The following solutions set out construction and operational phase opportunities and best practice. Most solutions are easiest to implement and most effective when incorporated at the design stage. Minimising sound from the design concept stage incurs fewer costs and ensures a healthier environment for building occupants and the local environment.
Environmental Health Officers within the district/borough councils of Hertfordshire are responsible for environmental health matters.
Wherever practicable, noise-sensitive developments are distanced from major sources of noise (such as road, rail and air transport and industrial development).
Designing in effective noise attenuation requires a thorough understanding and active management of incoming and outgoing noises.
The first steps are to:
- Identify the main sources and receptors of noise.
- Identify the nearest noise sensitive premises.
Design and layout proposals should take into account:
- Separation of noise sources from quiet areas by the greatest distance possible
- Positioning of buildings or rooms which are less sensitive to noise to act as screens or baffles between noise sources and quiet areas; e.g. a hallway or bathroom between a common stairway and a bedroom
- Consideration of the noise insulation properties of all building components. Sound resistant flooring and walling systems are readily available, while thicker, heavier doors and double glazed windows provide greater noise insulation
- Use of higher density materials, which typically provide a higher level of sound insulation than soft materials
- Positioning of building services – i.e. away from sensitive properties or opening windows
- Isolation of structural materials that could transmit noise between the source and sensitive receiver (e.g. by using discontinuous construction)
- Specification of low decibel (dB) motors and engines or adequate noise attenuation should be considered with technologies such as Combined Heat and Power (CHP) and source heat pumps
- Cumulative effects may need to be considered where multiple units are installed for example individual air source heat pumps to flats in a common area
Residential buildings (including hotel rooms and halls of residence) and schools are particularly sensitive to noise. The details of the acoustic requirements for such developments are clearly set out in Building Regulations Part E and are not repeated here.
The Robust Details Ltd (RDL) scheme provides an alternative to complying with Building Regulations Part E Requirement E1. The scheme avoids the requirement for pre-completion sound testing in new build attached houses and flats.
The RDL handbook - Robust Details Part E Resistance to the Passage of Sound, describes the separating walls and floors which may be adopted. All plots using Part E Robust Details must be registered with the RDL to obtain unique reference numbers and construction must follow the exact specifications of the relevant parts of the Robust Details Part E Handbook.
Further information on the scheme and the separating wall and floor constructions currently available can be found at: robustdetails.com.
University halls, hotels and hostels all have to comply with the Building Regulations Part E requirement, but are not eligible to use the Robust Details Scheme.
Construction noise is strongly regulated by legislation as noise from construction site operations can have negative health and productivity impacts for both site workers and occupants of neighbouring buildings.
Considerate Constructors Scheme
In addition to adhering to legislative requirements, contractors can sign up to the best practice Considerate Constructors Scheme (CCS) code of good practice. Many construction companies and clients register all their sites with the CCS.
The Scheme covers all aspects of site management, of which noise is one. Registered sites are randomly audited by CCS monitors. In addition, all registered sites display posters that set out the code to which the constructors are committed.
If passers-by wish to comment, the name and telephone number of the Site Manager is clearly displayed, together with the free phone telephone number of the scheme administration office.
Complaints received by the CCS are recorded. Information requested covers the name and contact details of the complainant and the nature of the complaint together with the site concerned.
The site manager is informed by a CCS representative of the nature of the complaint and is expected to deal with the concerns of the complainant within two days. In the event of the complaint not being adequately dealt with, CCS pushes the complaint higher up the contractor hierarchy, and ultimately raises it at company director level, to ensure it is appropriately dealt with.
In the case of the company failing to deal with the problem in an effective manner or for any other reason breaching the Code of Considerate Practice, the CCS General Manager will provide a report of the incident(s) to the Chairman of the Steering Group, for his decision to determine whether or not the site should be removed from the Considerate Constructor Scheme.
Best practice noise management techniques which facilitate a reduction or avoidance of noise, or lessen its cumulative effects include:
- Avoid site drilling wherever possible. For example specification of cast-in anchors instead of the drill-and-fix type
- Keep site grinding, cutting and similar activities to a minimum, using alternatives where possible
- Detail mesh enforcement to suit bay sizes rather than cut to suit on site
- Specify non-standard concrete blocks, so they are cut off site under controlled conditions
- Avoid vibro-compaction of ground as much as possible
- Specify the position of construction joints so to limit the size of concrete pours to what can be achieved in two hours
- Design for and specify the quieter methods of driving piles.
Use of off-site manufactured components
In addition to working legislative requirements, and best practice site management principles, another significant way in which noise can be reduced on site is to use off-site manufactured components.
Off-site manufacturing of elements such as walls and floors is rapidly gaining favour for a number of reasons, including:
- Rreduced site generated waste.
- Reduced on site labour requirement.
- Reduced construction programme.
Reducing on site labour and the construction programme has the added benefit of displacing construction generated noise to more controlled and specifically designed premises, i.e. manufacturing facilities, factories.
Building services represent a significant source of noise and provide pathways for sound transmission. Noise should be a core consideration when locating and specifying services.
Noise considerations when designing and fitting building services include:
- Design ventilation ducts such that air velocities are below the thresholds that would cause regenerative noise in internal areas
- Select fans for optimum efficiency. When fan noise levels are above the room design noise level, attenuators should be added to the inlets and diffusers. This also applies to air source heat pumps
- Select variable speed drives for larger fans. Speeds can be reduced at commissioning stage if over sized
- Size fans and ducts for a low overall system pressure drop
- Include silencers or acoustic louvers as necessary to reduce noise emissions on external exhausts subject to plant performance impacts
- Use antivibration mounts on larger plant to avoid vibration transfer through the structure
- For systems such as CHP specify motors with noise levels below acceptable thresholds
- Be aware of pipework installations which transfer pumping noises
- Easy access to plant and equipment to allow required maintenance should be included in outline designs
Regular maintenance of plant and equipment can reduce vibration and noise and optimise energy efficiency.
An effective way to manage noise from building services is to locate the services outside the building. The Lloyds Building in London is an example of this; building services are located outside, enhancing available interior space as well as addressing internal noise issues. It is important to consider how this might impact efficiency and ensure pipework is insulated to reduce heat loss.
However, as external building plant (e.g. chillers, ventilation etc.) can be a major source of complaint, its location should ensure it does not adversely impact on surrounding buildings.