Stairs, Fixed Industrial 29 CFR 1910.23 and

Fixed stairways mnst be provided for access from one structure to another where operations necessitate regnlar travel between levels and for access to operating platforms at any equipment that requires attention routinely during operations. Fixed stairs must also be provided where access to an elevation is daily, or at each shift where such work may expose employees to harmful substances or for purposes for which carrying of tools or equipment by hand is normally required. Spiral stairways are not permitted, except for special limited usage and secondary access situations where it is not practical to provide a conventional stairway. 

A stairway or ladder must be provided at all worker points of access where there is a break in elevation of 19 inches or more and no ramp, runway, embankment, or personnel hoist is provided. 

When there is only one point of access between levels, it must be kept clear to permit free passage by workers. If free passage becomes restricted, a second point of access must be provided and used. 

Stairways must be installed at least 30 degrees and no more than 50 degrees— from the horizontal. 

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