1.0 THE ASSOCIATION OF NOISE CONSULTANTS

The ANC was established in 1973 to represent the interests of noise consultants in the UK. Membership is on a company basis and since then it has grown to over one hundred member companies, including several international members and representing over seven hundred consultants.

Membership of the Association is open to all consultancy practices able to demonstrate the necessary professional and technical competence is available, that a satisfactory standard of continuity of service and staff is maintained and that there is no significant interest in acoustical products.

Members are required to carry a minimum level of professional indemnity insurance and to abide by the Association’s Code of Ethics. Members are consulted on impending and draft legislation, standards, guidelines and Codes of Practice before they come into force and have representation on many committees drafting these standards.

Membership of the Association is open only to those companies who can demonstrate they have the technical expertise to provide advice to clients, not merely testing services and companies which simply wish to undertake sound insulation testing would be unlikely to obtain membership. In this way the Association is able to ensure that expert advice is available to clients in the event of failure of a party wall or floor element.

Pre-completion Testing

The ANC Registration Scheme for pre-completion testing under Approved Document E: 2003, was established in response to this by members of the Association who were concerned at the cost and complexity of registration under UKAS, the only form of accreditation previously available.

Other areas of acoustic consultancy

Noise consultants provide advice on all aspects of noise and vibration. These include the design of sound insulation into, out of and between buildings, ensuring noisy plant doesn't annoy the neighbours and the noise and vibration impact of demolition and construction.
They work with planners to satisfy regulations relating to noise from roads, railways and airports, with architects to make theatres and concert halls sound good, undertake assessments of the noise impact of industrial installations including windfarms, petrochemical facilities and power stations.
They are involved with leisure noise including motorsport, pop concerts and even the noise from skateparks. This list is endless.

2.0 SOUND TESTING IN RESIDENTIAL BUILDINGS

A Brief History of Building Regulations

Building regulations have a long history, but the requirement for good sound insulation of walls and floors has a longer history than might be imagined. The earliest references are from ancient Babylon which are related to the structural stability of houses. The Babylonian ‘Law of Hammurabi’ is typically draconian:-

‘If a builder builds a house for someone, and does not construct it properly, and the house which he built falls in and kills its owner, then that builder shall be put to death. If it kills the son of the owner, then the son of that builder shall be put to death. ‘

After the Great Fire of London a Royal proclamation was issued and subsequently the ‘Fire prevention (Metropolis) Act of 1774 required buildings to have stone external and party walls. Again, whilst this is largely structurally related, they had an impact on the levels of sound insulation between properties.

In 1836 Professor Michael Faraday, who must have been a very busy man, turned his attention to the construction of prison walls. One must suspect, however, that this
interest was not so much about sound insulation as preventing escape! There are other historical references to ‘pugging’ in residential floors between working class houses in 1844, but specific consideration to defining actual levels of performance did not really happen until during and after the second world war.

In 1942 the ‘Committee on Sound Insulation and Acoustics in Buildings’ recommended a standard for party walls of 55dB and stated that a normal 9 inch brick wall provided about 50dB using the same metric. In modern parlance a 9 inch brick wall gives about 53dB:DnT,w.

In 1960 extensive measurements were carried out by the Building Research Station over 460 sites with many different types of constructions being tested. The Research Paper 33 – Field measurement of sound insulation between dwellings’ gave extensive test results.
These are still used today by acoustic consultants to establish the actual performance of some of the esoteric constructions which occur in building redevelopments where parts of the original construction from the first half of the 20th century are retained.

As a result of these extensive tests, ‘deemed to satisfy’ constructions were included in national regulation in 1965. Performance standards were first introduced as ‘Grading Curves’ Grade I and Grade II for residential accommodation in the Code of Basic data for the Design of Buildings: Chapter 3: Part 2: 1972 Sound Insulation and Noise Reduction. Based on social surveys and the measurements, Grade I was a level of sound insulation acceptable to the majority of neighbours for flats and houses and represented party walls with the performance of a 225mm brick wall. In the 1976, Part G of the Building Regulations contained actual performance requirements against different frequency bands.

Approved Document E [ADE] was first published in 1985 and contained performance standards and ‘deemed to satisfy constructions’ only for newly built properties. As a result of many complaints from the owners of houses converted into flats using the original Victorian timber floors as party floors during the 1980s, the next revision of ADE: 1992 contained performance standards and ‘deemed to satisfy constructions’ for converted properties, which was a major step forward for those living in flats. All of these revisions did not, however, have a requirement for pre-completion testing and relied on the inspections by Building Control to police the regulations.

The Need for Sound Testing in Residential Buildings

The previous versions of ADE were not in fact rigorously enforced by Building Control and as a result many properties with poor sound insulation were probably constructed. The lightweight floors (Type 3) and lightweight walls (Type 4), required careful construction and detailing to achieve the desired performance. But problems with even masonry walls
were quite common.

As consultants, only sites where there was perceived to be substantial problems were brought to our attention following complaints by residents. Some examples of bad
building are shown below.