Interlocked stair

The 2026 amendment to Approved Document B, Fire Safety, Volume 1: Dwellings, defines an interlocked stair as: ‘Two interlocking protected stairways providing two separate paths of egress within one protected shaft or separated protected shafts. These are also sometimes referred to as scissor stairs or stacked stairs.’

[edit] Related articles on Designing Buildings

• Approved document B.
• Escape route.
• Evacuation lift.
• Evacuation lift lobby.
• Evacuation.
• Fire.
• Lobby.
• Means of escape.
• Place of safety.
• Protected escape route.
• Protected shaft.
• Protected stair.