Method Statement Wall Airborne Sound Transmission Loss Testing.
Scope of works
This method statement describes the work process for the
airborne sound transmission loss test of the
subject areas.
Equipment
The proposed equipment for the testing is listed below:
- Sound Source: 1x JBL EON710 2 way 10” Powered Loudspeaker
- Sound Level Analyzer: NTi XL2 Type Approved S/N A2A-14983-E0 independently calibrated by
- Omega Measuring and Calibration Laboratory Cert.
- Handheld Calibrator: Larson Davis CAL 200 S/N 15632 independently calibrated by Omega.
- Measuring and Calibration Laboratory Cert.
- Signal Generator: NTi Minirator MR-PRO
- Signal to Sound Source Cable: Roxtone Mic cable [XLR]
Safety.
The following Personal Protective Equipment will need to be
worn at the time of visiting the site.
- Hard Hat
- High Visibility Jacket
- Safety Shoes
- Hearing Protection
Prior activities.
Prior requirements for the test are listed in points
below.
- 220v power is required to power the speaker (sound source)
- Blank any open duct/service penetrations (2 layers of plasterboard and insulation)
- Any opening through slab/floor to be closed out.
- Door openings to be closed (2 layers of plasterboard to be temporary held onto either side of the door opening with acoustic insulation in the formed cavity)
- All joints, penetrations, head and base of wall to be acoustically sealed with approved acoustic sealant.
- Façade and operable façade components to be sealed/closed and commissioned.
Procedure.
The acoustic airborne sound insulation testing will be
undertaken and processed generally in accordance with the following
standards.
BS EN ISO 16283-1:2014
Acoustics – Field measurement of sound insulation in
buildings and of building elements
Part 1: Airborne sound insulation
BS EN ISO 717-1:2013
Acoustics. Rating of sound insulation in buildings and of
building elements
ASTM E336 – 16a
Standard Test Method for Measurement of Airborne Sound
Attenuation between Rooms.
ASTM E413 – 16
Classification for Rating Sound Insulation.
Step 1: A single loudspeaker to be in the Source Room
Speaker to be in room corner away from the common subject
wall under test and operated as the noise source to create an even diffuse
sound pressure level across the partition.
As per standard the loudspeaker shall be moved to at least
two positions.
The Signal spectrum played through the speaker (source)
shall be Random Pink noise generated by NTi – Minirator PRO signal generator
and connected to the speaker via XLR cable.
Step 2: A handheld sound level analyser will be used to
measure the noise levels. The analyser is to be
checked with a handheld calibrator before the measurement.
Step 3: The handheld sound level analyser is used to measure
the noise levels in the source room and within the receiving rooms. (At least
two measurement(s) per source room speaker location).
A sweep- manual scan method is proposed to measure the
spatial average within the source and receiving rooms. (Refer Excerpt 7.5.5
Figure 6 below)
Note microphone position(s) during the scan of the room(s)
in accordance with the test standard requirements will be maintained >1m
from any floor/wall/façade/ceiling.
Step 4: The handheld sound level analyser will be used to
measure the ambient measurements in the
receiving room in the absence of source noise.
Step 5: Reverberation times will be measured in the
receiving room using the interrupted noise method.
The room decay will be measured for at least 3 locations (1m
or more apart where possible) for at least 3 decays in each location. {The
Reverberation time will be measured using the T30 function as part of NTi Type
Approved _ Type 1 Sound Analyser}
Step 6: The handheld sound level analyser is to be checked
with handheld calibrator after the measurement. Any drift will be noted.
Step 7: Process the results in accordance with the analysis
procedure.
Step 8: Prepare a detailed report suitable for client
submission. Report to include the site conditions at the time of testing, the processed results of
the subject wall acoustic performance compared with the project specification requirements and any
site observations.