Iron Ridge ground mount modifications.....

[Murby]

Going to be installing a 7.5kw system.. 3 rows up by 9 columns long.
The problem I'm having is that the Ironridge ground mount system puts the low side of the panels only 30 inches above the ground.. I wouldn't even be able to safely mow the grass without worry of a rock hitting them.. then there's the issue of snow here in Michigan... scraping snow off the panels would build up a mound on the low side pretty quick.

So, the easiest remedy is to simply lift the mounting system up another 24 inches.. that would do it. My thought is to simply extend the concrete pillars up.. instead of them being finished off at ground level, I would use sonotubes to raise the pillars an extra 24 inches and add some rebar.. Add in the 30 inches from the ironridge specs and that would give me a bit over 4 feet which would be satisfactory.

Anyone ever do this? The ironridge system calls for a 12 inch concrete post, I would change that to 16 inches.. the ironridge calls for 14 foot spacing, I would also reduce that to 10 foot. The iron ridge also does not require cross bracing (optional) and I would also install those.

They want $800 for the extra engineering and I think that's ridiculous just so they can tell me to use a larger pillar and decrease the spacing.

Opinions?

[bcroe]

Going to be installing a 7.5kw system.. 3 rows up by 9 columns long.
The problem I'm having is that the Ironridge ground mount system puts the low side of the panels only 30 inches above the ground.. I wouldn't even be able to safely mow the grass without worry of a rock hitting them.. then there's the issue of snow here in Michigan... scraping snow off the panels would build up a mound on the low side pretty quick.

So, the easiest remedy is to simply lift the mounting system up another 24 inches.. that would do it. My thought is to simply extend the concrete pillars up.. instead of them being finished off at ground level, I would use sonotubes to raise the pillars an extra 24 inches and add some rebar.. Add in the 30 inches from the ironridge specs and that would give me a bit over 4 feet which would be satisfactory.

Anyone ever do this? The ironridge system calls for a 12 inch concrete post, I would change that to 16 inches.. the ironridge calls for 14 foot spacing, I would also reduce that to 10 foot. The iron ridge also does not require cross bracing (optional) and I would also install those.

They want $800 for the extra engineering and I think that's ridiculous just so they can tell me to use a larger pillar and decrease the spacing.
Opinions?

Here in NW IL after 4 winters I have some opinions about dealing with snow on a ground mount. You can see more with
pictures on my thread SUN HOURS.

I always mow the first few passes around the array so that the discharge is AWAY from it. Not foolproof, but effective so far.

To keep snow from piling higher than lowest panels, and to GREATLY reduce manual labor in removal, I recommend at least a
6" gap between the lowest panels and the next higher, 8" is better, for all rows. A landscape panel will then mean minimum
distance snow must move to clear. Ground clearance needed is much reduced since much snow will fall beneath the array
instead of all in front of it.

If your array can be seasonably tilted up to near vertical in the snow months, you will greatly reduce the amount of work needed
to keep the snow cleared. This will not affect production much for those months, esp given the very short days and increased
cloud cover. Realize significant cloud cover can reduce your production to 10% of capacity. good luck, Bruce RoePV16D4.JPGPV16D2.JPG

[DanS26]

Are you designing with 2" gal pipe or 3" pipe? 3" pipe will give you a lot more flexibility with height. Just remember that the higher you go the more wind load stress on the array...that's why IronRidge wants $800 to do the calculations. If your AHJ needs a stamp you may have to bite the bullet.

[Murby]

Are you designing with 2" gal pipe or 3" pipe? 3" pipe will give you a lot more flexibility with height. Just remember that the higher you go the more wind load stress on the array...that's why IronRidge wants $800 to do the calculations. If your AHJ needs a stamp you may have to bite the bullet.

I'm going with 3 inch pipe... I'd go over-kill with 4 inch if the offered it but they don't... I seriously doubt my inspector will require a stamp.. I'm located in "corn fields and cows" territory and my town, 3 miles away, is only 2500 people.

Since neither of you has jumped all over me for the modification suggestion, I'm starting to get the idea that I'm probably already overkill.. I like overkill... If my panels get damaged, I want it to be a natural disaster, not my stupidity.

I'm an electrical engineer by the way and build things all the time so its not like I'm completely in the dark..

Thanks for the replies!

[J.P.M.]

Going to be installing a 7.5kw system.. 3 rows up by 9 columns long.
The problem I'm having is that the Ironridge ground mount system puts the low side of the panels only 30 inches above the ground.. I wouldn't even be able to safely mow the grass without worry of a rock hitting them.. then there's the issue of snow here in Michigan... scraping snow off the panels would build up a mound on the low side pretty quick.

So, the easiest remedy is to simply lift the mounting system up another 24 inches.. that would do it. My thought is to simply extend the concrete pillars up.. instead of them being finished off at ground level, I would use sonotubes to raise the pillars an extra 24 inches and add some rebar.. Add in the 30 inches from the ironridge specs and that would give me a bit over 4 feet which would be satisfactory.

Anyone ever do this? The ironridge system calls for a 12 inch concrete post, I would change that to 16 inches.. the ironridge calls for 14 foot spacing, I would also reduce that to 10 foot. The iron ridge also does not require cross bracing (optional) and I would also install those.

They want $800 for the extra engineering and I think that's ridiculous just so they can tell me to use a larger pillar and decrease the spacing.

Opinions?

Raising things by 24" will change the design and strength calculations, particularly with respect to the moment arm for the wind calcs., but for other things as well. The design may very well still be OK, but that's unknown from an engineering standpoint until checked.

Or, get a short person to cut the grass (or a goat).

[SunEagle]

Raising things by 24" will change the design and strength calculations, particularly with respect to the moment arm for the wind calcs., but for other things as well. The design may very well still be OK, but that's unknown from an engineering standpoint until checked.

Or, get a short person to cut the grass (or a goat).

They are now making those automated lawnmowers that are maybe 10" high.

[J.P.M.]

They are now making those automated lawnmowers that are maybe 10" high.

My landscaper has a guy working for him who's about - no kidding - ~ 3 ft. tall, but I don't think he chews grass.

[bcroe]

Raising things by 24" will change the design and strength calculations, particularly with respect to the moment arm for the wind calcs., but for other things as well.

There would be no need to raise the array another 24" for snow accumulation, if gaps are provided for snow to drop into. Bruce Roe

[J.P.M.]

There would be no need to raise the array another 24" for snow accumulation, if gaps are provided for snow to drop into. Bruce Roe

I'd probably agree, but my comment was only with respect to considerations dealing with raising the array and possible considerations before doing so. Besides, the need was for mowing access, not necessarily snow removal.

[bcroe]

As for mowing, I wouldn't consider driving directly under an array. Its actually pretty dangerous to do much under
the structure, and then the high voltage panels are so close. Practically no grass grows underneath; a little
ROUNDUP keeps things neat enough. Bruce Roe

[emartin00]

The extra engineering they will do will just tell you to add a diagonal brace between the front and back legs, and maybe a couple between the side to side legs as well.

I would advise against having the sonotubes run 2 feet above ground. It

[J.P.M.]

The extra engineering they will do will just tell you to add a diagonal brace between the front and back legs, and maybe a couple between the side to side legs as well.

I would advise against having the sonotubes run 2 feet above ground. It

And for the price you get something that the AHJ may like more than shade tree mechanic's guesses. If nothing else, it's a way to cover your ass with paper. Sometimes the way the game is run sucks, but it's still their table and their rules. Who knows, might even be safer.

[tyab]

As you have found out the IronRidge is a pre engineered system that is based around a limited set of parameters. Number of up panels 3 to 5. Snow loading, wind loading, soil type, either 2" or 3" pipe and hole diameter. And you can pick the tilt in 5 degree increments. That engineering is done for you - conforms to every states building code - and is included in the cost of the system but is based around a maximum height of the horizontal pipe from the ground to cover the forces for the distance of pipe in concrete. And they do have an optional diagonal North/South support but it is not needed unless the design tool says it is needed (high snow/wind loads). When I submitted my permit application, I included the relevant sheets from the engineering analysis document (about 4 from the set of almost 60 they provide), and the county approved it as is. I did build it to those spec and it was checked by the AHJ. I did not do any custom engineering and yes that South end is not very far from the ground.

Any changes outside of the pre engineering plan must be paid by the customer to cover the engineering analysis done by Starling Madison Lofquist in Phoenix. If you feel those fees are too much then nothing is preventing you from contracting with any other engineering firm and asking them to do the same type of work or you can try and find another mounting system.

Now your rural area may not be that strict (I'm in crazy Cal) and as long as you build something that you think is good it may be good enough for your AHJ. No one on this forum is going to recommend building anything that does not conform to your required building codes. Given your in a really small rural area, have a chat with the AHJ and see what your local building department is willing to accept.

To me $800 for custom engineering that conforms to your state building code seems like a good deal. I would expect from having to raise up the system would be deeper holes (thus more pipe in concrete) and spaced closer together. Possibly forced to use 3" pipe. Oh and be aware that 3" schedule 40 galvanized pipe is over 7 lbs per linear foot and it comes in 21' lengths (threaded both ends) and if you use it you will need to find someone that can perfectly square cut that and possibly thread it. I bring that up since in a rural area where I live there was only one well/pump guy that had the equipment for 3" pipe. Next guy that could do it was an hour drive. Be aware that the vertical pipes mate to the Iron Ridge end cap and it requires a perfect square cut of that pipe. Mine was done in a pipe cutting machine - no chop saw - and it was a perfect cut and those caps fit on it with no wobble at all.

And, as a plug for Iron Ridge - I like the system and found it both strong and easy to use. Just follow the torque settings to avoid damage to the parts. The XR1000 rail is really strong. And one final point, you might find it overall lower cost to take advantage of the 4 or 5 up layout and have a shorter East/West but with high tilt angles (which you will want to help with snow) that North end will start to get high off the ground. I did a 25 degree tilt in a 5 up but I only get snow maybe 4 times a year - nothing like you will have to deal with

[J.P.M.]

As you have found out the IronRidge is a pre engineered system that is based around a limited set of parameters. Number of up panels 3 to 5. Snow loading, wind loading, soil type, either 2" or 3" pipe and hole diameter. And you can pick the tilt in 5 degree increments. That engineering is done for you - conforms to every states building code - and is included in the cost of the system but is based around a maximum height of the horizontal pipe from the ground to cover the forces for the distance of pipe in concrete. And they do have an optional diagonal North/South support but it is not needed unless the design tool says it is needed (high snow/wind loads). When I submitted my permit application, I included the relevant sheets from the engineering analysis document (about 4 from the set of almost 60 they provide), and the county approved it as is. I did build it to those spec and it was checked by the AHJ. I did not do any custom engineering and yes that South end is not very far from the ground.

Any changes outside of the pre engineering plan must be paid by the customer to cover the engineering analysis done by Starling Madison Lofquist in Phoenix. If you feel those fees are too much then nothing is preventing you from contracting with any other engineering firm and asking them to do the same type of work or you can try and find another mounting system.

Now your rural area may not be that strict (I'm in crazy Cal) and as long as you build something that you think is good it may be good enough for your AHJ. No one on this forum is going to recommend building anything that does not conform to your required building codes. Given your in a really small rural area, have a chat with the AHJ and see what your local building department is willing to accept.

To me $800 for custom engineering that conforms to your state building code seems like a good deal. I would expect from having to raise up the system would be deeper holes (thus more pipe in concrete) and spaced closer together. Possibly forced to use 3" pipe. Oh and be aware that 3" schedule 40 galvanized pipe is over 7 lbs per linear foot and it comes in 21' lengths (threaded both ends) and if you use it you will need to find someone that can perfectly square cut that and possibly thread it. I bring that up since in a rural area where I live there was only one well/pump guy that had the equipment for 3" pipe. Next guy that could do it was an hour drive. Be aware that the vertical pipes mate to the Iron Ridge end cap and it requires a perfect square cut of that pipe. Mine was done in a pipe cutting machine - no chop saw - and it was a perfect cut and those caps fit on it with no wobble at all.

And, as a plug for Iron Ridge - I like the system and found it both strong and easy to use. Just follow the torque settings to avoid damage to the parts. The XR1000 rail is really strong. And one final point, you might find it overall lower cost to take advantage of the 4 or 5 up layout and have a shorter East/West but with high tilt angles (which you will want to help with snow) that North end will start to get high off the ground. I did a 25 degree tilt in a 5 up but I only get snow maybe 4 times a year - nothing like you will have to deal with

And that pretty much covers it.

[Murby]

As you have found out the IronRidge is a pre engineered system that is based around a limited set of parameters. Number of up panels 3 to 5. Snow loading, wind loading, soil type, either 2" or 3" pipe and hole diameter. And you can pick the tilt in 5 degree increments. That engineering is done for you - conforms to every states building code - and is included in the cost of the system but is based around a maximum height of the horizontal pipe from the ground to cover the forces for the distance of pipe in concrete. And they do have an optional diagonal North/South support but it is not needed unless the design tool says it is needed (high snow/wind loads). When I submitted my permit application, I included the relevant sheets from the engineering analysis document (about 4 from the set of almost 60 they provide), and the county approved it as is. I did build it to those spec and it was checked by the AHJ. I did not do any custom engineering and yes that South end is not very far from the ground.

Thanks, I am familiar with handling pipe up to 6 inches diameter as I've been building industrial machinery for 30 years so its not something new to me. I even have my own Toledo 999 pipe threader.. although it maxes out at 2 inches, I know where to find a 4 inch machine I can use. I think I got this part covered.

I also plan to install diagonal braces but instead of using the expensive ($110 each) IronRidge kit, I'm just going to make my own out of 304 stainless collars and some 2 inch galvanized pipe instead of their aluminum square tube. I think I have this covered too..

Any changes outside of the pre engineering plan must be paid by the customer to cover the engineering analysis done by Starling Madison Lofquist in Phoenix. If you feel those fees are too much then nothing is preventing you from contracting with any other engineering firm and asking them to do the same type of work or you can try and find another mounting system.

Probably cost prohibitive...

To me $800 for custom engineering that conforms to your state building code seems like a good deal. I would expect from having to raise up the system would be deeper holes (thus more pipe in concrete) and spaced closer together. Possibly forced to use 3" pipe. Oh and be aware that 3" schedule 40 galvanized pipe is over 7 lbs per linear foot and it comes in 21' lengths (threaded both ends) and if you use it you will need to find someone that can perfectly square cut that and possibly thread it. I bring that up since in a rural area where I live there was only one well/pump guy that had the equipment for 3" pipe. Next guy that could do it was an hour drive. Be aware that the vertical pipes mate to the Iron Ridge end cap and it requires a perfect square cut of that pipe. Mine was done in a pipe cutting machine - no chop saw - and it was a perfect cut and those caps fit on it with no wobble at all.

Yup.. I'm going to go a foot deeper and my concrete pillars will be twice the diameter just for good measure. Cutting pipe square is no big deal for me as I have a rigid pipe cutter. Not that its an issue, but I think you might be mistaken on the "must be a perfect square cut".. Mine will be square, but I see folks on youtube using sawzalls by hand..

And, as a plug for Iron Ridge - I like the system and found it both strong and easy to use. Just follow the torque settings to avoid damage to the parts. The XR1000 rail is really strong. And one final point, you might find it overall lower cost to take advantage of the 4 or 5 up layout and have a shorter East/West but with high tilt angles (which you will want to help with snow) that North end will start to get high off the ground. I did a 25 degree tilt in a 5 up but I only get snow maybe 4 times a year - nothing like you will have to deal with

Snow is actually a minor concern.. That's what push brooms and snow blowers are about.. I'm much more concerned with the western most side of the array being almost at ground level because my slope runs east to west..

Thank you very much for your lengthy response.. lots of good information and I appreciate when folks take their time to post like that.