Webinar on Acoustics and Natural/Hybrid Ventilation in Non-Domestic Buildings: 8 May 2018
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Naturally ventilated buildings use openings located in their facades to simultaneously supply fresh air and extract stale air. However, these openings also allow the ingress of environmental sounds, which when they are unwanted, unpleasant, loud, or disruptive are defined as noise. The very size of natural ventilation openings means that noise ingress can be significant, and an unintended consequence may be that occupants seek to control it by closing ventilation openings, which in turn can lead to under-ventilation, poor air quality, and overheating. However, there are solutions, achieved by carefully balancing all competing factors, by using good models, through intelligent product selection, and by the application of clear and intuitive guidance.
Non-domestic buildings are generally bigger and more complicated than houses. They have a greater number of systems and services, which themselves might be a source of noise, and they have greater geometrical variability that affects the transmission of environmental noise into a building. Here, it is important to assess the potential for noise transmission using surveys on existing buildings or by modelling future buildings. Then, appropriate sound insulation can be identified and installed.
To support engineers there is a lot of good guidance available, such as HTM 08-01 for healthcare buildings or BB93 for schools. BB93 gives different criteria for each type of ventilation system and provides typical solutions. However, this important information isn’t always properly understood and hence used appropriately to support ventilation design.
Acoustic problems are a significant source of commercial risk and so a working knowledge of appropriate guidance, assessment techniques, and modelling methods is required to solve Engineering problems. These topics provide the context for the CIBSE Natural Ventilation Group’s second webinar discussion on the interdependency of acoustics and the natural/hybrid ventilation in non-domestic buildings on Tuesday 8th May 2018 between 1300-1400hrs.
The Panel
Ze Nunes (MACH Acoustics)
Ze Nunes is director and founder of MACH Acoustics. He believes in lifelong education, and so when he’s not on site, reviewing designs or grinding out paperwork, he lectures at the University of Bath, delivers CPD events, and writes papers. Ze spearheads MACH Acoustics’ investment in R&D, a philosophy that had led to the invention of the NAT Vent Attenuator and funding from Innovate UK to research noise in natural ventilation. Ze relishes the interdisciplinary challenges of great architecture, and is always ready to break with convention in the quest for better answers.
Owen Connick (Breathing Buildings)
Owen Connick is Consulting Manager at Breathing Buildings, where he heads up the design and consultancy teams. After a first degree in Aerospace Engineering at Imperial College London, Owen stayed in academia and completed his PhD on the fluid mechanics of hybrid natural ventilation. Owen’s experience and expertise include the use of simple analytical models, and the use of water bath modelling to simulate buoyancy - driven flows in a laboratory environment. Since joining Breathing Buildings, Owen has developed significant expertise in the application of Dynamic Thermal Modelling to simulate thermal comfort and air quality in real buildings, with a particular focus on schools and UK design regulations. Owen has presented at numerous CIBSE/ASHRAE seminars, and is keen on many aspects of sustainability in the built environment.
Webinar on Acoustics and Natural/Hybrid Ventilation in Residential Buildings: 25 April 2018
Download Slides (PDF)
Naturally ventilated buildings use openings located in their facades to simultaneously supply fresh air and extract stale air. However, these openings also allow the ingress of environmental sounds, which when they are unwanted, unpleasant, loud, or disruptive are defined as noise. The very size of natural ventilation openings means that noise ingress can be significant, and an unintended consequence may be that occupants seek to control it by closing ventilation openings, which in turn can lead to under-ventilation, poor air quality, and overheating. However, there are solutions, achieved by carefully balancing all competing factors, by using good models, through intelligent product selection, and by the application of clear and intuitive guidance.
Noise is often given consideration in the planning process if a local planning authority identifies any significant noise sources affecting a proposed residential development. Although assessments generally refer to BS 8233, which indicates noise levels based on WHO Community Noise Guidelines that avoid adverse effects of noise on people, there is no explicit guidance on how to consider the effect of ventilation provisions. The Professional Practice Guidance on Planning and Noise (ProPG) was released last year; this describes good acoustic design within the context of Government planning and noise policy. The ProPG indicates that if the façade sound insulation design relies on closed windows to meet suitable internal noise levels, then there should be consideration of the acoustic impact of the ventilation strategy and provisions for mitigating overheating – typically, opening windows. To provide guidance on how to undertake this assessment, the Association of Noise Consultants (ANC) has published for consultation its Acoustics Ventilation and Overheating: Residential Design Guide. The challenges for Engineers to resolve between the acoustic, ventilation and overheating strategies are significant.
The Panel
Jack Harvie Clark (Apex)
Jack Harvie-Clark is the founder of Apex Acoustics, the current Chair of the Association of Noise Consultants (ANC) and a Board member of the Air Tightness Testing & Measurement Association (ATTMA). Apex has grown to 15 members and provides consultancy and testing in acoustics & air tightness across the construction industry. Jack has a strong interest in the interdependence of acoustics, ventilation & thermal comfort, and instigated the production of the current Guide by the ANC.
Jack studied Engineering at Cambridge University, specialising in thermodynamics and fluid mechanics; he worked on steam turbine blade development for Rolls Royce, undertook research into a novel thermal composite at Newcastle University and helped establish a renewable energy visitor centre before finding acoustics.
Anthony Chilton (Max Fordham)
Anthony Chilton is the head of acoustics at Max Fordham LLP, having been at the company for 14 years. He is also the chair of the Association of Noise Consultants’ Acoustics, Ventilation and Overheating working group. Anthony has had a long standing interest in acoustic design for sustainable buildings, and is the author of scientific papers on the Conflicts between Acoustics and Sustainability in Schools (Institute of Acoustics Conference, 2007), Natural ventilation and acoustic comfort (Acoustics 2012, in Nantes), and Acoustic design for sustainable open-plan offices (IOA Acoustic Design for Sustainable Building conference in 2015, where he was also the Chair).