Hydronic (Commercial) Perimeter Convector Temperature

Brad White_192

Hi Dave!

I do not have specific data but as part of commissioning several buildings with fin tube, I got readings of about 105-110 by my memory at the tops with about 180F entering the tubes. To be fair, at the time, the water temperature was not specifically noted but was "up there" being in the dead of winter during a heat soak.

My measurement were with a Raytek IR gun, more as a binary function of "yes, radiation is on" than for recording specific temperatures. This was on two-tier 18-inch high cover by the way.

A recent school with fin-tube (system playing catch-up and running 170F to the spaces at the time) under old brass fret grilles behind bleachers, I measured 94-95 degrees at the top. Of course there was a lot of bypass air dilution.

On a more recent building with condensing boilers (using 140F design in the top tube and descending in series to the bottom tube in counterflow) I read about 90-95 F.. Again, no concurrent water temperature noted and measurements for binary check purposes.

You can imagine a taller enclosure drawing more air in dilution even if not bypass, not knowing the temperature of that air- (always 65? HA!), all of those variables, I can see how it would take a lab setup to determine what you seek.

A more specific application was for some hospital work I was doing in NY state some years ago. The NY Dept. of Health stipulated a maximum 125F surface temperature to avoid scalding.

Specifically they allowed fin tube but forbade standing cast iron or in our case, Runtal panels unless we had a "fail to cold" mix-down system of compensated water. So, in NY state at least, fin-tube gets the "under 125F nod" FWIW.

Not definitive data (someone else may chime in) but my experience anyway.

Brad

Dave Elovitz

Commercail convector surface temperature

Does anyone have any data on the surface temperature of the enclosure of commercial (slope-top) perimeter convectors at various hot water temperatures in the finned element?