Yup, the co-op program requires at least 12 months of work term. This can be achieved in many ways.
1. You can do three 4-month terms each summer, between the school years. So, the summer after 1st year you can get a term, then the summer after 2nd year, etc. This will allow you to graduate within 4 years (or 5 yrs with Scty/Int/Mgmt).
2. You can do an 8-month work term. This is only allowed if you are in your next-to-last year of your program. You may do the 8-month work term after THIRD year, if you're in a 4 yr prog OR after your FOURTH yr if you're in a 4 yr prog.
You can pair this with a 4-month summer term to get your full year for the co-op requirement.
3. There's also a 12-month and 16-month work term. Again, you have to be in your next-to-final year for these.
So you have a lot of choices on how to get the co-op requirement. If you decide to do a term greater than 4 months, then yes, your stay in school is extended by a year. This is because you'll take a year off to work, then come back to finish your final year.
Hope that helped, and check out the website for more info