(A) Design requirements will be as follows: The city requires that all above ground BPAs be protected from freezing by installing a protective enclosure over the BPA. All BPA enclosures must meet the following performance requirements.
(1) Freeze protection. Enclosures must provide at least 6.5R factor insulation.
(2) Insulation. Attaching insulation to the BPA is not permitted.
(3) Accessibility; clearances. Minimum side, end and top clearances are as follows:
(a) One-quarter-inch through one-inch shall have a clearance of four inches from the end walls to ball valves, eight inches clearances on the side utilizing the test cocks and four inches on the opposite side.
(b) Two-inch through ten-inch shall be installed in a sealed H-20 traffic rated vault. The two-inch BPA shall have a clearance of four inches from the end walls to ball valves, 12 inches minimum clearance on the test side of the assembly and eight inches minimum clearance on the opposite side.
(c) Three-inch through ten-inch BPA shall have a clearance of eight inches from the end walls to the ball valves, 30 inches clearances on the test side of the assembly and 12 inches clearances on the opposite side.
(d) The clearance requirements under § 54.08(I) may be waived if:
1. Adequate access to all parts of the BPA (including the shut off valves) is readily provided; and
2. Access provided allows testing and maintenance activity to be completed without having to enter the enclosure, and the enclosure is lightweight (i.e., each section requires no more than three or four men to remove) and is fully removable intact or in panels.
(4) Drainage. Adequate drainage for reduced pressure principle BPAs shall be provided via drain ports along the bottom of one of the side walls of the enclosure.
(5) Restrictions on placement. Above ground installations must be located outside of all required sight triangles, rights-of-way and easements. They shall not impair line of sight or legal movement for vehicular or pedestrian traffic. There may be other project-specific conditions that, in the opinion of the ORC, warrant additional constraints on the location of the BPA.
(6) Below grade installations.
(a) Below grade installations of BPAs are not recommended. They are classified as confined spaces and are at increased risk of flooding due to clogged or undersized drains. Also, leaky or damaged assemblies are not as evident as they are in above ground installations. BPAs may be installed below grade if the design engineer for the project can demonstrate that an above grade installation is infeasible due to space availability of other constraints. Every attempt must be made by the design engineer to provide for above ground installation of BPAs. Approval of below grade installations will be at the discretion of the Backflow ORC.
(b) All below grade installations shall be in a vault with a water-tight hatch or door and shall drain to grade or to a stormwater catch basin. The drain pipe must be fitted with a vermin screen at each end.
(c) The following clearances shall be maintained around the BPAs within the vault.
1. Three-quarter-inch through one-inch shall have a clearance of four inches from the end walls to ball valves, eight inches clearance on the side utilizing the test cocks and four inches on the opposite side.
2. Two-inch through ten-inch shall be installed in a sealed H-20 traffic rated vault. The two-inch BPA shall have a clearance of four inches from the end walls to ball valves, 12 inches minimum clearance on the test side of the assembly and eight inches minimum clearance on the opposite side.
3. Three-inch through ten-inch BPAs shall have a clearance of eight inches from the end walls to the ball valves, 30 inches clearance on the test side of the assembly and 12 inches clearances on the opposite side.
(Ord. 07-14-03B, passed 8-8-2022) Penalty, see § 54.99