There are two codes now. One is a sealing application, so it's a vapour barrier, basically, a very thick piece of plastic that goes under the concrete slab, and there's also a rough-in for a radon mitigation system. One of the most significant parts of installing a radon reduction system is having to core through that slab. If you have that four-inch PVC pipe there, capped, and it's available, it's much easier to install a radon reduction system.
On June 18th, 2015. See this statement in context.