Breeam Assessments

There are various Breeam standards for new buildings and within these the availability of good levels of daylight is recognised as good for the health of the occupants of the building.

Visual comfort is an important part of ensuring building occupant health, comfort and wellbeing. Reducing glare that can cause discomfort and distraction, and enabling occupant lighting control, the building can increase productivity of its users. By reducing the impacts of glare that can cause discomfort and distraction, and enabling occupants to have a level of control over their visual environment, the building can increase productivity of its users. Maximising exposure to natural daylight and providing an external view out provides users with a connection to nature. This can in turn support mental wellbeing, for example by improving people’s mood and reducing the symptoms of depression. Increasing the level of daylight within the building also reduces the need for artificial lighting, which can reduce operational costs and environmental impacts of the building. Further to this, naturally lit environments increase occupant productivity and support the regulation of circadian rhythms.

Credits for good daylight is included in the Visual Comfort issue within the Health and Wellbeing category of credits. The stated aim of the credits are to encourage best practice in visual performance and comfort by ensuring daylighting, artificial lighting and occupant controls are considered.

• It is considered that visual comfort contributes to the health and wellbeing of the occupants through:
  Support the building occupier’s health, mental wellbeing and productivity.
• Help to provide a connection to nature by maximising natural daylight and encouraging an external view out.
• Help to reduce energy costs and environmental impact by reducing the need for artificial light.

The Breeam requirements regarding daylight availability within buildings focus on the Average Daylight Factor in relevant rooms and a measure of uniformity of daylight within the rooms. The actual minimum required Average Daylight Factor differs between building types and typically ranges from 1.5% to 3%. In addition to the Average Daylight Factor threshold the building spaces need to comply with one of two uniformity metrics:

• A uniformity ratio of at least 0.3. Or, a minimum point daylight factor of at least 0.3 times the relevant average daylight factor value in Table 5.1. Spaces with glazed roofs, such as atria, must achieve a uniformity ratio of at least 0.7. Or, a minimum point daylight factor of at least 0.7 times the relevant average daylight factor value
• At least 80% of the room has a view of sky from desk or table top height and The room depth criterion d/w +d/HW < 2/(1-RB) is satisfied.