Author(s): Angelo Verzoni. Published on July 1, 2019.

Delayed Response

Two years after the Grenfell Tower fire, thousands of buildings in the UK, and possibly worldwide, remain at risk from combustible exterior wall assemblies. Experts say that shouldn’t come as a shock.


On May 29, two weeks before the two-year anniversary of the Grenfell Tower fire, the New York Times published a story suggesting that tens of thousands of Britons are still at risk of dying in a blaze similar to the one that killed 72 people and injured 70 more in London on June 14, 2017.


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The Grenfell fire—which raced up and around the 24-story Grenfell Tower apartment complex at astonishing speed, leaving behind little more than a blackened shell—was fueled in large part by combustible plastics that were present in exterior wall materials that had been added to Grenfell a couple of years earlier as part of a renovation project. In the wake of the fire, government officials in the United Kingdom vowed to eliminate the risk from such materials throughout the country.

But the Times story indicates there’s still a long way to go.

“About 16,000 private apartments [in the UK] are still wrapped in the kind of exterior cladding that fed the Grenfell fire,” the newspaper said. “Their owners feel trapped in tinderboxes they cannot sell, and some residents have felt compelled to join round-the-clock patrols of their buildings, always on guard for a spark or whiff of smoke.”

For those who study the problem or who work to reduce the fire risk of combustible exterior wall materials like the ones that sheathed Grenfell, the Times piece was troubling but not surprising, given the expense and complexity of removing and replacing these materials. Furthermore, in recent conversations with NFPA Journal, these experts stressed that although the Times story implies the regulation of the materials is strong in other countries, such as the United States, the presence of combustible exterior wall assemblies—a term used to describe the entire exterior wall system of a building, which is often simply and erroneously referred to as “cladding”—should still be a concern worldwide, not just in the UK.

“It doesn’t surprise me,” Birgitte Messerschmidt, director of the Applied Research Division at NFPA, said of the Times’ reporting. “What happened at Grenfell was very scary, but I’ve seen similar conditions in many other buildings around Europe, as well as around the world.”

This video explains how the June 2017 Grenfell Tower fire in London demonstrated a breakdown in five of the components of the NFPA Fire & Life Safety Ecosystem

A costly, complicated task

According to the Times, since the Grenfell blaze, the UK government has allocated about £400 million, or a little over half a billion US dollars, to help local authorities strip and replace combustible exterior wall assemblies from hundreds of public housing buildings, and that work is ongoing. The bigger problem now, the newspaper said, are privately owned high-rise apartment buildings, for which “nobody want[s] to pay to remove the cladding.”

The situation doesn’t surprise Messerschmidt, who knows just how costly and complicated that work can be. “Imagine trying to peel a huge potato and then trying to put a new skin on it,” she said. “It takes a very long time, and it’s very expensive.”

The Times story didn’t come as a shock to Iain Cox, either. A former member of the UK fire service and current chair of the Business Sprinkler Alliance in London, Cox told NFPA Journal in a recent interview that for the last two decades or so, building practices in the UK have prioritized energy efficiency over safety, allowing plastic-laden exterior wall materials, like the ones that had been added to Grenfell, to proliferate. While they pose a fire risk, such materials increase buildings’ energy efficiency by, for example, allowing buildings to more easily retain heat.

Cox said it makes sense that it will take far longer than a couple of years to correct any damage that’s been done. “Suddenly everybody’s realizing what they’ve done is make buildings worse,” he said—even from a sustainability standpoint. “A building isn’t very sustainable if it burns down so easily.”

The situation has left some residents of these UK properties in a panic. “If you think about it all the time, you just go mental…you’re living in a building that’s fundamentally unsafe,” Rachel Guy told the Times. Guy lives in a privately owned apartment building in London that’s partially covered in the same metal composite material (MCM) panels as Grenfell. She said a firefighter told her flames could race up the 10 floors of her building in just seven minutes. According to the Times, Guy worries that her elderly mother would never make it downstairs in the event of a fire.

As part of an interim solution mandated by local fire brigades, residents like Guy have begun conducting fire watches inside their buildings, taking turns pacing hallways while their neighbors sleep, looking for any signs of smoke or flames, the Times said. It’s an archaic practice and perhaps the “lowest level of something you can do,” Messerschmidt said, but it’s better than nothing.

More involved efforts, such as installing fire sprinklers or updating alarm systems, would likely be less costly than replacing vast swaths of combustible exterior wall assemblies, but they could still be prohibitively expensive for many building owners. Plus, such measures have failed to receive government support.

According to the Times, new regulatory recommendations presented to Parliament a year after the Grenfell fire disappointed safety advocates by not recommending fire sprinklers in existing high rises or even in new buildings below 10 stories. They also failed to recommend more stringent requirements for including a second staircase in such buildings. Grenfell had just one staircase and no fire sprinklers. Its alarm system was not optimal for a building of its type and size, and tenants had allegedly been given the order by management to shelter in place in the event of a fire, provided that fire wasn’t in their unit.

In November 2018, the UK government announced a new ban on combustible exterior wall materials. While it was far-reaching in that it bans the presence of any combustible materials for use in exterior wall assemblies, it only applies to new residential buildings above 18 meters tall, or roughly six stories—stipulations that didn’t sit well with some safety experts.

“Why is the ban limited to buildings with a height greater than 18 [meters]?” James Dalton, director of general insurance policy for the Association of British Insurers, said in a speech about the ban. “I accept that 18 [meters] is the height limit after which fire is more challenging for the Fire and Rescue Service to combat, but I’m struggling to understand why someone could…build a care home or student accommodation in the future that is slightly lower than 18 [meters] in height and then cover it in combustible material.”

A statement released by the UK’s Fire Protection Association (FPA) in June also alluded to the ban, saying it doesn’t go far enough and calling for a new ban that prohibits the use of combustible materials in exterior walls for buildings of any height. “If we want to prevent another Grenfell Tower tragedy, it’s time for some immediate change,” FPA said.

Prioritizing risk for a worldwide problem

With no clear path to rectifying these issues in all of these buildings in the UK at once, prioritizing properties at the highest level of risk is critical.

“To tackle this whole thing, you have to do it on a risk basis,” Cox said. “Temporary measures like the fire watches help, but with humans being humans, if that goes on for three or four years, people’s vigilance will slip. We have to do remediation work, but we don’t have the resources to do every building immediately, so we have to prioritize risk.”

Construction workers remove combustible cladding from an apartment building in London in 2017. The work is costly and complicated, like “trying to peel a huge potato...and put a new skin on it,” according to one expert.Photograph: Getty Images

NFPA developed a tool to do exactly that after the Grenfell fire. The tool, known as the Exterior Façade Fire Evaluation & Comparison Tool (EFFECT™), has been active for just over a year. Users input data pertaining to a set of buildings—the materials used in exterior wall components and how those components are arranged, the presence of fire sprinklers, nearby ignition sources, and so on—to determine which factors combine to pose the highest risk for a fire involving exterior wall assemblies. In the roughly 15 months since EFFECT has been active, it has attracted over 500 users around the world—a sign that combustible exterior wall assemblies are a global problem.

The Times story, however, reported that the cladding that sheathed Grenfell “was banned in the United States and many European countries”—phrasing Messerschmidt describes as worrisome, as it could create a false sense of security. The reality, she said, is that experts still don’t know how widespread combustible exterior wall assemblies are. “Saying they don’t exist in countries like the US is naïve,” she said. In fact, NFPA data shows that from 2007 to 2011, about 5,300 fires involving exterior wall assemblies occurred in the US; in about 25 percent of those fires, exterior walls were the primary contributor to fire spread, even though the fire did not originate on exterior assemblies—a key indicator that the assemblies contained combustible materials. More recent data is not available.

In the UK, a “pretty strict” full-scale façade fire test exists, Messerschmidt said, which in theory should prevent fires like the one that tore through Grenfell. The problem, she said, is that the country has allowed buildings to pass the test based on an evaluation by a designer, which is called a desktop study, as opposed to conducting an actual, physical test.

In the US, NFPA 285, Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-Load-Bearing Wall Assemblies Containing Combustible Components, serves as the full-scale façade fire test. There is evidence the standard has gained some traction globally since Grenfell, too. A report published by the global reinsurance company SCOR in January 2018 said “the well-proven, decades-old NFPA 285 test involving full-scale testing is deemed as currently the most relevant [of all exterior wall assembly fire tests] and should prevail in cases of uncertainty or conflict with other standards.”

But as with any code or standard, it’s only effective if it’s followed. “If you’re totally following the standard, then it should not be a problem,” Messerschmidt said. “But we know that sometimes local jurisdictions give special permits, or people simply don’t comply.” 

ANGELO VERZONI is staff writer for NFPA Journal. Top Photograph: David Levene/The Guardian

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