BREEAM Visual comfort Glare control

1 Aim and benefits
2 When to consider
3 Step-by-step guidance
4 Questions to ask while seeking compliance
5 Tools and resources
6 Tips and best practice
7 Typical evidence
8 Applicable Schemes
9 Related articles on Designing Buildings Wiki.

[edit] Aim and benefits

To ensure occupant controls are considered at the design stage to ensure best practice in visual performance and comfort for building occupants. This involves reducing glare that can cause discomfort and distraction, and enabling occupant lighting control.

[edit] When to consider

The BREEAM assessor does not need evidential documents at a particular time, but designers may consider the potential opportunities for glare control as early as concept design.

Incorporating glare control at an early stage allows designers to propose building integrated options such as brise soleil or other innovative options, whereas if it is left to the end, blinds may be the only option.

[edit] Step-by-step guidance

Please note, not applicable to shell or shell and core assessments.

Check which areas will be relevant, i.e. areas where lighting and resultant glare control could be problematic, such as workstations, where projector screens may be used or sports halls.

Confirm with the design team which glare control method will be applied. Blinds are the simplest form of glare control. Where other methods are adopted, design data must be used to demonstrate compliance.

[edit] Questions to ask while seeking compliance

Shell and core - The design team must demonstrate how the glare control criteria will be met without a reliance on blinds when the building is occupied.

Compliant shading measures for meeting the glare control credit include:

Building integrated measures.
Occupant-controlled devices such as blinds (where transmittance value is <0.1 (10%)).
Bioclimatic design.
External shading or brise soleil.

[edit] Tools and resources

[edit] Tips and best practice

All building facades will need some shading protection, even if the sun does not shine directly into some areas of the building.

Ask the developer for their standard, or project, specification. Are blinds (or other features, such as brise soleil) included in the base building, or fit-out works?

Has the designer assessed solar effects on the building users and considered protection from these effects.

Is it too late to amend the design to improve shading control (e.g. by using over-hangs)?

Remember that protection must provide shading from high-level summer and low-level winter sun.

Automatic controls may provide compliance, but are not essential to comply with the requirements.

Curtains (where used without other forms of shading) do not meet the criteria for the glare control credit.

There are many means of controlling glare, such as blinds, brise soleil, building overhangs and even natural protection for some schemes. Keep an open mind about the potential solutions, where possible.

[edit] Typical evidence

Design stage:

Design drawings identifying relevant building areas, windows and any glare control such as the blinds specified.
Specification of glare control system such as occupant controlled blinds (confirming transmittance value of <0.1).
Drawings showing building integrated measures where applicable, such as the extent and height of eaves in relation to windows and building orientation.
Drawings/specification of any external shading systems or brise soleil.
Where fixed systems are used then design studies/calculations must demonstrate that sunlight will be prevented from reaching building occupants during occupied hours.
The simplest form of glare control is occupant controlled blinds.

Post construction stage:

As-built drawings/specifications for any glare control system - for blinds this could be manufacturer's literature confirming the transmittance value.
Assessor site inspection photos and report.

[edit] Applicable Schemes

The guidelines collated in this ISD aim to support sustainable best practice in the topic described. This issue may apply in multiple BREEAM schemes covering different stages in the life of a building, different building types and different year versions. Some content may be generic but scheme nuances should also be taken into account. Refer to the comments below and related articles to this one to understand these nuances. See this document for further guidelines.