Structural Panels Provide Fire Protection

When Incat Tasmania, a builder of high-speed ships for commercial ferry operators and militaries, was experiencing problems with their supplier of structural fire protection (SFP) panels, the company reached out to AYRES Composite Panels to develop and qualify a new SFP system for marine applications. AYRES took on the redesign of the panels for insulating the structure of aluminum ships with an eye toward helping the ship builder save weight and reduce costs.

“Most recently, Incat had been using a fiber mat pressed into boards with a hard ceramic facing. The board was relatively heavy, and the facing was easily damaged during installation and in service,” says Christoph Becker, Group CEO of AYRES Composite Panels, a global manufacturer of lightweight honeycomb panels for marine interiors headquartered in Bayswater, Western Australia.

AYRES named its new panels FReD, which derives from the International Maritime Organization’s Fire-Resisting Divisions in its safety codes for High-Speed Crafts. FReD panels are flat honeycomb panels with intumescent mineral fiber mat applied to one side. The heat of a fire causes the mat to expand into a stable thick blanket, insulating the support panel and ship structure.

AYRES collaborated with Technical Fibre Products (TFP), a supplier of the intumescent fiber mat, to develop the FReD panels. “TFP had been supplying a mat for similar applications in the past, which is why we were very interested to work with them,” says Becker. “However, current fire rules are more stringent than any mats TFP had qualified for to date, so TFP had to develop a new solution.”

The two companies began discussions in May 2019 with a goal of meeting a tight time frame of July 2020 to develop, test and qualify the panels before installing them in an Incat vessel. But it wasn’t all smooth sailing.

TFP visited AYRES’ Mobile, Ala., production facility to learn about the company’s production processes while AYRES’ engineers traveled to the TFP facility in Burneside, U.K., to witness the mat production and learn about the required physical and performance parameters of the mats. TFP manufactured a run of mats and AYRES built the FReD panels, but the initial results failed insulation and protection tests.

By directly observing how the failures occurred, AYRES was able to modify the construction to improve results. In January 2020, AYRES and TFP held in-depth discussions about the tests and ways to improve the results. By the end of February, a new design successfully met the International Maritime Organization’s stringent insulation and fire suppression test requirements.

“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.

The FReD structural fire protection panels were a minimum of 18% lighter than the previous panels, which helped Incat’s vessel achieve required speeds while minimizing fuel burn and emissions. Reduced weight also enables ships to operate in shallower waters and can be used to lower the center of gravity to decrease uncomfortable roll and pitch motions.

Incat installed the FReD structural fire protection panels on the Volcan de Taidia, a 111-meter-long ferry handed over to Spanish ferry operator Naveira Armas in July 2021. From start to finish, the FReD panels were designed, developed, tested, certified and installed into the Volcan de Taidia in a little over 2 years – extremely fast given the complexity of the project.

Patrice Aylward is a freelance writer in Cleveland. Email comments to paylward@aol.com.

The FReD structural fire protection panels were installed on the 111-meter-long ferry Volcan de Taidia in July 2021. The ship was built by Incat Tasmania for Spanish ferry operator Naveira Armas SA.

Photo Credit: AYRES Composite Panels