20163602 - Permit (2) - Laserfiche WebLink

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- If the iurisdiction is in a coastal region, consider asking, "ls the dwelling farther than 200 yards from the ocean or a large coastal bay?" to verify the dwelling is not in Wind Exposure D.'- If the.jurisdiction is in a Special Wind Region with design wind speeds between ll5and l30mph, consider verifying that the dwelling is in Wind Exposure B by asking, "ls the dwelling in an urban, suburban or wooded area, and !p! within 500 yards ofopen fields and grasslands?" - Ifthe jurisdiction is in a Special Wind Region with design wind speeds between I 15 and 130 mph, consider verifying that there are no significant topographic wind speed-up effects by asking, "ls the dwelling in a relatively flat area (grade less than 57o) and not within 500 yards ofthe crest ofa tall hill?" Roof Check - Based on the jurisdiction's one- and two-family housing stock and code compliance history, many CBOs will find it reasonable to assume that most dwellings' roof structures were designed to the building code in effect at the time the houses were built. Ifso, the roofstructure code compliance check consists of the Contractori visual roof audit, checking for unusual sagging or deterioration, without requiring additional measurements of existing rafters to check against span tables. - For CBOs ofjurisdictions with evidence ofslructurally deficient one- and two'family housing stock or poor structural code compliance history, the CBO may elect to add the rafter span check option described in the criteria. fhe Struclurol Toolkit ond CRC Wind Speeds The 2013 CRC contains an inconsistency related to wind speeds. Despite referencing ASCE 7-10 as its standard, the 2013 CRC's text and tables use outdated ASCE 7-05 wind speeds. Under the old ASCE 7-05ICBC 2010, the basic design wind speed in most regions ofthe state was 85 mph (max. 3 second gust in 50 years). Under ASCE 7-l)lCBC 2013, the design wind speed has increased to I l0 mph (max. 3 second gust in 700 years). Despite the different definitions of wind speed, design wind pressures remain essentially unchanged. Because the toolkiti structural document is intended to be forward looking, all wind speeds in the toolkit document are based on the ASCE 7-10. This is clearly stated in the caption to the state wind speed map, and in the Table I footnotes. This anticipates an obvious and expected correction to the CRC; otherwise the toolkit would become immediately outdated when the CRC is amended to change the base design wind speed from 85 mph to I t0 mph. 2013 CRC text (ASCE 7-05) wind speeds equivalent to the 2013 CRC and CBC Reference Standard (ASCE 7-10) are shown below. See ASCE 7-10 Table C26.5-6 for additional information. 2013 CRC text ASCE 7-05 85 mph 90 mph 95 mph 100 mph 105 rnph 2013 CRC and CBC Referenced Standard ASCE 7- r0 I l0 mph I l5 mph 120 rnph 126 mph 133 mph ([ntroductory texL provicled for iurisdictioni rel-erence only l)o not attach to Criteria that ti>lkrl'.)