How to store bulk gas products and reagents? Suppose I'm doing a batch process where an intermediate (non-hazardous) reagent is a gas, and I need to produce and temporarily store something on the order of a cubic meter of it to later feed back into a reaction.  Assuming the gas can't be condensed at anywhere near STP, isn't there some sort of standard flexible lab gas storage apparatus?

I've been looking for something like a large mylar (or other relatively impermeable) bag with a tube insert I can put on a barb and valve.  Either I don't know what this would be called, or it doesn't exist and I should be using something else.

I realize I could try to pump out a large rigid container, but once we're talking about a few cubic meters, and trying to avoid contamination, that seems like a pain compared to a flexible gas bag.
It probably depends on local regulations and the properties of the intermediates!

Gas bags might indeed be a viable solution. 

In the biogas community, see SolarCities for an example, PVC bags from PUXIN, a chinese supplier, are quite popular.