New Assembly Designs Exceed Code Requirements, Reduce Costs
Fire protection, occupant well-being and comfort are essential elements of successful design. For multi-unit buildings, passive-fire protection is provided by wall and floor compartmentation typically with one- or two-hour fire rated assemblies required by building codes. Fire protection design also includes early warning systems in all buildings and suppression systems in taller buildings. As a result of this balanced approach a high level of fire protection is achieved.
Codes also require sound control for the well-being of occupants. It is important for optimal occupant comfort to set a high level for sound control in the building, especially when constructing multi-unit buildings.
115-fire-resistant and sound-control assemblies featured
The new Canadian Gypsum and Insulation Systems Manual includes over 115-fire-resistant and sound-control assemblies for low-rise, mid-rise and high-rise buildings. The fire ratings range from 4 hours to ¾ hour. Sound control assemblies achieve up to an STC of 71. Several Apparent Sound Transmission Class (ASTC) ratings ranging from ASTC 47 (code minimum) to ASTC 54 as required by the National Building Code of Canada (NBCC) 2015 and many provincial building codes are included in the new systems manual.
Considerations for material selection when designing for acoustic performance of fire rated assemblies often ends with the stud size, spacing and insulation. The selection of a gypsum wallboard and sustainable insulation should also be considered together as they can provide a significant improvement on the acoustic performance. For the well-being of your customers consider STC 55 or ASTC 50.
Between living spaces, the NBCC 2015 requires the use of one-hour fire rated assemblies that meet a minimum acoustic performance of STC 50. Where an assembly separates a living space from mechanical rooms, garbage chute or elevator, the code requires a minimum acoustic performance of STC 55.
Innovative products allow for a simplified assembly design
Figure 1 illustrates the design of a cUL listed assembly that achieves a one-hour fire rating that, through third party testing for acoustic performance, has been shown to meet the requirements of the OBC for assemblies separating dwelling units. It does so using Type X fire-rated gypsum board and insulation.
Figure 1: One-hour fire rated STC 50 assembly.
Innovative gypsum products, along with specialized acoustic insulation, helps to significantly improve acoustic performance without impacting the fire rating. High acoustic performance gypsum board, for example, is an innovation which is changing the way gypsum has been thought about and how it can be used. The board is two thin and dense gypsum panels between which lies a thin layer of viscoelastic polymer. The polymer, which does not harden, absorbs sound energy thereby reducing sound transmission.
Figure 2 shows that with a simple change, this “Constrained Layer Damping” high acoustic performance Type X gypsum board can be used in place of traditional Type X while sound attenuating fibre glass batt insulation can also be substituted into the design. This system also exceeds the code requirements for sound control of a living space from a mechanical room, garbage chute or elevator.
Figure 2: One-hour fire rated STC 56 assembly
Simplification leads to reduced labour and material costs
These changes improve the STC rating by 6-points while lowering labour and material costs that are common with multi-layer gypsum systems. These innovative products improve occupant comfort while also meeting or exceeding the requirements of the code.
Bob Marshall is building science manager for CertainTeed Gypsum Canada and can be reached at robert.marshall@saint-gobain.com. He has been appointed by NRC to the Standing Committee on Energy Efficiency in Buildings.
For more information download your copy of Canadian Gypsum and Insulation Systems Manual: Fire Resistance and Sound Control Design -Division 09.
Plus, sound-control strategies that reduce project costs while increasing livable space.
