NR 811.64(8)(f)1.1. Vent pipes shall be constructed of ductile iron, steel, or stainless steel pipe. NR 811.64(8)(f)2.2. Mushroom caps shall be constructed of steel, stainless steel, or aluminum. NR 811.64(8)(f)4.4. Inner pallet screens of frost-proof mushroom cap vents shall be constructed of corrosion resistant material. NR 811.64(9)(9) Silt stop. The discharge pipes from all water storage structures shall be located in a manner that will prevent the flow of sediment into the distribution system. Removable silt stops shall be required where feasible. NR 811.64(10)(10) Roof and sidewalls. The roof and sidewalls of all storage structures shall be constructed to meet the following requirements: NR 811.64(10)(a)(a) Watertight construction. The roof and sidewalls of all structures shall be watertight with no openings except properly constructed vents, manholes, overflows, risers, drains, pump mountings, control ports, or piping for inflow and outflow. NR 811.64(10)(b)(b) Sealed openings. Any pipes running through the roof, floor or sidewall of a finished water storage structure shall be sealed watertight. Openings for metal tanks shall be welded or properly gasketed. Pipes running through openings in a concrete structure shall be connected to a standard wall pipe or run through a wall sleeve which were poured in place during the formation of the structure. These wall pipes and wall sleeves shall be metal and have seepage rings embedded in the concrete. Pipes running through a wall sleeve shall be provided with a department approved watertight seal installed between the pipe and the wall sleeve. NR 811.64(10)(c)(c) Roof curbing. Openings in a storage structure roof or top, designed to accommodate control apparatus, pump columns and other equipment, shall be provided with minimum 4-inch high curbing and sleeved with proper additional flashing to prevent the access of surface or floor drainage water to the structure. NR 811.64(10)(d)(d) Installation of appurtenances. Valves and controls shall be located outside the storage structure so that valve stems and similar projections do not pass through the roof or top of the reservoir unless the department determines that this requirement need not be met to fulfill the other requirements of this chapter. The department may allow floor drain piping carrying graywater or a trench drain carrying graywater, electrical conduits, water service piping, and chemical feed piping to be encased in a concrete reservoir roof. Other appurtenances, including drain piping carrying blackwater, shall not be encased in a concrete reservoir roof. Toilets shall not be located above the reservoir roof. NR 811.64(10)(e)1.1. In addition to meeting the requirements of s. NR 811.63 (6), the top of any earth covered reservoir shall be covered with a flexible waterproof membrane. The minimum membrane thickness shall be 0.060 inches. Department approval of the specific membrane proposed is required. Protective boards shall be placed over the membrane before applying the earth cover when recommended by the membrane manufacturer. NR 811.64(10)(e)2.2. Bentonite panel membranes may not be used to meet the waterproof membrane requirement. NR 811.64(10)(f)(f) Roof slope. The top of any storage structure shall have a minimum slope of 0.015 feet per foot to facilitate drainage. NR 811.64(10)(g)(g) Drainage for roof or cover. The roof or cover of the storage structure shall be well drained, but downspout pipes may not enter or pass through the reservoir. Where parapets or similar construction which would hold water and snow on the roof are constructed, adequate waterproofing and drainage shall be provided. NR 811.64(10)(h)(h) Exposed grouted precast concrete planked roofs. Grouted precast concrete planked roofs exposed to the environment shall meet the following requirements: NR 811.64(10)(h)1.1. A minimum 2 inch thick reinforced concrete topping shall be installed over the top surface of the grouted plank roof. Fiber mesh may be used to provide reinforcing. NR 811.64(10)(h)2.2. A minimum 0.060 inch thick flexible waterproofing membrane shall be installed over the concrete topping. Department approval of the specific membrane proposed is required. The installation of stone ballast over the membrane is optional. NR 811.64(10)(h)3.3. The roof planks, concrete topping, or any insulation boards installed over the topping shall be installed to provide the minimum slope of 0.015 feet per foot required in par. (f). NR 811.64(10)(i)(i) Exposed reinforced poured-in-place flat concrete roofs. Reinforced poured-in-place flat concrete roofs exposed to the environment shall be provided with a minimum roof slope of 0.015 feet per foot to facilitate drainage and a minimum 0.060 inch thick flexible waterproofing membrane installed over the roof. Department approval of the specific membrane proposed is required. The installation of stone ballast over the membrane is optional. NR 811.64(11)(11) Safety. Worker safety shall be considered in the design of the storage structure. The following shall apply: NR 811.64(11)(a)(a) Ladders, ladder cages or safety climbing devices, balcony railings, landing platforms, guardrails, and safe locations of entrance hatches shall be provided where applicable. NR 811.64(11)(b)(b) On elevated tanks where persons transfer from the access tube to the water compartment railings, handholds and landing platforms shall be provided, where applicable. NR 811.64(11)(c)(c) On elevated tanks with riser pipes over 8 inches in diameter, protective bars shall be installed over the riser openings inside the tank. NR 811.64(11)(d)(d) A handrail system shall be installed on the roof of any elevated tank. NR 811.64(11)(e)(e) Storage structures shall be constructed to meet applicable local, state, including applicable portions of ch. SPS 332, and federal OSHA codes for specific safety requirements.