Technical information for rooflight specifiers, installers and building occupiers

How rooflight area affects light levels, energy costs and CO2 emissions: the facts.

NARM, The National Association of Rooflight Manufacturers (now the Rooflight Association), has played an important role representing the UK’s rooflight industry in consultation with the Government and its subcontractors, CIBSE, AECOM and the BRE, on issues relating to Part L of The Building Regulations. The following article by NARM’s Technical Committee, explains how small differences…

Understanding the difference between ‘non-fragile’ and ‘walkable’ GRP rooflights

GUEST BLOG by John Godley, Technical Manager for Hambleside Danelaw. Before the HSE introduced the CDM Regulations, they had already done some preliminary work on roof fragility. A simple ‘drop’ test onto a roof assembly was proposed, and if the impactor was retained, then the roof was deemed to be non-fragile. This testing, defined in…

Don’t specify ‘walk-on’ rooflights if you mean ‘non-fragile’. The two terms have VERY different meanings.

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,…

What’s more important when specifying rooflights? Lowest U-value? or the rooflight area?

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…