Sorry, but as a teacher, I really object to those outside the system thinking Islamic prayers are "only 20 minutes a week." These prayers cause a lot of practical disruptions. 

First off, there is the set up of these prayers. Muslims wash up before prayers. Did you know that some bathrooms in Toronto schools are now set aside for Muslims? Did you know that the plumbing of some schools have been changed? 

Next there is the storage issue. Muslims typically pray on mats. Where are those mats going to be stored? Now a storage room is taken up. 

Now there's school discipline. How are teachers supposed to know what's going on in the halls when kids are wandering around outside of class time. 

Now there's assessment. Fridays are great days to do testing. Kids have had 4 solid days to learn a concept or a skill. Just before they leave for the weekend and forget everything, it would be great to test them on what they've learned. Are teachers even allowed to test on Fridays?