The Impact of Design on Occupant Wellbeing
Decarbonising current building stock has become a key concern in order to successfully fall in line with net zero targets in future. Moreover, continuing to create buildings that are ‘healthy by design’ is critical to successfully catering to the wellbeing of their occupants. Steve Richmond, Head of Marketing and Technical at REHAU Building Solutions, discusses how architects and contractors can successfully balance these dual concerns.
With research indicating that UK residents spend upwards of 90% of their time indoors, it goes without saying that building design is an inherent factor of occupant wellbeing, as well as wider quality of life. This is a phenomenon that has been increasingly recognised in recent decades, with growing trends towards incorporating features that enhance inhabitant health, comfort and performance.
In order to gauge current attitudes towards the impact that buildings have on their occupants, REHAU surveyed 520 M&E designers and architects for their 2021 report, Designing Healthy Apartments. The report forms part of a series which also spans the construction of hotels, healthcare and educational facilities. The top line finding here indicated that the overwhelming majority concurred with the earlier hypothesis, with leaving high-quality buildings for future generations a priority for 97% of respondents.
However, despite recognition of this fact, a further 44% believed that wellbeing is being ‘value-engineered’ out of building design further down the line, with cost-cutting coming at the expense of inhabitants. For this reason, there has never been a greater need to ensure that buildings are – and continue to be – ‘healthy by design’.
Current Attitudes and Regulations
Our report also revealed the design priorities for M&E designers and architects for the next ten years. In the face of ever-pressing net zero targets, sustainability understandably took top billing, with 41% of respondents citing it as a priority. This was closely followed by a number of factors pertinent to occupant wellbeing, including temperature control (40%), safety (35%) and drinking water quality (33%).
These concerns are detailed in current government building regulation in various capacities. For example, Fire safety: Approved Document B states that a building should be designed and constructed so there are provisions for the early warning of fire, as well as appropriate means of escape.
UK fire regulations came under intense scrutiny following the Grenfell Inquiry, with a national regulator being established to ensure that materials used to build homes are safer, while also possessing the power to remove any product from the market that violates these rules. For this reason, balancing the safety values of materials against other factors such as cost and practicality during specification will be key to ensuring healthy building design.
Resistance to sound: Approved Document E covers issues of noise, and stipulates that sound transfer from one flat to another must be reduced by at least 43-45 decibels (dB) through the partitioning wall or floor. However, this currently fails to extend to building service noise, while verification is conducted without any occupants in the building, calling into question its legitimacy.
As a result, many technical consultants choose to specify above the regulatory standard. Otherwise, a reduction in noise levels can be achieved by opting for insulation on utility infrastructure such as pipework, which minimises the noise of water movement in the building.
Requirements for effective ventilation and airflow are set out in Ventilation: Approved Document F , with a view to avoiding damage to building materials through condensation build-up. As such, ventilation strategies should be incorporated into the earliest stages of design to prevent this from becoming a problem for the occupant later down the line.
By making use of solutions that promote more optimal airflow and ensure temperature changes take place gradually, M&E designers can promote a healthier indoor environment for occupants, mitigating the risk of overheating and upholding higher air quality.
Lastly, and perhaps most pertinent to the nation’s net zero goals is Conservation of fuel and power: Approved Document L, which outlines energy performance standard for both new and existing buildings. Here, the Government aims to curb carbon emissions through a ‘fabric plus technology’ approach. This necessitates effective insulation and thermal performance for building stock, alongside the integration of low-carbon technologies such as district heating and heat pumps.
Findings from the aforementioned survey chime with this, indicating that 50% expect demand for district heating installations to increase in the next five years. This is largely owing to schemes such as the Green Heat Network Fund and Heat Network Transformation Programme, which are set to boost uptake.
Acoustic Performance and Fire Safety
A good starting point for healthy building design is acoustics. This is especially the case for multi-residential buildings, where occupants may live in close proximity to upwards of hundreds of other residents.
Unsurprisingly, results from the survey reflect this concern, with 95% of those surveyed stating that acoustics were either ‘somewhat’ or ‘very’ important when specifying building solutions. Moreover, 60% believed that the need for good acoustic performance has increased in the past five years, citing comfort, privacy and impact on health and wellbeing as the most popular reasons.
While acoustics are certainly important, it’s crucial to acknowledge the link between this factor and fire safety. For this reason, adopting a bigger picture approach to material specification may be one of the most effective methods of ensuring that multiple areas of the UK building regulations are met.
Making use of insulated piping that has been installed with the correct bracketing system, for example, is one of the most straightforward methods of guaranteeing compliance with both Part B and Part E. Here, the insulated nature of the pipework will minimise any noise from the movement of water, while also inhibiting the passage of fire in the event of a blaze.
Temperature Control and Ventilation
With the trend towards ensuring energy efficiency in buildings, this has incurred the challenge of excessive indoor temperatures, which can prove detrimental to building inhabitants. This is a particular concern for summer months, with warmer weather often exacerbating this to the point that it is health hazard. For this reason, the challenge for designers is to create buildings that remain warm in the winter and cool in the summer.
These concerns were recently highlighted in the Climate Change Committee’s (CCC) independent assessment of the Government’s Heat and Buildings Strategy. The CCC noted that while the strategy covers this issue for new buildings, it does not extend to existing stock. As such, there is a clear need to integrate effective temperature control from the design stage.
One of the most effective ways to do this is through Thermally Activated Building Structures (TABS). Here, the large thermal mass of the concrete structure is used as a buffer for the changing heat demands of the day, with hot or cool water run through pipes in the slabs to achieve the desired interior temperature. Crucially, this allows temperature change to take place gradually to retain optimum energy usage, rather than blast heating or chilling the space.
With summers becoming hotter by the year and a trend towards high-density building, technologies such as TABS will likely become central to construction moving forwards. TABS not only demonstrates compliance with Part F of the Government’s building regulations, but allows thermal efficiency to remain high without impacting upon occupants, which will be a key consideration as net zero goals press ever-closer.
Water supply and Waste
Perhaps most pertinent to the health of a building’s occupants is the supply of drinking water, with safe pipework critical to avoiding bacteria. Currently, copper is the most commonly used material in this area, followed by steel and polymer. Better hygiene and lower chances of leakage were cited as the most popular reasons for this choice, though this is also the case with polymer and multi-layer composite pipe (MLCP) solutions.
Though copper pipework has long remained the industry standard choice, there is a case to be made for polymer solutions such as our RAUTITAN MLCP plumbing system, particularly when attempting to create buildings that are ‘healthy by design’. Superior insulation values lead to a significant increase in energy efficiency, while polymer itself is less prone to leaching – a key consideration given that 58% of respondents specify fittings containing lead.
Leakage is also an issue – particularly given that some 3.1 billion litres of water is lost in England and Wales every day due to leaky pipes. Leaks lead to the presence of damp, creating the perfect environment for harmful mould to spawn. For this reason, building designers may want to consider installing smart leak detection systems, such as our RE.GUARD, to help avoid unnecessary water waste and potentially dangerous leaks.
The considerations outlined here offer only a glimpse into the methods as to which designers may create buildings that are ‘healthy by design’, with the boundary for which only set by the designer’s ingenuity. That said, the concerns touched upon here remain the primary sticking points for healthy building design, with innovation the key to solving this industry challenge.
By making progressive changes to the way construction is approached, the environmental impact of the built environment can be mitigated, while simultaneously bringing the wellbeing of building occupants back to the fore.
Steve Richmond is Head of Marketing and Technical at Rehau Building Solutions