| Why Acoustic Testing
Sound Insulation Testing (Part E)
Recent changes to The Building Regulations have led to sound insulation
testing becoming mandatory throughout residential developments unless
Robust Detailing is used. As such you may well have been requested to
carry out sound insulation testing by Building Control.
Air Pressure Testing’s sound insulation testing service is built
around customer satisfaction, specifically in terms of Speed, flexibility
and quality. This is ensured by having a team of highly trained test engineers
available at all times utilising the very latest equipment at the forefront
of technology. This allows you to carry on with your works without having
to shut the site for the duration of the Testing
Please click for swept sine technology.
Air Pressure Testing can undertake all
of your insulation testing in accordance with
Approved Document E
Why you should APT for all your part E requirements
• Testing is arranged as soon as possible as we are aware that
quick turnaround time is crucial for our clients.
• We offer highly competitive prices Click
here for a quote
• We use top quality instrumentation to ensure you get the best
service available.
What is Sound Insulation Testing FAQ (frequently
asked questions)
What is sound insulation?
Sound insulation is the property of a wall or a floor to resist the passage
of noise.
What is sound insulation testing?
Sound Insulation Testing is a method of quantifying the sound insulation
performance of a wall or floor. Sound insulation testing can be carried
out on party walls, party floors or facades of any building. The methodology
for sound insulation testing is set out in various parts of BS EN ISO
140 and ratings in parts of BS EN ISO 717.
Why do I need sound insulation testing?
The largest single reason for disputes between neighbours is noise complaints.
Approved Document Part E - Resistance to the passage of sound of the Building
Regulations describes minimum standards to be achieved by newly built
domestic dwellings. Sound insulation testing is also required in schools,
hospitals and workplaces where noisy activities need to be separated from
quiet activities.
The Building Regulations Approved Document Part E sets out minimum standards
for sound insulation performance to be achieved by party wall and party
floors. Building contractors may show compliance with Part E of the Building
Regulations by two methods. One method is to register plots to be built
with Robust Standard Details Limited and the other is to show as-built
performance by Pre-Completion Testing.
What is Pre-Completion Testing?
Pre-Completion Testing is method of showing compliance with Approved Document
Part E of the Building Regulations by testing a construction in-situ prior
to handover. Site Measurement Services Ltd offer competitively priced
sound insulation testing to both large and small building contractors
for any size of development.
What is a Robust Standard Detail?
A Robust Standard Detail is party wall or floor construction of proven
performance that is part of the Robust Standard Detail scheme. The Robust
Standard Detail scheme is provided by Robust Standard Detail Limited,
an organisation that oversees the registration, specification and construction
of party wall or floor constructions. RSD Limited produces a handbook
containing specifications and checklists for a restricted number of proven
constructions based on empirical data. RSD Limited carries out visual
inspections during construction of registered plots and spot checks a
sample following completion.
When are Pre-Completion Testing sound insulation
tests carried out?
Sound insulation testing required for Pre-Completion Testing (PCT) with
respect to Building Regulations Approved Document Part E are carried out
when the construction of party walls and floors are largely complete.
Windows should be in place with any vents closeable. Internal and external
doors should be in place, along with skirting, cornicing and plug sockets
in place. Sound insulation testing on floors must be carried out before
any soft coverings are in place.
Sound insulation testing following noise complaints from residents can
be carried out at any time when suitable access can be arranged.
Airborne Sound Insulation is determined by the difference D in sound levels
between a source and receiver room. This is corrected for reverberation
DnT, and weighted to give a single number value for the Sound Insulation
DnT,w + Ctr.
Impact Sound Insulation
Is determined by measuring the sound level L, in the receiver room.
This is corrected for reverberation, L’nT, and weighted to give
a single number value for Sound Insulation L’nT,w.
 Download
an electronic copy of Approved Document E here
Sound Insulation Testing (the facts)
Airborne Sound Insulation
Airborne sound insulation is determined by the difference D in sound levels
between a source and receiver room. This is corrected for reverberation
DnT, and weighted to give a single number value for the Sound Insulation
DnT,w+ Ctr.
Process
The loudspeaker in the Source Room emits a loud noise over a range of
frequencies (pink noise).
The microphone in the Source and Receiving Room measures the sound pressure
level. Using specialist UKAS Calibrated equipment, our acoustician then
calculates the airborne sound insulation (DnT,w + Ctr).
Impact Sound Insulation
Impact sound insulation is determined by measuring the sound level L,
in the receiver room. This is corrected for reverberation, L'nT, and weighted
to give a single number value for Sound Insulation L'nT,w.
Process
In the Source Room a tapping machine impacts repeatedly directly onto
the floor structure.
A microphone in the Receiving Room measures the sound pressure level and
the recorded level produces the Impact result (L’nT,w).
In order to comply with Approved Document E of the Building Regulations,
10% of plots used in each development for residential purposes should
be tested if robust detailing is not used.
Breaking News: Application of new measurement method
in building and room acoustics.
The classical methods of determining the sound transmission between rooms
have been with us for some time and their limitations are well known mostly
due to background noise being too high.
These difficulties are now recognised by the standards authorities and
in response they have published the BS EN ISO 18233:2006 Acoustics –
“Application of new measurement methods in building and room acoustics”.
This standardises measurement procedures based on deterministic signals
that can be used to obtain the impulse response of the test space which
in turn may be post processed to give both the level difference and reverberation
time.
Two methods have been standardised and these may be used as alternatives
for the classical methods described in BS EN ISO 140 (all parts) BS EN
ISO 3382 (all parts) and ISO 17497-1 when determining the reverberation
time or level difference for calculation of sound insulation parameters
as per BS EN IEC 717 series of standards
• The MLS method is implemented in the Nor-840 analyser and is best
suited to controlled conditions such as test laboratories etc.
• The Swept-sine method described in annexe B is implemented in
the Nor-121 analyser and as this is more robust in terms of test environment
and resistance to harmonic distortion is recommended for field application
impossible at low frequency bands by traditional techniques. This is due
to internal decay times of the filters used that limit the shortest possible
measurable decay. Norsonic have overcome this problem by the use of reverse
filtering with specially crafted filters that both provide short decay
times and conform to class 1 requirement of IEC 61260.
Advantages of Swept-sine Compared to MLS:
MLS measurement technique uses a Maximum Length Sequence (MLS) as the
excitation signal.
MLS is a deterministic binary sequence with frequency characteristic of
white noise. Similar to swept-sine, MLS technique uses deconvolution in
the analysis part. analyses, we can conclude that this is the case on
the lower frequencies. However this improvement was not enough to obtain
correct results at higher frequencies due to prevailing background noise.
The swept-sine technique not only provides higher level of excitation
but also suppresses the background noise. It can clearly be noted that
measured results are under background noise at higher frequencies. Therefore
swept-sine is capable of performing the correct measurements even in environments
with negative signal to noise ratios, being the only method that could
give the correct result in this example, this helps you as we do not require
total silence during the Acoustic testing.
A few of the advantages of swept-sine over MLS are
• Immunity against harmonic distortion?
• Higher excitation level might be used
• Robustness against time variance?
With swept-sine techniques higher loudspeaker output levels can be used.
This will result in higher level of excitation signal (highly desirable
feature as it increases SNR) but may also cause harmonic distortion due
to the non-linearity of the loudspeaker. This distortion will appear in
impulse responses obtained by MLS and swept-sine in two different ways.
In an MLS measured response, the distortion will appear as spurious peaks.
This reduces the SNR and may deteriorate the measured IR in such an extent
that it limits the applications. On the other hand, when the impulse response
is measured with the swept-sine technique, the effects of harmonic distortion
can be completely removed. Use of linear deconvolution makes distortion
components appearing at the “negative” times in measured impulse
response and these components can be removed by windowing. This useful
feature also makes it possible to reduce the size and weight of the excitation
loudspeaker, this helps when you are Acoustic testing a new build which
is abutted to an existing building, as the adjacent owners may complain
about the noise levels during the Acoustic test
Robustness Against comparison on those decays leads to no noticeable
increase of background noise level, which leads to conclusion that swept-sine
is the method of choice for outdoor and insulation testing
Checklist of Items to be completed prior to our
arrival on Site to undertake the Acoustic Test
The best time to carry out sound testing is towards the completion of
the project. In addition the optimum conditions are when the site is quiet.
If there is noise on the site from equipment and 'on going works' here
is an increased chance of a sound test failure. Housing developers and/or
site managers will have to nominate a day for testing and restrict any
noisy activity during the tests. The following list provides an indicative
checklist for site managers for the requirements of the plots and sites
where testing may be carried out.
A site is ready for testing when:
1. Windows are fully fitted with locks in place.
2. Window trickle vents are in place or temporarily blocked up for testing.
3. Room and front doors are in place and closeable.
4. All wall surfaces in rooms to be tested are complete (including sockets
and switches if applicable).
5. Floor and ceiling surface are complete.
6. Carpets or timber laminates have NOT been laid in rooms where floors
are to be tested (with the exception of bonded carpet).
7. Staff made aware that a quiet site environment is required during testing.
IF YOU HAVE ANY QUESTIONS ABOUT THE PREPARATION OR THE ACTUAL
TEST, THEN PLEASE RING OUR OFFICE TO DISCUSS THEM.
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