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Framework 鈥� a planned 12-story Pearl District mixed-use building that backers say will be the country’s first modern wood high-rise 鈥� cleared its latest hurdle when building panels passed two-hour fire tests.

The two tests, by London-based consulting firm ARUP, prove that a mass-timber assembly featuring cross-laminated timber (CLT) and glue-laminated timber (glulam) is safe for high-rises in the U.S., architect Thomas Robinson said.

鈥淚 would say by far this is the most stringent testing that’s been done with this type of assembly,鈥� he said. 鈥淢ost of the testing that’s been done in Europe is to 90 minutes, so this would be the first time that beam-to-column and floor components have been tested to two hours.鈥�

The tests show CLT’s compliance with building code sections regarding flame spread and fire rating requirements, Robinson said. The test specimens were fully-loaded, meaning that during the test a load was applied by a hydraulic actuator on top of the components being tested, he added.

The two-hour fire ratings achieved for the glulam-beam-to-glulam-column connection and the cross-laminated timber floors will allow some timber to be exposed in high-rise projects. In previous CLT projects, the structural timber frame has been concealed under layers of gypsum board.

Seismic testing for Framework is under way. The team expects those results back within the next few months. More fire tests are planned, with the intention of optimizing systems that have already passed.

Framework received the Portland Design Commission’s approval in July. Construction is scheduled to start in March 2017 and conclude a year later.

CLT performance details pertaining to Framework will become public knowledge at some point, Robinson said. This was a condition of the $1.5 million grant the Framework team received from the U.S. Department of Agriculture, he explained. The team leading the other project to garner grant money, in Manhattan, is still working with the New York City Fire Department and has yet to conduct project-specific tests.

CLT is legal in high-rise construction in other parts of the world, including Canada and Europe, but it has drawn opposition in the U.S. Building material interests, like the National Ready Mixed Concrete Association, have ramped up marketing campaigns opposing use of mass timber in high-rises.

People are sometimes afraid of change, Robinson said.

鈥淚t’s a new technology, but it’s shown to be safe and people are building buildings out of (CLT) in Europe,鈥� he said. I think the important thing is this is the start of a new way of thinking about building high-rise construction, and I think that the tests are significant in that they demonstrate scientifically that when the materials are engineered correctly 鈥� we can meet these stringent safety requirements.鈥�

Framework is being developed by project^. The contractor is Walsh Construction, StructureCraft is providing timber structure delivery and KPFF is the structural engineer. Home Forward will manage the building’s affordable units.

The CLT panels were manufactured in Riddle by DR Johnson, the only business in the U.S. licensed to make them.