It’s now widely accepted that natural daylight not only provides the best environment for people to work in: it saves energy and reduces CO2 emissions by reducing the need for electric lighting. However, the major concern with saving energy is not that the artificial lights get switched on; it is that they do not get…
This graph shows how roof light areas will affect illumination levels. In this example for a single storey building located in London, between the hours of 6am and 6pm daily, with roof lights providing 50% light transmission. You can see that as the roof light area along the bottom of the graph increases, the length…
As a general rule of thumb, daylighting in all types of building should be designed to provide adequate light levels in the room and on the work plane so that daylight is the main/or only source of light (autonomous) during daytime. For domestic properties, whilst there is little guidance on specific illumination levels in design,…
The BRE has published some fascinating insights into the positive effects of daylighting in healthcare establishments on its ‘Designing Buildings Wiki. The following are edited excerpts from this report: The issues associated with SBS (Sick Building Syndrome) and/or daylight deprivation, coupled with a renewed interest in the use of daylight in the design of low-energy,…
GUEST BLOG: John Godley, Technical Manager at Hambleside Danelaw, discusses the important factors to consider for an effective daylighting plan. Rooflights can provide up to three times more light than vertical glazing, and can provide more even and useable distribution of natural light into a building, particularly in large structures where light is required deep…
CIBSE Guide A provides data which allows us to determine the appropriate design and rooflight area to provide recommended light levels for a given application.Typically, for general retail and manufacturing areas, 500 Lux is the recommended level. The graph above shows how rooflight areas will affect illumination levels. In this example for a single storey…
There seems to be a lot of confusion out in the marketplace on this issue at the moment – with manufacturers making different claims and a general lack of clarity arising from what appear to be misunderstandings about the role and application of CE marks. CE marking is simply the manufacturer’s declaration that the product…
The growing popularity of ‘walk-on’ rooflights – very high specification glass structures designed to floor loadings and therefore unsuitable for most rooflighting applications – has led to confusion amongst specifiers who often refer to ‘walk-on’ specification, when in fact their requirement is simply for a non-fragile rooflight. In response to frequent occurrences of mis-specification, NARM,…
In a recent NARM member company survey, 78% of respondents said their level of business is affected by spurious claims by unscrupulous or misinformed roof light suppliers. Unjustifiable performance claims in terms of thermal performance appear to be the main cause for concern, with some companies making claims which are simply impossible when put under…
Rooflight manufacturers are right to publish and promote the U-values of their products and low U-values are indeed an important contributing factor to overall building energy efficiency. However, rooflight area is actually the more significant factor in achieving Part L compliance. Generally speaking the larger the roof light area, the greater the reduction in energy…