HVAC Code Requirements in Oregon

Oregon's 363-mile Pacific coastline experiences chronic erosion from winter storms and wave action. DLCD administers the Beachfront Protective Structures program and Ocean Shore permits. Tillamook, Lincoln, and Coos counties have the most active erosion. Oregon Beach Bill (ORS 390.605-390.770) establishes public beach access and restricts construction in active erosion zones. Geologic hazard assessments are required for coastal development.

Several Oregon counties fall within EPA Radon Zone 2 with predicted indoor screening levels of 2-4 pCi/L, including Lane, Jackson, Josephine, and portions of the Portland metro area. Volcanic geology and fractured basalt contribute to radon entry. IRC R324 radon-resistant new construction is recommended in Zone 2 areas. Oregon Health Authority maintains county-level radon data.

Oregon has Zone AE designations along the Willamette, Columbia, Rogue, Deschutes, and Umpqua rivers. The Willamette Valley from Eugene through Salem to Portland has extensive floodplain. The 1996 and February 2020 floods caused significant damage along the Willamette. NFIP requirements per 44 CFR 60.3 apply. Portland requires 1 foot of freeboard above BFE and has adopted a floodway development prohibition.

Eastern Oregon and Cascade mountain communities experience frost depths of 24 to 42 inches. Klamath Falls, Bend, La Pine, and Burns have the deepest frost penetration in the state. Foundation footings must extend below the local frost line per IRC R403.1.4. Central Oregon communities at 3,500+ feet elevation typically require 24-30 inch minimum footing depth. The Wallowa Mountains in northeastern Oregon have the deepest frost.

Southern Oregon (Jackson and Josephine counties) and parts of eastern Oregon contain expansive clay soils derived from weathered volcanic ash and sedimentary formations. The Medford area has particularly problematic swelling clays. Foundation design per IBC 1808.6 should account for soil expansion. Portland West Hills landslide-prone soils (Missoula Flood silts over basalt) require geotechnical investigation per IBC 1803.

Oregon has numerous National Register historic districts including Skidmore/Old Town (Portland), Jacksonville Historic District (entire town, one of the first in Oregon), Astoria Downtown, and Albany (four historic districts). Oregon SHPO review is required for projects involving state or federal funding. Local historic preservation ordinances apply in designated districts with design review requirements.

Oregon faces significant seismic risk from the Cascadia Subduction Zone (CSZ), a 600-mile-long megathrust fault capable of magnitude 9.0+ earthquakes. The CSZ last ruptured in 1700 and is overdue for the next event. Seismic Design Categories range from B (eastern Oregon) to D-E (Portland metro, Willamette Valley, coastal areas) depending on location and soil conditions. The entire state must address seismic design per ASCE 7-16. Water heaters must be seismically strapped per OPSC 507.2.

Portions of Oregon, particularly the Cascade Range, eastern mountains, and high elevation areas, experience significant snow loads. Ground snow loads range from 25 psf (Willamette Valley) to 100+ psf (Cascade peaks, Crater Lake area, Wallowa Mountains). Site-specific determination required per ASCE 7-16.

Areas designated as Zone A, AE, AH, V, or VE on FEMA Flood Insurance Rate Maps (FIRMs). Oregon has significant riverine flood risk along the Willamette River, Columbia River, Rogue River, and other major waterways. Coastal areas subject to storm surge. Flood Insurance Study (FIS) and FIRMs maintained by FEMA. Local floodplain administrators enforce National Flood Insurance Program (NFIP) requirements.

Areas with soil conditions susceptible to liquefaction during seismic events. Geotechnical investigation required per ASCE 7-22 Section 11.8.2.

Areas identified by Oregon Department of Forestry as wildfire hazard zones where local jurisdictions have adopted ORSC R327 Wildfire Hazard Mitigation requirements per ORS 455.433/455.612. Wildfire risk is significant statewide but particularly affects interior valleys, eastern Oregon, and areas adjacent to forest lands. Local adoption required - verify with jurisdiction. Voluntary compliance available statewide.

Coastal areas at risk of tsunami inundation from Cascadia Subduction Zone earthquake. Tsunami wave heights could reach 30-50 feet in some locations within 15-30 minutes of earthquake. ORS 455.446-455.447 regulates construction of essential facilities and critical facilities in mapped tsunami inundation zones. Affected coastal counties: Clatsop, Tillamook, Lincoln, Lane (coastal portion), Douglas (coastal portion), Coos, Curry.