Catch basin or manhole steps shall be steel-reinforced
copolymer polypropylene plastic steps conforming to current ASTM C-478-78a,
paragraph 11. Steel reinforcement shall be Grade 60, having a diameter
of not less than 1/2 inch. Step length shall be such that they may
be embedded not less than three inches into the concrete sections
(walls) and have a clear length from the inside wall to the outside
of the step of not less than 53/4 inches, for foot placement.
When a drainage pipe inlet, other than a driveway culvert, is open at ground level (and may allow children or small animals to enter the drainage system), the pipe opening shall be closed with a grillage per
Figure IV-4.