|Rooflights can be combined with efficiently controlled artificial lighting to provide specified illumination levels. Research has proven that horizontal rooftlights provide two and a half times more natural light than vertical windows - ideal for saving energy and reducing the carbon footprint of any building.
Additionally, rooflights can become an architectural statement - offering views of the sky that naturally elevate mood without the distractions associated with vertical windows. Indeed, natural daylight has been proven crucial to the well being, safety and efficiency of people at work - as acknowledged in the Workplace (Health, Safety and Welfare) Regulations, 1992, which state: “‘Every workplace shall have suitable and sufficient lighting which shall, so far as is reasonably practicable, be by natural light’. Something reiterated in the HSG38 ‘Lighting at Work’ booklet.
Building Bulletin 90 - “Lighting Design for School” - features specific guidance on natural lighting and rooflights in the education sector, covering both primary and secondary schooling as well as new and refurbishment projects. This guide stresses that, during daylight hours, natural lighting should always be the main source of light, supplemented by electric light when require - unless there is a specific, over-riding reason for artificial light to be used. BB90 also contains comprehensive sections on lighting design, and the use of rooflights. As the guide notes, rooflights are unique insomuch that they let in light from the brightest part of the sky and are not generally affected by nearby obstructions. Rooflights also provide a move even pattern of light than vertical windows.
Rooflights are also favoured in areas where vertical windows are not possible, to maintain ‘daylight contact’. Guidance is also included on how to avoid glare, which can occur if the rooflight glazing can been seen directly from normal viewing position at less than 35° above the horizontal - which can be combatted with rooflight ‘coffers’, kerbs or reflective sides to soften light distribution. When recommended daylight levels cannot be achieved, supplemental electric lighting can be introduced with suitable control systems - although this may need to be separate from the night time controls.
BB90 also highlights several educational application particularly aided by rooflights, such as areas where Display Screen Equipment is used which can be particularly problematic with vertical windows. The guide also includes examples of room lighting designs which explore alternatives such as adding rooflights above the furthest wall from a window to even-out natural lighting, or placing them centrally to provide consistent distribution. Rooflights are also highlighted as offering benefits to communal spaces such as atriums and circulation ‘streets’.