Under 29 CFR 1926.651(c)(2), trench excavations 4 feet or more deep need a stairway, ladder, ramp or other safe means of egress located so that workers travel no more than 25 feet laterally to reach it. Ladders must also extend at least 3 feet above the top of the trench (1926.1053(b)(1)).
How the calculation works
- Ladder count: each ladder covers 25 feet in each direction, or 50 feet of trench. The calculator divides the open length by 50 and rounds up.
- Placement: ladders are spaced evenly, with the end ladders no more than 25 feet from the trench ends.
- Ladder length: a straight or extension ladder set at the standard 4-to-1 angle needs a rail length of about (depth + 3 feet) × 1.03 to reach 3 feet above the top.
Practical tips
- Count the length where people actually work, including both sides of a trench box or plug.
- Put ladders inside the protected area, such as inside the trench box or shored zone.
- Secure ladders at the top, keep the top and bottom clear, and use non-conductive ladders near electrical hazards.
- Ramps and stairs work too. Structural ramps used by workers must be designed by a competent person.
Learn the rest of the edge rules in the free access, egress and spoil lesson.
Sources and official references
Last reviewed: October 25, 2026 · Free general education based on OSHA 29 CFR 1926 Subpart P. It does not replace the site-specific training and competent person your employer must provide, and it does not issue a certificate. Nothing you enter on this page is saved or sent.