SRP™ WHISPERWALL™ Information and Specifications

The SRP™ Whisperwall™ Stud wall has been developed and manufactured to provide superior acoustic properties with additional fire rated properties in interior wall construction.

It provides significant advantage over staggered SRP™ Stud walls [FIGURE 10] in installation and is test verified for superior acoustic results.

SRP™ Whisperwall™ is configured in 92mm x 42mm from 0.55mm BMT GALVSTEEL® coil manufactured by New Zealand Steel, whenever possible. SRP™ Whisperwall™ Stud is backed by a 50 year Durability Statement to demonstrate compliance with NZBC Clause B2-Durability, when used and maintained as described in the current New Zealand Steel Durability Statement.

In laboratory testing the SRP™ Whisperwall™ Stud Wall achieved an STC 52, STC 58 and STC 62 rating. Refer to TABLE 8 below for relevant GIB Noiseline® configurations.

To enable easy installation, SRP™ Whisperwall™ Studs are equipped with a generously knurled face providing a secure surface for attaching high density wall board products [see FIGURE 1 and FIGURE 2].

To achieve the tested STC values for SRP™ Whisperwall™, install Pink® Batts® Silencer glasswool acoustic insulation R1.8 [75mm]* between the SRP™ Whisperwall™ Studs. Cut the width of the Pink® Batts® to suit SRP™ Whisperwall™ Stud centres and ensure the insulation is expanded to fill the cavity.


No SRP™ Continuous Nog Tracks or spliced SRP™ Studs are to be used in SRP™ Whisperwall™ Stud Walls, as doing so will compromise the tested STC values.

For plasterboard lining, fastening, acoustic sealant and/ or jointing [stopping] details refer to GIB® Noise Control Systems March 2006, GIB® Fire Rated Systems October 2012 and this SRP™ Design Handbook.

*SRP™ Whisperwall™ has been tested using Pink® Batts® Silencer glasswool acoustic insulation R1.8 [75mm], other acoustic insulation with properties equal or better may also be used once verified by an acoustic engineer.

SRP™ Whisperwall™ STC 52, STC 58 and STC 62 Configuration

Download Figure 9


STC* Rw [dB] FRR** Material used
Sound Transmission Class Weighted Sound Reduction Index Fire Resistance Rating GIB Noiseline® Wall Lining – see specification below 75mm Pink® Batts® Silencer GIB® Soundseal for joint filler and perimeter sealant
STC 52 Rw 51 -/60/60 One layer of 13mm GIB Noiseline® on both sides
STC 58 Rw 57 -/60/60 One outer layer of 10mm GIB Noiseline® on one side only One inner layer of 13mm GIB Noiseline® on both sides
STC 62 Rw 61 -/60/60 One outer layer of 10mm GIB Noiseline® and One inner layer of 13mm GIB Noiseline® on both sides

NOTES: Values obtained by Laboratory Measurement of Airborne Sound insulation of building elements carried out by an Independent Laboratory: Acoustic Testing Services of Auckland UniServices Ltd, Test Report T1406 dated 21st March 2014 using the specified materials and installed in accordance with:

* GIB. Noise Control Systems March 2006 and relevant SRP™ Design Handbook and
** GIB. Fire Rated Systems Oct 2012. Also see Winstone Wallboards confirmation letter dated 11th June 2014 in the COMPLIANCE SECTION of SRP™.