Buildings of Type IV Heavy Timber construction, as defined by the International Building Code (IBC), can be constructed up to 85ft and are required to have member sizes that meet a prescriptive minimum dimension, to provide an FRR. Mass timber buildings, using engineered timber products such as glulam and cross laminated timber (CLT), are normally designated as Type IV construction.
Where glulam beams and columns intersect, the connectors need to achieve an FRR and how this is achieved is not well-detailed within the IBC or referenced guides. Typically, an FRR of 1hr is requested for Type IV connections, for building permit. The lack of an “off-the-shelf” fire rated solution for glulam beam to column connectors achieving a 1 hr FRR is a barrier to medium-rise mass timber construction (4 to 8 stories, below 85ft). The most widely accepted method for proving a building element achieves an FRR is through a fire test, to meet the requirements of Chapter 7 of the IBC.
To assist the construction industry, three different configurations of glulam beam to column connections were fire tested at an approved fire testing facility. The fire tests were carried out to meet ASTM E119-16a “Standard Test Methods for Fire Tests of Building Construction and Materials”, hence meeting Chapter 7 of the IBC. The completed fire tests and supporting reports allow engineers and architects to specify these tested connection assemblies and satisfy the requirements of the IBC. Approval by an authority having jurisdiction (AHJ) will therefore be easier for future building projects.
