Can I get away with using 1 1/2'' dia Galvanized pipe for my Ground mounting system?

[blacknbart]

Hello, looking to build 4 (8 panels) ground-mounted array's on my property for a 10kw system I'm installing for my Off-grid electric power. I've seen the 2'' and 3'' pipe fittings, but the prices are extremely outrageous. I know I will have to place more poles in the ground, but I was seeing if anyone has used 1 1/2 pipe for their solar array racking. My proposed Panel Array attached.

[Ampster]

That is an engineering question that would have to be acceptable to the local building officials. More poles means more concrete. I think and engineer has to show you the options to price out.

[blacknbart]

Yes, I will present this to my engineer for review as well as certification for our PV permit. The city doesn't have anything in writing as far as PV Ground mount systems. Mainly just as long it's high enough off the ground as well kept clear of flammable materials. Thanks for the reply.

[J.P.M.]

Yes, I will present this to my engineer for review as well as certification for our PV permit. The city doesn't have anything in writing as far as PV Ground mount systems. Mainly just as long it's high enough off the ground as well kept clear of flammable materials. Thanks for the reply.

While it's pretty likely - but not an absolute certainty - your AHJ (Authority Having Jurisdiction) may not have chapter and verse as to standards and requirements relating to ground or structure mounted PV arrays, most municipalities or county/state govts. have a lot of rules that require some things a lot of folks are unaware of until they want to do something. There's a lot more to it tahn you may know.

[blacknbart]

J.P.M. oh yeah I know all about it because I just went thru the Permit process to get my house built. I think as long I follow the city guidelines for a Ground Mounted PV System and have my structural engineer sign off on the calculations displayed on the plans I should be in the wheelhouse. I just wondered if 1 1/2 dia pipe was commonplace beside the wider 2'' to 3'' pipe. I'll have to run it by my structural engineer and report back. Thanks for the reply.

[J.P.M.]

J.P.M. oh yeah I know all about it because I just went thru the Permit process to get my house built. I think as long I follow the city guidelines for a Ground Mounted PV System and have my structural engineer sign off on the calculations displayed on the plans I should be in the wheelhouse. I just wondered if 1 1/2 dia pipe was commonplace beside the wider 2'' to 3'' pipe. I'll have to run it by my structural engineer and report back. Thanks for the reply.

You're welcome.

As for your question about 1 1/2" dia. pipe being commonplace, the answer is "it depends".

That is, if the array and its support structure are designed and calc'ed by a P.E. proficient in such things, it may/may not use 1 1/2" pipe for some portions of the support structure.

The min. required sizes, thicknesses and design of the array supports and structural components including foundations, fasteners and welds will vary as the magnitude, the nature and the various required loading combinations imposed by site location and conditions, and the requirements of any and all design code(s) in force.

So, whatever your structural engineer comes up with that subsequently gets signed off on by your AHJ ought to be, at least in theory, fit for purpose.

As long as you haven't jumped the gun and bought a lot of 1/1/2" pipe (or tubing) what does it matter ?

I'd also note that "guidelines" are just that, but may not cover all the gory details or recommended good practice. Just sayin'.

[Ampster]

....... I just wondered if 1 1/2 dia pipe was commonplace beside the wider 2'' to 3'' pipe.

The practical question is whether the rack system fittings are commonplace for that size pipe. Two of the most common rack systems are IronRdge and Unirac. They offer some engineering support so that your engineer does not have to reinvent the wheel. It is a system from the panels to the panel hold down to the rack supported by the pipe structure.