“It would not have been possible to meet insulation requirements in the required timeframe without TFP’s technical and manufacturing expertise,” says Becker. “We were under a lot of pressure to have our ducks in a row to be selected for a specific Incat vessel build. While initial failure always hurts, perseverance pays off.”
The redesigned FRP panel features a 12mm thick aluminum honeycomb, treated against saltwater corrosion, as a core material. “While one might think that aluminum is not ideal for thermal insulation, a non-metallic honeycomb would have been too expensive. We rely on the mineral fiber mat to provide the required insulation that protects the panel,” says Becker.
The intumescent mats are manufactured from high temperature-resistant mineral fibers, which are then integrated into the composite structure to impart integrated resistance to burn through and flame spread and to provide insulation from the heat of combustion.
The intumescent mineral fiber mat is installed on vessels facing the fire threat to maximize fire resistance. On a vehicle ferry, for example, the mat faces the vehicle deck and, in the event of a fire, insulates the supporting honeycomb panel and the aluminum structure of the vessel behind the SFP panels.
The aluminum honeycomb panel is skinned with a 0.01-inch glass/epoxy laminate face. The prepreg self-adheres to the aluminum honeycomb and simultaneously adheres to the intumescent mat. A flame, smoke and toxicity-compliant bright white washable finish is applied to the surface of the mat in the same single shot process, giving a finished overall panel thickness of ¾ inches and weighing just over one pound per square foot.
The various layers are laid up by hand and cured in heated presses. The thermoset epoxy matrix is shielded from excessive heat and flame by the mat so that the panels maintain support as the mat intumesces to form a 2½ -inch-thick insulating blanket when exposed to heat.
Structural fire protection requirements in marine applications can be extensive, with as much as 75,000 square feet on a vessel subject to safety standards. The FReD panels are built as large as 4 x 8 feet in a standardized construction process. The 4-foot width matches the frame spacings on the vessels for ease of installation, and most panels can be installed onsite without any cutting to size. The TFP intumescent mat is the same as the panel size to eliminate any gaps where fire could penetrate.