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93 TABLE 28 REQUIREMENTS FOR FIRE DETECTION AND FIRE ALARM SYSTEMS IN ROAD TUNNELS IN VARIOUS COUNTRIES Standards Detection Time Fire Load Detection Distance Germany RABT <60 s at V air up to 5 MW (17 MBtu/hr) <50 m (164 ft) 2003 6 m/s (1,181 fpm) CH 2001 Draft <60 s Under review <20 m (65.6 ft) Directive on Road Tunnels A RVS 9.282; V air up to 3 m/s (591 fpm) 1.5 MW (5 MBtu/hr) <10 m (32.8 ft) 4.7.2002 Pre-alarm <60 s and 9.261 Alarm <90 s; 3.5 MW (12 Btu/hr) V air over 3 m/s (591 fpm) Pre-alarm <120 s Alarm <150 s NFPA 502 Addresses delay expected <15 m (49.2 ft) between ignition occurring and (section 7.4.1.4) an alarm being initiated Source: Fire Protection in Vehicles and Tunnels for Public Support (59). mercial radio. Motorists can also be notified by a public emitting diode guidance system (62). The advantage of those address system once they are stopped and/or are out of their technologies is that they can be preprogrammed to guide tun- vehicles. nel users in the correct direction depending on ventilation system response. This is especially important when compli- Caution is placed when automatic notification is used for cated tunnel ventilation schemes are used to eliminate the the motorists. Tunnel fires may change quickly and can be dif- wrong direction for evacuation. ficult to predict. Using fire-detection systems to decide which direction to exit the motorists and to initiate suppression and TUNNEL EGRESS AND INTERNATIONAL ventilation is not foolproof. Directing the escaping motorists STANDARDS REQUIREMENTS in the wrong direction could dramatically increase their risks. However, using automatic detection to close the entrance por- Design provisions allow for safe evacuation during a fire tal and to warn motorists who are approaching an incident in when heat, smoke, and other products of combustion are the tunnel is an accepted practice in some jurisdictions. released into the tunnel. Road tunnels are long, narrow, and underground, often with limited opportunities for stair cores Conversely, using traffic controls to encourage motorists to grade. to continue to drive out of the tunnel may be important for tunnels that use longitudinal ventilation. In this case, traffic An emergency ventilation and fire suppression approach controls downstream of the portal may be essential to clear needs to be fully coordinated with the evacuation plan and the tunnel past the incident and to provide room for motorists the emergency response plan to provide a comprehensive so that they can drive out to safety before being overwhelmed overall life safety program for the tunnel. Egress systems by smoke and heat that has been pushed along the tunnel by must provide for safe evacuation under a wide range of emer- longitudinal ventilation. gency conditions. The emergency response plan must help facilitate evacuation and allow for appropriate responses to These notifications are a key ingredient for the incident emergencies. command by providing location, type of incident, conditions, and size of the incident. In turn, motorists can be instructed NFPA 502 does not allow for emergency exits or exit on what to do while emergency responders are enroute and doors leading to exits to be spaced more than 300 m (1,000 tunnel staff initiate their emergency procedures (60). ft) apart, with spacing justified by engineering analysis (63). For uni-directional traffic with a longitudinal ventilation sys- Recently, intelligent evacuation notification technolo- tem, this spacing will largely depend on the fire-detection gies have been developed. One of the vendors uses elec- system and its ability to detect fire as soon as possible such troluminescent lighting technology--an uninterrupted illu- that ventilation can be activated to take smoke under control. minated path to the exits with a continuous light source They differ between self-rescue and assisted rescue from located near the walkway floor (E-Lume-A-Path) (61). road tunnels. The majority of tunnel occupants are to rescue Another vendor uses a multi-directional low-level light- themselves during a fire event.