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Aron Faegre,AIA,PE 520 SW Yamhill Street Portland Oregon 97204 (503)222-2546 FAX/222-6529 faegre®earthlink.net Alternative Methods Appeal for Yellow Gate Corporate Hangar 4, Aurora Airport October 29, 2013 A' v r` Code Section for which alternative method being proposed: 412.4.1 Exterior walls. Exterior walls located less than 30 feet from lot lines or a public way shall have a fire-resistance rating not less than 2 hours. The following additional related code items are noted for context in the discussion: • The IBC Commentary(copy attached) says that the reason for this is to abate fire spreading from "a commercial aircraft hangar to adjacent buildings and structures." Proposed Design: • Fire water sprinklers for 100%of the building in lieu of 2 hour walls on the north and south sides of the building. Note: other sides of building have no fire resistance rating requirements per Type Il-B construction. Describe Reason for Alternative: • This is a private airport development which often has property lines between buildings, unlike a typical publicly owned airport development which does not have property lines between buildings. The intent of this code section was to protect other buildings and structures from aviation facilities-otherwise on public airports the 2 hour walls would have been required when hangars are located less than 30 feet apart independent of property lines. Thus we believe this code section is not appropriate for developments which have aviation hangar uses adjacent to each other. • Since sprinklering is not required by area analysis, for purposes of code compliance, we propose using it as an alternative in this case. Describe Why, How, etc. the Proposed Alternative is Equivalent and Meets the Intent of the Code in Terms of"Strength, Effectiveness, Fire Resistance, Durability, Health.and Safety": • Our work with the State Building Codes and State Fire Marshal's office has confirmed that fire sprinklering of hangars, and constructing them of non-combustible materials, is the most important method of maintaining fire safety in hangar developments. Copies of surveys of hangar fires(attached) supports this. • The attached area analyses show that fire sprinklering is not already required for this hangar, so the fire sprinklering for this project could be considered an alternate construction method. • Section 412.4.1 creates more restrictive standards for aircraft hangars than even H occupancies are required to comply with in Table 602, and does not even allow going to