Sufficient curtain wall and storefront door width is essential to facilitate the quick and safe passage of people during egress. The minimum width ensures that occupants can exit safely and that the design complies with accessibility and safety standards.
The criteria for determining the minimum door width is the clear width, also known as egress capacity width. The specific width requirement referenced in the building code dictates how these measurements are applied.
While specifying the actual door leaf width is relatively uncommon, building codes typically mandate the minimum clear width or egress capacity width. These measurements serve various purposes—calculating egress capacity, ensuring accessibility, and maintaining compliance with minimum width standards.
The allowable encroachments on the opening width may vary depending on the specific purpose of the door width measurement, so designers should verify the applicable code section before finalizing details.
Understanding how the clear width differs from the egress capacity width is critical. The clear width of a door opening is primarily used to meet minimum accessibility requirements—such as ensuring wheelchair users can navigate safely through the opening.
In contrast, egress capacity width determines how many occupants can pass through during emergency evacuation. This dimension is often less than the actual door leaf width because deductions are made for the frame and door stops that encroach into the opening.
Designers should account for these dimensional differences early in the layout phase of curtain wall or storefront systems to prevent conflicts between architectural intent and code compliance.
For further clarification and examples of proper egress door operation, consult NFPA resources such as:
These resources outline essential criteria for egress door design, including operational clearance, swing direction, and measurement methodology.
Properly sizing curtain wall and storefront door width is vital to meet safety, accessibility, and code requirements. Understanding the distinction between clear width, egress capacity width, and door leaf width helps architects design safe and efficient exit systems. Collaboration with code consultants and manufacturers ensures that designs comply with NFPA and local building codes while maintaining aesthetic and functional goals.
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