Cross passageways in tunnels

As with all public facilities, the safety and security of the users in a tunnel system is a key concern. The evacuation routes must remain free of fire products (smoke and heat) for the duration of the evacuation, regardless of the specific fire conditions. Recognizing that a diversity of conditions exist which could preclude the implementation of all standard requirements, there are cases when the easiest and fastest evacuation is accomplished through cross passageways between the incident tunnel and a non-incident tunnel or other facility. This paper contains recommendations and examples for emergency egress evacuation through cross passageways. Special attention must be given to cost implications for various design alternatives, however, recognizing that passenger safety is of paramount importance. (A)