111 SE EVERETT MALL WAY SUNRISE DENTAL 2019-10-02

1♦ Evergreen State Heat & AC A Division of Evergreen State Sheet Metal,Inc. Gwyther Salon May 24th, 2018 111 EMW Everett, WA 98203 Project Narrative Adding ventilation to comply with remodeling requirement. Applicable Code C503.4Mechanical systems Equipment: (2)MicrometalMB-GP20CA-D2DH 1,600 FM mixing boxes Issue: The space requires ventilation- engineering offers prescriptive requirement of 1,550 CFM of OSA and 1,420 of exhaust. These numbers, while being used as a"worst case"number does not reflect what can be measured by Co2 sensors and bringing in(and tempering the OSA)what is really needed that can be accomplished by demand ventilation. Adding a DOAS or ERV systems is not a solution for several reasons: lack of space (crawl has only 16-18 inches of space-requiring large holes cut into the foundation and digging, bringing it too much outside air, having to add a duct heater when OSA temps drop below @40 and the unit would not be able to cool when the temperatures exceed @80 degrees. Solution: Adding Carrier(approved)mixing boxes ducted to the return unit and outside for fresh air intake and ducting the excess air outside. Each has a capacity of 1,600 cfm and will be connected to 2X 3 ton split systems. The building owner will cut access holes near the units in the crawl space for access, install and maintenance. We'll measure the needed air by adding Co2 sensors and controlling the amount of air by demand ventilation with the Pelican control system. SNOPUD will be rebating this addition due to increasing efficiency and energy savings. NOTE: The current system is a heat pump-we are not adding any additional cooling. Ductwork will be limited to putting the mixing box in line with the return, @16" ductwork to a side wall penetration more than 10' from any exhaust/vent lines. Mark Payne Evergreen State Heat& A/C 2120 Pacific Everett, WA. 98201 425-252-3114 (f)425-259-6660