Project contact is Jianhui Zhou at the University of Northern British Columbia
Summary
Building acoustics has been identified as one of the key subjects for the success of mass timber in the multi-storey building markets. The project will investigate the acoustical performance of mass timber panels produced in British Columbia. The apparent sound transmission class (ASTC) and impact insulation class (AIIC) of bare mass timber elements as wall and/ or floor elements will be measured through a lab mock-up. It is expected that a database of the sound insulation performance of British Columbia mass timber products will be developed with guidance on optimal acoustical treatments to achieve different levels of performance.
This report is published as an addendum to NRC Research Report RR-335 “Apparent Sound Insulation in Cross-Laminated Timber Buildings." It is intended that this addendum will be merged with RR-335 in the future as a report for predicting the sound insulation in buildings using mass-timber constructions including NLT assemblies. This report presents the results from experimental studies of airborne sound transmission through assemblies of nail-laminated timber (NLT) with various linings. To put the data presented in this report in the proper context, this report begins with a brief explanation of calculation procedures to predict the apparent sound transmission class (ASTC) between adjacent spaces in a building whose structure is a combination of mass-timber assemblies such as nail-laminated timber (NLT) or cross-laminated timber (CLT) panels.
FPInnovations initiated this project to demonstrate the ability of wood exit stairs in mid-rise buildings to perform adequately in a fire when NBCC requirements are followed, with the intent of changing perceptions of the fire safety of wood construction. The objective of this research is to investigate further the fire safety afforded by exit stair shafts of combustible construction, with the ultimate objective of better consistency between the provincial and national building codes with respect to fire requirements for exit stair shafts in mid-rise wood-frame construction.
This Report presents the results from experimental studies of the airborne sound transmission of mass timber assemblies, together with an explanation of the calculation procedures to predict the apparent sound transmission class (ASTC) rating between adjacent spaces in a building constructed of mass timber assemblies.
The experimental data which is the foundation for this Report includes the laboratory measured sound transmission loss of wall and floor assemblies constructed of Cross Laminated Timber (CLT), Nail-Laminated Timber (NLT) and Dowel-Laminated Timber (DLT), and the laboratory measured vibration reduction index between assemblies of junctions between CLT assemblies. The presentation of the measured data is combined with the presentation of the appropriate calculation procedures to determine the ASTC rating in buildings comprised of such assemblies along with numerous worked examples.
Several types of CLT constructions are commercially available in Canada, but this study focused on CLT assemblies with an adhesive applied between the faces of the timber elements in adjacent layers, but no adhesive bonding between the adjacent timber elements within a given layer. These CLT assemblies could be called “Face-Laminated CLT Assemblies” but are simply referred to as CLT assemblies in this Report. Another form of CLT assemblies does have adhesive applied between the faces of the timber elements in adjacent layers as well as adhesive to bond the adjacent timber elements within a given layer. These assemblies are referred to as “Fully-Bonded CLT Assemblies” in this Report. Because fully-bonded CLT assemblies have different properties than face-laminated CLT assemblies, the sound transmission data and predictions in this Report do not apply to fully-bonded CLT assemblies.
Forest Service/USDA Wood Innovations Grants
Recipient Point of Contact: Sandra Lupien
Location: East Lansing, Michigan
Summary
Over the past decade, interest in and demand for mass timber have been increasing steadily across North America for the materials’ ability to support healthy forests and rural economies while creating beautiful, innovative structures that both benefit the people who live, work, and learn in them and improve the carbon footprints of our built environments. The MassTimber@MSU program – supported in large part by funding from the Michigan Department of Natural Resources (DNR) and the Michigan Department of Agriculture and Rural Development (MDARD) – harnesses stakeholder engagement, outreach, communications, research, and education to advance mass timber construction and manufacture in Michigan and the surrounding region. Since the program’s launch two years ago, increased outreach leveraging new mass timber buildings in the region – the Michigan State University (MSU) STEM facility, the Intro project in Cleveland, and the Ascent Tower in Milwaukee – has intensified mass timber buzz in Michigan, where architecture, engineering, and construction (AEC) firms are reporting a steady stream of inquiries from developers studying mass timber for their projects. With this increased interest in mass timber construction come both concerns that demand could soon outstrip supply and significant interest in a secure Michigan-based supply of mass timber.
Some Michigan forest products industry entities are investigating the potential of expanding to manufacture mass timber products like cross-laminated timber (CLT) and glue-laminated timber (glulam) but are hesitant to make the capital investment without formal evidence of regional demand for mass timber products generally as well as for such products made in Michigan from Michigan wood specifically. In addition, potential manufacturers need to better understand feedstock supply to determine the best location, scale, and mass timber product lines for Michigan mass timber. That means Michigan CLT and glulam won’t become a reality for at least 2-5 years. At the same time, State agencies are eager to quickly harness the forest health and economic development opportunities associated with using wood sourced from State, Federal, and private Michigan forestlands in Michigan-manufactured mass timber.
Nail-laminated timber, a more species-agnostic form of mass timber panels that can be manufactured using nail guns on a project site or in a warehouse nearby, presents a unique “first-generation” mass timber opportunity for Michigan – one that can begin this year – that can help pave the way for larger scale operations in years to come.
With this project we propose to demonstrate the use of Michigan-sourced-and-made NLT in two projects –Shophouse Park and the Great Lakes Boat Building School’s new building – in the Upper Peninsula. We will document the processes and outcomes of these projects and share theme – along with best practices – with key manufacturing, AEC industry, community development, and other stakeholders. We expect the project will increase market demand for mass timber, including Michigan-sourced-and-made mass timber, and catalyze Michigan-based manufacture of mass timber from wood sourced from Michigan and the surrounding Great Lakes. Surveying AEC and developer stakeholders at the start and end of the project will both inform our understanding of the project’s impact and provide evidence of demand to prospective manufacturers.
This study on Circular Economy & the Built Environment Sector in Canada was carried out by The Delphi Group in collaboration with Scius Advisory and completed in March 2021 on behalf of Forestry Innovation Investment Ltd. (FII) in British Columbia and Natural Resources Canada (NRCan) as the co-sponsors for the research. The work identifies a broad range of current efforts across Canada and undertakes a deeper dive on design for disassembly and adaptability (DfD/A) best practices, including an analysis of the ISO Standard 20887:2020 (i.e., design for disassembly and adaptability) in line with current Canadian industry practice and market readiness.
Concealed spaces, such as those created by a dropped ceiling in a floor/ceiling assembly or by a stud wall assembly, have unique requirements in the International Building Code (IBC) to address the potential of fire spread in nonvisible areas of a building. Section 718 of the 2018 IBC includes prescriptive requirements for protection and/or compartmentalization of concealed spaces through the use of draft stopping, fire blocking, sprinklers and other means.
In many mass timber buildings, CLT or nail laminated timber (NLT) floors are designed with a concrete topping to improve acoustic separation, reduce vibration or act as a fire barrier. Little research has examined the fire behavior of these floor systems, but some preliminary tests involving LVL show that they may be able to meet three-hour fire resistance ratings, which could potentially open up the use of mass timber in Type I buildings, representing a large market opportunity. This project will test the behavior of composite floors under fire loading conditions considering the following parameters: shear connector type, mass timber panel types and thicknesses and concrete thicknesses. It will also test and validate an innovative fire research methodology using radiant panels.
Nail-laminated timber (NLT) is a large built-up member often used as interior structural members for floors, roofs, walls, and elevator/stair shafts. Because prolonged wetting of wood may cause staining, mould, excessive dimensional change (sometimes enough to fail fasteners), and even result in decay and loss of strength, construction moisture is an important consideration when building with NLT. This document aims to provide technical information to help architects, engineers, and builders assess the potential for wetting of NLT during building construction and identify appropriate actions to mitigate the risks.
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