Oklahoma Administrative Code
Title 252 - Department of Environmental Quality
Chapter 656 - Water Pollution Control Facility Construction Standards
Subchapter 5 - Sanitary Sewer Standards
Section 252:656-5-4 - Construction standards
Current through Vol. 41, No. 13, March 15, 2024
(a) Sewer. Lay sewers in straight alignment with uniform grade between manholes. Protect all pipe from traffic load damage. Install metal tracer wire on all non-ferrous piping.
(b) Trench. The width of the trench shall be ample to allow the pipe to be laid and joined properly and to allow the backfill to be placed and compacted as needed.
(c) Separation. Sanitary sewers located in the street right-of-way shall be located on opposite sides of the streets from potable water lines and shall comply with the following:
(d) Stream crossings - aerial. Support all joints in aerial crossings. Design crossing supports to prevent frost heave, overturning and settlement. Use concrete encasement (except around PVC pipe) or riprap where the pipe enters stream banks. Use expansion joints between above-ground and below-ground sewers and force mains, and protect them from freezing. Protect pipes that cross streams from the impact of flood waters and debris.
(e) Stream crossings - below-grade. The top(s) of all sewers entering or crossing stream beds shall be at least 3 feet below the natural bottom of the stream bed. Construct or encase the crossing with ductile iron pipe using mechanical joints. Sewers shall remain watertight and free from changes in alignment or grade. Trench backfill shall be stone, coarse aggregate, washed gravel or other material that will not cause siltation. Specify construction methods to minimize siltation and bank erosion.
(f) Flood plain structures. Protect sewer outfalls, headwalls, manholes, gate boxes and other structures located in flood plains from stream erosion. Locate structures so they do not interfere with the free discharge of flood flows.
(g) Manholes. Manholes shall be installed at the end of each line; at all changes in grade, size, or alignment; at all intersections; and at distances not greater than 400 feet apart for sewers 15 inches in diameter or less, and 500 feet for sewers 18 to 30 inches in diameter. Greater spacing may be permitted in larger lines, those carrying a settled effluent or where adequate modern cleaning equipment for such spacing is provided. Lampholes and cleanouts shall not be substituted for manholes nor installed at the end of laterals longer than 250 feet. [See 252:656-27-2(b) (relating to separation distance requirements).]
(h) Inverted siphons. Inverted siphons shall have at least two barrels with a pipe size at least 6 inches in diameter. Provide necessary appurtenances for convenient flushing and maintenance. Construct manholes with adequate clearance for rodding the pipes. Provide sufficient head and select a pipe size for a velocity of at least 3.0 fps for average flows. Arrange the inlet and outlet details so normal flow is diverted to one barrel and either barrel may be taken out of service for cleaning. The vertical alignment shall permit cleaning and maintenance.
Added at 17 Ok Reg 1140, eff 6-1-00; Amended at 23 Ok Reg 937, eff 6-15-06; Added at 28 Ok Reg 1282, eff 7-1-11