Hitting the reset button on high-rise exterior panels
A recent article in the Wall Street Journal — Stricter Limits on Combustible Panels in High-Rise Construction Could Be Coming — reported that manufacturers of metal composite exterior panels with combustible cores, similar to those that burned last year in a deadly high-rise fire in London, are backing stricter height limits for their use on buildings in the U.S. The panel manufacturers, led by the Metal Construction Association, state that issues such as elevation, the reach of fire equipment and the inability of interior sprinklers to have any impact on an exterior fire were not considered.
The International Code Council’s fire-safety committee considered proposals last month during its 2018 Committee Action Hearings in Columbus, Ohio, to roll back a section of the code that has allowed panels with polyethylene cores or other combustible materials to be used on high-rise exteriors of any height, under certain conditions, since 2012. Numerous code changes to address the fire safety attributes of exterior walls, including cladding, were submitted. While the majority of the other proposals were disapproved, one proposal that would limit the use of exterior aluminum-sheet panels with polyethylene cores or other combustible material to 40 feet above ground was approved by the committee.
The next step in the process will be the submission of public comments, which are due July 16, 2018. The Code Council anticipates that many of the proposals dealing with exterior wall panels will receive comments and will be on the agenda at the Public Comment Hearings in Richmond, Va., this fall.
The tragic Grenfell Tower fire in London — and a small number of high-rise fires in Dubai, Australia, Azerbaijan and elsewhere — brought extensive public focus on combustible exterior wall systems, often called “cladding,” prompting many questions as to how these types of fires can occur and what the risks are of such a fire in the future. In retrospect, London officials were forced to admit that Grenfell Tower — a building not constructed in strict compliance with the International Building Code (IBC) — was a fire hazard. In addition to its flammable exterior panels, which had been installed in a recent renovation, the apartment building had no sprinklers, no building-wide fire alarms and only one stairway.
While buildings with exterior facades that are made of flammable aluminum panels present a special problem, modern high-rise structures and skyscrapers are built with firewalls and doors and other features meant to contain smoke and flames in the area where they originate. Sprinkler systems, long required in new high rises, can extinguish small fires and suppress larger ones long enough for people to escape and firefighters to arrive. Generally, the presence of such exterior facades is viewed as less of a threat in the United States than overseas — there has never been a multi-fatality here in which flammable panels were implicated.
In addition to stringent requirements for the use of combustible exterior wall systems, the IBC requires many safety features for all new high-rise buildings, including noncombustible, fire-resistance-rated construction; at least two ways of exiting the building via shafts of fire-rated construction; automatic sprinklers; fire alarm and smoke detection systems for early warning; and emergency voice/alarm communication systems. Also required are inspections by independent third parties to ensure that the materials are installed in accordance with their product listing or label and the code.
As codes and standards specialists, building and fire safety is constantly at the forefront of our minds at the International Code Council. To help navigate the use of combustible exterior wall systems for buildings constructed to the IBC, ICC developed its Combustible Exterior Wall “Cladding” Systems: An ICC Perspective.
Beth Tubbs, a senior staff engineer with the International Code Council Codes and Standards Development department with extensive experience in fire protection engineering, also shared insight on the lingering effects of the Grenfell Tower fire in London last year and how the Code Council and others in the codes and standards community have responded. Click here to view the ICC Pulse Podcast.