DESIGN PROCESS
JUNCTION DETAILING Suitable detailing of the junction between the through-wall system and the primary structural frame is an important part of the design process. This section presents some typical details and guidance on specific aspects to be considered. INTERFACE WITH STRUCTURE The detailing of the interface of the SFS with the structure will need to be considered and this could be: • A concrete slab • Structural steel that is fire-protected with a reactive coating • Structural steel that is board protected. Note: each of the above may include Z bars in cantilever.
Note: any encasement to structural beams that may be exposed to the elements during the construction phase should use weather-resistant boards. Cladding systems and their components will be routinely tested to establish properties such as watertightness, airtightness and resistance to wind load. Guidance on envelope sealing testing can be obtained from the Centre for Window and Cladding Technology (CWCT). Other options include: • Fixing directly into the steel beam – consideration must be made if interfacing with an intumescent painted (reactive coating) fire-protected beam • Fixing into Z bars or cleats that are fixed into the steel – consideration must be made if interfacing with an intumescent painted (reactive coating) fire- protected beam and how to fire protect the Z bars • Refer to the ASFP Advisory Note 18: ASFP Position on Installing Partitioning to the Underside of Structural Steel Sections Coated with a Reactive Fire Protection System. If the structural steel is not board-protected, consideration must be given to cold bridging and air sealing the beam to the through-wall interface.
Cavity barrier
Concrete
Fire protected primary steel structure
Insulation
Z BARS AND CLEATS FOR FIXING TO STRUCTURAL STEEL
Infill SFS including boards and framing
Cladding
Cavity barrier
Concrete
Generic detail of through-wall (steel frame)
Check with the system owner that fixing through fire protection boards, as illustrated above, is an acceptable approach when interfacing with the structural steel beams. Any potential movement/rotation of the head channels when the SFS is subjected to loadings such as wind could result in damage to the fire protection.
Cantilevered Z Bars used as a stand-off to structural beams with reactive coating
The designer should specify the method of fixing to the structure, and this should include the type and gauge of any Z bars or cleats. The designer may be
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