The importance of MVHR in building design
Ventilation is an essential part of modern properties, yet on many occasions this vital component isn’t considered until late in the construction process. Lee Caulfield looks at the importance of MVHR systems being considered as early as possible during a building’s design.
Over the years, the UK housing sector has experienced many changes and advancements, particularly in the design of properties and the products used within them. Boilers are more efficient, windows have reduced U-values and loft insulation is getting thicker and more effective. Another product that has evolved is mechanical ventilation with heat recovery (MVHR). However, while the virtues of MVHR are recognised, there is still one obstacle to overcome: integrating ventilation system design at the very beginning of a project.
Ventilation is one of the biggest and most important parts of a building’s design, layout and integration of services, yet it is often neglected or overlooked. This is certainly not ideal – ventilation systems should be a key part of the design process, rather than an afterthought, with manufacturers consulted from a project’s inception. For instance, aesthetics and ceiling heights are often considered during the early stages, yet we have experienced scenarios where MVHR has been overlooked until construction is already well underway! Ventilation really does need to be considered from the outset; i.e. by designing the ceiling voids in preparation for MVHR, it will be easier and more efficient to install duct runs at a later date, rather than add them to a property’s structure and design retrospectively.
|Today's MVHR products can have a big impact on better IAQ for occupants|
Including MVHR systems at the design stage also ensures a building has the quietest and most efficient means of ventilation possible. Any potential issues can be identified and solved, avoiding costly and awkward alterations later on. Whether it is minimising noise, positioning ducting or calculating airflow rates, utilising the manufacturer’s knowledge and expertise as early in a project as possible can only be beneficial in the long-term. Again, liaising with the manufacturer will help identify the best product(s) for the application in hand, as well as flag any potential pitfalls before they become problematic.
As a ventilation manufacturer and designer of MVHR systems, once a project starts on site, we rely on M&E contractors to supply as many details as possible, as they are the ones overseeing all the different components and products used in a building’s construction. The main issues for manufacturers include making sure they are kept up to date with any changes that could potentially impact the ventilation system design and performance. It is also important they gain regular project update information noting any changes to the structural layouts, as well as details about lighting and electrics, so that MVHR can be successfully ‘designed in’ to a dwelling’s infrastructure.
If ventilation manufacturers are supplied with up to date floorplans and schematics, there is no need to undertake a site visit (unless the project happens to be a complex refurbishment or there are complications to overcome).
Plan to avoid problems
It is important, however, that as much information is provided as soon as possible – everything, from restrictions, ring beams and steels, needs to be outlined from the outset, in order to prevent any issues at the installation stage.
Other common factors encountered include contractors’ use of bespoke ventilation termination points; these do not always comply with the necessary regulations, and can be a case of appearance over functionality. Using these is unwise, as it can affect the whole ventilation system’s ability to meet the performance criteria – akin to having a car with a high performance engine, but then attaching a low budget exhaust pipe on the end.
|MVHE: better indoor air quality|
The test standards for ventilation termination points are outlined as part of BS EN 13141-2 (‘Ventilation for buildings; performance testing of components/products for residential ventilation’). To avoid applications where terminations look pretty to the eye, but don’t actually work, Titon can test bespoke louvres on their systems to ascertain their effectiveness. Again, doing this as early in a project as possible will ensure a system complies with all necessary legislation and avoids any expensive replacements at a later date.
Space, or rather the lack of it, is another common issue which rears its head when ventilation has not been fully considered at the start of a project – particularly in blocks of flats in city locations, where space is at a premium. MVHR units usually end up housed inside storage cupboards which are extremely cramped. Once a boiler and a washing machine have been put inside them, there is not always space for the MVHR unit, which can impact installation, commissioning and future maintenance, which could have been avoided at the design stage.
There are some design tools available to help avoid space issues, such as the latest CAD and BIM packages, although we find a lot of designers are still drawing early stage plans by hand and only considering ventilation further down the line. To assist with the design process the Titon Ventilation sales team visit designers, specifiers and contractors, conducting CPDs, assisting with the design process and explaining the features and benefits of products, alongside the system requirements and relevant legislation.
So, we have seen there are a number of issues which can arise if ventilation systems and MVHR selection is not considered during the design stages of a development. However, if architects, designers and contractors can work closely with ventilation manufacturers from the outset, any potential issues can be identified and rectified, ensuring everything runs according to plan, resulting in an integrated design and, ultimately, delivering a successful project.
Lee Caulfield is sales director at Titon