Requirements for gauging the condo soundscape are evolving in Ontario now that new amendments to the provincial building code have come into force. As of January 1, developers will no longer have to meet a challenging standard for the comprehensibility of voice communications systems, and they can take an alternative approach to calculating sound transmission between dwelling units that’s considered a more accurate evaluation of how sound reaches and affects building occupants.
Code specialists predict the latter amendment, opening up the option for the Apparent Sound Transmission Class (ASTC) rating, will one day become the mandated method. This accounts for what’s known as flanking — sound associated with shared building systems and components, such as ducts and pipes, or anything that might be attached to a partition between rooms or units. For now, though, the incumbent Sound Transmission Class (STC) rating, which is a simpler measurement of a wall, floor or ceiling’s ability to muffle sound, continues to be recognized.
“In future, I think they will want to go totally with the ASTC,” Alek Antoniuk, consulting architect with CodeNews Consulting Corp. and the former manager of code development for Ontario’s Ministry of Municipal Affairs and Housing, recently told seminar attendees at The Buildings Show in Toronto. “It’s more complex than a straight STC, but that’s the way the world is going.”
ASTC debuted in the 2015 edition of Canada’s model national building code. In support, the National Research Council developed a software tool to help builders and designers calculate direct and flanking sound transmission, which is freely available online.
The move to adopt ASTC and a plethora of other amendments into Ontario’s code reflects an ongoing agenda to harmonize the national and provincial codes as much as possible. Still, Ontario’s code has always varied to some extent from the national model and has often been seen as a leader in accepting innovation and/or introducing more stringent performance requirements.
The most recent changes, outlined in a regulation published in May 2019, are in lieu of an expected 2018 edition of the code, which had been prepared but not yet adopted prior to that year’s provincial election. Instead, the new government invoked a host of amendments tallying to 1,220 replacement pages in the 2012 code.
“It practically replaces the whole code, but is still an amendatory code,” Antoniuk said.
An amendment rescinding the requirement that voice communication systems perform at 0.70 on the common intelligibility scale (CIS) responds to widespread failure to meet that score. The benchmark — which equates to the average listener being able to comprehend 80 per cent of words and 95 per cent of sentences delivered through the system — was added to the 2012 Ontario code following its introduction in the 2010 national code.
“It was found to be an unachievable target,” Antoniuk reported.
Future residents of newly constructed condo and apartment buildings may also notice a quieter gush of water from bathroom taps. As of January 1, the maximum flow rate for lavatory faucets in residential occupancies has been reduced from 8.35 to 5.7 litres per minute.