The BS 40102, a fresh standard introduced in 2022 (draft released) by the British Standards Institute, focuses on assessing the health, wellbeing, and indoor environmental quality (IEQ) of buildings. It incorporates an updated best-practice method for addressing thermal comfort, indoor air quality, and overheating in buildings.

Regarding the new exposure limits, they are derived from various sources, including the DEFRA Daily Air Quality Index, WHO Air Quality Guidelines 2021, BREEAM and WELL Guidelines, and British Standard BS EN 16798-1.

Part 1 – Health and Wellbeing in Buildings

• BS 40102-1 gives recommendations for the measuring, monitoring and reporting of the well-being and IEQ performance of an occupied building and the associated building services.
• BS 40102-1 provides an evaluation and rating system (IEQ performance score), the aim of which is to enhance IEQ, to create healthier buildings and improve the well-being of building occupants; including but not limited to staff, visitors, tenants and customers. 

The standard applies to all types of non-domestic buildings, including those that already exist. It can be utilized, alongside other design guidance, in both renovation projects and new construction developments, serving as a tool for establishing targets and evaluating performance. The standard encompasses a best practice approach to evaluating the air quality, light quality, thermal comfort, and soundscape quality.

Part 2 – Thermal Comfort, Indoor Air Quality and Overheating

Part 2 of the standard will build upon Part 1 by establishing technical benchmarks to enhance the thermal comfort and indoor air quality, thereby promoting the health and wellbeing of occupants. These benchmarks encompass factors like air temperature, air movement, relative humidity, and measures to prevent overheating. Additionally, the standard addresses the regulation of various pollutants such as carbon dioxide (CO2), carbon monoxide (CO), nitrogen dioxide (NO2), volatile organic compounds (VOCs), particulates, microbes, and mold.

Furthermore, Part 2 provides guidance on managing risks associated with inadequate design and occupant behavior. It also outlines a comprehensive approach to achieve net zero emissions without compromising occupant safety, thereby facilitating a sustainable and environmentally friendly building.

	PM2.5
Level	Description	24h average
0	Very High	≥32 μg/m3
1	High	16-32 μg/m3
2	Acceptable	10-16 μg/m3
3	Low	5-10 μg/m3
4	Very Low	<5 μg/m3

	PM2.5
Level	Description	24h average
0	Very High	≥32 μg/m3
1	High	16-32 μg/m3
2	Acceptable	10-16 μg/m3
3	Low	5-10 μg/m3
4	Very Low	<5 μg/m3

	CO
Level	Description	15min average
0	Very High	>100 mg/m3
2	Acceptable	60–100 mg/m3
3	Very Low	<60 mg/m3

	TVOC
Level	Description	8h average
0	Very High	≥1000 μg/m3
1	High	500 – 1000 μg/m3
2	Acceptable	300 – 500 μg/m3
3	Low	100 – 300 μg/m3
4	Very Low	<100 μg/m3

	NO2
Level	Description	1h average
0	Very High	≥401 μg/m3
1	High	201 – 401 μg/m3
2	Acceptable	135 – 201 μg/m3
3	Low	68 – 135 μg/m3
4	Very Low	<68 μg/m3

	O3
Level	Description	8h average
0	Very High	≥97 μg/m3
1	High	61 – 97 μg/m3
2	Acceptable	40 – 61 μg/m3
3	Low	20 – 40 μg/m3
4	Very Low	<20 μg/m3

	CO2
Level	Description	Real-Time
0	Very High	≥1800 ppm
1	High	1000-1800 ppm
2	Acceptable	800-1000 ppm
3	Low	550-800 ppm
4	Very Low	<550 ppm

The standard will utilize the existing material collected for PAS 3003 as a foundation for assessing buildings, identifying areas of concern, and establishing criteria for monitoring and evaluating health and wellbeing parameters. Over the past few years, regulatory and commercial pressures have prompted designers, constructors, building owners/landlords, tenants, and maintenance teams to prioritize the reduction of operational energy costs which has come at the expense of unintended consequences such as inadequate ventilation and issues, which can compromise occupants’ physical and metal health.