Scissor Stairs and Egress

We have once again started a national debate about how many means of egresses or stairs are required or accessible for occupant egress. This US concept of two egresses has been a staple of life safety design for decades after many devastating fires that lacked modern day egress requirements. These egresses must be separated to provide egress within specified travel distance and allow occupants to safely exit from buildings.

What are Scissor Stairs?

scissor stairs

Much of the debate is centered around the use of scissors or interlocking stairways. Scissor stairs were often used in the early 1900’s to separate men and women from traveling in the same areas.

These stairs usually contain two separate stairs within a single stair enclosure. They can in some scenarios provide separation but since they are enclosed in the same enclosure, they do not meet the model code requirements as two separate egresses. They can be disorienting in design for occupants and present significant challenges for fire department operations during emergencies.

Many argue that the need for affordable housing, basic esthetics, and wasted space of two separate stair enclosures out ways the need for multiple egresses within a building. But we have a long history and many significant fires to show the need for two ways out of any emergency.

The biggest benefit for the use of scissor stairs is in large capacity venues where multiple scissor stairs are used for mass evacuations as seen in large convention centers. While they don’t count as separate egresses, they do allow for large numbers of occupants to egress two stairways within a single egress.

Standpipe Hose Connections and Scissor Stairs

The NFPA 14 Standard for the Installation of Standpipe and Hose Systems formed a stair task group to look at all stair requirements during the 2019-2024 standard cycle. The discussions center around reviewing requirements and making any needed changes for standpipe requirements. The conscious was the standard already provide requirements for separate standpipe hose connections in each interior or exterior exit stair within a stair enclosure(s) but for clarification the technical committee added new language in Section 9.3.2.

scissor stairsSection 9.3.2 Scissor Stairs

Where scissor stairs are provided, separate standpipes shall be provided for each stair within the exit enclosure(s).

The committee statement supporting the clarification is precise and clear.

The requirement for scissor stairs added as each inside of a stair enclosure is considered separate. Separate standpipes are required to ensure that firefighters can get to a hose connection regardless of which stairway they enter.

The use of different types of egress in different occupancies can be complicated but needs to provide multiple ways out of a building or structure and fire protection designed for not only occupant protection but meeting the operational needs of the fire service.

Further Reading

The Ups and Downs of Understanding High-Rise Stairwells

More about the Author:

Terin Hopkins has 34 years of experience in public safety and is currently the Manager of Public Fire Protection for the National Fire Sprinkler Association. He represents NFSA (National Fire Sprinkler Association) on many NFPA and UL (Underwriters Laboratories) technical committees, including NFPA 14 for Standpipes.


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