BS 40101 – An Overview of the New British Standard
This British Standard is currently in draft form, but it provides a good reference for implementing energy efficiency measures. It covers Building Performance Evaluation (BPE) of Occupied and Operational Buildings. The final standard will be released in 2022.
There has been call for more modern building standards for years, but this was once again highlighted at the recent COP26 summit. Industry experts called for standardisation and radical collaboration to achieve net-zero goals – could this new British Standard be a step in the right direction?
“The study of the performance of buildings and the relationship amongst building performance attributes, building and occupant health, occupant wellbeing, flows of electrical energy, fuel, water, CO2 and other emissions across the building system boundary has been attracting interest since, at least, the 1970s, with the PROBE studies of the 1990s being the first to attract significant professional interest” (BSI 2021).
The Building Performance Evaluation forms the basis of the standard and allows stakeholders to set out a benchmark for aspects of their building, including design, construction, maintenance, ventilation, lighting, temperature, energy consumption, water consumption and much more.
Over the last decade, BPE has become a focus area for both CIBSE and RIBA. It features in the UK Government’s Transforming Construction Challenge and increasingly underpins initiatives to deliver better-performing new buildings and retrofit improvements.
“The aim of the study is to find out how the building you live in/work in/visit performs, including understanding how much energy is needed (and what this means in terms of carbon dioxide (CO2) emissions), how much water is needed and how well the building satisfies your needs including maintaining a comfortable temperature, healthy indoor air quality, good levels of lighting and noise prevention.
The results will be used to identify improvements to your home/the building/your heating system and check that the building performance is as specified” (BSI 2021).
Why is the standard needed?
We have seen an increased interest in the health and wellbeing of building occupants, partly accelerated due to the pandemic. There is a need to understand the performance of buildings in terms of the effect on human health, wellbeing, productivity and learning.
Alongside this is also the urgent need to address the sustainability of buildings; being able to analyse energy data and understand just how efficient or inefficient building stock is and what can be done to improve it is essential to reduce the environmental impact. It is vital that, as an industry, we work towards delivering on the UK’s 2050 commitment. This encompasses both the new build and retrofit markets and requires dramatic upskilling across the supply chain from design, construction and building services.
We know that 80% of buildings that will be in use in 2050 have already been built, so the potential within the retrofit process is huge.
The UK has relatively poor energy performance of building stock (for example, in comparison to other European countries). It is imperative that new buildings are net-zero ready, and there is a clear standard to follow to help achieve this.
Advances in sensing, monitoring and measurement technology have increased the ease and affordability with which performance measurements can be made, and key parameters monitored are beginning to be normalised (e.g., carbon intensity, energy use per m2, thermal comfort, humidity, light levels, air quality, acoustics). This data provides useful, comparable parameters whilst also retaining the measured data (and published data such as carbon factors) from which these performance parameters are derived. This approach is important because it ensures calculations can be revisited with reference to the most basic of test and monitored data.
Who is it for?
A BPE study provides valuable insight for many different stakeholders, including but not limited to:
Specifiers, designers, commissioners and procurers of buildings, their construction, modification, refurbishment or retrofit
Those delivering a new building
Those assessing the opportunity to improve an existing building
Those modifying, refurbishing or retrofitting a building
Those financing construction works (as lender, grant provider/administrator, or self-funder)
Those insuring a building; building owners, leaseholders and occupiers (e.g. for health, productivity and cost of occupancy)
Those offering a building for sale or lease
Owners and leaseholders of buildings and portfolios of buildings
Occupants/users of the specific study building(s) or of similar buildings
Stakeholders wishing (or being required to) disclose their CO2 emissions (this may be finance providers, corporate or public sector owners)
Those concerned with the health and wellbeing of occupants, either through social or contractual responsibility
Those studying the performance of the building stock to support the derivation of statistics (e.g. fuel poverty), inform policy, devise programmes, contribute to sector knowledge and report on any of these.
How does it work?
You conduct a BPE to see how your building performs and use it as a benchmark going forward. Below is a breakdown of the BPE schematic:
By providing this British Standard, the practice of BPE can be mainstreamed and learning from individual and aggregated results can inform the practices and assumptions made during modelling, design, construction, commissioning and operation.
It enables key stakeholders to achieve better-performing building stock (including the indoor environments that influence occupant wellbeing). It accelerates the trajectory to net-zero carbon buildings, supporting and informing the energy system transition, which, in turn, reduces waste and running costs.