Metal Frames#
In a double panel wall, there are various ways in which the two sides of the wall can be connected. These connections provide a path for the transfer of vibrational energy which is then radiated as sound.
Some of the steel or metal frames included in INSUL are discussed below.
Steel Studs#
Steel studs are used to construct framed partition walls. In some countries, they are used extensively almost to the exclusion of timber studs. They generally provide much higher sound transmission loss performance than timber studs because they are far less rigid than timber studs. Typically steel studs would be C or Z shaped in cross-section and come in various cross-sectional widths (51, 63, 92 mm wide). From the test data that is available steel studs seem to work about as well as a timber stud frame with resilient rails.
Base Material Thickness
The list of steel studs available in INSUL includes a range of different BMT's (Base Material Thickness) or thicknesses of steel.
For metric steel studs the range spans from 0.5 mm to 1.15 mm.
For imperial studs, the range spans from 19 mils to 54 mils. In previous versions of INSUL, the BMT for imperial studs was expressed as gauge, however this can introduce ambiguity in some cases, so in INSUL 10 they have been re-expressed in mils (thousandths of an inch).
BMT in mils |
Approximate equivalent gauge |
|---|---|
| 19 mils | 25 ga |
| 30 mils | 20 ga drywall or interior |
| 33 mils | 20 ga |
| 43 mils | 18 ga |
| 54 mils | 16 ga |
Steel Studs and Resilient Rail#
INSUL includes an option to predict steel studs with a resilient rail. This predicts better performance at higher frequencies as the degree of decoupling between the two leaves increases.
WIth this frame type, INSUL assumes that the steel stud frame has a base material thickness of 0.55 mm.
Resilient rail/bar Direct Fixed
INSUL also includes a connection for a resilient rail without a frame, called Resilient rail/bar Direct Fixed. This frame type can be where a resilient rail is fixed directly to a wall layer such as plywood or concrete rather than to a timber of steel stud frame.
CH Studs#
There is an option to predict CH studs. These are typically robust steel studs used to form Shaft risers in multi-storey buildings and are shaped somewhat like a C on top of an H, hence the name. Typically, the stud will accommodate a 25 mm thick board which provides the fire rating required for shafts.
Acoustic Studs#
Acoustic studs are specifically designed to improve sound transmission loss of plasterboard walls by introducing more compliance into the stud by changing the stud's profile.
INSUL's acoustic stud type could be used for the acoustic studs offered by different manufacturers such as:
- Knauf Acoustic C studs
- Winstone Wallboards Quietstud
- Peer Acoustic Stud
- Siniat GETEC
Z Girt#
A Girt is a horizontal structural member in a framed wall (The corresponding member in a roof is a purlin).
Z Girts are used in many countries in the construction of industrial buildings that are typically clad with profiled steel sheets. Z Girts are typically steel of 1.2 mm thickness, bent to a Z profile and fastened horizontally to steel frames, with the weatherproof cladding fixed to the Girt.
The Z Girt modelled in INSUL is of 1.2 mm thickness. If a girt has a steel thickness greater than this, then INSUL may over-predict its performance and it may be better to use a solid connection (eg timber stud). This connection may also be used for steel purlins of 1.2 mm thickness.
Suspended Ceiling Steel & Neoprene Hanger#
Laboratory tests show that the Kinetics ICC-50 Deck-Suspend Ceiling Hangers give isolation equivalent to a separate joist construction. That is the ultimate isolation and is rarely seen in an acoustic isolator.
For modelling floor/ceiling constructions using this hanger use the "Steel Spring Hanger". Similar units from Mason Industries, for example, would be expected to perform similarly.
Double Steel Studs#
The principles of sound insulation discussed for Double Timber Studs are also applicable for Double Steel Studs.