Klamath County Community Development

Building Division Code & Design Criteria (as of7/1/11)

The following codes are currently in effect in Klamath County:

  • 2010 Oregon Structural Specialty Code (OSSC) based on 2009 IBC
  • 2010 Oregon Fire Code (OFC) based on 2009 IFC
  • 2010 Oregon Mechanical Specialty Code (OMC) based on 2009 IMC
  • 2011 Oregon Plumbing Specialty Code (OPSC) based on 2009UPC
  • 2011 Oregon Electrical Specialty Code (OESC) based on 2011 NEC
  • 2011 Oregon Residential Specialty Code (ORSC) based on 2009 IRC

General Design Criteria is as follows:

1. OSSC section 1613 is used to design for earthquake loads. Seismic design category shall be “D” unless site specific conditions increase design category to “E or F” (reference codes American Society of Civil Engineers ASCE/SEI 7-05). Residential projects falling under the ORSC shall use seismic zone D1.

2. OSSC section 1609 is used for wind design. The design wind speed is 94.5 miles per hour (3-second gust). See section 1609.3.1 for additional design information. Residential projects falling under the ORSC shall use a design wind speed of 100 miles per hour (3-second gust). See section R301.2.1.3 for additional design information.

Most areas of Klamath County can be classified as wind exposure category C. However, some areas may meet the criteria for exposure B (typically within Urban Growth/ City Limits). The design professional is responsible for justifying the exposure selected for the specific area of construction.

3. Soils bearing pressure is 1,500 pounds per square foot, unless justified by a soils report. A lesser bearing pressure may be required in specific locations.

4. Ground snow loads are site specific and are published from the Structural Engineers Association of Oregon “Snow Load Analysis for Oregon” 3rd edition Dec 2007. However design snow loads shall be a minimum of 25 pounds per square foot, with factors: slope, exposure, thermal, importance, drifting, etc.

5. Rainfall design is site specific and based on U.S. Weather Bureau Technical paper #40: 100-year 60 minute storm. Klamath County has four rainfall zones (3, 9, 10 & 13).

6. The frost depth for foundation design is 24” below grade.

7. Flood Loads section 1612 (if applicable)