Skip to Main Content View Text-Only

The City of Portland, Oregon

Development Services

From Concept to Construction

Phone: 503-823-7300


1900 SW 4th Ave, Portland, OR 97201

More Contact Info

Subscribe to RSS feed

Most Recent

View Less

Commercial Building Permits: Kitchen Exhaust Systems


September 22, 2017

Commercial Building Permits: Changes to mechanical permit requirements regarding kitchen exhaust systems for new construction

As of January 1, 2018, domestic kitchen exhaust equipment for new commercial construction must meet the 2014 OMSC Section 505.1, and the 2014 OSSC Section 714 - as written. Currently, kitchen subducts may be considered part of the larger ventilation environment.  Exhausts may terminate inside a rated subduct shaft without air stream separation. To better align BDS inspection and plan review services, starting January 1, 2018 exhaust requirements must directly meet the OMSC and OSSC code citations to be independent of all other exhaust systems. A continuous exhaust fan shall be connected to a standby power source on the top of the shaft. Building plans must show how Section 505.1 of the Oregon Mechanical Code is met.

OMSC Section 505.1 Domestic Systems. Domestic range hoods and domestic appliances equipped with downdraft exhaust shall discharge to the outdoors through sheet metal ducts constructed of galvanized steel, stainless steel, aluminum or copper. Such ducts shall have smooth inner walls, shall be air tight, shall be equipped with a backdraft damper, and shall be independent of all other exhaust systems.

Permit applications received prior to January 1, 2018, will have the option of meeting either the current or new interpretation. Applications received on or after January 1, 2018, will be reviewed against the new interpretation. 

For more information, please contact Thomas Ng at or (503) 823-7434.

Please subscribe to receive other Bureau of Development Services notification.


The City of Portland is committed to providing meaningful access. For accommodations, modifications, translation, interpretation or other services, please call 503-823-7300, the TTY at 503-823-6868 or the Oregon Relay Service: 711. 503-823-7300 Traducción e interpretación | Chuyển Ngữ hoặc Phiên Dịch | 翻译或传译 Письменныйили устный перевод | 翻訳または通訳 | Traducere sau Interpretare 번역 및 통역 | Письмовий або усний переклад | Turjumida ama Fasiraadda