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• <br /> 4.3 Performance and General Design Criteria <br /> 4.3.1 East Clearwell <br /> The Design-Builder shall design and construct the East Clearwell Acceptable Roof System, including <br /> Ancillary Features, in accordance with the following criteria: <br /> Table 4.1: East Clearwell Performance and General Design Criteria <br /> CRITERION REQUIREMENT <br /> General <br /> Operability, • Provide for easy,safe and efficient operations and maintenance and access by <br /> Maintenance, personnel. <br /> and Repair • Structures,equipment, piping,and other facilities and systems shall provide for future <br /> maintenance and repair and inspection (to the extent practical)without requiring taking <br /> the East Clearwell off-line. <br /> Service Life and • All components shall be Utility Grade. <br /> Durability • Roof structure shall be designed consistent with a 50-year service life based on City and <br /> industry standard practices. <br /> • Mechanical components(e.g.,washdown system)shall be designed to be compatible <br /> with existing City components and to be consistent with a 30-year minimum service life <br /> respectively.Also,the design shall be consistent with low incidence of failure,ease of <br /> operations and maintenance,and with a high expectation of continued manufacturer <br /> support and service. <br /> • The roof fastener system shall be leak-proof and not require fastener maintenance or <br /> tightening of fasteners over time. <br /> Functionality • Provide a new roof system. <br /> • Roof systems,their connection to existing structure,and access hatches shall be water <br /> tight and shall be designed to prevent birds,animals, insects,excessive dust, and other <br /> potential vector and contaminant intrusion into the clearwell. <br /> • The roof slope shall allow for water drainage so that no water ponding occurs on any <br /> surface of the roof accounting for individual member structural deflection and historical <br /> precipitation intensity for the area. <br /> • The new roof structure support system shall not result in an overall clearwell storage <br /> volume reduction of more than[X%]or required change in operating water surface level. <br /> [NOTE TO PROPOSERS:%TO BE COMPLETED BASED ON SELECTED PROPOSAL.CITY <br /> STRONGLY PREFERS MINIMAL OR NO REDUCTION] <br /> • The roof shall be walkable. <br /> • Provide a roof access safety system with one cable on each side of the roof peak,with <br /> safety connection points for personnel accessing the roof. <br /> Architectural • The roof and support system shall completely integrate with existing infrastructure. <br /> Proposed architectural treatments,colors and textures of exterior materials shall be <br /> consistent with existing WFP facilities. For steel roof systems, roof color shall match <br /> existing WFP blue as closely as reasonably possible,with color samples submitted for <br /> City Approval. For aluminum roof systems provide standard mill finish. <br /> Ventilation • Vents shall be aluminum hoods that are tamper proof and protected from vandalism. <br /> • Design vents with hoods to minimize the potential for water intrusion.Design to prevent <br /> birds,animals, insects,excessive dust,and other potential vector and contaminant <br /> intrusion. <br /> • Design vents in accordance with AWWA D100-11. <br /> • Design vents with a maximum air velocity through each vent of 500 feet per minute. <br /> Vents shall be screened.Vents shall be sized to allow air into the clearwell at a rate <br /> City of Everett September 13,2017 <br /> Water Filtration Plant Clearwell Roof Replacement DB Project Supplementary Conditions Page 7 <br />