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Ballasted Roof Mount Design Assistant™

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Project Information

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Seismic Importance Factor (IP)

13.1.3 Component Importance Factor. All components shall be assigned a component importance factor as indicated in this section. The component importance factor, Ip, shall be taken as 1.5 if any of the following conditions apply:

1. The component is required to function for life-safety purposes after an earthquake, including fire protection sprinkler systems.

2. The component contains hazardous materials.

3. The component is in or attached to an Occupancy Category IV structure and it is needed for continued operation of the facility or its failure could impair the continued operation of the facility.

All other components shall be assigned a component importance factor, Ip, equal to 1.0.

USGS Ss Values

In order to calculate the amount of ballast required for a BRM array, we need to know the Spectral Response Acceleration (Ss) value for the project location.

To find the correct value, contact IronRidge support, or you can obtain it from the USGS yourself.


Usgs_ss_calculation
"Optimize Ballast" vs. "Optimize Price"

"Optimize Ballast" places deflector panels on all modules. This is typically for installations where roof loading should be kept to a minimum.

"Optimize Price" places deflector panels only on the two most northern rows and the east and west edges of a given subarray. This is typically for installations where roof loading is less of a concern.

Ballast Block Weight

The BRM System is intended to be used with standard 4"x8"x16" solid concrete blocks weighing 35 lbs or standard 2"x8"x16" solid concrete blocks weighing 13.5 lbs.

Important: Actual concrete block weights vary by manufacturer. It is the sole responsibility of the installer to confirm the actual weights of the concrete blocks used and that sufficient ballasting is installed as required by the stamped project certification letter and drawings.

Roof Friction

We assume a Friction Coefficient of 0.5 between Support Assemblies and Roof Surface. The 'coefficient of friction' is a dimensionless scalar value which describes the ratio of the force of friction between two bodies and the force pressing them together.

The coefficient of friction depends on the materials used; for example, ice on steel has a low coefficient of friction, while rubber on pavement has a high coefficient of friction.

Setting Up A Subarray

To set up a subarray, first set the grid size in the upper right corner by selecting the maximum number of rows and columns of your subarray. Next, simply click and drag the cursor to highlight the modules (or cells) of your subarray. You can select or deselect the modules by utilizing the three tools in the upper left corner. The Icon_pencil toggles the selected module, the Icon_shape_handles_add adds modules and the Icon_shape_handles_delete removes modules.

The system will automatically save your changes before you go to the next tab. However, if you'd like to check on the subarray status in the upper right corner (# of modules, watts, etc.) you must first "save" the subarray by clicking on the Icon_disk icon. To add a new subarray, simply click the "Add New Subarray" button at the bottom left corner. A "Subarray" is defined as a single array of connected modules (no discontinuity in subarray).

Note: This configurator is for quotation purposes only and is a graphical representation of your array. This configurator may not be used to determine physical layouts. All modules are assumed to be within Roof Zone 1. If you have additional questions regarding roof zone compliance, please contact IronRidge sales at sales@ironridge.com

Wind Exposure Category Definitions

Exposure B: Urban and suburban areas, wooded areas, or other terrain with numerous closely spaced obstructions having the size of single family dwellings.

Exposure C: Open terrain with scattered obstructions having heights generally less than 30 feet. This category includes flat open country, grasslands, and all water surfaces in hurricane prone regions.

Exposure D: Flat, unobstructed areas and water surfaces outside hurricane prone regions. This category includes smooth mud flats, salt flats, and unbroken ice.

Wind Speed

Determine the wind speed by consulting your local building authorities. (3 second gust)

Ground Snow Load

Determine the snow load by consulting your local building authorities.

Least Horizontal Dimension

The Least Horizontal Dimension is the least "major" horizontal dimension of the building. For example, if the building is 150' x 100' then the Least Horizontal Dimension is 100'.

Least_horizontal_distance1 Least_horizontal_distance2
Max Dead Load + Wind/Snow

The Max Dead Load + Wind/Snow is the maximum combined loads on the roof and is due to Dead Load (Racking + Ballast + Modules) + Combined Wind and Snow Loads. This value is calculated by using Section 2.4.1 of ASCE 7-05.

Occupancy Category

Occupancy Category is a category used to determine structural requirements based on occupancy which can range from I to IV. The categories are used to classify buildings and other structures based on occupancy level and nature of use.

Occupancy Category I buildings represent a low hazard to life in the event of failure, while Occupancy Category IV buildings are considered essential facilities. Occupancy categories differ between building codes, so it is important to make sure and specify which building code is assigned to your project.


Occupancy
Category
Nature of Occupancy
I. Building and other structures that represent a low hazard to human life in the event of failure, including agricultural, temporary, and minor storage facilities
II. All other structures that aren’t in categories I, III, or IV
III. Building and other structures that represent a substantial hazard to human life in the event of failure including:
  • Covered structures the primary occupancy of which is public assembly with an occupant load of 300.
  • Buildings and other structures with elementary-school, secondary-school, or day-care facilities with an occupant load greater than 250.
  • Buildings and other structures with elementary-school, secondary-school, or day-care facilities with an occupant load greater than 500 for colleges or adult-education facilities.
  • Health-Care facilities with an occupant load of 50 or more resident patients without surgery or emergency-treatment facilities.
  • Jails and detention facilities.
  • Any structure with an occupant load greater than 5,000.
  • Power-generating stations, water-treatment facilities for portable water, waste-water-treatment facilities, and other public-utility facilities not included in Occupancy Category IV.
  • Buildings and other structures not included in Occupancy Category IV containing sufficient quantities of toxic or explosive substances that would be dangerous to the public if released.
IV. Building and other structures designated as essential facilities, including:
  • Hospitals and other health-care facilities with surgery or emergency-treatment facilities.
  • Fire, rescue, and police stations and emergency-vehicle garages.
  • Designated earthquake, hurricane, or other emergency shelters.
  • Designated emergency-preparedness, communication, and operation centers and other facilities required for emergency response
  • Power-generating stations and other public-utility facilities required as emergency-backup facilities for Occupancy Category IV structures.
  • Structures containing highly toxic materials as defined in Section 307 of the 2006 International Building Code.
  • Aviation control towers, air-traffic control centers, and emergency-aircraft hangers.
  • Buildings and other structures with critical national-defense functions.
  • Water-treatment facilities required to maintain water pressure for fire suppression.
Setback Distance

The Setback Distance allows for the definition of Roof Zones 1, 2 and 3. The BRM System is intended to be installed in Roof Zone 1. Therefore, the Setback Distance is the minimum required distance from the edge of the building to the BRM System. If your layout is within Roof Zone 2 or 3 or if you have additional questions regarding roof zone compliance, please contact IronRidge sales at sales@ironridge.com. Further description of the ASCE method used is described below.

The following describes the method developed by the ASCE building codes in order to define setback distance "a". Setback distance "a" (ASCE 7-05), is defined as either

Setback_distance
Actual Spacing and Tilt

The BRM System is a 10 degree ballasted roof mount system. The 10 degree tilt and spacing is based on a standard 39"xL" module. However, since the BRM adjusts to fit varying module sizes the actual spacing and tilt are defined by the module size. For example, if a module is smaller than a standard 39"xL" module than the spacing will be smaller and the tilt will be higher. Adversely, if a module is bigger than a standard 39"xL" module than the spacing will be larger and the tilt will be lower.

Module_with_deflector Module with deflector
Module_without_deflector Module without deflector
Support_assembly Support Assembly
Support_assembly_max_load Support Assembly with maximum dead or combined load
Support_assembly_90_percent_load Support Assembly with dead or combined load >= 90% of maximum
Microinverter Kits

The Microinverter Kit will allow you to attach your micro inverter to the Support Assembly. The mounting kit will work with most Enphase Micro Inverters and SolarEdge Power Optimizers.

Roof Pad

These pads are to be used as a protective barrier between the Support Assembly and the roofing material.

Important: If the roof is under warranty, you must consult with the local roofing manufacturer representative to determine warranty requirements. Some roofing manufacturers require pre-installation approvals and the use of proprietary materials for a protective barrier between racking components and the roofing material.

East-West Wire Clip

The EW Wire Clip is a simple and easy snap-in cable tie that attaches to the ballast tray and can hold up to 50 lbs. The Wire Clips made of durable UV Resistant Nylon and can hold wire bundles from 1/16”-1” in size.

Brm_wire_clip
East-West Wire Tray

This EW Wire Management Tray provides an effective, clean and convenient way to manage your electrical wiring in the east to west direction. The tray interior measures 1 1/4"x 1"and accommodates approximately 15 x 7mm PV cables.

To determine the number of EW Wire Trays needed for your installation, first determine how many rows in each sub array require trays. Next, using the 'Layout Tab' determine the row length of each sub array and multiply that by the number of rows with EW Wire Trays. Then enter the number of wire trays in the required field.

For example: 5 (Rows with EW Wire Trays) x 24 ft. (Length of sub array row) ÷ 8 ft. (Length of Wire Tray) = 15 EW Wire Trays

North-South Wire Tray

This NS Wire Management Tray provides an effective, clean and convenient way to manage your electrical wiring in the north to south direction. The tray interior measures 1" x 2.5"and accommodates the needs of even the largest installations.

To determine the number of NS Wire Trays needed for your installation, first determine how many columns in each sub array require trays. Next, using the 'Layout Tab' determine the column length of each sub array and multiply that by the number of columns with NS Wire Trays. Then enter the number of wire trays in the required field.

For example: 2 (Columns with NS Wire Trays) x 24 ft. (Length of sub array column) ÷ 8 ft. (Length of Wire Tray) = 6 NS Wire Trays

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