Tunnel Vision?
National views of fire sprinklers differ.

NFPA Journal®, March/April 2008

From April 16 through 18, 2008, the Society of Fire Protection Engineers will host the 7th International Conference on Performance-Based Codes and Fire Safety Design Methods in Auckland, New Zealand. These bi-annual conferences are known not only for the excellent technical papers presented, but also for the case studies that have been part of each conference since 1998.

Before the conference, fire protection engineering teams are assembled from multiple countries to participate in a common design challenge. Not all countries are represented each time, but Australia, Japan, and the United States have been consistent in their participation. The teams work independently to develop design solutions that will provide economical and effective fire safety. While not a competition, the proposed solutions are presented in a single session to allow review and comparison.

Theoretically, performance-based approaches should objectively assess the value of automatic suppression systems and other fire protection features. However, a comparison of the performance-based solutions submitted by teams at past conferences suggests the decision to use or omit fire sprinklers is more related to the nationality of the submitting team than to the occupancy.

Use of fire sprinklers
We don’t know whether national variations in the cost of system installation, availability of adequate water supplies, or degrees of training and experience become subliminal factors in the decision to use automatic suppression systems. While the differences might be interpreted as national biases for or against active fire protection in some countries, they are not always consistent. For example, Japan appears mainly as a “no sprinklers” country, but can be considered the world leader in terms of water-based protection of road tunnels, routinely fi tting its Class AA and A tunnels with deluge sprinkler systems, typically arranged in zones of approximately 54 yards (50 meters). These categories include all tunnels more than 3,281 yards (3,000 meters) long and shorter tunnels with traffi c volumes of more than 4,000 vehicles a day.

By contrast, although the U.S. teams appear to recognize the value of sprinklers in buildings, very few road tunnels are currently equipped with automatic fire suppression systems. Seattle, Washington, provides the exception, with three tunnels along its interstate highways protected with foam-water sprinkler systems because the state needs to allow hazardous cargo through these routes.

One of the significant changes to the 2008 edition of NFPA 502, Road Tunnels, Bridges and Other Limited Access Highways, is the elimination of many outdated annex statements regarding potential adverse impacts of water-based fire suppression systems. Another is the dramatic increase in the values of expected heat release in tunnel fires. Both changes refl ect international fire experience and the growing use of sprinkler and water mist systems to protect road tunnels.

As the international fire protection engineering community gathers in New Zealand in April, teams from Australia, Japan, Hong Kong, Sweden, and the United States will present their design challenge case studies. This year’s project is a 20-story apartment building served by two elevators and a single stairway. It will be interesting to see if such a building can be considered safe in some countries without the inclusion of an automatic fire suppression system.