Will the glass be installed in a ‘hazardous’ location subject to frequent human contact?
Fire-rated glass installed in such locations, including doors and sidelites, must now defend against the spread of fire and meet high impact-safety criteria. In Canada, this is a recent and important change to note.
In 1990, when the Canadian General Standards Board (CGSB) first published its fire-safety codes, wired glass was the only glazing material that could offer adequate fire protection for a reasonable length of time. Although it could only resist 4.8 kN/m2 (100 ft-lb) of impact, the absence of a fire-rated glazing material with the desired impact-safety performance led to the issuance of CAN/CGSB 12.11-M90, Wired Safety Glass, which allowed use of monolithic wired glass in hazardous locations.
Recognizing injuries can follow such use of wired glass, CGSB spent the last three years working on a new safety glazing standard. In February, it released CAN/CGSB 12.1-2017, Safety Glazing, and withdrew CAN/CGSB 12.11-M90. The new standard supersedes CAN/CGSB 12.11-M90, Tempered or Laminated Safety Glass, and requires all safety glazing, including wired glass, to meet the Class A rating at a minimum, resisting 7.2 kN/m2 (150 ft-lb). (Products satisfying the more-stringent Class B rating can resist 19 kN/m2 [400 ft-lb] of impact.)
The Canadian Commission on Building and Fire Codes (CCBFC) has taken steps to appoint a task group to assess whether to begin immediate proceedings to adopt the new safety standard or wait for a new model building and fire code development cycle. Although no formal confirmation exists yet, immediate adoption proceedings are expected to begin in the near future.
For building industry professionals used to specifying traditional, monolithic wired glass in hazardous locations, the good news is there are a number of readily available, wireless fire-rated glass alternatives that can meet the new criteria. Clear fire-protective-rated glass products, such as fire-rated glass ceramic, provide exceptional surface clarity and meet strict Class B criteria. Many fire-resistive-rated transparent glass wall panels also offer high levels of impact safety.
If questions arise during the specification process, it is best to contact the manufacturer or supplier to answer questions and provide supporting literature.
Does the fire-rated glazing support
While fire-rated glass is best known for its fire- and life-safety protection capabilities, it is also proving an important ally in daylighting designs. Glazing can help draw light into spaces that would otherwise require opaque fire-blocking materials like gypsum and concrete to meet building codes. This is becoming increasingly beneficial, as building teams are more frequently incorporating strategies for maximizing daylight capture within their building plans to reduce energy usage and costs, as well as to support student and teacher wellbeing.
While fire-protective and fire-resistive glass have different use and installation parameters, both can support daylighting designs in educational facilities. For example, installing fire-protective-rated glass with exceptional clarity in transoms, borrowed lites, and doors can help maximize light transfer and views in schools. Kaeyer Garment & Davidson Architects used this approach in Post Road School in White Plains, N.Y., specifying fire-rated glass ceramic with superior optical quality to help illuminate hard-to-light spaces like the library, stairwells, and corridors while protecting children and staff from the threat of fire. To further bolster daylight transfer, the design team oriented the facility around an interior courtyard. This helped the school’s interior glazing assemblies capture more of the sun’s rays.
When specifying fire-resistive-rated glass in schools, daylighting design options expand beyond what is possible with fire-protective glazing. Since fire-resistive products are not restricted to 25 per cent of the total wall area, design teams can use them to extend the surface area through which light can transfer in areas subject to building codes. These sophisticated fire-rated glass assemblies can extend from floor to ceiling, wall to wall, and across multiple storeys while providing schools with around-the-clock defense against fire. Notable fire-resistive-rated glass systems able to supplement daylighting designs include:
- full-lite door assemblies;
- transparent glass walls;
- curtain walls;
- silicone-glazed curtain walls; and
- glass floors and roofs.
Building teams can also employ these expansive fire-resistive-rated glass applications in a range of settings to draw light deep into a building’s core. For example, placing fire-rated glass floor systems above open interior spaces can help stream light to lower levels while also providing a barrier to fire. Christopher Newport University (CNU) Student Success Center in Newport News, Va., demonstrates the powerful, multi-faceted benefits of this orientation. Glavé & Holmes Architecture specified a 4.6-m (15-ft) diameter fire-resistive-rated glass floor system that functions as light portal, supports loads up to 732 kg/m2 (150 psf), and extends usable walking space on the fourth floor with its textured top-surface glass.
While CNU is just one illustration of how advanced fire-rated glass systems can support light transfer, there are many other beneficial orientations, including:
- placing fire-rated glass curtain walls directly in line with non-fire-rated curtain walls;
- incorporating fire-rated glass panes in corridors and gathering areas;
- using fire-rated glass in the interior walls of stairwells and in corridors;
- placing fire-rated glass floors above multi-storey shafts and atriums; and
- incorporating exterior fire-rated glazing systems (e.g. curtain walls) to provide lot line defense and support light transfer.