The original design of the grouped bath/kitchen and dryer vents at SWC presented several problems for the Construction Company and Architect to overcome. In most cases these three vents exit the building near the front door ways. In some cases they vent elsewhere. The following influenced a solution:
The prior design was not allowed to be reused (City of Redmond Prohibited It). This originally included a single large "hood" and a single screen over all. Screens are not permitted over dryer ducts.
The original builder at SWC grouped three large ducts into a 12" space where it should have needed 14" or more. The result is all ducts are deformed to an oval shape. This could not be changed without major reconstruction involving the interior of all units.
We wanted a solution that kept the exterior size of the hood as small as possible.
There is no "off the shelf" solution, so any fix had to be built.
The present design is the 2nd or 3rd in a couple of solutions. The present fix includes a protective rain hood with rubber flaps to cover the opening(s). These flaps are supposed to lay closed when the fan is not operating and open when the fan/dryer is turned on. An owner has indicated that the flap is not swinging open enough, allowing moist air from the dryer to re-enter his bath vent. A modification of the present design is planned and will be tested. A dividing element between the different exhaust openings will be installed so as to direct any vented air outwards. Additionally, the "flaps" will be divided so as to be more easily opened by vent air.
