UW-11(a)(5)(b)/UW-12(d) - Type (2) Joggled Heads
UW-11(a)(5)(b)/UW-12(d) - Type (2) Joggled Heads
(OP)
I have the following design scenario:
Two seamless Type No. 2 joggled heads with one plate offset being welded to a rolled cylindrical shell that has a long seam.
Per UW-12(d), thickness calculations of seamless heads can use a value of E=1.0 when Spot RT per UW-11(a)(5)(b) is met and E=0.85 when Spot RT is not met. UW-12(d) applies to Type No. 1 and Type No. 2 joints.
My questions are:
(1) Do the values presented in UW-12(d) override those listed in Table 12 for Type No. 2 joints?
(2) In order to meet Spot RT per UW-11(a)(5)(b) and in fact use E=1.0, am I required to complete a spot RT shot for each of the head to shell circumferential seams of the respective vessel OR is one shot sufficient for both circumferential seams (or more for identical vessels) if the increment is less than 50ft and there is only one welder/welding operator?
Ryan
Two seamless Type No. 2 joggled heads with one plate offset being welded to a rolled cylindrical shell that has a long seam.
Per UW-12(d), thickness calculations of seamless heads can use a value of E=1.0 when Spot RT per UW-11(a)(5)(b) is met and E=0.85 when Spot RT is not met. UW-12(d) applies to Type No. 1 and Type No. 2 joints.
My questions are:
(1) Do the values presented in UW-12(d) override those listed in Table 12 for Type No. 2 joints?
(2) In order to meet Spot RT per UW-11(a)(5)(b) and in fact use E=1.0, am I required to complete a spot RT shot for each of the head to shell circumferential seams of the respective vessel OR is one shot sufficient for both circumferential seams (or more for identical vessels) if the increment is less than 50ft and there is only one welder/welding operator?
Ryan





RE: UW-11(a)(5)(b)/UW-12(d) - Type (2) Joggled Heads
In general if spot RT is used at the round seam to give the head E = 1.0, then that spot cannot be used to satisfy spot requirements for the rest of the vessel as per UW-11(a)(5)(b).
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: UW-11(a)(5)(b)/UW-12(d) - Type (2) Joggled Heads
I tend to agree with you on your statement that the spot cannot be used to satisfy other spot requirements for the rest of the vessel. However, UW-11(a)(5)(b) says, "as a minimum, meet the requirements for spot radiography in accordance with UW-52." And UW-52 specifies the minimum extent of examination, i.e. 50 ft increments per welder/welding operator.
Regards,
Ryan
RE: UW-11(a)(5)(b)/UW-12(d) - Type (2) Joggled Heads
Last sentence of UW-11(a)(5)(b) governs: "Spot radiographs required by this paragraph shall not be used to satisfy the spot radiography rules as applied to any other weld increment". Meaning, if you make use of UW-12(d) which invokes UW-11(a)(5)(b), then that shot can be used for that seam only.
Is your shell seamless or does it have a long seam?
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: UW-11(a)(5)(b)/UW-12(d) - Type (2) Joggled Heads
Thanks,
Ryan
RE: UW-11(a)(5)(b)/UW-12(d) - Type (2) Joggled Heads
RE: UW-11(a)(5)(b)/UW-12(d) - Type (2) Joggled Heads