NOTE This standard governs the materials, configuration, and installation of fire-resistance-rated gypsum shaft wall assemblies enclosing vertical shafts, including elevator hoistways, exit stair towers, mechanical and plumbing chases, duct shafts, and pipe or cable risers. (1.1)

NOTE A gypsum shaft wall assembly is a proprietary, factory-tested wall system that encloses a vertical shaft and is installed entirely from the building side, without access to or scaffolding within the shaft. The defining characteristic of this system is single-side access: 1 in. gypsum shaftliner panels are friction-fit edgewise into the slotted webs of light-gauge C-H or E-studs from the building side, and the face-layer gypsum board is then applied to the building face. This single-side erection is what separates a shaft wall from an ordinary partition — an ordinary fire-rated partition carries gypsum board on both faces of the studs and is built from a workable space on each side; a shaft wall is built from one side only because the other side is an open, often hazardous, vertical void. The board-on-both-sides details, cavity-blocking details, and fastener schedules of a standard partition therefore do not apply to a shaft wall assembly. (1.2)

NOTE The fire-resistance rating, allowable height, and acoustic performance of a shaft wall are properties of a complete tested assembly, not of any single component. (1.4)

NOTE The shaftliner thickness and type, the stud profile, depth, and gauge, the number of face layers, the fastener pattern and screw type, the stud spacing, and the head and base details are all variables in the listing, and changing any one of them invalidates the tested rating unless the substitute is covered by its own listing. (1.5)

NOTE Shaft enclosures are governed by IBC Section 713, which classifies them as fire barriers under Section 707 and sets the required rating from the number of stories the shaft connects. (1.6)

NOTE Materials, framing, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited or a specific edition is enforced by the authority having jurisdiction. (2.1)

NOTE The installer shall be experienced in the erection of fire-rated gypsum shaft wall assemblies and shall have completed assemblies of comparable scope and rating. (4.1)

NOTE Substituting any component of a listed assembly without a covering listing is the single most common cause of a failed shaft wall, because the laboratory rating applies only to the exact tested combination. (4.2)

NOTE The required fire-resistance rating of a shaft enclosure is set by IBC Section 713.4 from the number of stories the shaft connects: 1 hour where the shaft connects fewer than four stories, and 2 hours where the shaft connects four or more stories. (5.1)

NOTE Because most commercial and multifamily buildings exceed three stories, the 2-hour assembly is the prevailing default, achieved with a double layer of Type X face board over the same liner-and-stud core used for the 1-hour assembly. (5.2)

NOTE Elevator and equipment noise transmitted through shaft walls is a leading occupant complaint, and the acoustic rating of the assembly is governed by the stud depth, the face-layer count, and any supplemental cavity insulation. (6.1)

NOTE An STC 50 floor is the practical minimum for elevator hoistways and many jurisdictions require it; leaving acoustic performance unspecified is a frequent and avoidable source of post-occupancy complaints. (6.2)

NOTE Standard paper-faced gypsum shaftliner is suitable for dry, conditioned shaft interiors, but it is not appropriate where the shaft is exposed to recurring moisture, condensation, or groundwater. (7.1)

NOTE Mechanical-room shafts subject to condensation, exterior-adjacent shafts, and elevator pits exposed to groundwater require a moisture-resistant, glass-mat-faced shaftliner to resist mold growth and core degradation over the building life. (7.2)

NOTE The shaftliner is the 1 in. nominal Type X gypsum panel that forms the shaft-side face of the assembly; it is friction-fit edgewise into the slotted web of the C-H or E-stud and is the primary fire-resistive core of the system. (8.1)

NOTE Shaftliner panels are nominally 24 in. wide so that their edges land in the studs at the standard 24 in. on-center spacing; this dimensional match between panel and framing is integral to the listed assembly and is why stud spacing cannot be changed at will. (8.2)

NOTE The face layer is the Type X gypsum board applied to the building side of the framing; the number of face layers is the primary variable that distinguishes a 1-hour from a 2-hour listed assembly. (9.1)

NOTE The framing is a light-gauge cold-formed steel C-H or E-stud system with matching head and base track; the stud web is slotted to capture the edge of the shaftliner panel, which is what allows single-side erection. (10.1)

NOTE The two common profiles solve the same problem differently: the C-H stud captures the liner edge between the C-shaped flange and the central H-web, while the E-stud uses an alternate profile compatible with the same liner panels. Both are erected from the building side and both are available in proprietary systems from multiple framing manufacturers. (10.2)

NOTE Stud depth and gauge together set the allowable assembly height: a deeper, heavier stud carries more lateral load and spans taller floor-to-floor heights. The 2-1/2 in. 25 ga stud covers standard commercial elevator shafts up to roughly 12 to 14 ft floor-to-floor, while 4 in. and 6 in. profiles and the heavier 20 ga gauge are required for taller floors or higher lateral loads. (10.3)

NOTE The maximum height of a shaft wall is bounded by the tested limiting height for the selected stud profile, depth, gauge, and spacing under the design lateral load; exceeding it without engineering justification is a code deficiency. (10.5)

NOTE Approximate limiting heights for 25 ga C-H studs at 24 in. o.c. are 12 to 14 ft for a 2-1/2 in. stud, 16 to 18 ft for a 4 in. stud, and 20 to 22 ft for a 6 in. stud; a 6 in. 20 ga stud reaches roughly 26 to 28 ft. These ranges vary by manufacturer and design lateral load. (10.6)

NOTE The head of a shaft wall must accommodate vertical movement of the floor structure above without transferring load into the wall; this is done with a slip-track (J-runner) deflection head that lets the structure deflect while the wall stays in place. (11.1)

NOTE A J-runner is a deep-leg track that receives the top of the studs and the head of the liner panel, sized so that the structure can move through its design inter-story drift without bearing on the studs. An undersized slip track is a common defect: when the floor deflects more than the track allows, the studs are loaded in compression and the face board cracks or delaminates at the head. (11.2)

NOTE The required deflection allowance is a structural input, not a default; it must come from the structural engineer's inter-story drift values for the specific building. (11.3)

NOTE The base of a shaft wall is set in a runner track on the shaft floor and is the starting point for the friction-fit erection of the liner panels working upward. (12.1)

NOTE Where the shaft height exceeds the length of a single shaftliner panel, the panels are stacked and a horizontal joint is created in the liner; this joint must follow the tested horizontal joint detail of the listed assembly. (13.1)

NOTE Untested horizontal joints are a common code deficiency finding. The listed design specifies the joint detail, often a steel H-clip or equivalent, and the joint locations and detail shall be coordinated and shown on the shop drawings before erection. (13.2)

NOTE Openings through a shaft wall — access doors, elevator entrance interfaces, and duct openings — interrupt the fire barrier and must be framed and protected so the rating is maintained. (14.1)

NOTE Opening protectives in shaft walls are governed by IBC Section 716, and the rating of the door or access panel must correspond to the rating of the shaft enclosure. Duct openings through the shaft wall additionally require fire dampers per IBC Section 717 unless an exception applies; the damper and its firestopping are a separate scope and shall be coordinated with the mechanical work and Firestopping. (14.2)

NOTE Shaft wall erection follows a fixed sequence dictated by the friction-fit system: the base and head tracks are set, the studs are plumb-set from the shaft floor upward, and each shaftliner panel is slid edgewise into the slotted stud webs before the next stud is set, so the panel is captured between adjacent studs. (15.1)

NOTE Installing the liner panels out of sequence — for example, after the studs are fully fastened — prevents the friction-fit and voids the assembly. The single-side erection that defines the system depends on this sequence being followed. (15.2)

NOTE There is no standard destructive field test for a shaft wall; acceptance is by AHJ inspection of the assembly sequence, the joint taping, the fastener pattern, and conformance to the listed design number. (16.1)

NOTE Where the AHJ or the owner requires it, a smoke or air-leakage test of the completed shaft enclosure may be performed; this is established by the project documents, not by this standard alone. (16.2)

NOTE Gypsum shaftliner and face board are moisture-sensitive and are easily damaged on edge, so they must be kept dry, flat, and supported until installed. (17.1)

NOTE The shaft wall warranty covers material defects; the fire-resistance rating itself is a property of the listed and inspected assembly, not a warrantied performance level. (18.1)