Tragedy in Context

A fire engine on its way to the Triangle Fire, 1911:

I’ve been reluctant to discuss the fire at the Grenfell Tower in London, largely because I didn’t see that I had anything original to say about it. I’m only slightly familiar with codes and practice in the UK and this horrific tragedy doesn’t lend itself to armchair forensic analysis. David West’s comments today on an article in ArchitectureAU triggered a semi-new thought on context, which is what follows.

It’s common knowledge that tragedies spur regulation. Modern egress provisions in building codes, for example, began with the Triangle Fire. From a forensic engineer’s point of view (or from a cynical one, which is not the same thing), current codes are collections of experience about building failures. Each time something has gone wrong, a code provision is added or edited to try to prevent the same event from reoccurring. Since there are a nearly infinite number of ways that buildings can fail, code writers are forever playing catch-up. This cycle of failure and code revision would be of interest only to the designers and builders who have to implement the codes were it not that the failures usually involve tragedy, with people wounded and killed. People who write about this topic, including me, have a tendency to present the cycle as a ratchet capable of one moving in one direction, toward more safety, but that is not true.

There are literally hundreds of years of experience and building regulation regarding the flammability of exterior walls. Events such as the Great Fire in London showed that flammable exterior walls spread fire between buildings and from lower floors of buildings upward within the buildings. By the time that lightweight curtain walls became popular in the U.S. in the 1950s, it was understood that such walls had no adverse structural impact, so much of the discussion about their use centered on fire rating: could glass or metal-panel walls be shown to be as safe as the masonry walls they were superseding?

Structure has been mature technology for a long time. This means that we are surprised when it fails, because it has succeeded so well so many times. Fire-protection is less mature but has succeeded: we no longer have regularly-occurring city-wide conflagrations. We are not surprised by fire damage, but we are surprised by a total failure of passive fire-protection such as occurred at Grenfell. We are not surprised at all by waterproofing failures, because they are so common. I mention this because the best justification for the installation of the metal-panel skin at Grenfell was to address waterproofing.

There’s one last thread to this discussions and David described it without using its most common name. David’s list of “performance specification, subcontractor bid-shopping, the progressive emasculation of [standards]” is usually called, in the U.S., “value engineering.” That phrase, which is meant to describe a potentially valuable process, is most often used to describe something else entirely. The origin of value engineering was the idea that not every goal is equally important and money can be saved by matching intensity of design and construction to priorities. Going to a less expensive window that has similar construction (and therefore similar structural, sound, thermal, and waterproofing performance) but thicker (and therefore more visible) mullions when compared to a window originally specified is a good example of value engineering. Good appearance is a goal, but one that is less critical than the physical performance goals.

An example of bad value engineering, in my opinion, is the substitution of steel studs and gypsum board for concrete block as the back up for EIFS facades. The stud system is cheaper but (a) has little inherent water resistance, so it transfers all of the weatherproofing to the EIFS, (b) as is often designed, is more flexible under wind load the block, which contributes to cracks in the EIFS which decreases the weatherproofing, and (c) when wet, the gypsum board can serve as a growth medium for mold. This is an example of bad value engineering not because I don’t like EIFS over metal stud (and I don’t) but because there is no prioritization other than money. The new system is worse in every way than the old, so its use is simply a matter of saving money and accepting the consequences. That may be okay but it’s not value engineering.

How this all comes together: deregulation in the building industry is value engineering writ large. It might make sense if the process began with examining various goals of regulation and prioritizing them. For example, we as a society could decide that we can’t afford aesthetics or history, and eliminate historic landmarking. Obviously I disagree with such a change in goals, but it’s a legitimate position: aesthetics and history are less important than, for example, life-safety and housing for all. (It’s probably important to state here that I disagree with this position because I believe it’s possible to meet all of these goals.) Allowing flammable cladding on buildings, which flies in the face of hundreds of years of experience and all modern theories of fire protection, is simply saving money. And we’ve seen, again, where that leads.