{{Short description|Measure of light reflected from a surface}} {{Refimprove|date=May 2013}} thumb|LRV on Paint Swatch In architecture, '''light reflectance value''' ('''LRV'''), is a measure of visible and usable light that is reflected from a surface when illuminated by a light source.<ref name=Jeffries2010>{{cite web |last=Jeffries|first=John |title=The use of Light Reflectance Values (LVRs) in achieving visual contrast |url=https://www.scribd.com/document/322174388/Ttf-Information-Sheet-5|publisher=BRE CIAT RIBA Technical Taskforce |accessdate=1 May 2013 }}</ref> The measurement is most commonly used by design professionals, such as architectural color consultants, architects, environmental graphic designers and interior designers.[https://spiradesign.co/what-is-lrv]<ref>{{Cite web |title=What is LRV? |url=https://spiradesign.co/what-is-lrv |access-date=2026-03-02 |website=spiradesign.co |language=en}}</ref>
LRVs are frequently reported on paint chips or paint samples. A spectrophotometer can be used to determine the LRV of a surface.
==Guidance== Designers of buildings must comply with the building codes applicable to the structure under consideration. Since 2004 guidance has existed in England on access to and use of buildings.<ref name=Gradus>{{cite web|title=Specification Guidelines, Design Service & CPD|url=http://www.gradusworld.com/files/webfm/uploaded/Downloads_PDF%20Brochures/Catalogue%20-%20Stair%20Edgings%20&%20Floor%20Trims%20-%20Section%20-%20Specification%20Guidelines.pdf|publisher=gradusworld.com|accessdate=29 January 2015}}</ref>
These regulations exist under the broader legal requirement of the Equalities Act (2010) which The guidance is particularly concerned with provisions to assist the disabled, including those who are visually impaired. The guidance highlights the need for certain surfaces and features to contrast visually with their surroundings. Areas of particular interest are wall-to-ceiling and wall-to-floor junctions, exposed edges of sloping floors, seating and its surroundings, leading edges of doors, door opening furniture and door surfaces, sanitary fittings and grab bars.
There is a free online tool which automates this compliance at www.spiradesign.co [https://spiradesign.co/lrv-calculator]<ref>{{Cite web |title=LRV & Visual Contrast Calculator {{!}} Spira Design {{!}} Doc M & BS 8300 Compliant |url=https://lrvcalculator.com/ |access-date=2026-03-02 |website=lrvcalculator.com |language=en}}</ref>
Within England, this is a requirement for all non-domestic buildings, such as hospitals, schools, hotels, and theatres.
==Codes of practice== Built Environment:
The British Standards Institute's guidance in the Regulations and in the relevant Codes of Practice, BS 8300:2018, is that adequate visual contrast is provided if the light reflectance values of the contrasting areas differ by at least thirty points. The current British Standard for the measurement of LRV is BS8493:2008+A1:2010.
The United Nations Economic Commission for Europe uses a difference of sixty points between the LRVs for the contrast requirement of signage in "Railway Applications — Design for PRM Use - General Requirements — Part 1: Contrast."<ref name="UNECE (2017)">{{cite web|title=United Nations Economic Commission for Europe 'Railway Applications — Design for PRM Use - General Requirements — Part 1: Contrast.'|url=https://www.unece.org/fileadmin/DAM/trans/doc/2016/wp29grsg/GRSG-112-03e.pdf|website=UNECE|accessdate=24 April 2017}}</ref>
Manufacturers are advised by the Guild of Architectural Ironmongery to publish the LRV for their products.<ref name="Jeffries2010" />
Web Design:
The Americans with Disabilities Act Standards for Accessible Design does not recommend a light reflectance value for contrast on signage with words or pictograms, but instead it provides that "characters shall contrast with their background with either light characters on a dark background or dark characters on a light background" in § 703.5.1 <ref name="ADA Standards for Accessible Design (2010)">{{cite web|title=ADA Standards for Accessible Design (2010)|url=https://www.ada.gov/regs2010/2010ADAStandards/2010ADAStandards.pdf|website=ADA Standards for Accessible Design (2010)|accessdate=15 September 2010}}</ref>
The International Code Council utilizes the ADA approach and does not use a light reflectance value in the 2017 update to the standards for ICC A117.1 in § 703.5.3.2 <ref name="ICC (2017)">{{cite web|title=International Code Council 'Accessible and Usable Buildings and Facilities (2017)'|url=https://codes.iccsafe.org/content/icca117-12017/chapter-7-communication-elements-and-features#ICCA117.12017_Ch07_Sec703.5.3.2|website=International Code Council A117.1-2017 Accessible and Usable Buildings and Facilities (2017)|accessdate=29 June 2017}}</ref>
==References== {{reflist}} * Bradshaw, Vaugh, P.E. ''Building Control Systems''. New York: John Wiley & Sons, Inc. Second Edition, 1993.
==External links== *https://spiradesign.co/what-is-lrv *https://spiradesign.co/lrv-calculator *[http://thelandofcolor.com/lrv-light-reflectance-value-of-paint-colors/ LRV - What is it? How is it used?] * Measurement: http://www.lucideon.com/industries/construction/building-products/light-reflectance-value-testing [link is not valid]
Category:Interior design Category:Color appearance phenomena Category:Lighting designers