2707 COLBY AVE MOSS ADAMS 2017-08-10

nbbj 'MEMORANDUM April 5,2016 Mr.Tony Lee Building Official City of Everett 3200 Cedar Street,2nd Floor Everett, WA 98201 Dear Mr.Lee, Thank you for your time and assistance in working through various proposed code alternatives for the Moss Adams Everett office,located at 2707 Colby Avenue,on the 8'floor of the Everett Mutual Tower. Below,please find a summary of our discussions via email,which are reflected in the Permit Drawings submitted under separate cover. Alternate Means of Egress from Elevator Lobby Section 1021.2 of the International Building Code requires two exits from a floor and generally requires access to at least two exits.The IBC Code Commentary also makes it clear that two exits must be available to a person once they have left an elevator lobby.At the same time,the code allows for alternative designs which comply with the intent of the code and which are,for the purpose intended,equivalent to the prescriptive requirements in the code.NBBJ proposes a corridor extension from the elevator lobby directly to one stair—labeled as"Corridor 801"in the Permit Drawings. Since this,by itself,would not comply with code,we have provided a 1 hour fire rating for"Corridor 801."This would provide a protected path to a stair and,given that this is a high rise building,it should be possible to transfer to the other stair on one of the floors below if the fire alarm is activated.An elevator lobby door providing access to the second stair via the open tenant space(door 850)will be equipped with hardware that is"fail safe,"unlocking during power failure and under fire alarm(which is connected to smoke alarms throughout the floor). We believe this would provide reasonably equivalent protection, trading free access to both exit stairs for a protected corridor environment with access to the second stair available through the"fail-safe"door. Glazed System at One-Hour Corridor The one-hour rated corridor referenced above is desired to have a lot of glass at the entrance to the tenant space from the rated corridor.There are glazed systems available that can provide the fire rating using steel frames and Firelite or similar products but they are very expensive.As an alternative,we are utilizing a system with aluminum frames,regular tempered glass,and special Tyco sprinkler heads on both sides of the glazing as described in report ESR-2397, available at http://www.icc-es.or reports/pdf files//ESR-2397.pdf.This system is evaluated for fixed glazing only and provides a rating of 2 hours vs. the required 45 minute minimum rating for a sidelite or fire window.At the opening into the tenant reception space(door 80 1) we have provided a 20-minute rated glazed door and frame,with smoke and draft control ratings. 223 YALE AVENUE NORTH SEATTLE WA 98109 T{206 223 5555 F) 206 621 2300