BALLAST - LAYOUT

Disqualifications: Auto re-roofs include: wood shake, metal shingle, clay tile, more than one layer of shingles, and singles on flat roofs (less than 10 degree pitch.

Roof Repair: Used when we need to repair some of the roof material but the roof is in overall good condition.

Re-roof: Used when the overall condition of the roof is not suitable for installation.

Rake: The slanting edge of a gable roof at the end wall of the house (eave to ridge)

Ridge: The line of intersection at the top between the opposite slopes or sides of a roof

Eave: The lower border of a roof that overhangs the wall

Hip: The external angle formed by the meeting of two sloping sides of a roof that have their wall plates running in different directions

Valley: The place of meeting of two slopes of a roof that form on the plan a reentrant angle

1 | LAYOUT CONSIDERATIONS

ROOF AREA

Special consideration is needed for roof mounting area aside from default setbacks and spacing mentioned above. You will need to account for the following:

Avoid any structurally disqualified roof areas.

Do not straddle roof pitch changes with your arrays
- This includes a roof with a typical ridge, hip, valley or crickets around parapets that assist with roof drainage.

Keep away from HVAC units and other mechanical units.
- 3' clearance will need to be included for these units and will need to be drawn on the plans.

Just as with a typical racking system, do not install directly over roof obstructions
Specifically with HVAC stacks, keep a 12" minimum clearance.

Exception: we MAY install over flush wiring/conduits on the roof as long as the cable is well managed.

Flush Conduit:

This is an example of conduit that could be considered flush:

3 inches or less above the roof
uniform space between the roof and conduit

This would be the maximum hieght off of the roof that could still be considered flush.

Non-Flush Conduit:

This is an example of conduit that could NOT be considered flush:

More than 3 inches above the roof.

EXAMPLE

In this particular example, the proposed roof area has no obstructions.

RAFTER SPAN

It is recommended that you take rafter spans as part of the planning process prior to completing your layout. Using the load bearing wall sketch completed by the surveyor, you should be able to extrapolate two main data points that you can use to help get the correct span:

The direction of the rafters.
Dimensions of interior walls.

You will want to flag any preliminary structural reviews before completing the layout. Getting these spans will be key to your success.

EXAMPLE

In this example, we have a 16" x 6" beam breaking up the total span.
We also know that the full max span is about 25'
- We can reduce the span by half: 12.5' or 150"

Make sure to vet the structural calculations before moving forward with the layout:

Ensure that structural passes with the roof/structural specifications at this span.
- Don't worry about BOM/Racking errors as we will be entering this input later with the rest of the design deliverables.
- Look for green "OK" statuses on the structural calcs.
If it does not pass, send for Preliminary Structural Review.

For more information on structural measurements, click here.

2 | AURAORA

ARRAY BASICS

For ballast arrays:

Rows must be spaced 15" apart.
- This will be manually changed in Aurora.
A minimum setback of 18" from all roof edges, though Fire Setbacks will not be enforced on flat roofs and therefore no setback needs to be drawn on the plan set.
- This setback increases if there are parapets.
  - This is to give extra space and account for shading cast by parapets when applicable.

EXAMPLE

The system size in this case will be 4.6kWh according to the proposal. We will use 380W panels spaced at 15". Note that at the time of this publishing, we have began using 400W panels, however the same principles will still apply:

Set modules to landscape.
Set tilt to 10 degrees relative to the roof pitch
In Advanced Settings, row spacing will be the minimum spacing of 15".

Remember that there will be bays at the front and back of your array as well. This will need to be considered when designing the layout:

ARRAY ORIENTATION

When both possible and practical, you should orient your modules at a 180 degree azimuth due south. This will change based on the following conditions:

Significant shading concerns coming directly from the south.
Mounting area is significantly impacted by using this orientation.
Overcomplicated racking layout will cause difficulty at install.

Just as with any residential account, if you cannot yield 3% increase in production by using a less preferred layout, then it is not worth the risk.

How to adjust your array orientation to 180 degree azimuth:

Take the apparent azimuth of the roof and subtract 180 from this number:
Use this number in the "rotation" field for your module defaults.

You shouldn't try this if it is apparent that it won't be practical:

Use your discretion to decide if it is worth trying to orient your array due south or not.
An experienced designer will know that on a roof with a limited area , it will likely not be worth it to make this adjustment.

This is an example of utilize the method above to orient the modules due south:

We have rows of modules that do not line up.
- This will result in these rows being considered separate arrays in the Unirac report.
We are also severely limited on roof area for our PV array.
- This customer was sold on a 12 module system, but we're maxed out at 10 modules using this orientation.

This is an example is more realistic, but the orientation was rotated -90 degrees relative to the natural azimuth of the roof:

Note that we are somewhat close to the pitch change where the roof changes from Rolled Comp to Comp Shingle.
- We should try to maintain an 18" offset from roof edges. You might be able to get closer to pitch changes, but this layout is a little riskier.

This example may work, but we should try one more.

This is an example is the most realistic layout possible though the orientation of the modules is the same as the natural azimuth of the roof section which is 233 degrees.

Note that we have maintained 18" clearance on each side of the array.

Now that we have narrowed down to two possible layouts, we can compare production to decide if the slightly less conservative layout will be worthwhile

The less conservative layout yields 6509 kWh/year

The more conservative layout yields 6530 kWh/year

The more conservative design is clearly the best and most practical design in this case.

2 | UNIRAC

MODULE SELECTION

At the time of this publication we are using the SIL-400 HC+ which does not currently have specs imported in unirac, so you will need to add this yourself:

Start with a comparable 400W panel.
Look at the imperial measurements on the spec sheet for the SIL-400 HC+ and adjust the dimensions accordingly.

LOCATION AND LEADS

When you plug in the address to Unirac, it will most likely default to design criteria from the ASCE-7 Hazard Tool database which is not always the most up to date. This criteria will not be as accurate as the AHJ specifics that have been collected by our compliance team. For that reason, you will need to reference the AHJ database to update the local structural loads and criteria such as:

Wind Speed
Wind Exposure Category
Snow Load
Seismic Risk Category

BUILDING AND RACKING OPTIONS

Make sure to get a fairly accurate height on the building. Round up to the nearest 5'.

Also be sure to put in a fairly accurate roof area:

minimum width/length is 25'
round tot he nearest 5'

Include parapet heights as applicable. Parapets are retaining walls that are often seen on the roof edges on flat roofs, especially in the southwest.

On this particular model, we do not have any parapets, so we can default to 0.

For some of the equipment input questions, you will need to make sure changes:

Use Special North Bays: Select "No"
- The north bays are shaped a little differently, but there is no need to use them.
- You can use the standard bay in their place of special north bays which will make the design much simpler and less expensive.
Allow Rounding to Half Blocks: Select "No"
- We don't do half blocks
Ballast Blocks Weight (lbs): Make sure the input is "32"
- This is the correct weight of the blocks we use here at ION.
Allow Mechanical Attachments: Select "No"
- Mechanical Attachments would be attachments that embed into the structural members or sheathing.
  - Here at ION, our ballast systems will consist of ballasts only with no mechanical attachments.

Make sure to save changes.

COMPLETING THE UNIRAC LAYOUT

Now we can complete the layout in accordance to what the layout looks like in aurora.

Start by clicking the "+" for "Roof Area 1"

Update the name from "Roof Area 1" to "Roof Section 1."
- This will make the engineering forms more consistent with the other references on the plan set document.

Now click in the roof area and start drawing your array.
- You can click and drag to quickly create rows and columns.

If you overbuild the array, simply click on the modules you want to delete.

Multiple Arrays:

Under some circumstances, modules on the same roof section might need to be represented as a separate array on the Unirac report for racking and loading purposes.

Example:

For the sake of this training, we will use the same roof and assume there is an AC unit in the middle of the roof. Now our layout looks like this:

As you can see, we have a row that is now 4 feet away from the other two rows. This will need to be treated as another array.

How to show this in Unirac:

Build out the array as if it was 4 rows instead of three
Now delete the extra row and revise the second row down to the correct quantity of 2.

This will result in the two connected rows having a corresponding front and back row of bays.

Likewise, the isolated row will now be called out with a front and back row of bays.

Multiple Roof Sections:

When there are multiple roof sections, Follow these steps next:

In the navigation window on the upper right, click the gray area outside of "Roof Section 1" Area.

Click "Draw Shape," to create a new roof section.

Click on the "+" in "Roof Area 2" to begin working on your second roof section
- Follow the same steps as with the first roof section and don't forget to update the naming to match our "Roof Section" format.

GENERATING UNIRAC ENGINEERING DOCUMENTS

Parts:

Hit "Continue" to access the parts menu

From here, we need to make some small adjustments. We only want to order the following equipment:

Ballast Blocks
Ballast Bays
Clamps
RM Hex Bolts

Zero out the quantity on anything else that populates here as we do not use equipment such as Roof Pads.

These are the only adjustments needed for the ballast equipment.

Engineering Documents:

Hit "Continue" to access the Engineering Documents.

From here, hit "Print All"
- This should populate a new window in your browser with all the engineering pages merged into one document.
- If a new window does not populate, you may need to click "Print All" again and wait a few moments.

Before printing, we should ensure that the PSF Average is in an acceptable range for engineering purposes:

You can hit "CTRL + F" to quickly search for instances of "PSF" in the document as needed.
Our standard here at Ion is as follows:
- For low snow load regions, we need an Average of 10 PSF or less.
- For high snow load regions, especially in Colorado, this figure is reduced down to 7 PSF or less.
- If the PSF of any array is over 10, or 7 for the homes in Colorado, this will need to be sent for PSR (preliminary structural review). This is the case for manufactured truss and regular rafter framing.

Once you have checked your structural, you can now print the reports and save them to be added to the plan set:
- Save in the parent folder for the design using the proper naming convention.
- You may call this the Unirac Engineering Docs for now.
  - Remember these pages will be added to the plan set later.

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