2023/08/30 Council Agenda Packet

Page 8 of 23 Category 2: Sensitive information Category 2: For official use only / disclosure permissible by law. i. Frames and covers must be gray cast iron, according to ASTM A48, and shall meet AASHTO H- 20 loading requirements. ii. Doors must have hot-dipped galvanized frame and covers. Covers must have diamond plate finish. Each door to be equipped with a recessed lift handle. Doors must meet AASHTO HS-20 loading requirements for traffic, plus the ability to support the city’s design vehicles identified in the attached drawing “Stormwater Structural Loading Design Vehicles” in Appendix B. iii. Steps must be constructed of copolymer polypropylene conforming to ASTM D4101. Steps must be driven into preformed or drilled holes once concrete is cured. Steps must meet the requirements of ASTM C478 and AASHTO M199. The ½” Grade 60 deformed reinforcing bar shall meet ASTM A615, where required. iv. Access covers shall be designed in accordance with Section 4-4.2 (3) of the City of Everett’s Design and Construction Standards and Specifications and the following: a. All lids, grates, and hatches larger than 24 inches in dimension must be constructed in a manner that allows a single individual to open them without special equipment. b. All lids, grates, and hatches must be equipped with a pick-hole or handles. 4. Internal components of the unit must include: i. Components must be provided by the manufacturer in accordance with the manufacturer’s published specifications and the requirements of the Washington State Department of Ecology’s GULD approval. ii. Filter media must be provided by the manufacturer or an approved alternate source. Filter media must consist of the following, as specified in the drawings, or approved equivalent: a. Filter media or equivalent must be made from Perlite pellets with activated alumina bound to the surface. The Filter media pellets or equivalent must be granular and have a bulk density from 18 to 25 lbs/ft3. The pellet size should range from that passing through a U.S. Standard ¼ inch sieve and retained on a #8 sieve. iii. Cartridge must be 27-inch size and of the quantity identified in Drawing SD3. B. Modular Wetlands System (MWS) - Linear: 1. Unit must be a Modular Wetlands vault type system of size and type indicated in the Drawing SD4. 2. Unit must provide a two-stage treatment that includes a pretreatment filter media and primary treatment biofiltration media. 3. Unit must include the required filter media for operation. 4. Unit and all its components, including filter media, must be self-contained within the concrete structure. Vault components shall be as specified by the manufacturer’s published specifications and shall comply with the following: i. Filter media must be located at least 2” from the structure walls. ii. Unit must be constructed of concrete with a minimum 28-day compressive strength of 5,000 psi.