Horizontal Sliding-Door Systems: Opening New Opportunities for Design Flexibility
Learning Objectives - After this course, you should be able to:
- Understand the evolution of fire and building codes in the U.S., for emergency egress, fire resistance, and building security requirements.
- Learn the current framework for fire and building codes in the U.S., which allow the use of horizontal sliding doors in any application.
- Analyze the different uses of horizontal sliding-door systems.
- Examine the advantages of sliding door systems for the disabled under Universal Design.
- Understand how horizontal sliding-door systems work and what they are made of.
Many design professionals may not know it, but changes in fire and building codes since 2000 have made it possible to use horizontal sliding-door systems in a wide variety of applications, opening up new possibilities for emergency egress and the juncture of internal spaces, while protecting against fire and smoke, ensuring life safety and enhancing building security.
The changes mark a radical departure from codes developed over the 20th century that allowed horizontal, accordion-style sliding doors in only selected applications, and forced architects to provide emergency exits and separate internal spaces with standard, wood or steel-framed, hinged swinging doors, a minimum of four feet wide.
Today, the acceptance of horizontal, accordion-style sliding-door systems is for all applications except in certain occupancies which typically involve the storage of flammable material, the categorization known in codes as Group H. The sliding-door systems can be used regardless of the occupancy type or occupancy "load" of the building or the space being served. This has liberated design professionals to take new approaches with openings in required fire separation such as airports, schools, hospitals and museum galleries, while still maintaining fire and life safety standards.
Retractable horizontal sliding-door systems-allowing free-flowing openings some of the time and secure closure when needed-has not only been approved by the two U.S. national buildings codes, the International Building Code and the National Fire Protection Association (NFPA) 5000 Building Code, but has been deemed ideal and in many cases preferable to traditional hinged swinging doors. As a result, design professionals have many more options for this essential component of their craft: the entrance and exit, the free-flowing passageway, the atrium and the juncture of spaces.
Codes Over Time
An important driver of the design of front entrances in the 20th century has been energy concerns, which led to the development of the revolving door, and later the sliding glass door and protected vestibule, which provided a seal against the elements, while accommodating the passage of large numbers of people.
The separation of internal spaces, before the development of fire codes and increased security requirements, could be designed with few restrictions, such as the wide-open passageways separating the galleries at the Louvre Museum in Paris. Ancillary means of egress was likewise a straightforward affair: standard swinging doors at stairwells and back-of-house exits, with little or no requirements for how they would actually function in an emergency or be used by different groups of people, such as the disabled, patients in health-care facilities, or large crowds in entertainment or shopping venues.
All of that changed over the course of the last century, after tragedies that revealed the need for functional emergency egress and fire protection, and led to the development of strict standards in detailed fire and building codes.