A well established commercial building built in the late 70’s had been upgraded structurally to meet the required % NBS. Unfortunately, large areas of standard float glass were prevalent on many main escape paths from the building. There were concerns that during a major earthquake event safe passage egress from the building could be restricted.
GlassProtech was called to provide a solution for the large expanses of clear float glazing. A 4mil (100 micron) Clear Safety and Security film was applied to the interiors of all safe egress paths and laboratories that were identified as critical safety concerns.
Upon completion the glazing now complied with AS/NZS:2208 – Safety Glass in Buildings. An added benefit was a 99% UV rating for the film which helps to reduce fading and damage to internal fittings and fixtures from harmful UV rays.
The upgrade to NBS may not legally require that glazing be upgraded, but many building owners and facilities managers are now realising a moral obligation or duty of care to protect building occupants (and also persons outside of the building envelope) in the case of multi-story buildings.
Excerpts from Dr. T. C. Hutchinson’s (University of California – San Diego) 2009 Study on Seismic Effects.
Even a moderate amount of film (2 mil) suppresses damage to the window system and greatly assists with retaining the glass itself, thereby reducing the potential for the safety hazard of glass fallout.
When there is no film applied to the glass, the effects of extensive cracking cause on average 74% of the glass to fallout (range of 20%). With only minimal film application (2mil), less than 1% of glass is observed to fall from the specimen. Increased film thickness (4 and 2-ply 8 mil) increases the level of containment further to less than 0.75% glass fallout.
These numbers mirror our own in-house testing for glass retention, and in the Christchurch earthquake, buildings with glazing retrofitted with GlassProtech Safety and Security film performed as expected, even when the buildings had major structural failures. In some cases entire window frames were destroyed and shaken from the building, yet the glazing was retained by the film.