How strong is pvc pipe?

 I'm trying to build a bed loft type thing similar to this

I'm thinking about using pvc pipe though because its cheaper/easier, but my only worry is if it will  hold weight. I want to put a hammock on the bottom (occasionally 2 people so ~250lbs) and a piece of plywood on top to make a shelf. 


You'll need to use a well braced design with it, not only because the PVC's weaker but it's also much more flexible, so you'd have a lot of rocking.

It might not be easy to build a bed out of PVC in terms of price, because you'd be using more pipe...