IMC Table 403.3.1.1---domestic kitchen exhaust and recirculation

[MinnesotaSlinger]

We're working on a large apartment complex project that will need to comply with 2015 International Mechanical Code. One of our concerns is whether or not we need to exhaust air from each apartment unit's kitchen. In Table 403.3.1.1, 25 CFM constant or 100 CFM intermittent is required for kitchen exhaust, and that didn't change from previous version of IMC. Also, recirculating air from space is not allowed. However, 2015 changes to allow recirculating air that is completely within the space. Does that mean that a recirculating (ductless) range hood can be used but that a ducted kitchen exhaust (be it on the range hood or the ceiling or the wall) is required? That seems like the simplest interpretation; I'm just wondering if it's right and why the IMC change was made. In any case, it sounds like we will need to duct kitchen exhaust from each unit but I'm just looking to see what options we have for doing so. Thanks.

 

[dbill74]

Have you tried contacting your AHJ/Code official. They should be able to provide some guidance.

 

[SAK9]

Recirculating hoods are useless as the odour still stays in the house.If local codes permit a vertical duct upto the roof with a kitchen exhaust fan on the roof will be a simple option.Alternatively go for the more appropriate solution of an independent exhaust for each apartment with a fan on the roof.This would be flexible in that the fan can be turned off if the kitchen is not in use.