It has been a long time in the works and a topic of much debate, but as of February 2017, being a 'qualified' sprinkler and fire protection installer will be mandatory in Ontario. While the Red Seal for Fire Protection Installer has been around for a while and is mandatory in some jurisdictions, it never has been in Ontario.
There is a process being implemented to grandfather and transition current sprinkler fitters into the accepted installers category. There are timelines to transitioning and all fitters should be aware of their options.
Keep posted for more information as timing is going to play a huge role in transitioning for many of the qualified workers in the trade.