pex degradation from UV exposure

[Deleted User]

I knew pex was not to be exposed to direct sunlight, but have recently read that pex should not be exposed to indirect sunlight or flourescent light for that matter. I may have shot myself in the foot on this one. I 'gradually' (over a few years) converted rooms from convectors to staple-up radiant. I placed the pex in the bays (a few yrs ago), but never stapled and insulated until I was ready to convert a room over (I know...not the most effecient way to proceed). Is the pex any good? I know pex degrades with exposure but I couldn't find any info that quantifies the degradation. What are the risks? Are there any telltale signs of premature failure? Arrrgh. Thanks! jd

BAB

stress

PEX is cross-linked polyethylene. When overstressed by sunlight, chemicals & such the surface may become more cloudy or turn a very slight color, usually whitish or yellowish. High stress areas like sharp bends, corners or squashed tubing may exhibit very very small stress cracks. Even with all the above slightly visible stress degragation the material may never fail until moved, vibrated or flexed. Like a stressed windshield as a result of a thrown pebble, it may go on for years. But when the right extenal force is applied in just the right way the overstressed material will instantly fail.

Bob Bona_4

Uponor

gives a month of UV exposure and then all bets are off.

I would agree, and also if you can't read the printing on the pipe anymore, I would say the barrier is gone

Ron Gillen

Get the Rep's number

I would call your supplier and get the Rep's number for advice. If indirect UV in the joist bays is an issue, there must be a million unfinished basements that need their tubing replaced. I can't see that being the case. I once saw a video of Wirsbo tubing that has been under constant test for 30 some years and the room was very bright.Don't know what the source of the light was.