The UL Fire Safety Research Institute (FSRI) announced that the peer-reviewed journal article, “Experimental Study of Heat Transfer Through Windows Exposed to a Radiant Panel Heater”, has been published in Fire Technology. As part of the WUI Heat Transfer research project, the paper examines how different commercially available window construction models protect against external heat flux, similar to a WUI fire. This research was conducted in partnership with the University of Maryland Department of Fire Protection Engineering, as part of the UMD fellowship with FSRI,
The team compared several window assembly characteristics: glass type (plain or tempered), number of panes (one or two), type of gas between the panes (air or argon), and the presence of a low-emissivity coating. To conduct this study, researchers exposed windows to various heat fluxes ranging from 10—50 kW/m2 from a radiant panel to each of the 23 cm by 23 cm window samples. They then measured the heat flux through the window and the time until either pane cracking or failure.
The results included:
- In some cases, the heat flux measured behind the windows was greater than the critical heat flux required to ignite common household furnishings. It is important for people in WUI fire areas to move curtains, furniture, and other household materials away from windows before evacuating.
- Double-pane windows prevented more heat transfer through a window than single-pane windows (measured 13—43% and 39—60% of the incident heat flux, respectively).
- The addition of the low-emissivity coating further reduced the heat transfer through the window.
- Plain glass structurally failed earlier than tempered glass.
- The heat transfer through air-filled versus argon-filled double-pane windows was not significantly different.
- The most protective window construction was the tempered glass double-pane window with argon gas between the panes, and the low-emissivity coating applied.
