Optimal Stair Angle: Balancing Safety, Comfort, and Space

A critical aspect of stair design is the angle of the stair, which can significantly influence its functionality, safety, and user experience. This is especially applicable in commercial settings, where factors like accessibility and space efficiency are paramount.

The angle of a staircase, often measured in degrees from the horizontal, determines the steepness of the stairs. Common angles range from 30 to 50 degrees. However, a widely accepted standard for the most comfortable and safe stair angle is around 37 degrees.

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37° is widely accepted as
the standard for safety and comfort

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Why 37 Degrees?

1. Ergonomic Efficiency: At 37 degrees, the ratio of the tread (the horizontal part where you step) to the riser (the vertical part between treads) is optimized for average human stride lengths. This angle ensures that the stairs are not too steep or too shallow, providing a natural and comfortable ascent and descent.
   
2. Safety Considerations: Stairs steeper than 37 degrees can increase the risk of falls and are more challenging for people with mobility issues. On the other hand, stairs less steep than 37 degrees consume more horizontal space and may not be practical in all settings.
   
3. Space Utilization: For commercial spaces where efficiency is key, a 37-degree angle offers a good balance between the vertical and horizontal space used. It allows for a comfortable rise without extending the staircase too far into the space.

Code Compliance

IBC – The International Building Code (IBC) typically requires stair slopes to not exceed a 7:11 ratio, approximately 37 degrees, with a maximum riser height of 7 inches and a minimum tread depth of 11 inches. These guidelines ensure safety by preventing stairs from being too steep and maintaining consistency in step dimensions.

ADA – Similar to IBC, the ADA requires stairs to have risers no higher than 7 inches and tread depths of at least 11 inches, ensuring a slope that typically aligns with IBC standards of around 30 to 37 degrees. Uniformity in riser heights and tread depths across all steps is crucial for safety and accessibility under ADA guidelines.

OSHA – OSHA standards for fixed industrial stairs require an angle between 30 and 50 degrees to ensure safety in workplace environments. The maximum riser height is set at 9.5 inches, and the minimum tread depth should also be 9.5 inches. These guidelines are designed to prevent accidents and facilitate safe and efficient movement in industrial settings.

Conclusion

While the 37-degree angle is a general guideline, stair design can vary depending on each project’s specific needs and constraints. Upside Innovations, with its commitment to safety, efficiency, and sustainability, ensures that each staircase is optimally designed for its intended use, keeping in mind the comfort and safety of its users.