What’s ASCE 7? Sean White on Calculating Wind, Snow, and Structural Loads

When it comes to snow loads, wind loads, and other structural forces on a building, the International Code Council (ICC) codes give you a general framework. To run the actual calculations, like sizing a beam for a specific roof slope, span, and snow load, engineers reach for a different reference entirely: ASCE 7, Minimum Design Loads and Associated Criteria for Buildings and Other Structures.

We sat down with Sean White, a lead instructor for HeatSpring’s PV Associate (PVA) and O&M Associate Technician (OMAT) courses, to talk about what ASCE 7 is, how it’s used to calculate wind, snow, and structural loads (like PV mounting systems) and where it fits alongside the more familiar ICC codes.

Want to build a deeper foundation in the basics of codes and standards, along with the rest of the PVA and OMAT curriculum? Sign up for the PVA course or the OMAT course to get started!

Transcript

Here’s an interesting one: what do people use to calculate loads like wind loads, snow loads, and structural loads?

There are the ICC codes — the International Code Council codes — which include the IRC (International Residential Code), the IFC (International Fire Code), and the IBC (International Building Code). Those will help you figure out some baseline information about snow loads and similar requirements.

But to do the actual calculations — say you’ve got a beam on a 4:12 slope, spanning 20 feet, and you need to know how thick it has to be in a given snow load area, how much load it will carry, and what safety factor you need — that’s a different level of detail. If you’re an engineer, you’ll go a step further than the plain ICC code and use a different reference entirely.

So what book is that? If you don’t know it, don’t worry — I didn’t either, until I did. It’s ASCE 7 — that’s A-S-C-E, like “ACE” with an S in it — 7. The full name is Minimum Design Loads and Associated Criteria for Buildings and Other Structures. It’s used to calculate wind loads, snow loads, and other structural loads, including for PV mounting systems — and probably for something like putting an energy storage system on the third floor of a building. If you’re an engineer or designer, this is the reference you’d use to determine those forces.

And honestly, I’d just recommend going to engineering school, getting your PE license, and then you can charge $100 a minute for stamping drawings. Right, Brit? Why don’t we just do that instead? …Because we’re not in it for the money — we’re saving the planet and saving lives by teaching safety. That’s right.