Attachment 10-Air Quality and Odour Assessment · MCU23/0078

           dispersion or stack configuration
           proximity of receptors
           size of kitchen in terms of servings or guests
           cooking type based on odour and grease loading
It is important to note that while dispersion of smoke and fumes through exhaust stacks is considered a
minimum requirement for all kitchens, it is acknowledged that stack configuration may be constrained. These
limitations are reflected in the dispersion scoring points provided in Table 6.1. Using the criteria outlined in
the table, restaurants can be classified based on their potential impact level ranging from low to medium,
high, or very high impact risk.

Table 6.1: Risk assessment scoring criteria (Adapted from Control of Odour and Noise from
Commercial Kitchen Exhaust Systems, DEFRA, 2018)

 Impact Risk                                              Significance Score*
 Low to Medium                                            Less than 20
 High                                                     20 to 35
 Very high                                                More than 35
 * based on the scoring criteria below
 Criteria                                Score            Score          Details
 Dispersion                              Very poor        20             Low level discharge, discharge into courtyard
                                                                         or restriction on stack
                                         Poor             15             Not low level but below eaves, or discharge at
                                                                         below 10 m/s
                                         Moderate         10             Discharging 1 m above eaves at 10-15 m/s
                                         Good             5              Discharging 1 m above ridge at 15 m/s
 Proximity of receptors                  Close            10             Closest sensitive receptor less than 20 m from
                                                                         kitchen discharge
                                         Medium           5              Closest sensitive receptor between 20 m and
                                                                         100 m from kitchen discharge
                                         Far              1              Closest sensitive receptor more than 100 m
                                                                         from kitchen discharge1
 Size of kitchen                         Large            5              More than 100 covers (1 cover is equivalent to
                                                                         a single serving for one guest) or large sized
                                                                         take away
                                         Medium           3              Between 30 and 100 covers or medium sized
                                                                         take away
                                         Small            1              Less than 30 covers or small take away1
 Cooking type (odour and grease          Very high        10             Pub (high level of fried food), fried chicken,
 loading)                                                                burgers or fish & chips, Turkish, Middle
                                                                         Eastern or any premises cooking with solid
                                                                         fuel
                                         High             7              Vietnamese, Thai, Indian, Japanese, Chinese,
                                                                         steakhouse
                                         Medium           4              Cantonese, Italian, French, Pizza (gas-fired)
                                         Low              1              Most pubs (no fried food, mainly reheating
                                                                         and sandwiches, etc.), Tea rooms1
 Note 1: A pragmatic view can be taken when assessing whether certain low risk kitchens require any odour
 abatement to be fitted. In reaching this decision, the nature of the food being cooked and/or the size of kitchen
 and/or its location may be considered.




237401.0145.R01V02                                                                                                 Page 16