Best Practices for Managing Commercial and Industrial Rooftop Solar Installations

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Before We Start

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Meet your Speakers Jeremy Taylor Product System Engineer -  Started in early grid tied market in 2002 as an

Installer -  Became NABCEP certified in Installation in 2007 -  Worked on the Engineering aspects for Developers,

EPC’s, Manufacturers, and as a Design Consultant for over 5 years

-  At SunModo supports project implementation and product development

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Meet your Speakers

Brandon Gwinner Account Executive -  Construction and Sales for over 15 years -  SunModo brand representative for over 5

years -  OSEIA board of Directors

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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

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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 $3.30 $3.40 $3.50 $3.60 $3.70 $3.80 $3.90 $4.00 $4.10

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

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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

PostCap SunBeamRail PipeClamp AngleMount Solidbaseandaluminumpost

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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 144 126 120 3L 126 108 108 4L 120 96 90 2P 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

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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

020406080

100120140

1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1

Tem

pera

ture

°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.

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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

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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)

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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

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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

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Questions?

Brandon Gwinner-Account Manager [email protected]

Jeremy Taylor- Product System Engineer [email protected]

For more information, visit our website or call www.sunmodo.com (360) 844-0048

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q  This webinar will be available at solarpowerworldonline.com & email

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