Pollution Control PPT03A 1

POLLUTION CONTROLPOLLUTION CONTROL an Overview an Overview

What is the problem?• Most country / local codes call for commercial kitchen exhaust air to be

discharged at building roof level.

• Kitchen extract ducts running up the outside of a building are expensive,

ugly and frequently refused planning permission.

• Kitchen extract ducts running vertically up the inside of a building are

seldom an option due to the need for co-operation / permission from

the occupants of the upper floors.

• Internally-run kitchen extract ducts are often extremely large in

cross-section due to the need for external fire cladding.• Typical sizes of riser ducts:-

- extract flow rate 1000 l/s (1.0m3/s) = 400 x 400 (1 x 2.5m long wall hood)

- extract flow rate 1500 l/s (1.5m3/s) = 500 x 500

- extract flow rate 2000 l/s (2.0m3/s) = 575 x 575

- extract flow rate 2500 l/s (2.5m3/s) = 650 x 650

- extract flow rate 3000 l/s (3.0m3/s) = 700 x 700 (2 x 3m long island hoods)

Pollution Control PPT03A

There is an alternative to Kitchen Extract Riser Ducts

2

What is the alternative?

Clean up the exhaust air such that it can be discharged at low-level from the building.

Pollution Control PPT03A 3

What are the 5 key pollutants?

• Grease• Cooking odours• Smoke• Ozone• Heat

Pollution Control PPT03A 4

Grease

• The filtration system within the hood should be as near to 100% efficient as possible.

• Grease-laden kitchen extract ducts, apart from being a significant fire risk, serve to continuously “odourise” the exhaust air ……….even when there is no cooking in operation.

• Grease deposits must not build up on the discharge louvres as this impairs system performance and is a hygiene risk.

Pollution Control PPT03A 5

Cooking Odours

• For a low-level discharge, these odours need to be substantially reduced.

• There are no defined set limits for cooking odours……. They are simply acceptable or not acceptable!!

• This is extremely subjective and customers / specifiers must be warned in advance that no system provides 100% odour removal.

Pollution Control PPT03A 6

Smoke

• It is essential that airborne particulate (smoke) is removed from the airstream prior to low-level discharge, not least of all, because it conveys cooking odours.

• The generally-accepted level for discharged smoke is 0.3 microns, as this is deemed to be invisible to the naked eye.

Pollution Control PPT03A 7

Ozone (O3)

• If ozone producing UV light (185nm wavelength) is used as part of the hood filtration system, then care must be taken not to exceed the World Health Organisation’s permissible level of ozone discharged to atmosphere, which is 0.06 ppm.

Pollution Control PPT03A 8

Heat

• Generally speaking, this is not a problem as the maximum discharge temperature, even with gas-fired cooking equipment and a short duct run between hood and discharge, is unlikely to exceed 30 to 350C.

• However, the designer needs to take care that the low-level kitchen exhaust isn’t being discharged into a small enclosed area where heat build-up could be a problem. (ie. adjacent to intake louvres, openable windows, air-cooled condensers, etc etc)

Pollution Control PPT03A 9

How can we, as Halton Foodservice, provide a system-based solution to overcome these problems?

The combination of UV-C and Pollustop.

Pollution Control PPT03A 10

Grease

- KSA high-efficiency multi-cyclone primary grease filters plus coalescer secondary filters plus Reactocell UV-C will provide almost 100% grease removal.

Pollution Control PPT03A 11

Cooking Odours

- Experience has shown that if the Reactocell UV-C cassette installed in the hood is carefully designed / selected, then the cooking odours will be substantially reduced.

Pollution Control PPT03A 12

Smoke

- 3-stage filtration in the Pollustop unit will reduce the smoke levels to < 0.3 microns.

Pollution Control PPT03A

Note: For low-level discharge systems, we recommend 3-stage filtration rather than Electrostatic Precipitators (ESP). This is because, although the efficiencies are similar, disposable filters will clog and thereby keep the nuisance in-house, whereas coated precipitator plates will allow the smoke particles to pass through to atmosphere until the equipment is maintained.

13

Ozone

- An activated carbon filter bank, incorporated within a Pollustop unit, providing it has NFX granules, will reduce the O3 levels to <0.06ppm.

- NFX is designed for the absorption of Ozone. The Ozone keeps the carbon clean and we have some activated carbon filters that have now been installed in Pollustop units for over 24 months without the need for replacement.

Pollution Control PPT03A 14

Heat

- If heat at the discharge is likely to be a problem, install a runaround heat recovery coil within the Pollustop unit.

Pollution Control PPT03A

Note: For UK applications, we recommend air-to-water, rather than air-to-air, recovery as this means that energy is being saved for each and every hour that the cooking process is in operation.

15

Summary

• In many cases there is no alternative but to have a low-level discharge.

• In many cases, the added cost to the customer of Reactocell UV-C and Pollustop in a commercial kitchen ventilation system is still less than the cost of a riser duct running to the roof of the building.

• Since December 1999 we, at Rochester, have successfully installed over 1200 UV-C systems and the vast majority of these were for low-level discharge.

• The dual keys for a successful system are:

a) careful design, and

b) ongoing maintenance

Pollution Control PPT03A

Halton Foodservice offer Pollution Control SOLUTIONS not Products.

16

17Pollution Control PPT03A

Care for Indoor & Outdoor AirCare for Indoor & Outdoor Air .....thank you for your attention......thank you for your attention.