Seismic Restraint of ducts, sprinkler pipes, etc in Canada

[atrizzy]

Howdy folks, I posted this over in HVAC but I don't think they're keen.

I'm a structural engineer looking for a bit of input from you HVAC folks experienced with the West Coast of Canada.
Are there any guides or codes that need to be followed in addition to the requirements of NBCC 4.1.8.18 for restraining ductwork, sprinkler piping, etc? Or is this stuff typically allowed to swing and deflect providing nothing is at risk of damage and that the anchorage is 2x what's required for vertical support?

The NBCC seismic components of buildings clause above seems appropriate for heavy units, AHUs, pumps, etc if suspended from a ceiling, but it seems a little stringent for ducts and small, light pipes.

What do you say? And thanks in advance!

 

[NorthCivil]

Have done a bit of this at a couple different small outfits in the Vancouver area.

There is almost no code or standards to guide it. Once I chased the building code reference to an electrical standard that I bought for $230 for the one line of the standard that said "any suspended electrical fixtures weighing over 5lbs shall be restrained"

When it comes to pipes and ductwork, I always visualized the pipe and duct networks taking on their own funny mode shapes during a seismic event that would lead to the whole installation falling apart and falling down that way. as pipes and ducts are assembled with so many parts fitted together, you cant reasonably cable each part to the ceiling, so you should reasonably restrain the assembly, thoughtfully. its a practical exercise.

big HVAC units on the roof, hot water tanks suspended 20ft up, etcetera, need to be strapped tight to something that aint falling down.

its nice work IMO.

 

[TLHS]

I have dealt with this a lot. You can't even get places like BC Hydro doing things consistently, so it is not ideal. It is not specified well, and I've asked questions of the code writers and I'm pretty sure they just don't have time to deal with that section of the code. Some of the R values don't really line up with current understanding, and the new rules for spectrum construction for buildings haven't been carried through to non-structural components. Basically, use a pragmatic and consistent approach and, if this is going to be a thing you do a lot of, read everything you can.

A couple of sources to start:

Electrical Contractors Association of BC Seismic Manual
- For some reason they don't actually seem to have a page describing this on their site. It has separated the province into zones and then has a bunch of pre-designed restraint details and sizes for trays, conduits, equipment and similar. Some of this would transfer well into non-electrical equipment. The audience is installation contractors.

Kenetics Noise Control Seismic Manual

https://kineticsnoise.com/seismic/seismic_design_guidelines.html

-This deals with Canadian and US codes. They're not based on the latest code rev, but the last couple of code revs haven't really touched the non-structural components section

On top of that, the non-structural component stuff is based on the same research in Canada and the US. So look at ASCE-7. The formula is phrased slightly differently, due to where a couple of factors are hidden in the codes, but otherwise are the same. So it's nice to look at their code, even though the provisions can't be relied on. They have specific requirements for different types on non-structural components.

I'll try to grab some more specific stuff in the next few days. ASHRAE and SMACNA have guides that don't apply to Canada directly, but are still generally applicable as long as you don't start using exemptions that are in the US codes but not the Canadian ones.

Some construction groups in Ottawa put a guide together, it basically points at non-Canadian standards to help decide what mechanical elements need to be restrained. I generally agree that this is reasonable, but you might get stuck trying to justify an alternate solution depending on the authority having jurisdiction, which can be annoying.

https://www.walmarventilation.ca/uploads/cEMY1hGD/OCAGuidelineforSeismicRestraintinOttawaRegion.pdf

You can also use CSA S832-06 to do risk evaluation, but it's a weird standard to try and reconcile with the building codes. It's taking a good, but very different type of swing at the problem.

 

[atrizzy]

That's super helpful. I found some other guidelines from ASCE and IBC which appear to be more detailed and reasonable than the very blunt wording in NBCC.