Insulating skin on high-rises has fueled fires before London

For the past decade, engineers specializing in fire safety have worried about the hidden danger posed by the kind of insulated metallic skin that transported flames up a high-rise apartment building in London, killing dozens.

Panels of the armor-like “cladding” have become a popular facade on tall buildings worldwide, both for their sleek look and energy-saving virtues. They also have helped fuel spectacular infernos in the Middle East, Europe, Asia and the United States.

Some fire experts worry that, with energy efficiency a priority worldwide, the proliferation of “green” buildings has the unintended consequence of fanning fire danger. Though cladding can be flame-resistant, the result can be deadly when it is not.

At London’s Grenfell Tower, flames raced with alarming speed up 24 stories of cladding in which a plastic core was sandwiched between thin sheets of aluminum. That composite is one of several kinds of exterior paneling that helps moderate inside temperatures.