Unreinforced branch connections EN 13480
Unreinforced branch connections EN 13480
(OP)
I have had a quick look at set-on branches DN15 (WT = 2mm) onto a DN600 (WT = 6.3mm) pipe, but my results don't meet the conditions required by BS EN 13480. The piping system design pressure = 5 bar and design temperature = 100 Deg C. I have tried adjusting wall thicknesses of the pipes but to no avail. Could anyone help me out as I know a DN15 set-on a DN600 is acceptable without re-inforcement from a demo software program.
The following is from BS EN 13480:2002 (Incorporating
amendment no. 1 and corrigendum no. 1)
8 Openings and branch connections
8.3.3 Types of reinforcement
Set-on or set-in welded branches which are only seal-welded shall not be considered as reinforcement, and shall
be calculated in accordance with 8.4.2.
8.4.2 Unreinforced openings
Reinforcement shall not be required if the following condition is met:
di <= 0.14 x SQRT(Deq x eas)
My workings for the above is:
di <= 0.14 x SQRT(Deq x eas)
19.8 <= 0.14 x SQRT (605.5 x 4.51)
19.8 <= 7.31
The following is from BS EN 13480:2002 (Incorporating
amendment no. 1 and corrigendum no. 1)
8 Openings and branch connections
8.3.3 Types of reinforcement
Set-on or set-in welded branches which are only seal-welded shall not be considered as reinforcement, and shall
be calculated in accordance with 8.4.2.
8.4.2 Unreinforced openings
Reinforcement shall not be required if the following condition is met:
di <= 0.14 x SQRT(Deq x eas)
My workings for the above is:
di <= 0.14 x SQRT(Deq x eas)
19.8 <= 0.14 x SQRT (605.5 x 4.51)
19.8 <= 7.31





RE: Unreinforced branch connections EN 13480
RE: Unreinforced branch connections EN 13480
I'm not worth it.
I'm not the calculating guy,
but my opinion in this is You should use a weldolet not smaller than DN20 and a reducer + flange DN15.
Never saw a pipespec using that small branches(dn15).
And if You still do, reinforce it with three strips ~40x4 aside the dn15 pipe.
Or You can look in API650 for nozzle welding details.
My humble opinion only.
Greetings
RE: Unreinforced branch connections EN 13480
I have seen a few of your posts and you seem to be one of the few that deal with European standards.
With regard to the sizes (DN600 and DN15), they were the first sizes that popped into my mind at the time.
I have done the calculations for reinforcing pads using a spreadsheet I have created and many of the sizes don't require re-inforcing pads, but you can only tell after the calc is done.
The initial check(Reinforcement shall not be required if the following condition is met: di <= 0.14 x SQRT(Deq x eas)) doesn't seem to hold true for any size combinations.
I can post my spreadsheet if you would like to have a look (I would need instructions as to where to upload it to).
RE: Unreinforced branch connections EN 13480
I never felt the need to calculate this.
5 bar= 50 N/cm2 on the circ. weld is very little.
(it´s just a calculation from the schoolbooks)
The issue is about the mechanical strenght in case of
damaging the nozzle.
I seldom make pipespecs myself.
Sorry to disappoint You.
Greetings