Stairway Lighting requirements (C) Carson Dunlop Associates Stair Building Codes
Model Codes & Adopted Codes for Stairway, Railings & Landing Construction

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Stair, railing, guardrail, handrail, landing & platform building codes & design specifications:

Provides citations of stair and railing code & design specifications quoted from model building codes. For each stair specification & code citation we include links to in-depth articles providing more details.

This article series lists all major building code specifications for stairs, railings, landings, and guardrails - information useful for constructing or inspecting indoor or outdoor stairs, railings, landings, & treads, and for evaluating stairways and railings for safety and proper construction. We compare stair and railing code requirements for various model, national, state and local building codes and we include explicit text & specifications from those building codes.

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Model Building Code Citations for Stairs & Railings + Full Code Texts, Dangers, Safety

Stairway Lighting requirements (C) Carson Dunlop Associates

[Click to enlarge any image] Sketch at above left provided courtresy of Carson Dunlop Associates.

BOCA National Property Maintenance Code 1993

PM-305.5 Stairs and Railings in Good Condition

all interior stairs and railings shall be maintained in sound condition and good repair.

Commentary: Handrails, treads and risers must be structurally sound, firmly attached to the structure, and properly maintained to perform their intended function safely. During an inspection the code official should inspect all stringers, risers, treads, and handrails.

PM-305.6 Handrails and guards

Every handrail and guard shall be firmly fastened and capable of supporting normally imposed loads and shall be maintained in good condition.

Commentary: This section provides for the safety and maintenance of handrails and guards. See Section PM-702.9 for additional requirements.

PM-702.9 Stairways, handrails and guards

Every exterior and interior flight of stairs having more than four risers, and every open portion of a stair, landing or balcony which is more than 30 inches (762mm) high, nor more than 42 inches (1067mm) high, measured vertically above the nosing of the tread or above the finished floor of the landing or walking surfaces. Guards shall be not less than 30 inches (762mm) high above the floor of the landing or balcony.

Commentary: Handrails are required on all stairs more than four risers in height. Handrails cannot be less than 30 inches nor more than 42 inches above the nosing of the treads (see Figure PM-702.9).

Guards are required on the open side of stairs and on landings and balconies which are more than 30 inches above the floor or grade below. The guard must be at least 30 inches above the floor of the landing or balcony.

Guards are to contain intermediate rails, balusters or other construction to reduce the chance of an adult or child from falling through the guard. If the guard is missing some intermediate rails or balustrades, it is recommended that the guard be repaired to its original condition if it will provide protection equivalent to the protection it provided when originally constructed.

International Building Code 2000 (BOCA, ICBO, SBCCI) Stair & Railing Codes

1003.3.3.4 Stairway Landing Codes

There shall be a floor or landing at the top and bottom of each stairway. The width of landings shall not be less than the width of stairways they serve. Every landing shall have a minimum dimension measured in the direction of travel equal to the width of the stairway. Such dimension need not exceed 48 inches (1219 mm) where the stairway has a straight run.

1003. Handrail Grasp Ability (Graspability) Requirements

Handrail graspability demonstrastion (C) Daniel Friedman

Our photo (left) illustrates the author (DF) holding on to a secure, graspable handrail in a building in Bar Harbor, Maine. Also see

Handrails with a circular cross section shall have an outside diameter of at least 1.25 inches (32 mm) and not greater than 2 inches (51 mm) or shall provide equivalent grasp ability.

If the handrail is not circular, it shall have a perimeter dimension of at least 4 inches (102 mm) and not greater than 6.25 inches (159 mm) with a maximum cross-section dimension of 2.25 inches (57 mm). Edges shall have a minimum radius of 0.125 inch (3.2 mm).

100333.11.4 Handrail or Guardrail Continuity

Handrail-gripping surfaces shall be continuous, without interruption by newel posts or other obstructions.

1607.7 Loads on Handrails, guards, grab bars and vehicle barriers

1607.7.1.1 Concentrated Load on Railings

Handrail assemblies and guards shall be able to resist a single concentrated load of 200 pounds (0.89kN), applied in any direction at any point along the top, and have attachment devices and supporting structure to transfer this loading to appropriate structural elements of the building.

1607.7.1.2 Component of Railings and Guardrails

Intermediate rails (all those except the handrail), balusters and panel fillers shall be designed to withstand a horizontally applied normal load of 50 pounds (0.22 kN) on an area not to exceed one square foot (305mm2) including openings and space between rails.

Full Text of IEBC International Existing Building Code & Definitions of Dangerous Building Conditions

By its definition of "existing buildings" this model building code incorporates standards and advice for structures built before current building codes.

EXISTING BUILDING. A building erected prior to the date of adoption of the appropriate code, or one for which a legal building permit has been issued.

Full Text of IRC Building Codes 2006, 2012

The ICC has free, limited, live, online access to some of the latest codes, but I couldn't find the free link for IRC immediately.

Florida State Building Codes - Stairs & Railings

2008 New York State Residential Building Code Stair Design Specifications

This building code update for stairway design specifications was provided courtesy Arlene Puentes.

R311.5.3.1 Stair Riser Height Codes

The maximum riser height shall be 8 1 / 4 inches (209 mm). The riser shall be measured vertically between leading edges of the adjacent treads. The greatest riser height within any flight of stairs shall not exceed the smallest by more than 3 / 8 inch (9.5 mm).

R311.5.3.2 Stair Tread Depth Code Requirements

The minimum tread depth shall be 9 inches (229 mm). The tread depth shall be measured horizontally between the vertical planes of the foremost projection of adjacent treads and at a right angle to the tread's leading edge.

The greatest tread depth within any flight of stairs shall not exceed the smallest by more than 3 / 8 inch (9.5 mm). Winder treads shall have a minimum tread depth of 10 inches (254 mm) measured as above at a point 12 inches (305) mm from the side where the treads are narrower.

Winder treads shall have a minimum tread depth of 6 inches (152 mm) at any point. Within any flight of stairs, the greatest winder tread depth at the 12 inch (305 mm) walk line shall not exceed the smallest by more than 3 / 8 inch (9.5 mm).

R311.5.3.3 Stair Tread Nose Profile Code Requirements

The radius of curvature at the leading edge of the tread shall be no greater than 9 / 16 inch (14.3 mm). A nosing not less than 3 / 4 inch (19 mm) but not more than 1 1 / 4 inch (32 mm) shall be provided on stairways with solid risers.

The greatest nosing projection shall not exceed the smallest nosing projection by more than 3 / 8 inch (9.5 mm) between two stories, including the nosing at the level of floors and landings.

Beveling of nosing shall not exceed 1 / 2 inch (12.7 mm). Risers shall be vertical or sloped from the underside of the leading edge of the tread above at an angle not more than 30 (0.51 rad) degrees from the vertical. Open risers are permitted, provided that the opening between treads does not permit the passage of a 4-inch diameter (102 mm) sphere.

Exceptions to Stair Tread Nose Requirements:

1.     A nosing is not required where the tread depth is a minimum of 11 inches (279 mm).

2.     The opening between adjacent treads is not limited on stairs with a total rise of 30 inches (762 mm) or less

Stair Tread Anti-Slip or Coefficient of Friction Recommendations for Safe Walking Surfaces

[Not found in NYS Code]

A walking-surface that provides a coefficient of friction of 1.02 dry and 0.98 wet will comply with ADA, OSHA, and most local building codes and insurance requirements. Other sources (cited in the two articles listed just below) cite a coefficient of friction of 0.5 (OSHA) or 0.6 (ADA) as the minimum recommended COF to avoid slippery walking surfaces and stairways.

See Algae, Ice, Fungus, Wet Surfaces & Other Stair Slip, Trip & Fall Hazards for details.

Also see EXTERIOR STAIR FALLS for a catalog of causes of falls on stairs that includes surface conditions and other defects.

R311.5.8.1 Spiral Stairway & Circular Stairway Building Codes

2006 IRC Spiral Stair Code Illustration (C) adapted from Juneau AK publication

Above; minimum tread dimensions for a spiral stairway, adapted from the 2006 IRC as published by Juneau AK IRC R311.5. [Click to enlarge any image]

Spiral stairways are permitted for interior use as a component of the means of egress from a habitable room, a basement or an attic, provided the minimum width shall be 26 inches (660 mm) with each tread having a 7 1 / 2 -inch (190 mm) minimum tread depth at 12 inches from the narrower edge.

All treads shall be identical, and the rise shall be no more than 9 1 / 2 inches (241 mm).

A minimum headroom of 6 feet 6 inches (1982 mm) shall be provided. A spiral stair is not permitted to be the only means of egress from a story of a building.

Many codes require use of a guard or rail to prevent walking too close to the inside of a circular stair where the tread dimensions are too small for safe use.

Stair Codes for Spiral Stairs, Curved Stairs, Circular Stairs, Winder Stairs

Curved stair tread dimensions adapted from 2006 IRC as published by Juneau AK (C)

Above; minimum tread dimensions for a Curved stairway, adapted from the 2006 IRC as published by Juneau AK IRC R311.5. [Click to enlarge any image]

Winder stair tread dimensions from 2006 IRC (C) adapted from Juneau AK code

Above; minimum tread dimensions for a Winder stairway, adapted from the 2006 IRC as published by Juneau AK IRC R311.5. [Click to enlarge any image]

OSHA Regulations for Temporary Stairs & Railings

STAIRWAYS - see OSHA at references

The following general requirements apply to all stairways used during the process of construction, as indicated:

The following requirements apply to stairs in temporary service during construction:

OSHA Regulations for Stair Railings & Guardrails


The following general requirements apply to all stair rails and handrails:

Canadian Occupational Safety Regulations - Stairways & Fall Prevention

Why do we need to worry so much about falls on stairs?

Stairs of all types have been used since ancient times, and because they are inherently hazardous, people have been falling on them, getting hurt or even killed in the process. In North America tens of people die and tens of thousand people get injured every year from the falls on stairs. The American National Council on Compensation Insurance estimated in 2001-2002 that the cost of such fall injuries was second only to those caused by motor vehicles.

The vast majority of stairway falls result from a loss of balance, just as falls are on the level.

A very common contributing factor is neglecting to use handrails. The consequences can be quite nasty.

Because stairway accidents can cause severe injury and even death, building codes for stairs and ramps are justifiably very rigorous. Good design can substantially reduce the potential for mis-stepping by providing us with the means to retrieve our balance, but even the best design cannot eliminate falling hazards entirely. The need for proper design also applies to ramps. The fact is that some incidents can be caused by inattention and unsafe behaviour.

The best approach to minimize the hazard of falling down stairs is to encourage the building of well-designed stairways, combined with training focused on raising our awareness of the potential for disaster.

Details about inspecting for stair hazards likely to cause a slip, trip, or fall injury are at

Also see the Canadian OSHA Answers document on Prevention of Slips, Trips and Falls.

What factors must we consider in designing safer stairs?

Stair dimensions - Canadian Rules

Figure 1 shows the recommended dimension ranges for all the important elements of stairways.

Figure 1: Legend

* Values are from the National Building Code of Canada (2005). Always check with your local jurisdiction as requirements are different in each area.

The maximum range for a stair slope is 20º-50º. However, because the majority of people prefer a slope of 30º-35º, this is the recommended range.

Steeper stairs change the way you climb them because the steeper they are the more effort you exert. The ratio of riser height and tread depth has to be adjusted accordingly. (See Figures 2 and 3)

Stair dimensions Stair Dimensions

From: Kodak's ergonomic design for people at work. 2nd ed. John Wiley & Sons, 2004. p.244

The dimension of risers or treads in a stairway should not vary more than 1 cm. When doors open directly into the stairwell, a 50 cm-wide platform should be provided beyond the swing of the door. The recommended maximum number of steps between landings is 18, with no more than two flights without a change of direction. The depth of any landing should be at least equal to the width of the stairs.

Stair surface - Canadian Rules

To reduce the risk of slipping on stairs, non-slippery surface on the whole steps or at least on the leading edges is crucial. Such a surface can be made of rubber, or metal or painted with special slip-resistant paint. Regular maintenance of the stairs in good repair plus good housekeeping can reduce hazards for tripping.

Stair handrails - Canadian Requirements

Attempts to design aesthetically pleasing stairways including handrails must not compromise functionality.

The prime function of the handrail is for holding as support while going up or down stairs.

It is therefore crucial to be able to grasp it quickly, easily and firmly if you should start losing your balance.

Figure 4 (left) shows the recommended cross-section and dimensions of a good handrail. Ideally the cross-section should be round (diameter 4-5 cm, with circumference of 12-14 cm) to allow for a good firm grip.

You should be able to run your hand smoothly along the entire length without having to adjust your grip. You should apply the so-called "tennis-racket grip" at all times when possible.

Guardrails of at least 40 cm above the surface of the stairs are needed to prevent falls off the side of the stairs that are not equipped with a banister.

Visibility on stairs

Improving visibility on stairs significantly reduces the risk for common mishaps caused by misjudging distances. Otherwise you can trip on a step or miss it completely. You can catch a heel on the edge of a step. Such mishaps are a routine cause of twisted ankles, sprained knees or more serious injuries incurred by a total fall.

Work activity on stairs

Housekeeping Requirements for Stairways

Good housekeeping is also vital to stair safety:


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