"The attached picture is from a presentation making the e-mail rounds accompanied by dire fire safety warnings about trusses without gusset plates. But what are the facts? These 'gusset-less' trusses were introduced in 1989 and are used primarily to support floors. They usually are found in residential construction, but can be used in any construction type that allows wood floor joists. The trusses shown here are made using a glued finger-joint process. Finger-joints can occur wherever two wood members need to be joined. The adhesive used in these trusses is phenol resorcinol. Phenol resorcinol adhesive's autoignition temperature is approximately 1,130 °F (610 °C) compared to wood's 520 to 880 °F (270 to 470 °C). The glue does not soften, lose bonding capabilities, or break down chemically at temperatures below the wood's charring temperature."
Coffee Break Training - Hot Coffee Series No. HC-2006-0706
United States Fire Administration: http://www.usfa.fema.gov/