Louvers as openings

[Boiler106]

I have a single story precast manuf building on the US east coast (IBC 2018) with inoperable louvers on one wall that i have considered asce wall 'openings.'

The louvers attach to ductwork and function as fresh air intake. The ductwork connects to mechanical units in the interior of the building. The openings push me into a 'partially enclosed' classification.

Am i incorrect in assuming these are openings if 100% of the opening is connected to ductwork? Is there a distinction?

Again, these are inoperable and, in any case, must be open in order for the building to function, even during a hurricane event.

Any references would be appreciated.

 

[Kuhladula]

I've personally always used louvers in my partially enclosed vs enclosed ASCE7 calculations because of the same reasons you stated above. They're always open and allowing wind to flow. I'm surprised that a louver is the tipping point for your enclosure category though. What size of louvers do you have?

 

[r13]

What effect the air flow in the HVAC duct has to affect the building, other than vibration near the frame, nothing has changed in the building interior. You are correct if the louver is open to the building though.

 

[structSU10]

I understood the 'partially enclosed' being more due to the wind getting in an affecting the internal pressure of the building. If it is being brought into a mechanical units which processes the air to push it through the building, I don't think it is creating the effect the code is after with that designation.

 

[Boiler106]

I understood the 'partially enclosed' being more due to the wind getting in an affecting the internal pressure of the building. If it is being brought into a mechanical units which processes the air to push it through the building, I don't think it is creating the effect the code is after with that designation.

I agree however there is no allowance in the code to account for this.

“Openings” are specifi cally defi ned in this version of
the standard as “apertures or holes in the building
envelope which allow air to fl ow through the building
envelope and which are designed as “open” during
design winds.” Examples include doors, operable
windows, air intake exhausts for air conditioning and/
or ventilation systems, gaps around doors, deliberate
gaps in cladding, and fl exible and operable louvers.

 

[r13]

Thanks for providing the code reference, I usually won't argue with the code, but I think the example (air intake exhausts for air conditioning and/or ventilation systems) defies the phenomenon it intended to address - openings that causing change of building internal pressure.

 

[r13]

I suggest to read the linked materials, an old thread Link, and an example from ICC Link. Then be the judge yourself.

 

[r13]

From the linked example, it leaves me with the impression that, a building can be categorized as a "partially enclosed building" is when the air paths on the windward wall is much less than the sum of openings on the other walls, for which the air escapes slowly, so the pressure will build up. Note that the code considers the gaps around openings as air path too. If this interpretation is correct, then most of the buildings shouldn't be classified as "partially enclosed", but enclosed - air out greater than air in. Gees!