Best Practice for Managing Commercial and Industrial

Rooftop Solar Installations

THE NEXT

GENERATION

IN SOLAR RACKING

OUR

RACKING

SOLUTIONSJeremy Taylor

Product System Engineer

- Started in early grid tied market in 2002 as an Installer

- Sales, Design, and managed installs as a contractor in 2004-5

- Became NABCEP certified in Installation in 2007

- Became NABCEP certified in Technical Sales in 2013

- Worked on the Engineering aspects for Developers, EPC’s,

Manufacturers, and as a Design Consultant

- At SunModo supports project implementation and product

development

MY STORY

2

THE NEXT

GENERATION

IN SOLAR RACKING

OUR

RACKING

SOLUTIONSBrandon Gwinner

Account Executive

- Construction and Sales for over 15 years

- SunModo brand representative for over 5 years

- OSEIA board of Directors

MY STORY

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Founded in 2008

SunModo means “The Way of the Sun”

HQ: Vancouver, Washington

Culture of Innovation: 15 patents and growing

Differentiator: Complete line of racking solutions for roof & ground

mount systems with support/consult, as needed, engineering model

Mission: Drive down the total cost of solar system

Vision: Accelerate the adoption of affordable clean energy

technologies worldwide

OUR STORY

OUR FOCUS

THE PROFESSIONAL INSTALLER

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Project Gallery

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• Due Diligence: Costing, Warranties, Structural Assessment

• Contract, Design, Engineer, Procure, and Build

Course Overview:

Commercial & Industrial (C&I) Low Slope Roofs

THE NEXT

GENERATION

IN SOLAR RACKING

OUR

RACKING

SOLUTIONS

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Design-Build Process

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• ProForma: early costing, finance assumptions, modeled performance, billing scenarios

• Due Diligence: membrane warranty/maintenance, layout fit with aisles and obstructions, and

structural feasibility (full structure weight <10% & member additional capacity)

• Structural Engineering: Modeling of racking in wind, snow, and seismic, with building checks

• Process Methodology: Development revisions (ROM), submittals (Bid, Permit, &

Construction), procurement (BOM), and Project Scheduling/Staging

• Installation Best Practices

Commercial and Industrial (C&I) Low Slope Roofs

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Due Diligence: Best Practice for C&L Low Slope Roofs

Flat Roof

Solutions

• ProForma model based on real site specific data (can vary 50% in racking or ~10% of project)

• Preliminary Assessment: satellite imagery, photos, and building plans w/ framing dimensions

• Structural feasibility assessment for contract is prudent

• Attachment member point loads (up/down) is an easy place to start

• Additional capacity in building framing structure

• Pricing typically lasts 90 days (and NET60 to pay)

• Commercial projects 6-12 months: ROM @ Contract

• Preliminary BOM for Bids and final BOM for build

• Engineering after contract

• Rests on preliminary costs and feasibility specs

• Avoid structural retrofit. Can push over budget

• Be flexible – don’t over fill or neglect spacing

• Cost safe assumptions and then value engineer

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Design Iterations: How to minimize rework and delays

Flat Roof

Solutions

• Assume middle model of module and check manufacturer’s availability forecast

• Module frame dimensions should be interchangeable – more risk with odd sizes

• Assume comfortable string size for module changes and layout accordingly w/o split strings

• Mechanical simplicity – modularity in standard, mechanical–structural, optimized detail

• Use concept, schematic, and design development phases to evolve CD’s effectively

• Stanchion/Flashing count reduction with longer rows and optimized spans

• Electrical capacity sizing should come first, but the details should follow structural design

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Roof Warranty Concerns

Flat Roof

Solutions

• Critical to consider the building owners documents with roof manufacturer and roofer in loop

• If warranty is in place, recommend and obtain preliminary approval of attachment detail

• Sub scoping to roofer is key – roofer last pass through is recommended

• If no warranty then a lifecycle assessment of roof is necessary

• System removability or reroof considerations – Elevated post design w/ enough clearance

• Coordinate the scope delineation and phased construction for clarity

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Configuration Choices

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Single Row Tilt-Up (SRTU)

• Max kWh/kW and lightest attached (expensive modules or higher investor hurdles)

• Adjustable tilt legs provides tailored array angle up to 40 degrees

• Low point load system ideal for light roof structure application (portrait or even shared rail)

• Loads work on older buildings

• No seismic or skid issues

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Mounting options (flush-ballasted, elevated and tilt-up)

- Ventilation and performance

- Cost-Benefit analysis

C&I Preliminary Design Decisions

Flat Roof

Solutions

• Pay for tilt in wind uplift, post height, and lost roof space/project size

• Make decision from LCOE (max kWh/kW) or NPV (max capacity) customer specific

• value engineer: cost increase vs. energy gain to find law of diminishing returns

• typically going to need to see three points to see the break or value balance

$3.20

$3.40

$3.60

$3.80

$4.00

$4.20

100 99 98 97 96 95

System Price to Energy

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• Installed over some roof obstructions (more adaptable coverage to crowded roofs)

• Easily customizable and adjustable for any tilt designed (even mixed pitches)

• Provides valuable shade for roof and AC units (increase longevity of neighbor systems)

• No system removal needed for roof maintenance (hard flashing and counter flashing)

• 30-50% more kW on cluttered roofs with tall parapets (best long term value and performance)

SunBeam: System Overview

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SunBeam: Featured Articles

SunBeam: Elevated Design

• Elevated above fan units (non-vertical), HVAC ducts, vents, piping and conduits

• Allows maintenance under the racking: preset posts and provide reroofing ease

• Best practice: check with AHJ for preliminary approval

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SunBeam: Components

Post Cap SunBeam Rail Pipe Clamp Angle MountSolid base and aluminum post

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SunBeam: Configuration

• Critical dimensions for inter-row or parapet setback

• Ideal to coincide with required walkways

• Share attachments with long rows

• Repeatable detail per building optimization

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SunBeam: Post Spacing

• Configuration for point load

• Vs. Roofing cost reduction

I-Beam Span Tables

E-W: I-Beam Spans, 30 deg tilt, 115 mph, 30 ft elevation, Exposure B, deflection limit = Length of span:

No Snow, Exp B

25 PSF Snow, Exp B

25 PSF Snow, Exp C

2L 144 126 1203L 126 108 1084L 120 96 902P 120 102 102

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Triangle BoxBeam: Configuration

• 30’ spans: single row is possible with only four posts

• 12-18’ spans: 3up configuration to minimize posts

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Side Mount Post Cap (SMPC): Configuration

• 6’ x 6’ post layout is typically cheaper with re-roof

• Depends on framing or slab thickness

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Shared Rail: Configuration

• Can be tilted up with additional lateral support

• Need to check module attachment locations and engineer with frame strength values

Engineering Details

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Structural Engineering (S-PE Stamp for Permit)

Flat Roof

Solutions

• Wind zone – 100mph is lowest under ASCE 7-10, 110, 120, 140

• Snow loads – 0-40psf

• Seismic – I, II, III

• Exposure category- B, C, D, E, F

• Wind KZT factor – topographical adjustment maps

• Occupancy type – A (assembly), B (commercial), D (Industrial), E

(emergency), F (shop), H (Housing), M (merchant), R (residential), S

(storage), & U (utility)

• Importance factor – adjustments based on occupation capacity

• Roof zone – I middle, II edge, III corners (factors accordingly)

• AHJ’s code cycle - ASCE 7-05, 7-10, 7-16 (different methods)

• Product/fastener testing values (pounds pull out, shear or pascals)

• Tributary Area (Array surface to each load path)

• Spans and supporting members

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Structural Best Practice: How to avoid revisions and delays

• Preliminary S-PE Feasibility Report on building loading and member capacity

• Full roof survey of obstructions, parapet, and member locations for contractual fit

• Get a sense of what is possible and allow for flexibility in attachment or fastener frequency

• Get design past concept with Interconnection and mechanical details prior to final S-PE

• Permit and BOM post stamp

• Then finish electrical detailing string layouts for construction

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Roof Framing

Flat Roof

Solutions

• Avoid structural retrofit by choosing right solution

• Attach correctly – 2 hole standoff

• Attachment frequency often dictates racking type

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C&I Preliminary Design-Engineering Decisions

Flat Roof

Solutions

Adder: Roofing costs affecting warranted “per attachment cost”

Drivers: Heat process, multiple layers, site elements, and scope disruption

Factor: More cost per attachment: lean to less attachments

Adder: Limited structural capacity- overall and point load

Drivers: Engineered truss (steel web or wood), barrel, TJI, concentrated snow loads, wider spacing

Factor: Less Attachments = More expensive span member

Adder: Building member attachment type

Drivers: Epoxy concrete anchors, locating on post tension, hardware per attachment, frequency

Factor: More labor at each attachment

Adder: Structural Retrofit

Drivers: required support and distribution of wider spans

Factors: Biggest Project Adder

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Procurement Strategy & Construction Schedule

Flat Roof

Solutions

• Assume model of module in middle of the spectrum for availability forecast

• Preliminary ROM for pricing +/-10% pre-engineering (+/- 1% of project cost)

• Flexibility means “attachment spacing TBD” but feasible (tend to safe side and then reduce)

• After Engineering – firm up BOM and order NET60 means the permit in hand with

progress payment upon delivery (JIT Delivery – Just in time for task)

• Schedule mechanical installation accordingly well before module arrival

• Series/Parallel crews seems to work well on medium or larger projects – Work Flow!

• Mechanical in first, get way ahead

• Roofers in soon after mechanical (or posts only) and final pass after heavy work

• Electrical can attach modules and wire at same time, then drop back

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Construction Practices

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Thermal Expansion

-40

-20

0

20

40

60

80

100

120

140

1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1

Tem

per

atu

re °

F

Variable Gap Distance in inches

Expansion Gap (range over temperature)

Extreme@40'/Mild@80'

Moderate@40'

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Pitch Pocket: Installation

- Could be up to 12” deep

- Get down to flat structural member (perpendicular upward)

Cut Scrape Drill

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Pitch Pocket: Epoxy Anchor Setting

1. Drill –

Drill hole to specified

diameter and depth.

2. Blow –

Remove dust from hole

with oil-free compressed

air for a minimum of 4

seconds. Compressed

air nozzle must reach

the bottom of the hole.

3. Brush –

Clean with a nylon brush for a

minimum of 4 cycles. Brush

should provide resistance to

insertion. If no resistance is

felt, the brush is worn and

must be replaced.

4. Blow –

Remove dust from hole

with oil-free compressed air

for a minimum of 4

seconds. Compressed air

nozzle must reach the

bottom of the hole.

Pitch Pocket: Set Anchor and Plate

• Laser/String align for Beam from end posts (minor adjustability in post cap)

• Washer will keep epoxy on plate only so it can be tightened

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Pitch Pocket: Roofing Scope

• Boot is cheap, flexible, but can crack and

require disassembly for replacement

• High End - liquid urethane, polyglycol

rubber, and polyurethane foam

• Best Practice: metal flashing/counter flashing

• Elevated for run off (no pooling at post!)

• Stabilize post with additional hardware if

required for re-roof

Grounding and Bonding

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Lightning Protection

Lightning Strike Myths

• Hits tallest object

• Grounded tower more likely to be hit

Lightning Protection Truths

• Lightning hits ungrounded/charged objects

• Strikes when charge needs equalization (Standby then Surge)

• Auxiliary Electrode if over 100’ from Main Electrode

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Rooftop Array – Grounding Clarity

PV System Grounded or Ungrounded?• Has a bonded conductor (+/-, or neutral)

Finer array grounding points:• System Grounding GEC required?

• One bond point per isolated system

• Isolated MicroInverters: SMA, ABB, APS

• Racking holding transformers

• Ungrounded System requirements?

• Enphase, SMA-TL = Transformer-Less (TL)

• More important that system be bonded to detect faults (especially if there are no MLPE)

• More important to honor requirement of EGC only and PV-Wire in raceway

• Auxiliary Electrode is advised in lightning prone areas for rooftops

• Dissipating static charge to reduce lightning possibility

• Path for lightning to ground in rare cases

• But must be bonded to common ground to NOT draw lightning surge

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Grounding for Every Application

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UL 2703 & NEC 690 Article Review

• Safety – faulted equipment or wiring

• NEC 690.43 Equipment Bonding

• NEC 690.35 Ungrounded Systems – Metal jacketed wiring, Raceway

• NEC 690.45 Size of Equipment Grounding Conductors (EGC 250.122)

• NEC 690.46 Array EGC – wire protection from physical damage w/ exception for under rack

• NEC 690.48 Continuity of EGC- removal with jumper (advantage of our racking)

• Zero potential system reference

• NEC 690.41 System Grounding – Ungrounded, 2 Wire, 3 Wire

• NEC 690.42 Point of Grounding Connection – bond through GFPD (before fault)

• NEC 690.47 Grounding Electrode System – System and/or Array Electrode

• NEC 690.49 Continuity of GEC- irreversible or listed permanent connection

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What is imparted by UL 2703

UL2703 racking bonds all equipment as EGC (rated for 30A at every pin-clamps/2per module)

SunModo UL2703 racking is also a GEC (rated 60A or more Splice, Lug, and T-Bolt itself)

Functionality Notes:

• Dual pins on clamps Per NEC 690.43 (E ): ensures removing a module doesn’t break the continuity

• Bonded Splices makes EGC for NEC 690.43(C ) with each continuous row

• SunModo Lugs were tested in Short Circuit w/ 1520A for 6seconds (#6AWG GEC 1/0 Conductors)

• Serrated ¼” T-Bolt for MicroInverters (Equal size to #6AWG for GEC or array electrode)

SERVICES

• Assembly Drawings for Projects

• Wet Stamped Engineering Available

• Configuration Tool and Calculators

• Custom Racking Solution

• Superior Technical Support

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Engineering & Technical Support

Catalog, Manuals, Guides, and Appl Notes

• Roof Attachments (Comp, Metal, and Tile)

• Pitched Roof Systems (UL 2703 Racking)

• Flat Roof Tilt Up Systems

• EZ SunBeam Roof Systems

• EZ SunBeam Ground and Foundations

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Online Resources

Brandon Gwinner-Account Representative

brandong@sunmodo.com

Jeremy Taylor- Product System Engineer

jeremyt@sunmodo.com

For more information, visit our website or call

www.sunmodo.com (360) 844-0048

• Innovative & Cost-Effective Racking Solutions

• Superior Engineering and Technical Service

• Continuous Improvement and New product Development

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Summary