Do I need a China VISA to fly from Montreal to Hong Kong with a 12 hres transit at Beijing airport?

I know I dont need VISA for Hong Kong, but for Beijing, I read on www.visaforchina.org that I dont need one if I stay on airport territory for less than 24 hrs, but I want one more opinion. I never passed by China Mainland so I am not taking any chance for my next trip...