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Snow Creek Cabin - Fire Safety Assessment - Install Fire egress ladders on exterior of building.

Yosemite National Park » Snow Creek Cabin - Fire Safety Assessment - Install Fire egress ladders on exterior of building. » Document List

A preliminary fire and life safety assessment of the Snow Creek Cabin was conducted by the Yosemite Fire Marshal. This cabin is available for public access only during the winter months by foot (snowshoe or skiing) and is approximately seven miles from Yosemite Valley. The elements identified for safe occupancy are common to buildings having historic significance and have been addressed in the past through careful review and compliance decisions. The fire marshal's recommendations are based on the assessment of risk, review of applicable policy, various codes and applying sound fire and life safety principles. The Snow Creek Cabin is classified as an existing hotel by National Fire Protection Association Life Safety Code, National Fire Protection Association (NFPA) 101 and Residential Group R-1 by the 2012 International Building Code.

This project addresses the installation of two fixed ladders on the building exterior for second floor evacuation in the event of a structural fire. The primary escape path is the cabin's front door. This door is located on the first floor, providing escape directly to the outside. There are no secondary escape paths except the first floor windows.

NFPA Code requires escape windows for the second floor sleeping rooms (one escape window per sleeping room) to be provided with fixed emergency escape ladders leading to ground. Collapsible escape ladders and devices such as those available for single family homes are not suitable for this cabin for numerous reasons. These ladders are only effective with intimate familiarity and repeated practice use by the occupants. Not all devices function in the same manner. Some devices are subject to deployment failure. Devices can be moved, hidden from view or removed. Devices do not provide for a stable easily accommodating platform and are slow to use. Devices are intended for single room evacuation serving typically lower single family dwelling occupant numbers per device.
The ladders will be attached perpendicularly to the building side wall with two stand-off brackets measuring six inches. Fabricated angle iron straps (2" x 5") will be welded to each end of the angle to create a flange. Each strap will bolt to the wall and to the side rail of the ladder. Two diagonal braces of angle iron bolted to the wall and connected to the outer rail of the ladder will brace the ladder perpendicular to the wall. There is solid backing in the wall next to the window provided by internal log framing members in a studded wall configuration.

This cabin does not have the typical residential use protections offered by contemporary building fire resistance and limited flame spread characteristics providing additional time for device deployment. Code for this type occupancy does not recognize these devices as an acceptable escape means. Secondary escape is traditionally dependent on rapid response of fire department rescue efforts (not available in this remote location) through windows large enough for firefighter access and temporary areas of refuge such as balconies and roofs accessible by fire department ladder.