In January's article on radiant heating, Paul
Hanke discussed the use of polybutylene (PB)
plastic, cross-linked polyethelene (PEX) plastic
and EPDM rubber tubing as alternatives to copper
pipe in hydronic radiant slabs. As he mentioned,
each of these products is susceptible to
the phenomenon of "oxygen diffusion,'' which
can cause corrosion elsewhere in the system.
This month, Paul expands on the issue with
this special, in-depth report. He explains how
the problem arises, its extent, and what can be
done about it during the design and installation
of radiant heating systems.
Most readers probably are aware that water
in the form of gas (i.e., vapor) can pass
through the solid walls of a house. It