- Part L Compliance
- Building Physics Modelling
- Thermal Comfort Assessment
- Façade Optimisations
- Passivhaus Consultancy
When testing the performance of the NAT Vent Attenuator at Winford Primary School, we performed a noise break in assessment whilst opening a window. The video above illustrates the sound level difference has a steep decay from a small opening.
London and West London Academies, two large £30M+ Academy are both designed around a natural ventilation, incorporating cross ventilation. Both schools were required to meet BB93 and BB101 ‘Ventilation of School Buildings’. MACH Acoustics worked with Fosters and Partners to develop a practical solution. Our findings were that the cost of conventional attenuators along with their size and short falls in performance prohibited the use of these devices but allowed for the NVA.
With the window facade bulkhead, we were able to implement cost savings by negating the need for expensive weather louvres, using actuated windows instead. Not only was the cost significantly reduced but the installation was greatly simplified – both points highly valued by the contractor.
Environmental noise break-in can be a significant issue when naturally ventilating a building located on a noise site, even if the noise is only moderate. Dartington school, previously reviewed within this blog with regard to the creative room acoustic treatment, also required creative forms of noise control measures to prevent noise break-in to noise sensitive teaching spaces.
The first stage of any noise break-in assessment is to establish noise levels across the site. This was done by carrying out noise monitoring throughout the site, over the full operational hours of the school. During the noise survey addition data was collect with respect to traffic flow levels and other data need to build a noise map of the site. A noise map was used such to assess the effects of the new school and to establish noise levels across all facades.
The result of the original noise mapping exercise is shown above in the left hand image. The results of this assessment indicated that noise levels at the facades to the classroom block where higher than desirable. The solution was to use an acoustic screen and strategically placed earth bund to reduce noise levels at the classroom. The tire wall is shown on the front cover of “BD Reviews” was used to form the required acoustics screen. This design is highly sustainable since these used tires did not go to land fill. Aesthetically there is a strong recycled image and additionally over time the vegetation shown in the image will cover the wall to form a green, live acoustics screen.
A second observation from the above noise mapping exercise was that noise levels at the sports hall were too high to allow for natural ventilation by means of simple openable vents. The solution was to added attenuated vents using the NAT Vent Attenuator. The photo below shows this vent and the diagram provides 3D view through the vent box.
|The BaleHaus @ Bath University|
As a supporter of low-energy, sustainable design, this project was of great interest to MACH Acoustics. We were thrilled when be asked to be involved in the ongoing research into the properties of this ‘carbon-negative’ construction material.
|Testing in progress|
The aim of MACH Acoustics is to become one of the leading acoustic consultants in the field of sustainable building design. This aim means that we specifically focus on projects around sustainable architecture and Eco buildings. A considerable portion of our time is therefore spent looking to solve some of the conflicts between acoustics and low carbon, sustainable constructions.
Acoustics and sustainability are not often spoken about together. On the other hand, air conditioning systems are often used to overcome noise ingress issues. Thermal mass cooling; exposed concrete soffits for example, can make buildings sound loud, harsh and noisy. Cross ventilation, exhaust stacks and other air ventilation systems can compromise the acoustic cross talk between office buildings accommodation and teaching spaces within educational buildings. Vented facades in combination with ventilation louvers and other types of air ventilation systems within the fenestrations of a building are often used to prevent noise ingress. Buildings are often built using high mass structures to achieve acoustic requirements.
These factors clearly show the link between acoustics and sustainability. Acoustics can therefore have a significant impact upon the levels of carbon emissions, ventilation system and the level of embodied energy in the buildings frame and other factors affecting the sustainable architecture of a given building. With changes to Building Control Documents Part L and Part E, along with new client expectations, there is an increasing importance to ensure that building designs become more integrated and greener.
MACH Acoustics view is that the best way to overcome the limitations imposed by acoustics on sustainable buildings is to increase our knowledge base. This simple goal is therefore the aim of this blog. We aim to provide a point of reference where detailed information will be regularly uploaded relating to residential buildings and the code for sustainable homes. We will be looking at Eco buildings and acoustic materials which match requirements for sustainable building design. Ventilation systems including vented facades, acoustic ventilation louvers, attenuators within facades, passive house systems, heat recovery systems, exhaust stacks and other air ventilation system will be discussed over time.