International Mechanical Code & Hydronic Tees

Dave E.

I think I must be misunderstanding this, or else it seems to outlaw diverter tees. I suppose the branch opening must be the middle opening. But then, the illustrations I've seen of the main riser from a boiler connected to the middle opening of a tee, one side to a boiler drain and the other supplying the radiation, seem to be against this code. So I still don't know what's up.

Dave E.

Code Limitation on Tees

While tinkering with my water boiler hydronic piping and reading my 2003 International Residential Code (which consists of sections of other International codes) I ran accross:

"M2101.7 Prohibited tee applications.Fluid in the supply side of a hydronic system shall not enter a tee fitting through the branch opening."

Does anyone know the reason for this? I thought it would be a good way to put a gauge in the line if I ran the supply through the branch openings and used the middle opening for the gauge.

bruce_21

I think this means bullheading a tee on the supply is outlawed. "shall not enter a tee through the branch"

Mike T., Swampeast MO

That's a prohibition against attempting to equally split flow via supply through the branch of a tee. The "middle" opening is the branch and such is perfectly suited for mounting a gauge.

[Deleted User]

NO BULL...

headed tee's allowed.

Exceptions include primary secondary applications, variable speed injection applications, and diverted prioritized flow considerations.

I attempted to write a clarification to the IMC regarding this statement, only to be told that all references to it were yanked in the new code.

Guess the enforcers couldn't interpret it either :-)

ME

Robert O'Connor_12

Section 1206.1.1

If your IMC has figure 1206.1.1 on the next page, as others have posted it is perfectly code compliant to install a gauge in the branch (bull) connection. The figure will make you aware as to this sections meaning.

1206.1.1 shows both an acceptable tee and a prohibited bull-head tee arrangement. Installation of bullhead connections creates excessive pressure drop, flow resistance and poor system perormance. The intent is to prevent supply-side fluid flow from entering the side (branch) opening of a tee when that opening connects to a main, and the straight-through (run) opening of the tee are used as branch connections flowing in opposite directions.

Hope this helps!


Robert O'Connor/NJ

Dave E.

Thanks, I'm using the International Residential Code for One- and Two-Family Dwellings, which omits figure 1206.1.1
Now I know.