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HomeMy WebLinkAboutPEC120044 Zehren letter - East Restroom Venting ZEHREN AND ASSOCIATES ARCHITECTURE • PLANNING • INTERIORS P.O. Box 1976 • Avon, CO 81620 • (970) 949-0257 • FAX (970) 949-1080 • vail@zehren.com 101 El Paseo. • Santa Barbara, CA 93101 • (805) 963-6890 • FAX (805) 963-8102 • santabarbara@zehren.com www.zehren.com Tuesday, December 18, 2012 Mr. Bill Gibson Planner II The Town of Vail 75 South Frontage Road Vail, Colorado 81657 Via email to: bgibson@vailgov.com RE: Ford Park – Gerald R. Ford Amphitheater East Restroom Exhaust Venting Architect’s Project Number: 20112137.01 Dear Bill: An issue of potential restroom odors impacting the guest experience at the lawn seating areas was raised at a recent meeting of the PEC to review the modification to the Conditional Use Permit. We are writing this letter in response to the topics discussed and to provide clarifications of our design intent. The plumbing system is designed such that the stack vents are combined to a single roof penetration located at the eastern edge of the building above the central plumbing wall. This location is approximately 24 feet from the nearest lawn seating and in an area not accessible to the public. This location is also set back from the pedestrian walkway to the east by approximately 15 feet, and is located 12 feet above the walk; the vent is screened from view by a parapet wall. Inside the building, the bathroom fixtures are equipped with automatic flush valves and back flow preventers, and are designed to fully comply with all adopted plumbing codes having jurisdiction. This vent is designed to introduce air into the system. • During normal use (i.e., when events are taking place), the flushing action of the fixtures will keep the toilets cycling through with clean water and therefore prevent sewage odors from entering the vent. Odors will not be a concern during the event season. • During times of minimal use (i.e., the offseason), it is possible that odor will enter the stack vent and therefore potentially could be detected by people on the lawn. That concern is counterbalanced by the understanding that neither the restrooms nor the lawn will be occupied during this time. Therefore, we have concluded that odors will not be a concern during the offseason. ARCHITECTURE • PLANNING • INTERIORS P.O. Box 1976 • Avon, CO 81620 • (970) 949-0257 • FAX (970) 949-1080 • vail@zehren.com 101 El Paseo. • Santa Barbara, CA 93101 • (805) 963-6890 • FAX (805) 963-8102 • santabarbara@zehren.com • www.zehren.com In order to provide future flexibility within the system we have introduced a tee intersection to the stack vent above the roof, but screened behind the parapet wall. Initially, this tee will be capped; in the event that odors from the stack are present during events, the GRFA will have the ability to terminate this stack remotely. To do so, the stack vent will be capped, and an extension introduced at the tee, then will penetrate the parapet wall below grade and run underground to a remote location, where it will terminate well above the seating surface. The restroom space itself will utilize fresh air exchanges to prevent the buildup of ambient odors within the space. The intakes are located in the soffit above the restroom entry adjacent to the Stage Right Service and seating areas. The discharge occurs in the building soffits on the North side of the building, adjacent to a landscape area located below the elevation of the lawn seating areas and screened from the activity of the amphitheater. This mechanical fresh air exchange system will be activated by a motion detector within the restrooms, and will be timed appropriately to prevent buildup and disperse odors. Considering these factors, it has been determined that the potential of sewer gases being detected on the lawn is not a concern. We believe that this letter adequately addresses the concerns about this issue that have been raised. If any questions or further clarifications are necessary or arise, please do not hesitate to contact me and we will be happy to discuss them. Sincerely, David Baum, Architect, LEED AP Zehren & Associates, Inc.