Q: The vendor that did our annual fire door inspection cited a deficiency that the viewer/window in our existing fire doors did not have a label. Are viewers/windows in existing fire doors required to be labeled?

A: The fire door inspector contractor is correct. NFPA 80-2010, section 4.4.1 says only labeled fire-resistance-rated or fire-protection-rated glazing materials are permitted in fire door assemblies. Section 8.3.3.1 of the 2012 Life Safety Code requires fire-rated doors to be inspected and tested in accordance with NFPA 80. Therefore, existing fire-rated doors must have fire-rated glazing.