen by means of the canopy or ventilated ceiling, or through the HVAC system or by a combination of both.

 

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