Background and goals
WELL is the first standard of its kind that focuses solely on the health and wellness of building occupants. The scope of WELL extends significantly beyond the building fabric as such.
New and Existing Buildings, New and Existing Interiors, and Core and Shell. Pilot programmes are available for other building types such as multifamily residences, retail, and restaurants.
WELL is also designed to work harmoniously with other, more comprehensive green building rating systems such as LEED, BREEAM, and the Living Building Challenge. The initiators of the standard “encourage projects to pursue both WELL and standards that address environmental sustainability”.
The WELL Building Standard is organised into seven categories of wellness called Concepts: Air, Water, Nourishment, Light, Fitness, Comfort and Mind. These are comprised of a total of 105 features.
Some WELL features are categorised as preconditions that must be fulfilled for all levels of WELL certification. So-called optimisations, in contrast, are not mandatory for basic (Silver level) certification but create a flexible pathway towards higher levels of certification.
WELL is largely performance based; in most cases, specific, measurable ‘markers’ (thresholds) must be met. In other cases, particular strategies are required, as strong evidence suggests there are benefits to implementation.
Indoor air quality and ventilation
With 29 single features, this is by far the most comprehensive of the seven concepts in WELL. The standard sets limits for formaldehyde and VOC emissions, as well as particulate matter and radon emissions in the indoor air. VOC emissions are also tackled at source by specifying low-VOC interior paints and coatings, sealants, floorings and furniture. Operable windows or a demand controlled ventilation system have to be installed to keep CO2 levels permanently below 800 ppm. A voluntary optimisation feature requires that the ventilation system be capable of maintaining relative humidity between 30% and 50% at all times by adding moisture to or removing it from the air.
Alongside requirements for visual task lighting (min. 300 lux at the work plane) and glare control, WELL also comprises a dedicated feature that deals with circadian lighting design. The metric used here is ‘equivalent melanopic lux’ – which corresponds to the vertical illumination at eye level multiplied by a weighting factor that depends on the spectral composition of the light source. According to WELL, “this light level [of 200 melanopic lux] may incorporate daylight, and is present for at least the hours between 9:00 AM and 1:00 PM for every day of the year.” Three more optimisation features (Right to Light, Daylight Modelling and Daylighting Fenestration) also make direct reference to daylight. Among other things, they limit the distance from regularly occupied spaces to windows and set minimum requirements for the spatial daylight autonomy, as well as the window-to-wall ratio.
WELL recommends a number of measures aimed to improve users’ mental health and well-being. These include designated quiet spaces and facilities for short naps in office buildings. Furthermore, design teams are encouraged to integrate design features and artwork that stimulate human delight and celebrate culture, spirit and place.
Building operation and evaluation
In order to achieve WELL certification, the building must undergo a process that includes an on-site assessment and performance testing by a third party.
Smoking is banned from all WELL-certified buildings and the use of pesticides has to be eliminated in the outdoor areas. Owners are required to set up a cleaning plan for all occupied spaces. A voluntary optimisation feature recommends that the building is ‘flushed’ with large volumes of fresh air after completion and prior to occupancy. Additional points can be gained by monitoring particulate matter, CO2 and ozone levels in the indoor air, and by displaying temperature, humidity and CO2 to building users in real time.
The Mind category also comprises measures that can be applied to increase users’ satisfaction and health. Post-occupancy surveys have to be conducted annually with at least 30% of the users. Furthermore, employers are encouraged to subsidise wearable health sensors (e. g. for activity and heart rate, as well as sleep duration and quality) for the use of their employees. WELL also rewards companies for limiting late-night work, night-time business flights and the overall travel time on business trips.