2207 GRAND AVE 2016-01-01 MF Import

A. UBC Section 508 is utilized to substitute sprinkler protection for 1-hr. fire resistive construction with the following exceptions: 1. Occupancy separations are not applicable. 2. Exterior walls do not require protection due to proximity to the property line. 3. Area separations are not applicable. 4. Dwelling unit separations comply with the one-hour passive construction requirement of 310.2.2. 5. Shaft enclosures are not applicable to my knowledge, but will be one hour if they occur. 6. Corridors do not exist in this context. 7. Stair enclosures are not applicable. 8. Exit passageways do not exist. 9. Type of construction separation is not applicable. 10. Boiler separation is not applicable. B. The building has been constructed as Type V-1 hr. throughout, so applying the "508" substitution to only the exterior walls is not unreasonable. The exterior walls as constructed calculate to a fire resistance rating of 45 minutes as follows (UBC Vol. III, Tables 7-7-W-A, -C, & -D): 1• 1/2" exterior plywood sheathing: 10 minutes 2. wood studs at 16" on center: pp u 3. R-19 fiberglass insulation: 15 „ TOTAL: 45 minutes The inside surface calculates to a rating of 75 minutes because it enjoys 5/8" type X gypsum board � 40 min., studs � 20, insulation at 15, and resilient channel � 5. Therefore, the additional sprinklers are used to offset only 15 minutes of exterior fire resistance deficiency. I believe professionally that this is a better solution than simply adding the exterior gypsum board. Please call with any questions at your convenience. Sincerely, t�� W. B. Lehner, P.E. Fire Protection Engineer LEHNER ENGINEERING 97002.0-Rpt.1-DC,CApts cc.