Stairways designed to limit the penetration of smoke, heat, and toxic gases from a fire on a floor of a building into the stairway and that serve as part of a means of egress are called?

Stairways designed to limit the penetration of smoke, heat, and toxic gases from a fire on a floor of a building into the stairway and that serve as part of a means of egress are called?

• A. Area of Refuge
• B. Smokeproof Enclosures
• C. Public Way
• D. Clear Width

Answer: (B)

Stairways that stay tenable during a fire by limiting penetration of smoke, heat, and toxic gases are called smokeproof enclosures. They are built to keep the evacuation route free from smoke, often with fire-resistance rated construction and doors designed to resist smoke entry, sometimes with stairwell pressurization to maintain a safe path. This protection directly supports people moving through the means of egress to safety. An area of refuge is a safe waiting space for occupants who can’t use stairs, not the protected stair itself; a public way describes the exit path accessible to occupants but doesn’t imply a smoke-protected enclosure; clear width is simply a dimension, not a protective enclosure.

Stairways that stay tenable during a fire by limiting penetration of smoke, heat, and toxic gases are called smokeproof enclosures. They are built to keep the evacuation route free from smoke, often with fire-resistance rated construction and doors designed to resist smoke entry, sometimes with stairwell pressurization to maintain a safe path. This protection directly supports people moving through the means of egress to safety. An area of refuge is a safe waiting space for occupants who can’t use stairs, not the protected stair itself; a public way describes the exit path accessible to occupants but doesn’t imply a smoke-protected enclosure; clear width is simply a dimension, not a protective enclosure.