Tunnel Emergencies and the Need for Firefighter Air Replenishment Systems (FARS)

By Chief Gordon Routley, Chief Gary English, and Captain Mike Gagliano

The expanding need for public transportation in large- and medium-sized cities is driving the development of mass transit systems that typically include underground tunnels. Emergencies in underground tunnel systems can present complex problems for rescuers attempting operations that are long distances away from air and water supply.

Water supply is typically addressed by robust standpipe and water pumping systems that ensure a sufficient supply of water to attack the fire. No one would ever argue that standpipes providing an adequate and continuous water supply are anything other than a mandatory requirement and absolutely necessary in the design of tunnels.

But water supply is only half the equation. Air supply is equally necessary for rescuers to achieve a sustained presence in underground tunnels. During a fire, these structures become hot, smoky, disorienting, and toxic environments — and they can be hundreds if not thousands of feet away from access to fresh air.

In most existing tunnels, the plan for air supply is based on hand-carrying replacement SCBA cylinders (air bottles) to the staging area, along with other equipment like hose and tools. Firefighters can only hope enough air bottles can be delivered to conduct operations without interruption and before they are low on air. This begs the question: Why not deliver air in the same manner as water by using a firefighter air replenishment system (FARS)?

FARS are a standpipe for air, permanently installed in large, complex structures. They deliver a safe, instant, endless supply of air replenishment. Firefighters can refill their air bottles in two minutes or less at fill stations located throughout the interior of a structure while breathing air in a backpack bottle, and return immediately to the firefight. Codes requiring FARS in new construction of high-rise buildings and in large, big box-style structure are proliferating in jurisdictions across the country. As underground construction expands, it makes sense to include an air standpipe system, as well as the standard water standpipe system, in the requirements for new tunnel construction.

There are four primary reasons a robust air replenishment system is essential in underground emergencies. Let’s take a quick look at them:

  1. Long travel distances

In a tunnel fire, firefighters will be required to travel long distances to reach the location of the incident. Often, they will use full respiratory protection, which will deplete their air supply before they arrive on scene or shortly after beginning operations. Once committed to the inside of train cars, they will work to extinguish fires and rescue victims within tight areas that are still producing smoke, heat, and toxic gases. These operations are likely to be lengthy and complex, and will require personnel, equipment, and supplies to be transported to the location of the problem.

Modern tunnel ventilation systems are designed to control smoke movement and deliver fresh air, but even the best engineered ventilation system is simply not designed to clear all the smoke inside a train car. Thus, firefighters must be on air while conducting firefighting operations or performing search and rescue. They will need air resupply. Without FARS, this will require that the fire department use limited personnel resources to shuttle replacement air bottles to a staging area, where they will be available for firefighters who have depleted their air. The staging area must be established in a location that cannot be contaminated by heavy smoke or gases, since the firefighters will have to go off air supply to swap out their bottles.

With FARS in place, the refill location will be in close proximity to the emergency. Firefighters can remain on air, connect to the emergency air fill panel to refill their air bottle, and return immediately to the operation.

  1. Complex layout

Tunnels are confusing in the best of situations. While it seems straightforward to simply follow the same long passages that the trains do, there is often much more complexity involved, especially when the tunnel is dark or filled with smoke. Familiarization drills and tours are an essential part of the training program, but they cannot replicate the challenges presented in actual emergencies where time is critical for those needing rescue. This is especially true if the situation occurs far from the closest firefighter entry point. Firefighters must have enough air to get to the objective, do their work, and stay in the area for extended and/or complex rescues. And, of course, they must have sufficient air supply to safely exit the smoky tunnel.

All of these challenges can be alleviated by the simple addition of FARS. No matter how complex the path to the emergency scene, firefighters have easy access to air replenishment every step of the way. Every firefighter who has participated in emergency drills in tunnels full of smoke knows how long the distances feel and how easy it is to get turned around and lose your way. Changing circumstances at the scene of the emergency and setbacks like delays, vehicle transport malfunction, or simply getting lost or disoriented may happen. But FARS can prevent them from turning deadly.

  1. Reliance on ventilation system

Modern mass transit systems are constructed with complex engineered ventilation and smoke control systems that are designed to provide safe exiting for passengers. The smoke evacuation

systems are designed to extract smoke from the tunnel to provide clear air for egress in one direction or the other. When operating correctly, these systems are invaluable and are an essential part of any installation. But like all complex systems, they are subject to malfunction, failure, tampering, and human error and provide little help for the interior smoke conditions that can be expected in the vicinity of the fire. These include smoke and gas production inside the train cars and other close spaces.

One of the authors of this article had a close call at a tunnel fire when the ventilation system was suddenly shut off. The conditions for both victims and rescuers immediately became treacherous, and all involved agree they were fortunate to get out alive. If FARS had been installed, the rescuers would have had access to immediate and sustained air resupply and would not have been put in a such a too-predictable, now preventable, life-threatening situation.

  1. Extended operations requiring large amounts of air resupply

The potential scenarios in underground tunnels are limited only by the depths of your imagination. Everything from gas leaks and fires in the cars to larger scale derailment and criminal/terrorist actions have occurred in recent years. So-called “simple emergencies” above grade are anything but simple underground due to the time required to get first responders into and out of these spaces and to resolve the incident.

The reasons for the time-consuming nature of underground operations are many, starting with the long distances and complex nature of egress to safety, i.e., everyone on the train must leave by a very narrow emergency walkway, or jump down to the tunnel bottom and potentially contact the energized third rail. The underground environment can be bewildering under normal conditions, as most responders will have limited experience in these conditions. Add to that the fear and anxiety inherent with any accident or situation where things have gone wrong, and you have a challenge just moving people away from danger and towards safety and help.

In addition, some victims may be seriously injured, non-ambulatory, or just “freaked out,” adding to the challenge of resolving these incidents quickly. Rescuers must plan on being in the underground spaces for lengthy periods of time and will need air for much of the emergency operation.

A constant and reliable supply of air should be viewed as essential, especially considering FARS, a cost-effective solution, have been operating effectively in the U.S. for more than 20 years.

Time to ask the hard questions of those making these decisions

Twenty years ago, the concept of an “air standpipe” was developed for high-rise buildings, large horizontal structures, and underground installations. Its application has been adapted more recently for mass transit tunnels. Most firefighters who have experienced, trained for, or even thought about fighting a fire in a tunnel will recognize the value of a FARS installation. Decision-makers who are responsible for the design, construction, and operation of these systems often do not have the same perspective and need to be educated on the need for this type of system. In the future, we may see it fully incorporated into the applicable standards and regulations, but why wait? Jurisdictions can require these systems now, and many do.

FARS is a proven and reliable means of having all the air you need, right where you need it in the underground environment. If the solution is readily available, why isn’t it a mandatory part of the construction process when tunnels are built in all of our cities and towns? Firefighters are going to be expected to go in and save those in harm’s way, and they will need lots of air and water to do it.

The water standpipe is the essential mechanism necessary to take care of the need for water. No jurisdiction would approve an exemption, bargain, or trade-off in the building planning and permitting process that would remove the requirement for water standpipes.

It’s time for the “air standpipe” to be viewed in the same manner: as a mandatory requirement. Agencies responsible for their passengers’ safety and the lives of firefighters must understand that without FARS, the ability of responders to save the lives of their passengers and get themselves out alive is seriously jeopardized. They must act to rectify this situation.

For more information on FARS, please visit https://aircoalition.org/firefighter-air-replenishment-systems/.


Gary English has more than 30 years in the fire service, including 14 years as Assistant Fire Marshal for the City of Seattle on major transportation projects. He is a Technical Committee Member of NFPA 130 Transit Rail Tunnels and NFPA 502 Road Tunnels. He serves on numerous scientific committees including the International Symposium Tunnel Safety & Security and International Safety and Ventilation in Tunnels. He has participated in multiple research projects with the Transportation Research Board. He is also a member of the Permanent International Association of Road Congresses (PIARC) committee on road tunnels.

Mike Gagliano has more than 33 years of fire/crash/rescue experience with the Seattle Fire Department and the United States Air Force. He retired as the captain of Ladder 5 and remains a proud member of Fire Station 31. Captain Gagliano is the author of numerous fire service articles, and co-authored the bestselling books Air Management for the Fire Service, Challenges of the Firefighter Marriage and the SCBA chapter of the Handbook for Firefighter 1 & 2 from Pennwell. He is a member of the Fire Engineering/FDIC Advisory Board, the Firefighter Air Coalition board of directors, serves on the advisory board of the UL-Firefighter Safety and Research Institute and teaches across the country on air management, fireground tactics, leadership, and company officer development.

Gordon Routley has been a firefighter in Canada and the United States for more than 50 years. He is a registered professional engineer and a fellow of both the Society of Fire Protection Engineers and the Institution of Fire Engineers. He is currently serving as Assistant Director of the Montreal Fire Department.



By Chief Gordon Routley, Chief Gary English, and Captain Mike Gagliano The expanding need for public transportation in large- and medium-sized cities is driving the development of mass transit systems that typically include underground tunnels. Emergencies in underground tunnel systems can present complex problems for rescuers attempting operations that are long distances away from air […]

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