29 CFR § 1910.24 - Step bolts and manhole steps.
(a) Step bolts. The employer must ensure:
(1) Each step bolt installed on or after January 17, 2017 in an environment where corrosion may occur is constructed of, or coated with, material that protects against corrosion;
(2) Each step bolt is designed, constructed, and maintained to prevent the employee's foot from slipping off the end of the step bolt;
(3) Step bolts are uniformly spaced at a vertical distance of not less than 12 inches (30 cm) and not more than 18 inches (46 cm) apart, measured center to center (see Figure D-6 of this section). The spacing from the entry and exit surface to the first step bolt may differ from the spacing between the other step bolts;
(4) Each step bolt has a minimum clear width of 4.5 inches (11 cm);
(5) The minimum perpendicular distance between the centerline of each step bolt to the nearest permanent object in back of the step bolt is 7 inches (18 cm). When the employer demonstrates that an obstruction cannot be avoided, the distance must be at least 4.5 inches (11 cm);
(6) Each step bolt installed before January 17, 2017 is capable of supporting its maximum intended load;
(7) Each step bolt installed on or after January 17, 2017 is capable of supporting at least four times its maximum intended load;
(8) Each step bolt is inspected at the start of the workshift and maintained in accordance with § 1910.22; and
(9) Any step bolt that is bent more than 15 degrees from the perpendicular in any direction is removed and replaced with a step bolt that meets the requirements of this section before an employee uses it.
(b) Manhole steps.
(1) The employer must ensure that each manhole step is capable of supporting its maximum intended load.
(2) The employer must ensure that each manhole step installed on or after January 17, 2017:
(i) Has a corrugated, knurled, dimpled, or other surface that minimizes the possibility of an employee slipping;
(ii) Is constructed of, or coated with, material that protects against corrosion if the manhole step is located in an environment where corrosion may occur;
(iii) Has a minimum clear step width of 10 inches (25 cm);
(iv) Is uniformly spaced at a vertical distance not more than 16 inches (41 cm) apart, measured center to center between steps. The spacing from the entry and exit surface to the first manhole step may differ from the spacing between the other steps.
(v) Has a minimum perpendicular distance between the centerline of the manhole step to the nearest permanent object in back of the step of at least 4.5 inches (11 cm); and
(vi) Is designed, constructed, and maintained to prevent the employee's foot from slipping or sliding off the end.
(3) The employer must ensure that each manhole step is inspected at the start of the work shift and maintained in accordance with § 1910.22.