Guardrail Height and Opening Limitations on an Elevated Exterior Deck
A final inspection of a new two-story commercial building reveals an exterior second-story deck open to the public. The deck is 12 feet above grade and is protected by a guardrail with a top rail at 38 inches above the deck surface. The guardrail has horizontal balusters spaced 5 inches apart on center, with the bottom rail 6 inches above the deck. The deck also has a stairway with open risers leading to grade. The contractor states that the 38-inch height meets the code and that the baluster spacing is acceptable because the building is not a residential occupancy. The inspector must determine whether the guardrail and stairway comply with the code's guard and handrail provisions for commercial occupancies.
1. Evaluate the guardrail height and opening limitations.
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The inspector should evaluate height and openings as separate requirements.
Height. The guardrail is 38 inches above the deck. The code generally requires guards on open sides of walking surfaces more than 30 inches above the floor or grade below, with a minimum height of 42 inches for commercial occupancies. A 38-inch guard is therefore likely noncompliant for a commercial deck, even though it might be acceptable in some residential applications. The inspector should confirm the applicable height in the locally adopted code, because some jurisdictions permit 36 inches in certain existing or residential contexts.
Opening limitations. The code limits openings in guards so that a sphere of a specified diameter cannot pass through. The commonly applied criterion is that openings must not allow passage of a 4-inch sphere. With balusters spaced 5 inches on center, the clear opening between balusters depends on baluster width; if the clear space exceeds 4 inches, the guard is noncompliant. A 6-inch gap at the bottom rail is also a concern because the bottom opening must likewise reject the 4-inch sphere.
Conclusion. The contractor's argument that baluster spacing is acceptable because the occupancy is commercial is incorrect. The 4-inch sphere criterion applies to commercial guards as well. The inspector should issue a correction requiring the guard height to be increased to the code minimum and the baluster spacing and bottom gap to be reduced so that a 4-inch sphere cannot pass at any point.
2. What must the inspector check on the open-riser stairway?
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The stairway introduces several distinct code requirements.
- Guard and handrail continuity. The stairway must have guards on open sides and a handrail on at least one side, with the handrail height typically between 34 and 38 inches above the stair nosing. The inspector should verify handrail height, clearance from the wall, and continuity around landings.
- Open risers. Where risers are open, the code limits the size of the opening so that a 4-inch sphere cannot pass through the triangular space between treads and risers. The inspector should measure the clear opening at its widest point.
- Tread and riser dimensions. The inspector should verify uniform riser height and tread depth within the tolerances allowed by code, since open risers often reveal inconsistent dimensions that create trip hazards.
- Landings and headroom. Verify that landings are provided at the top and bottom, that the landing dimensions meet code, and that headroom above the stair is adequate.
- Conclusion. The inspector should not limit the review to the guardrail height. The open-riser stairway must be checked for sphere-passage openings, handrail compliance, and dimensional uniformity, and any deficiency should be cited in the correction notice.