This will expand on the guidance provided by the National Fire Protection Association’s (NFPA) guidelines, NFPA 502, NFPA 72, NFPA 101, and NFPA 170, and assist tunnel operators in the United States as they address various aspects of tunnel safety.
During an emergency, people have a tendency to wait for information or instruction rather than seek it out. If and when people do decide to exit a tunnel in the face of a recognized danger, they have a tendency to try to reach the main tunnel portal, rather than emergency exits for pedestrians, which may be nearer. In fact, drivers may not be aware of the existence of emergency exits or cross-passageways, and therefore may not recognize the purpose of exit doors along the tunnel wall. Additionally, people tend to overestimate the amount of time they have to evacuate during a fire - a potentially fatal mistake since fire and smoke can spread quickly in a tunnel.
In the absence of emergency responders to give directions, in-tunnel signs, marking systems, lighting, and/or audible signals must provide direction to tunnel users. Both the need to evacuate and the location of the nearest emergency exits must be clearly communicated.
The report give recommendations on the following topics:
- Emergency Exit Signs
- Emergency Exit Door and Directional Sign Formats
- Emergency Exit Door Sign Location
- Emergency Exit Directional Sign Location
- Exit Sign Size
- Sign Luminance
- Exit Door Lighting and Markings
- Illumination of Exit Doors
- Emergency Exit Marking Lights
- Audible Beacons
- Exit Path Marking Formats
- Location of Exit Path Markings
- Spacing of Exit Path Lights
- Emergency Messages
- Dynamic Message Signs (DMS)
- Auditory Messages
Further one the report give recommendations on installation and maintenance considerations, considerations for emergency response procedures and training and considerations for public outreach and education.
http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_w216_brochure.pdf (Report: Proposed Guidelines for Emergency Exit Signs and Marking Systems for Highway Tunnels)
http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_w216.pdf (Final report: Emergency Exit Signs and Marking Systems for Highway Tunnels)