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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
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.