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Better building acoustics – some sound advice

Pointing out that while building codes in most other countries follow minimum acceptable standards and regulations to deal with acoustical issues, there is a lacuna in this area in the Middle East, Gerald Stewart advocates having a set of region-specific and enforceable codes to help curb noise in apartments.

| | Oct 16, 2013 | 10:03 am
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“Hello, this is Gerald”

“Ah, yes, good morning, Gerald. I have a problem. I’ve moved from a wonderful, quiet and secluded three-bedroom house in the suburbs where the sound of birds was about the only thing that I could hear early in the morning, to an apartment in the city where I can’t sleep because every time my neighbours turn on the shower, I hear the water noise squeal through my apartment. And the noise from the dump trucks picking up waste next door wakes me at five in the morning, and every time my neighbour upstairs uses the laundry, I can hear the thumping noise on the ceiling. And then when he walks on his floor all I hear is footsteps…. What can I do?”

When these types of phone calls come to my desk, I reflect on the words of George Carlin:

“The paradox of our time in history is that we have taller buildings, but shorter tempers; wider freeways, but narrower viewpoints. We spend more, but have less; we buy more, but enjoy less. We have bigger houses and smaller families; more conveniences, but less time. We have more experts, yet more problems; more medicine, but less wellness. We have multiplied our possessions, but reduced our values. We’ve learned how to make a living, but not a life. We’ve done larger things, but not better things….”

And so it goes that as the “advantages” of leaving the suburbs for the city life is now an only option for many people trying to get ahead, one of the major issues that are seldom thought about is that of noise. In fact, it’s not until you have moved into your wonderful three-bedroom beach view, million-dirham apartment and your neighbours get home from work that you realise there is a problem.

In my time as an acoustic engineer, I have had only one call from a client who wanted the private residential building he was considering purchasing checked out for acoustics prior to signing the purchase agreement. This doesn’t surprise me, in that most people would assume that our building codes and regulations are being enforced at some stage throughout the design or construction process. The sad fact is that this rarely happens, and it is typically left to the owner to rectify any issues that arise after the builder/developer and the architect have long gone.

The Middle East acoustic fraternity has been concerned for some time that there are minimal building regulations or standards that encompass all aspects of the acoustical qualities of apartments, townhouses and other multi-tenancy dwellings. The result has been that owners of luxury apartments built in the UAE have become dissatisfied with the acoustic performance, which in their view, is not commensurate with the price they have paid.

Building codes in most other countries, for example, regulate minimum acceptable construction standards for buildings and also deal with other acoustical issues, such as noise intrusion from outside or noise generated by building services even down to things like setting allowable times for mowing lawns.

Building designs would normally include an acoustic consultant’s report, and this report would be included into the architect’s design and the acoustic consultant is commissioned to continue during the construction to certify the building has met the codes. The fact that the codes are not changing as fast as the high-power ratings of the average home stereo is one of the main causes of many problems, but the bigger problem is that of perception of sound.

If I made a comment that one sound is 5dB less than another, many would have no idea how much difference that is, and a lot would think that it is not much. But if I said in the same sentence that to get one room 5dB less noisy than another, it would cost nearly twice as much to build, you would start to take a bit more notice of the actual amount of noise that is around.

City living, by its very nature can be as much as 20dB louder than its suburban counterparts. An example is my home in Australia is 45dB quieter than my Apartment in JBR Sadaf 7. But does this necessarily mean that the noise level in a bedroom in an apartment say on level 15 of a beach tower should be 20dB louder than a bedroom in The Springs? No, according to the average of the rest of the world standards, it should not be, and because of those guidelines it should achieve the “required ratings” as set by the relevant codes, or in some cases, the additional “value added” requirements as set by the designers or developers if they are setting a standard of higher than normal quality.

The fact is that most suburbs are inherently quieter, and hence the noise levels that are inside houses in these areas are much quieter is a factor to take into consideration. But I challenge that even the most astute acoustic design in the noisiest part of town won’t cost a small fortune to implement if it is done correctly.

I remember moving from my house in Melbourne a few years ago to an apartment in JBR. The first year, the construction noise in the middle of the night was awful and, then, there was the 2 to 4am “The Walk” car show horn blowing and the fireworks in the wee small hours and the neighbours in the units next door banging about at their leisure. I can hear people say, “You chose to live there.” And with this I absolutely agree. But if I responded with, “I also lived in New York for a time in a second floor apartment on East 27th Street and it was 25dB quieter than my 15th floor apartment in Dubai, then it may help to show that while the UAE is growing very quickly, it is also a little alarming at how noisy it has become in reference to other very busy cities in the world.

This same reason, I am sure, will apply to many people who either have had family and now want to move to the city to get the views or take the traffic jams out of the way of their day-to-day life experience, or those that simply need to get into the housing market by buying “off the plan”. And there are, of course, those who want to be involved in a community lifestyle that only apartment living can deliver, and want to share in the spirit of the dream, albeit 2013-style, with inner city living. But this lifestyle is going to become the way of life for many more people in the future.

I discovered early that the more I stressed about the noise, the worse the noise got, and hence conformed to my knowledge of psycho-acoustics. So I decided that it would be best to just relax and view the experience from the framework of “I don’t have to tackle traffic jams in the morning; I don’t have to worry about getting in my car to go to the shops or out for coffee or dinner as the local area has a fantastic lifestyle.” So, all of these things combined gave me a reason to be there that outweighs the desire to have a perfectly quiet sleep, and besides, ear plugs work a treat.

So, back to our friend who can hear everything that goes on in the apartments around him, and to the challenge of what can acoustics do to help. And here it must be noted that the current UAE regulations, in so far as acoustics is concerned, have the lowest level of wall isolation in any of the developed countries, meaning that dividing walls between apartments are only generally built by conscientious architects to a mixture of Australian, UK and American standards, but are not mandatory. Basically, the standard that is offered up is that to which the acoustics consultant on the project is used to specifying, but what gets built is based on cost and speed alone. These International standards don’t relate specifically to the UAE, and this is where more work should be done and promoted strongly, and they at minimum, should be administered on site and confirmed.

What can be done to alleviate the problems? There isn’t going to be a code that says the street must not be used by traffic between the hours of x and y. There isn’t a code that says your neighbour must be in bed and fast asleep by 10pm, and there are certainly no current codes that mention anything about sound transmission isolation. Although there are Federal guides and decrees to the amount of noise that can be made at certain times, having these codes enforced is something that just isn’t done.

So, I suggest that having codes that are specific and enforceable may help to curb the way for the protection of the future generation of Emiratis, and this can only be a good thing.

A Middle East Acoustic Standard should be developed that adopts one or more of the options outlined below. But before these are implemented, a series of numbers in a rating system needs to be identified that is Middle East specific. The rating system must include all factors on the built form and be focused on the amenity of people above all else. The rating system could have factors of other countries embedded into it, but it must be unique and regulated and consider adequately the local provisions and the local environment. This is to say that it is pointless to impose a background noise level, for example, next to Sheikh Zayed Road that implores a 45dB Leq 18/hr external noise level. It is not achievable now or forever more, as the built environment in the UAE is well past that point of no return.

As a basis for the design process, the following simple methods for achieving construction approval could be implemented and administered:

Prescriptive Approach — Deemed-to-Satisfy Systems

This option uses only systems which comply with Deemed-to-Satisfy Provisions. These building elements would be constructed and installed as outlined in the regulations.

The construction of the building elements should be inspected and evidence documented that the building elements are in accordance with the provisions of the regulations. The evidence can be in the form of a summary of building materials used on site, regular memorandum of inspections, overall list of defects, construction photographs of key elements and a summary of the rectification measures undertaken on the project.

Acoustic certification for occupancy is issued when all defects have been rectified to the satisfaction of the acoustical consultant.


Prescriptive Approach —Laboratory-Tested Systems

This option uses only systems which have been verified by testing in an approved testing laboratory. These building elements would be constructed and installed as those systems tested in the laboratory. The

construction of these building elements would be inspected and evidence documented that the building elements are in accordance with the tested systems. The evidence can be in the form of a summary of building materials used on site, regular memorandum of inspections, overall list of defects, construction photographs of key elements and a summary of the rectification measures undertaken on the project.

Performance Approach — Verification Methods — Field Testing

For this option, it is expected that only systems that are likely to comply when tested on site would be used.

The building elements would be constructed as recommended, including any additional detailing to limit flanking noise. Inspections would be conducted, defects rectified and documentation produced, which demonstrates compliance with the construction requirements. Testing is then conducted on a suitable number of building elements. Typically, at least 10% of all wall systems should be tested. For some complicated sites, this may be 40 to 50%. The documentation can be in the form of a summary of building materials used on site, regular memorandum of inspections, overall list of defects, construction photographs of key elements, a summary of the rectification measures undertaken on the project and a copy of the results of acoustical testing.

Performance Approach — Checking for Compliance — Expert Judgement

This option uses only systems, which in the opinion of an expert acoustical consultant, would meet the required performance scheduled in typical standards. The ability of a consultant to make an expert judgement needs to be documented as does the basis of their opinion.

Typically, testing would need to have been conducted on the proposed system. The consultant would, then, need to form an opinion that the proposed system complies with the provisions of the regulations.

The building elements would be constructed as required. Inspections would be conducted, defects rectified and documentation produced, which demonstrates compliance with the construction requirements.

Performance Approach — Comparison with Deemed-to-Satisfy Systems

This option uses only systems which, in the opinion of an expert, would match the performance of deemed-to-satisfy systems.

The ability of an expert to make an expert judgement needs to be documented as does the basis of his/her opinion. Typically, testing would need to have been conducted on a proposed system, and an expert would have formed an opinion that the proposed system is no worse than a deemed-to-satisfy system based on these test results.

The building elements would be constructed as required, inspections would be conducted, defects rectified and documentation produced, which demonstrates compliance with the construction requirements.

The intent of this approach is to consider treatments for services noise insulation and for impact rating of walls. An example is to measure the noise intrusion level from waste pipes adjoining the room and comparing these levels with the equivalent level from a deemed-to-satisfy system. The impact rating of walls is a more difficult undertaking, as no test method is universally acceptable to all interested persons.

What if there is a problem in the building you are living in now?

In the most part, we are able to provide solutions to everything, but these solutions are sometimes expensive to install “post-completion”.

We have found in most cases that buildings don’t have a satisfactory level of isolation between floors. This is not the error of the design or builder, but the lack of enforceable relevant codes (repeating that the current federal standards in the Middle East don’t have any codes to protect impact noise from transmitting between floors). Often, apartments are stacked, and the worst- case scenario is where a tiled floor is located above a bedroom – that is, a bathroom or laundry above a bedroom, which, of course, leads to complaints. It is this very problem that is prevalent in practically 95% of the apartment buildings in the UAE.

Walls that are built to provide “only just” the level of transmission loss required (normally for reasons of cost) will typically fail “in the field”, as the ratings that are measured in a controlled laboratory environment are usually 3-5 rating points higher, but the construction leaves gaps and holes. The result is possibly 10-15 rating points lower than tested. These factors all add up to a very insecure place for a developer or architect to be in and, hence, the reliance on acoustic consultants has grown stronger, especially with regards to residential apartments in city areas.

The next issue is that most of the noises that affect one person may not affect another, and we, therefore, have a different perception level and, hence, the acoustics of a space become “subjective”, which in effect, is exactly what it is. The mere mention of running finger nails across a blackboard will send a shiver through many people, but not even raise a twinge in others, or the scraping of a shovel on concrete will have some looking for ear plugs, but others trying to compose musical shows for Broadway.

This “subjectiveness” is where developers, architects and authorities become perplexed, as they do not have the “historical and relevant judgement” to be able to quantitatively state that a certain construction is satisfactory or not. This is, therefore, where people like acoustics consultants and other professional engineers have come to play an important part in the development of many of the codes and regulations in place in our world today. These by standards committee process are used so that this “often subjective” quantitative element can be removed from the design, and, instead, replaced with “definitive” design goals and testing methods to allow for a detailed method of quality assurance to precede the building industry.

This must, however, lead from the purchaser as the more acoustic consultants are involved in the rectification of problems with buildings, the more we tend to report these sub-standard building methods back to our relevant societies so that those methods can, then, be assessed and standards raised for the next one, and so on. With this raising of standards, the cost associated with building better, quieter buildings will also rise, but until which point? Obviously, no one wants to hear their neighbour do the washing the same as we don’t want to design walls that are a metre thick. But there must be some ground covered by consultants, architects and developers alike that show responsibility to the purchaser in the way of “reasonable amenity”. And we should all strive to define that “reasonable amenity” and a method of construction to achieve it.

The writer is the Victorian Acoustics Section Manager of Wood and Grieve Engineers. He is a member of the Middle East Acoustic Society (MEAS). He can be contacted at gerald.stewart@wge.com.au

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One comment on “Better building acoustics – some sound advice”

  1. Gerald Stewart says:

    Hi just a note to let you know that i no longer have the email address as noted above. it is now Gerald.Stewart@inhabitgroup.com

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