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Building with Science #004: Standards vs Understanding

Shawn McIsaac

Standards are not a replacement for mastery, they are not a best practice guide, they aren’t even applicable in many cases. They are just a benchmark of some sort of performance or some way of doing or testing something that a group of people have deemed to be relevant. They are often correct (in so far as what they are trying to benchmark, they may benchmark the wrong thing though) but often confused for mastery or the only measure of success. “It meets the standard”. What standards do provide is a common way of comparing one thing to another and that can be useful, if relevant.

Standards are a way to protect against something bad happening if you don’t actually understand what you are doing or you need a repeatable test result to design with. They serve as a benchmark to compare against, they are a paint by numbers approach to design, they give lawyers and expert witnesses something to quote and bring up in court. They can be thought of as a minimum duty of care in some instances. So we’d like to think the standards may be at least somewhat correct, perhaps through some sort of expert peer review process and that the standard has a reasonable application to the thing we’re trying to design.

Unfortunately, this is true for only a handful of New Zealand Standards.

Some examples?

Sure. I’ll elaborate on each of these in the coming weeks as separate articles because they are so unbelievable they’d be dangerous to consume all at once.

NZS4284 – Conclude a cladding system will comply with the building code because it kept water on the outside of the cladding, one time, in a laboratory, despite the fact we have $47 billion dollars worth of proof you can’t make a cladding waterproof in the field. Make two Verification Methods based on this premise.

NZS4858 – Conclude a waterproof membrane is waterproof if the particle board below it doesn’t go above 10% moisture content in 7 days because that could rupture the membrane when the particle board expands (I can’t make this up). Test using conditions with no relevance to construction (0% RH). Make numerous technical assessments based on this premise.

NSZ 4201 – Conclude a building wrap is waterproof enough after 24 hours of testing, a criteria that plywood can pass (we did it, it worked better than the rigid air barrier you are probably using). Promote absorbent underlays, clearly the opposite of what we want. Base an Acceptable Solution and numerous technical assessments based on this premise.

NZS 4214 – Determine the thermal resistance of a wall using a 2D calculation method. Ignore inconvenient facts like slab edges, wind, moisture content, temperature dependency. Add convenient facts like contact resistances, air layers, insulation values from rainscreen claddings. Make it all up anyways when you provide an H1 report to council. Write 5 iterations of this as a guide for everyone to follow and an Acceptable Solution.

NZS 2699 – Masonry Wall Design – Assume and encourage brick masonry to attract shear forces and crack under the smallest of seismic events. Include a requirement that water can’t track from one side of the tie to the other for no reason. Include this as an Acceptable Solution.

Standards are the enemy of innovation and the nemesis of understanding. They aim to make everything fit into a neat box based on what has been done before. No where in a standard does innovation become prominent and when the standard is asking the wrong question, you keep getting the wrong answer. Sometimes those wrong answers cost people lots and lots of money and often those people don’t even know the standard isn’t relevant.

I’m going to suggest something radical, maybe:

NZ shouldn’t have our own standards because we keep getting them wrong. 

Maybe Europe and North America have a touch more population and expertise and they might even know a thing or two about buildings. Of course, we’d have to update those overseas standards to suit our unique New Zealane science that we have here.

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