Types of Sound Insulation Testing

There are two types of sound insulation testing, Airborne and Impact. As the two types of testing are quite different here is a quick article explaining both types.

Airborne Sound Testing

Airborne sound testing is undertaken to walls & floors. Firstly a controlled noise is generated by an amplifier and loudspeaker across a broad range of frequencies. The generated noise is very loud and is often in excess of 100dB. Initial measurements are taken using a class 1 sound level meter within the ‘source room’ followed by further measurements in the ‘receiver room’ on the other side of the wall or floor under investigation. The source room speaker position is then changed and the measurements repeated either side of the partition under test.

Thereafter background noise measurements are made using a class 1 sound level meter in the receiving room and are used to apply appropriate corrections for external sound such as traffic noise. Similarly the reverberation time (the time taken for sound to decay by 60dB) is measured within the receiving room using the sound source and a sound level meter to determine the corrections that must be applied to account for the characteristics and absorptiveness of the room.

 The difference in the two airborne noise levels (for walls and floors), corrected for background and reverberation characteristics determines the airborne sound insulation performance of the wall, or floor. A greater airborne noise difference between the source room and the receiver room determines a higher airborne sound insulation performance.

The time taken to undertake sound testing varies from project to project as no site is exactly the same. Taking into account standard site conditions a set of tests on houses -two airborne walls will take one to two hours. A six pack of tests on flats – 2 airborne wall tests will usually take between one and two hours, although this is dependent on our engineers having full free uninterrupted access between all the units/rooms under investigation.

Impact Sound Insulation Testing

Impact sound transmission testing is undertaken to floors only. This test is different; a calibrated Norsonic ‘tapping machine’ which comprises of five ‘hammers’ driven up and down by a cam and electric motor is used to “tap” the floor surface by applying a known force on the floor structure. The machine is placed in several pre-determined positions. The resulting noise is measured in the dwelling below, using a sound level meter.

Thereafter, background noise measurements are made using a class 1 sound level meter in the receiving room and are used to apply appropriate corrections for external sound such as traffic noise. Similarly the reverberation time (the time taken for sound to decay by 60dB) is measured within the receiving room using the sound source and a sound level meter to determine the corrections that must be applied to allow for the characteristics and absorptiveness of the room.

The measured noise levels in the receiving room are corrected for background and reverberation characteristics determine the impact sound insulation performance of the floor. For the impact noise the lower the measured level, the better the performance as less sound is being transmitted into the dwelling below.

The time taken to undertake sound testing varies from project to project as no site is exactly the same. Impact testing is usually undertaken as part for a 6 pack test, consisting of 2 airborne walls, 2 airborne floor and 2 impact sound tests. A standard 6 pack test will usually take between two and three hours, although this is dependent on our engineers having full free uninterrupted access between all the units/rooms under investigation.

If you require sound insulation testing, and/or acoustic design advice then please contact us now at info@aptsoundtesting.co.uk  or phone me (Darren) directly on 07775623464.

Top Tips for Passing Your Air Tightness Test

APT Sound Testing has carried out thousands of air tightness tests on residential and commercial buildings. Over the last 12 years, we leaned quite a few things on how to seal buildings to pass air tightness testing to achieve building control sign-off. To try and help clients prepare their buildings, we have collated our top 10 tips to pass your air testing. :

1. Design and apply an air tightness strategy from the start of the project.

Once the design air permeability rate has been established, sit down with the design team and subcontractor trades to ensure they know the importance of designing and constructing the building to be air tight.

The air tightness line needs to be established as early as possible. This can be as easy as drawing a red line through all the elements that separate heated and unheated elements – such as plant rooms or external store rooms. Also, it is also important to have an air tightness coordinator on site to check consultant details and the associated on site construction.

2. Onsite construction signoff sheets throughout the build

An onsite inspection regime should be put in place throughout the construction phase to ensure that the air barrier is not compromised by poor workmanship. If the building fails the air tightness test, it can lead to very expensive remedial works.

Air leakage commonly occurs due to the inner lining of the building envelope being breached during construction. One way to prevent excess air leakage paths is to use joist hangers, rather than ‘built in’ floor joists.

3. Careful sealing during the Drylining phase

In our experience dot and dab plasterboard is often a major cause of air leakage, as any missed leakage due to unfilled mortar joints in the brick or blockwork, has a potential path from behind the board to the floor slab and up behind and through the walls.

To lower the chance of air leakage on these areas or use solid lines of adhesive around all sides of the board and any cut outs for sockets and/or parge coat the masonry walls first. It is also recommended you seal at the skirting boards/floor/wall junction wherever possible.

4. Seal around service penetrations – waste and supply pipework

Ensure all service penetrations such as waste and supply pipework is sealed where it penetrates through walls and floors. Use mastic/gunned sealants on smaller gaps; on larger gaps use pre-compressed flexible expanding foam strips or plasterboard fillets.  Do not use expanding foam as it can shrinks and break away from the surrounding construction. There are flexible foams, which are tested for air tight applications which should be fit for purpose.

5. Seal around Windows and Doors

We still see large amounts of ceilings and doors which have not been adequately sealed or are not fitting properly and need to be adjusted or eased. Use suitable draught strips, seals and sealants and to ensure there are no gaps or cracks around all window/door jambs, sills and lintels and ensure that the installers have properly checked the doors and/or windows to ensure they are closing tightly against the surrounding frames.

6. Seal around Radiator Pipes and Manifolds

Also many radiator pipes penetrate the wall behind a rad, or through the floor – which are not always obvious. Manifolds from underfloor systems are often not sealed into the floor screed, which is then covered up with carpet which still results in a large air leakage path. Carefully check and seal the areas prior to finishes being applied.

7. Seal around Loft Hatches and Eaves Cupboards

With space at a premium many dwellings have rooms designed in the roof; unfortunately this can often be the main air leakage area in dwellings. Historically, we have seen a lot of air leakage through loft hatches, eaves cupboard doors and service cupboards. As the cupboards are usually unheated the door need to be sealed as well as external doors and windows.

8. Ensure light fittings are sealed.

Down lighters can be a major cause of air leakage. Seal holes around light fittings and pull cords in the ceiling, choose airtight fittings if possible, otherwise install air tight boxes over the fitting in the ceiling void”.

9. Seal around mechanical and electrical services

It is essential that water, drainage, gas pipes, boiler flues and electricity cables are fully sealed prior to the air tightness test. Historically we often find leakage in kitchens, bathrooms, and boiler cupboards due to leaky services.

10. Kitchens and Bathrooms the main air leakage culprits

The main areas of air leakage in most new dwellings are usually within kitchens and bathrooms. Kitchens should be finished, with all mechanical and electrical service penetrations completely sealed as well as sealing to the wall/floor junction – there is not usually skirting board installed behind kitchen units as they can’t be seen once the kitchen units are in place. All appliances should be installed and all service boxing such as SVP drops fully sealed at the wall/floor junction. All extractors are fully fitted.

Bathrooms should be carefully checked and sealed around all SVP and waste pipe work. All bathroom fittings should installed and fully complete. Bathrooms often suffer with excess air leakage due leaky bath panels and waste pipe work, also the wall/floor junction is usually unsealed. You should ensure air leakage paths are fully sealed before fitting bath panels, shower bases. All boxing to vanity unit and extractors should also be sealed. For more tips on air leakage paths, see our air tightness checklist

11. Apply all temporary seals before we get to site:

If you seal all the temporary seals before we get to site it can help to expedite the test, to allow for comprehensive smoke testing in the event of a test failure.

Official guidance has set firm guidelines around what can and can’t be temporarily sealed when it comes to air tightness testing. The main contractor has the responsibility to put temporary seals in place in line with the guidelines published by ATTMA. Temporary seals can be achieved simply by using low tack masking tape as not to damage the surrounding finishes.

The allowed temporary seals are:

• Chimney flues
• Mechanical ventilation systems such as kitchen and bathroom extractor fans
• Trickle vents
• Air conditioning grilles
• Passive ventilation such as air bricks, passive stacks and sub floor ventilation systems

12. Don’t undertake the Air Tightness Test too early

In our experience a large amount of air tightness tests failures are due to us being called in too early.

This can be a very costly mistake, which may result in re-tests, as well as the wasted man hours for the clients sealing teams as well as penalties imposed for delayed handovers. Our air tightness checklist helps our clients to check that their project is fully prepared to undertake the air tightness test.

Contact us now

If you would like more information on how to prepare your building to pass an air tightness test please visit our website at www.aptsoundtesting.co.uk or contact us at: info@aptsoundtesting.co.uk

Room Integrity Testing in London
There are literally tens of thousands of protected enclosures throughout London and the South East. With many of the banking and commercial institutions based in the capital the requirement to provide a safe environment of for critical equipment is greater than ever.

It is now a requirement of the BFPSA that all protected enclosures such as server rooms and/or data centres have valid enclosure certification – it is also a requirement of all major commercial institutions. The benefits of ensuring room integrity are widely recognised by insurers and regulatory authorities, who frequently require room integrity testing in London to prevent critical system failure on valuable assets such as server rooms and data centres.  It is also worth noting that you may negate your buildings insurance if you don’t have the valid certification.

Enclosures protected by gaseous fire suppression system -such as server rooms should be tested for air-tightness upon commissioning of the system and annually thereafter. This is critical to ensure that the system will work effectively when activated; too much air-leakage will result in the concentration of the fire suppressant agent falling too quickly resulting in rapid fire spread as shown in the image below.

For most extinguishing system types, a retention time of ten minutes is the minimum period the suppressant agents is required to be retained for within the enclosure. NFPA 2001, Standard on Clean Agent Fire Extinguishing Systems, requires that a minimum concentration of 85% of the adjusted minimum design concentration be held at the highest level of combustibles for a minimum period of 10 minutes. This is usually long enough to prevent re-ignition for most deep-seated fires and should provide adequate time for the emergency services to attend and prevent the fire taking hold.

Unfortunately, in the relevant ISO standard BS EN15004if you don’t have valid room integrity certification you may negate your buildings insurance in the event of a fire. In all instances the integrity certification should always be attached to the front of the protected enclosure/s to show it has valid certification and to clearly show the dates of the next test. The certification also has other useful information that should be adhered to at all times. If you don’t have integrity test certification fixed to the front of the enclosure, then the chances are that your enclosure may not have valid certification.

Within the In many cases the stakeholder may not be aware that any modifications have been undertaken to the room’s envelope as this may further reduce the integrity of the enclosure envelope.  That is why it’s always best to plan any works within protected enclosures so that everyone’s aware of the importance of maintaining the integrity of the enclosure envelope and the requirement for a fresh integrity test after any modifications have taken place.

Smoke Testing to Find Air Leakage Paths

APT’s highly trained and experienced Enclosure Testing Engineers will be able to locate the problem areas and identify where air is leaking out of the building by walking around the test enclosure with a localised smoke puffer – as shown in the image below)  checking the most common problem areas first.

By combining our door fan blower equipment and a small smoke puffer we can quickly locate any penetrations in in the enclosure envelope as the smoke is more visible. Smoke leaking from the enclosure can be easily seen and photographed to provide a record of any external leakage paths.
Pressurised smoke tests are ideal for identifying both generic and torturous areas of air leakage. Crucial remedial sealing work should then be undertaken to reduce the leakage from the enclosure. The sealing works may include:

•             Sealing all holes, cracks or penetrations

•             Pipe chases and cable trays to be sealed

•             Walls to be caulked around the inside perimeter

•             Sealing of porous block walls

•             Addition of drop seals, weather stripping around jambs

•             Sealing of windows/glazed sections to the area

One of the advantages of the sealing works being conducted whilst a test fan kit is in place, is that it can be seen if the works being conducted are effective via ongoing smoke testing and sealing works. Once the appropriate remedial work has been undertaken the enclosure should be retested to confirm the acceptable retention time as been achieved – usually 10 minutes.

Air Pressure Testing provides the necessary Room Integrity Testing & air tightness testing in London to the required NFPA 2001 or ISO 14520 methodologies. We have undertaken hundreds of enclosure integrity tests around the UK and Europe.

As part of our service, we can also arrange an annual test plan and remind you when the enclosure test/s are required to make sure your building’s insurance is not at risk. If you require room integrity testing in London, please call: 07775 623464 or visit the APT Sound Testing website today.

Room Integrity Testing Terminology

A gaseous fire suppression system is a highly effective method of protecting your server rooms etc. from fire. To ensure it works properly, it is important that room integrity testing is carried out when the system is first installed and thereafter at least once a year to ensure the protected area remains adequately sealed; unfortunately, this is often overlooked by the building management.

Room integrity testing checks whether the server room or enclosure – where the fire suppression system has been installed, is adequately sealed.

When undertaking the integrity testing of a new system the company tasked with undertaking the works requires quite a lot of information, which the client often struggles to answer. To try and help with this we have tried to explain the differences between a Descending Interface, Continual Mixing and Extended Discharge.

What is a Descending Interface?

The fire retardant agent is discharged from the ceiling –highest point) into the protected enclosure. An ‘interface’ with a constant concentration – known as the Initial Concentration) descends from the discharge level as gas leaves escapes from the enclosure via air leakage paths. The time it takes for this ‘interface’ to reach the minimum protected height such as the top of the server racks is defined as the Hold time. The time retention time for a Room Integrity Test Pass is usually set at 10 minutes.

What is Continual Mixing?

The suppressant Agent is discharged at near-ceiling level into the enclosure, thereafter fans circulate gas throughout the room, resulting in a uniform agent concentration. This concentration begins at initial concentration and lowers until it eventually reaches a specified minimum concentration. The time it takes for the initial concentration to reach the minimum concentration is defined as the hold time.

What is an Extended Discharge?

Typically extended discharges consist of an initial discharge for 10 to 60 seconds to get the concentration up to the design concentration. Then the extended discharge will continue at a lesser rate. The intention is for the extended discharge to replace the agent that leaks out of the room. It is assumed that the extended discharge will create enough turbulence to create a continual mixing situation throughout the extended discharge period.

We hope the above information has helped you.

If you would like some more information on our Room Integrity Testing services please call 01525 303905 or for more information please visit us at the APT Sound Testing website.

Acoustic Design and Sound Testing in London

We are currently experiencing a large rise in the amount of housing stock that’s requiring sound testing in London. As commercial buildings such as offices etc. are converted into residential dwellings sound testing then becomes are requirement under Part E of building regulations. We have carried out a large amount of sound testing in office conversions with varying success as office buildings are not usually designed with acoustics in-mind.

To reduce the chance of sound testing failure, it is imperative that flanking transmission is considered at the design stage and any construction detailing is specified to minimise any potential of noise flanking which will downgrade the acoustic performance. Good detailing at the design stage will minimise this effect and optimise the overall levels of acoustic privacy achieved. If designing for residential units, design advice on flanking details must be followed to maximise the possibility of achieving the specified acoustic performance. It is imperative that the design advice is followed, otherwise the site sound insulation values may not meet the performance criteria required and subsequent expensive remedial treatment may be required.

If the onsite construction has gaps, cracks or holes it will conduct airborne sounds and can significantly reduce the sound insulation of a construction. For optimum sound insulation a construction must be airtight. Most small gaps can be sealed at the finishing stage using Gyproc jointing compounds. Small gaps or air paths around perimeter Gypframe framework can be sealed with sealant. At the base of the partition, gaps will occur which can be filled with acoustic mastic.

The most common noise flanking pathways are as follows:

1. Dividing Ceiling Partitions – Above and Through the Ceiling Space (where an adequate acoustic break has not been carried on through the ceiling void)
2. Dividing Floor Partitions – Through Floor and Floor Joist Space (if insulation has not been installed or direct fixing to joists without a drop ceiling below the partition under test)
3. Shared Structural Building Components – Floor Boards, Floor Joists, Continuous Drywall Partitions, Continuous Concrete Floors, and Cement Block Walls.
4. Through Structural Steel (structural steel beams are often a major cause of noise transmission as plasterboard is often fixed directly to the steel without sound breaks)
5. Plumbing Chases – Junctures Between the Walls & Floor Slab Above or at the Exterior Wall Juncture (this should be filed with mortar etc. to add mass to this weakened area)
6. Through Windows (if they are no double glazed or have secondary glazing as a minimum)
7. Fixtures & Outlets – Light Switches, Telephone Outlets, and Recessed Lighting Fixtures (if penetrations have been cut back to back with the opposite dwelling under test)
8. Structural Joints – Perimeter Joints at Wall & Floor, Through Wall & Ceiling Junctures (these should be filled with acoustic mastic)
9. Around the End of the Partition Through the Adjacent Wall (acoustic mastic should be used to seal this junction)

When offices are converted into dwellings we often undertake sample sound tests to check the existing sound levels prior to the commencement of works, once we have established the sound test results we can then come up with a more cost effective design to comply with Part E of Building Regulations. 

Historically we have found that if the floor structure is a typical 200mm concrete slab the sample airborne results are coming close to the requirements of Part E without any modifications to the existing slab; however, the impact results are poor. This is because the airborne sound is broken down by the mass of the concrete slab, therefore sounds such as speech & TV etc. are minimised. Unfortunately, impact sound results are poor due to the lack of isolation within the slab, therefore the sound travels straight through the slab to the area below. Sound such as people walking can be very loud and unacceptable.

To help reduce potential control noise issues APT Sound Testing can undertake an acoustic  design review of the floors after sample sound testing to ensure both the airborne and impact sound tests pass Part E of Building Regulations. Using our extensive knowledge regarding the way different materials and construction methods can influence the results of sound testing we can offer easy to follow acoustic advice on the most awkward developments.

We can advise on all types of Acoustic Design and Sound Testing in London, whether it’s accomplished during initial construction or during a refurbishment/renovation project. We also undertake UKAS accredited sound testing providing a ‘one stop’ solution for all your acoustic requirements. If you would like more information in regards to sound testing please follow our blog at: http://soundtestinguk.blogspot.co.uk or visit our website at: www.aptsoundtesting.co.uk