Non-fragility

Non-fragility

Glass Rooflights

Roofglaze can provide CWCT TN 66, CWCT TN 67 and CWCT TN 92, Class 1 and Class 2 compliant, non-fragile glass rooflight solutions on request. You can find out more about these measures of non-fragility on the CWCT website.

Please feel free to Contact Roofglaze to discuss your project requirements with our expert team.

Polycarbonate Rooflights

The Red Book (ACR[M]001:2014) defines a test for non-fragility which can be applied to any polycarbonate roof assembly, intended to indicate whether or not the roof can support the instantaneous loads imposed on it by a person falling or stumbling on it. It is not a product test as such, but roofing products like rooflights can be tested as part of the roof assembly.

The test defines 3 Classes of non-fragility (A, B or C). Most roof constructions without rooflights are Class B or C (very few achieve Class A). Rooflights should generally match the performance of the roof (i.e. if the surrounding roof without rooflights achieves Class B, so should a roof assembly including rooflights). Roofglaze can provide non-fragile polycarbonate rooflights on request.

fragility chart

Practical Recommendations

  • Define the non-fragility classification required. Avoid use of terms such as ‘walk-able’ or ‘man-safe’ – these terms are undefined so can result in use of lower grade products.
  • Request specific evidence for any non-fragility claims (a detailed test report, signed by a competent person, or compliance with GN2006/1) and ensure this covers the application/assembly in which the product is to be used; do not rely on general statements.
  • For rooflights, method of fixing is critical – always fix the rooflight as recommended and tested. A poorly installed rooflight is potentially as much of a hazard as a fragile product.
  • Never wilfully walk on any rooflight. This will encourage dangerous practice as not all rooflights are made to be non-fragile and any foot traffic may damage the rooflight.

Further Information

More details can be obtained from the ACR (Advisory Committee for Roofsafety), or from NARM (National Association of Rooflight Manufacturers).