ASCE 7-22 for Solar Mounting: Wind, Snow, Seismic, Tornado, and What Changed for PV

ASCE/SEI 7-22 is the current US loading standard for buildings and other structures. It is adopted by reference into the IBC, IRC, IEBC, and NFPA 5000. For solar mounting, the practical question is simple: which load cases changed, which new PV sections exist, and what must appear on a stamped design package when an AHJ enforces 7-22 instead of 7-16.

This note is written for EPC engineers, structural reviewers, and procurement teams who specify rooftop, ground-mount, and carport/canopy racking. It combines the official ASCE 7-22 change set with industry guidance on solar-specific sections and a structural-engineer seminar summary of the wind and tornado chapters.

Calculation basis at Solaracks: site wind, snow, and seismic design for carport/canopy and other open structures can be run to ASCE 7-22 (alongside AS/NZS 1170.2 and other project codes). Stamped design and quote within 24 hours when site data is complete.

1. What ASCE 7-22 is (and is not)

ASCE 7 prescribes design loads for dead, live, soil, flood, tsunami, snow, rain, atmospheric ice, seismic, wind, fire, and load combinations. ASCE 7-22 also adds a full tornado chapter and updates reliability-targeted environmental loads.

It is not a product listing standard for racking hardware. It does not replace local amendments, IEBC renovation rules, or manufacturer test data (wind tunnel / ASCE 49). It is the load and combination framework your structural package must satisfy when the jurisdiction has adopted it.

Useful free tools

Grey bars in the standard mark revised text. Always check the latest errata before final calculations.

2. Why solar teams care now

Adoption is jurisdiction-by-jurisdiction. Florida was among the early movers on structural-load criteria tied to 7-22. Many AHJs still accept 7-16 packages. The risk is not “the standard exists.” The risk is submitting 7-16 wind maps, six roof C&C zones, or missing ground-mount solar language in a city that has already flipped.

For PV, four hazard families dominate:

1. Wind (Ch. 26-31), maps, C&C zones, elevated buildings, rooftop and ground-mount solar, canopies
2. Snow, reliability-targeted ground snow, drifts, roof factors
3. Seismic, multi-period spectra, nonstructural component loads on modules
4. Tornado (new Ch. 32), Risk Category III/IV in tornado-prone regions

Industry summaries for solar racking commonly report:

• Roof C&C zones simplified (6 zones → 3 on many low-rise roof figures)
• Higher design wind speeds in parts of the hurricane-prone region (site-specific; some inland cities saw small decreases)
• Clearer treatment of exposed modules on pitched roofs
• Wind-tunnel path referenced to ASCE 49
• Ground snow design values often ~10-20% higher regionally (order-of-magnitude industry average ~12% roof load increase at many sites)
• New or refined horizontal demand on modules in seismic design
• Tornado provisions mainly for RC III and IV, not typical open-field RC II commercial PV

Those headlines must always be checked against the site report from the Hazard Tool and the adopted code edition on the permit.

3. Wind loads: Chapter 26-31 changes that hit PV

Source backbone for this section: SEAOG 2025 seminar Wind Loads: What’s New in ASCE 7-22 (John O’Brien, P.E., S.E.), plus ASCE’s published 7-22 highlights.

3.1 Hazard maps and site factors

• Special wind regions updated; Gulf Coast hurricane speeds revised.
• Topographic effects included on Puerto Rico and US Virgin Islands maps.
• Topographic factor Kzt (26.8.1): “isolated and unobstructed / significant feature” gates from 7-16 were removed. More sites need a Kzt evaluation.
• Ground elevation factor notation clarified (ze vs old zg confusion).
• Velocity pressure coefficient Kz: small reduction for typical heights in Exposure B and C; no change for D; very tall structures can see Kz up ~20%.
• Directionality Kd moved out of the velocity-pressure term into the pressure equations (MWFRS, C&C, and tornado variants).
• Wind-borne debris region (26.12.3.1): hurricane-prone areas where V > 140 mph, or V > 130 mph within 1 mile of coastal mean high water with Exposure D upwind.

Georgia RC II basic wind speed examples from the seminar (7-16 → 7-22): Atlanta 107→105; Augusta 113→110; Savannah 135→135; Valdosta 113→114. Local maps matter more than national slogans.

3.2 MWFRS and elevated buildings

• Chapter 27 Part 2 and Chapter 28 Part 2 tabular simple-diaphragm methods removed (content moved toward guides/software).
• Elevated buildings are new in 7-22 for MWFRS and C&C: blocked-area tests under the structure; lateral loads on elements below; external loads on the horizontal bottom surface of the elevated floor/roof.

– Net force coefficient 1.3 on projected area of elements below (seminar summary of 27.3.1.1.2). – qz elevation taken at h1 + 0.25 h2 in the cited provisions.

Open carports, canopies, and some elevated amenity decks sit close to this logic. Treat underside uplift and column/drag loads explicitly; do not assume a solid low-rise box.

3.3 Chapter 29: other structures, solar called out

3.4 Components and cladding (Chapter 30)

• Tabular C&C methods removed from the standard body (relocated to the ASCE 7-22 wind guide / software).
• Low-rise gable and hip external pressure coefficient figures simplified vs 7-16 ridge/eave/corner zoning.
• Hip roofs: h/B dependence removed; θ band cleanup (interpolate between figures for intermediate slopes).
• Roof overhang GCp treatment narrowed (overhang detail concentrated; wall +GCp on bottom surface with roof −GCp on top in the cited overhang approach).
• h > 60 ft wall GCp: small effective wind area values aligned with 10 ft² end of the curve.
• Stepped roofs: zone mapping process retained; figure revisions expected via supplement (watch local amendments).

Installer-facing outcome: simpler zone maps on many pitched roofs, but do not paste 7-16 GCp tables into a 7-22 calculation. Rebuild C&C from 7-22 figures and the project risk category.

4. Snow loads (solar span and ballast implications)

ASCE’s published 7-22 highlights and solar-industry integration notes agree on the direction of travel:

• Ground snow loads rebuilt from more recent data and reliability-targeted values (not a simple map reprint).
• Drift method revised and includes a wind parameter.
• Importance-factor style snow handling shifted toward reliability by risk category.
• Many sites see higher design roof snow (industry racking notes often cite ~10-20%, with ~12% as a working average for “most sites”).
• Lower load factors in combinations can partially offset higher characteristic snow, but high-snow regions still tend toward tighter spans, more rows of fasteners, or more ballast.

For ballasted flat-roof PV and long-span carports, snow drift against parapets, taller array rows, and adjacent roof steps remains a primary layout driver. Always pair the Hazard Tool ground snow with project-specific thermal and exposure factors from the standard.

5. Seismic loads and nonstructural PV

7-22 seismic updates that show up in racking conversations:

• Multi-period response spectrum replaces the simple two-period shape for many applications.
• Site class table expanded (three new classes tied to wave velocity behaviour).
• Fa / Fv handling simplified or removed in situations defined by the standard.
• Nonstructural component equation Fp refined.
• Solar-specific practice notes emphasize horizontal load requirements on modules and closer AHJ review in high-seismic states (e.g. California), including ballasted systems that once relied only on friction narratives.

For open structures (carports, ground mount), seismic design of the steel/aluminum frame, connections, and module clamps must be consistent with the site class and risk category on the structural drawings. Friction-only stories without calculated demand rarely survive plan check in high Ss regions.

6. Tornado loads (Chapter 32), scope before panic

Chapter 32 is new. It is not a second copy of Chapter 26 with a different map.

Scope filters (all must be understood before applying tornado pressures):

• Building is Risk Category III or IV
• Site is in the tornado-prone region
• Tornado speed VT exceeds the threshold path in the standard (seminar summary: VT > 60 mph and comparisons such as 0.5V / 0.6V / 0.67V vs Exposure B/C/D basic wind)

Intent: improve life safety and resiliency for about EF0–EF2 events. These provisions are not storm-shelter design (ICC 500 / FEMA P-361). A shelter in one wing of a hospital does not waive Chapter 32 for the rest of the building.

Selected mechanics (seminar summary):

Design impact pattern: low-rise buildings; interior roof zone uplift; wall C&C. NIST TN 2214 is cited in the seminar for construction cost impact on the order of < 0.25% for many building cases, still project-specific.

Documentation (IBC 1603.1.4): tornado speed VT, effective plan area Ae, tornado internal pressure coefficients, and C&C as the maximum of wind or tornado.

Renovations: no blanket “always tornado.” Follow IEBC by scope (major repair, Level 2/3 alteration, substantial structural alteration, occupancy change that raises risk category, non-independent addition, relocated building). Where IEBC points back to IBC 1609, tornado content can apply.

Most open-field commercial PV and standard carports on RC II sites will not trigger Chapter 32. Hospitals, emergency facilities, high-occupancy schools, and similar RC III/IV projects in tornado-prone states can. Ask for risk category and Ae early.

7. Practical checklist for a 7-22 solar structural package

Use this as a submission gate list.

8. What this means for Solaracks systems

Solaracks designs mounting for pitched roof, flat roof, ground mount, and carport/canopy structures used as parking shade and PV generators. Product pages for canopy systems list calculation basis options including ASCE 7-22, with site wind speed driving member sizing and every design issued stamped.

Implications of 7-22 on typical Solaracks scopes:

• Carport / canopy: treat as open elevated structures. Column drag, beam torsion, purlin C&C, and underside pressures matter as much as top-of-module uplift. Long spans still reduce foundation count, but snow and wind control checks must use current maps.
• Ground mount fixed-tilt: align analysis with §29.4.5 language and site exposure; tracker systems remain outside that fixed-tilt section and need a defined method (tunnel, recognized guide, or AHJ-accepted analysis).
• Roof parallel attach: apply §29.4.4 equalization only when geometry matches the figure limits; edge zones still govern many residential and metal-roof layouts.
• High-snow and high-seismic exports: expect tighter rail spans or heavier sections versus a pure 7-16 habit; say so in the quotation assumptions.
• RC III/IV tornado-prone sites: confirm whether Chapter 32 governs the host building before locking carport member sizes attached to or beside that building.

Materials commonly used on Solaracks carports (e.g. anodized 6005-T5 aluminium, HDG or ZAM steel where specified) are selected for corrosion category and stiffness. Load standard and material standard are separate lines on the data sheet; both must be correct.

Lead time pattern: complete site inputs (location, risk category, module layout, wind/snow/seismic notes, corrosion environment) → structural calculation and quote target within 24 hours for standard scopes.

9. Sources

This article is engineering guidance for discussion with the project structural engineer of record. It is not a substitute for the copyrighted ASCE 7-22 text, local amendments, or a sealed calculation for a specific site.

Next step: send location, risk category, array type (roof / ground / carport), module data, and target code edition. Solaracks returns a stamped design path under ASCE 7-22 when that is the permit basis.

Be supported.