Building Code Question

[vargo320]

Is the 150 ft X 150 ft maximum pv array size also required on flat commercial roofs? Looking at the code and it is listed under residential code.

 

[c_picard]

Which jurisdiction?

 

[ggunn]

Is the 150 ft X 150 ft maximum pv array size also required on flat commercial roofs? Looking at the code and it is listed under residential code.

Usually, yes, and it's not a 150' X 150' maximum, it's a maximum of 150' in any dimension.

 

[jaggedben]

You're not typically going to see a 150ft long roof that isn't flat and commercial. That's the type of roof they had in mind when they wrote the restriction.

I believe if your jurisdiction adopts a version of the International Building Code then the restriction will apply. As ggunn said, that's usually the case.

 

[Carultch]

Usually, yes, and it's not a 150' X 150' maximum, it's a maximum of 150' in any dimension.

A 150'x150' square has a diagonal of 212'. Does that dimension matter at all per this rule?

Also, does it matter if parts of the racking system bleed outside of the 150 ft limit, as long as the modules themselves are limited to 150 ft?

 

[vargo320]

Which jurisdiction?

NY

 

[c_picard]

NY

You won't find it in the building code. Effective October, 2016 commercial roofs in NY state(other than Group R-3 building) are subject to the 2015 IFC. See 605.11.1.3.3

Setbacks are also found in the NY amendments to the 2015 IRC for Group R-3.

 

[ggunn]

A 150'x150' square has a diagonal of 212'. Does that dimension matter at all per this rule?

Also, does it matter if parts of the racking system bleed outside of the 150 ft limit, as long as the modules themselves are limited to 150 ft?

I don't have the code in front of me, but IIRC it says 150' in any dimension. Also IIRC, it merely says "the array" must conform. I wouldn't design a system where the racking made it break the rule.

 

[Anode]

I don't have the code in front of me, but IIRC it says 150' in any dimension. Also IIRC, it merely says "the array" must conform. I wouldn't design a system where the racking made it break the rule.

I'm looking in IFC, is there a difference? In that:

The key in the code is "in either axis" the diagonal is not a standard axis. So 150' feet in the x & y.

Quote from 605.11.3.3.3 Smoke ventilation.
"1. Arrays shall be no greater than 150 feet (45 720 mm) by 150 feet (45 720mm) in distance in either axis in order to create opportunities for firedepartment smoke ventilation operations."


Also, there are many good diagrams interpreting this code, so you don't need to search to long before you find one of the same one's circulating. Mostly likely any diagrams you find will be found from Solar Abc's great guiding documents which many of the jurisdictions around my area have copied from.

That is here:
http://www.solarabcs.org/about/publications/reports/fireguideline/pdfs/CslFire_studyreport.pdf

More on understanding fire requirements from Solarabc's:
http://www.solarabcs.org/about/publications/reports/fireguideline/

 

[GoldDigger]

Any guidance how wide the ventilation aisles need to be before starting a new 150' array?

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[vargo320]

I believe it's a 4 ft minimum pathway.

 

[pcanning87]

CalFire requirements are not code required in NY. It's generally accepted as a best practice, and many tacking manufacturers will require breaks at 150' for thermal expansion and contraction.


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[c_picard]

CalFire requirements are not code required in NY. It's generally accepted as a best practice, and many tacking manufacturers will require breaks at 150' for thermal expansion and contraction.

Calfire isn't code anywhere, including California.

NY does now have setback requirements, I've posted them earlier in this thread. If you're working in NY you might want to find a code update class.

 

[jaggedben]

Calfire isn't code anywhere, including California. ...

Yes, but the California Fire Code and California Residential code are both pretty close (even they don't entirely agree with each other :roll.

 

[pv_n00b]

CalFire requirements are not code required in NY. It's generally accepted as a best practice, and many tacking manufacturers will require breaks at 150' for thermal expansion and contraction.

True, but the fire department AHJs have decided to adopt the CalFire requirements before they are in the code in many jurisdictions. That’s why you have to check. Typically no one wins a fight with the fire department over what they want, code or not.