ISO PAS 16940:2004 pdf download Glass in building — Glazing and airborne sound insulation — Measurement of the mechanical impedance of laminated glass
Scope
This Publicly Available Specification describes a method for the measurement of the loss factor and theequivalent bending rigidity modulus of laminated glass test pieces. The aim is to compare the properties ofinterlayers. These two parameters (and others such as density and thicknesses of glass components) can berelated to the sound transmission loss (STL) of the glazing itself.
NOTEThe Cremer equation as shown in Annex C can be used to determine the STL.
2 Normative references
The followina referenced documents are indispensable for the application of this document. For datedreferences, only the edition cited applies. For undated references, the latest edition of the referenceddocument (including any amendments) applies.
SO 12543-1:1998, Glass in building – Laminated glass and laminated safety glass — Part 1: Definitions anddescription of component parts
ISO 140-1, Acoustics — Measurement of sound insulation in buildings and of building elements — Part 1:Requirements for laboratory test facilities with suppressed flanking transmission
ISO 140-3,Acoustics – Measurement of sound insulation in buildings and of building elements — Part 3:Laboratory measurements of airborne sound insulation of building elements
ISO 717-1, Acoustics – Rating of sound insulation in buildings and of building elements — Part 1: Airbornesound insulation
3 Terms and definitions
For the purpose of this document, the terms and definitions given in ISO 12543-1 and the following apply.
3,1
aminated alass
assembly consisting of two sheets of glass joined together with the interlayer that will be characterized by themethod of this Publicly Available Specification
NOTE 1Adapted from ISO 12543-1:1998.
NOTE 2The interlayer type and makeup should be specified.
4 Test method
4.1 Measurement of mechanical impedance (MIM) of laminated glass
4.1.1 Principle
The loss factor and the eauivalent bending riidity modulus are determined from the measurement of the inputimpedance of a glass beam sample. The input impedance is the transfer function between the injected force inone point and the velocity. This transfer function has resonances corresponding to a maximum of theresponse of the system (resonance frequency).
4.1.2 Measurement
The input impedance is measured with an impedance head giving both parameters (force and velocity) at thefixation point of the tested structure. Tested samples are beams of dimensions (25 2) mm x (300 + 1) mm.this limits the number of resonances in a given frequency band compared with a plate sample. The glasspanes shall be nominally 4 mm thick for comparison purposes. The input impedance is measured at thecentre of the sample, i.e. at half-length. For the fixation, good balance between left and right sides is needed.and the centre part shall be precisely determined, The vibration mode of the sample shall be as shown inFigure 1, i.e. a bending vibration of two “free clamped” half beams.

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