High excitation purity light sources
Approved document L, Conservation of Fuel and Power, Volume 2: Buildings other than dwellings, 2021 edition incorporating 2023 amendments, defines high excitation purity light sources as:
Colour-tuneable light sources that can be set to at least the colours listed in Table A1 and which have for each of these colours, measured at the dominant wavelength, the minimum excitation purity shown. Intended for use in applications requiring high-quality coloured light.
Table A1 High excitation purity light sources
| Colour | Dominant wavelength (nm) | Minimum excitation of purity (%) |
| Blue | 440–490 | 90 |
| Green | 520–570 | 65 |
| Red | 610–670 | 95 |
[edit] Related articles on Designing Buildings
Featured articles
Check out some of the best features and news from Designing Buildings as well as key stories from around the web.
Passive fire protection webinar
MEP services penetration seals.
Where its at podcast (and video) - The role of the Architectural Technologist as an Expert Witness.
More than 200 remarkable buildings added to SAVE’s Buildings at Risk register.
Government scraps pre-application consultation for Nationally Significant Infrastructure Projects.
Historic England and infrastructure
New projects offer opportunities for the historic environment and local communities.
Construction Management, 2 July
Construction deaths halve in two years.
Green Book changes to drive investment in all parts of UK.
Minimum energy efficiency standards (MEES)
CIAT briefing on response to consultations for privately rented non-domestic properties.
Connect, collaborate, shape the future
Registration now live for UK Construction Week Birmingham.
CIOB announces Saul Humphrey FCIOB as new President for 26/27 term.
A quick, simple, and zero-bills solution to prevent overheating.
The adaptive reuse of large industrial structures.
Promoting the circular economy by extending the life of buildings.