This article is about a unique approach to custom home design involving fire safety for a home elevator.
Sure did surprise this custom home designer: Home elevator design seems not to involve a shred of home fire safety code to be had across the fruited plain far as he can tell. (Now, there is a U. S. elevator code in the form of ASME A17.1 Safety Code for Elevators and Escalators, which addresses essential safety concerns, e.g., access, switching, guardrails, and such but not home fire safety.)
A home elevator design inherently includes a shaft, or hoistway, that could make a swell chimney, and double the peril by holding within the cab those who could be the most physically vulnerable folks in the house.
Much codified ado is made of home fire safety in regard to residential fire-blocking, but nothing specific about home fire safety in home elevator design that the author can reckon about the potentially airflow-permissive [read: smoke and flame flow-permissive] elevator shaft. (Fire safety regarding vertical shaft enclosures gets some considered attention, e.g., IBC 2000 707.1ff, but not “ for openings totally within an individual dwelling unit and connecting four stories or less.” IBC 2000, 707.2, Exception 1.)
In regard to home elevator design and home elevator construction, what’s at stake here is fire-degraded wood stud walls and wood ceiling joists collapsing within a hoistway, or shaft, engaging cab and contents, including human contents, in smoke and fire.
Home Fire Safety – Home Elevator Design, Fire Safety Guidelines
A home elevator shaft, or hoistway shall be framed with lightweight, or cold-formed, steel – not wood, where exterior surfaces are available for wallboard application, exterior walls. It shall be finished with not less than 1 layer-5/8″ Type-X gypsum wallboard glued, screwed and taped and shall be mudded not less than 3 coats, paying particular attention to screw pocks which shall be taped, too.
The interior wall surface shall be finished with not less than 2 layers-5/8″ Type-X gypsum wallboard glued, screwed, and taped and shall be mudded not less than 3 coats, paying particular attention to screw pocks which shall be taped, too.
NOTE: Remember to adjust the home elevator system’s manufacturer’s shaft framing dimensions to accommodate thicker interior clad; advise the elevator system manufacturer (and your local Fire Marshal) of your specific intentions in regard to home fire safety methods and materials early-on.
The shaft ceiling shall be framed and sheathed on exterior and interior as the walls (see above). It shall be enclosed by not less than 1 door at each stop, which door shall be not less than 1-hour fire-rated, self-closing, shall be self-latching, and smoke-sealing.
Within the cab and outside the door at each stop, a smoke detector shall be applied according to manufacturer instruction, shall be permanently connected to each other overall throughout the residence such that when one or more alarm, all alarm throughout the entire house.
Each alarm shall run on both permanent 120V and replaceable battery, shall feature a combination of ionization and photoelectric sensors, shall not disconnect by wall switch, and shall be connected to a 120V line as first load on a frequently used lighting circuit with overcurrent protection at the panelboard suitable for a double tap.
Within the cab, there shall be not less than 1 dry-chemical, portable fire extinguisher rated not less than 2A:10B:C mounted at 3′-6″ above finish floor level to carrying handle.
At each stop, a hallway or other space to which there is direct access from the cab shall have passage within line of sight at two linear feet outside the cab door on-center to not less than two means of emergency egress, not more than one of which means may be an emergency egress window.
Comment: Please note that an electrical box attached to steel frame shall be metal and grounded to Code.
Comment: In sum, the steel’s there to break down more slowly when engaged, proposedly to wrack and sag but not to cinders and ash; the tight sealing is intended to counter smoke intrusion; the extra layers of Type-X are there to better hold its form and hold flames from you on your travel through the hoistway.