API STD1104, ASME/ANSI B31.4, ASME/ANSI B31.8
Table 3-1 is applicable in determining the size and type of discontinuities when viewing
radiographs for final acceptance in accordance with API STD 1104, ASME/ANSI
B31.4, Paragraph 434.8.5, and ASME/ANSI B31.8.
Table 3-1 – Acceptance Criteria for API STD 1104
Unacceptable if any of the following conditions exist:
Indication/Defect
Inadequate Penetration
(IP) (without high-low)
Inadequate Penetration
due to High-Low (IPD)
1.
2.
3.
1.
2.
Length of an individual indication of IPD exceeds 50.8 mm (2.0").
The aggregate length of indications of IP in any continuous 304.8 mm (12")
length of weld exceeds 76.2 mm (3.0").
1.
2.
Length of an individual indication of IF exceeds 25.4 mm (1.0").
The aggregate length of indications of IF in any continuous 304.8 mm (12")
length of weld exceeds 25.4 mm (1.0").
The aggregate length of indications of IF exceeds 8% of the weld length in any
weld less than 304.8 mm (12") in length.
Incomplete Fusion (IF)
3.
Incomplete Fusion due to
Cold Lap (IFD)
1.
2.
3.
Internal Concavity (IC)
Length of an individual indication of IP exceeds 25.4 mm (1.0").
The aggregate length of indications of IP in any continuous 304.8 mm (12")
length of weld exceeds 25.4 mm (1.0").
The aggregate length of indications of IP exceeds 8% of the weld length in any
weld less than 304.8 mm (12") in length.
Length of an individual indication of IFD exceeds 50.8 mm (2.0").
The aggregate length of indications of IFD in any continuous 304.8 mm
(12") length of weld exceeds 50.8 mm (2.0").
The aggregate length of indications of IFD exceeds 8% of the weld length.
Any length of IC is acceptable provided the density of the radiographic image of
the IC does not exceed that of the thinnest adjacent base metal. For areas that exceed
the density of the thinnest adjacent base metal, the criteria for burn through are
applicable.
Pipe OD  2-3/8"
1.
2.
Burn-Through (BT)
3.
Maximum dimension exceeds
6.35 mm (¼") and the density of the BT's
image exceeds that of the thinnest
adjacent base metal
Maximum dimension exceeds the thinner
of nominal wall thicknesses joined, and
the density of the BT's image
exceeds that of the thinnest
adjacent base metal
Sum of maximum dimensions of separate
BTs whose image density exceeds that of
the thinnest adjacent base metal exceeds
12.7 mm (½") in 304.8 mm (12") of weld or
the total weld length, whichever is less.
Pipe OD < 2-3/8"
1. Maximum dimension exceeds
6.35 mm (¼") and the density of
the BT's image exceeds that of
the thinnest adjacent base metal
2. Maximum dimension exceeds the
thinner of nominal wall
thicknesses joined, and the
density of the BT's image
exceeds that of the thinnest
adjacent base metal
3. More than one BT of any size is
present and the density of more
than one of the images exceeds
that of the thinnest adjacent base
metal.
Table 3-1 – Acceptance Criteria for API STD 1104 (Cont'd)
Indication/Defect
Unacceptable if any of the following conditions exist:
Slag Inclusions
Elongated(ESI)
Isolated (ISI)
Note: ESI indications
separated by approx.
width of root bead
(wagon tracks) to be
considered as a single
indication unless the
width of either > 1/32".
In that event, they
shall be considered as
separate indications.
Pipe OD  2-3/8"
Unacceptable if:
1. ESI length > 2"
2. ESI width > 1/16"
3. Sum of the lengths of ISI > ½" in
12" of weld.
Porosity - individual /
Scattered (P)
Note: Size based on
maximum dimensions
Unacceptable if:
Porosity - Cluster (CP)
Porosity - Hollow-Bead (HB)
Cracks (C)
4. Width of ISI > 1/8"
5. > 4 ISI with maximum width of
1/8" in any 12" of weld.
6. Sum of the lengths of ESI & ISI >
8% of weld length.
Pipe OD < 2-3/8"
Unacceptable if:
1. ESI > 3 X nominal WT of the
thinner thickness joined.
2. ESI width > 1/16"
3. Sum of ISI lengths > 2 X nominal
WT of thinner thickness joined
and ISI width > ½ nominal WT of
thinner thickness joined.
4. Aggregate length of ESI & ISI >
8% of weld length.
1. Size of individual pore > 1/8"
2. Size of individual pore > 25% of thinner WT joined
3. Distribution of Porosity exceeds API STD 1104 Porosity Charts.
Unacceptable if:
1. CP dia. > ½"
2. Aggregate length of CP > ½" in any continuous 12" of weld
3. An individual pore within a cluster > 1/16" in size.
Unacceptable if:
1. Length of individual HB > ½"
2. Sum of HB lengths > 2" in any continuous 12" of weld
3. Individual HB > ¼" separated by < 2"
4. Sum of HB lengths > 8% weld length.
Any size or location of cracks are unacceptable except for shallow crater or
star cracks. Shallow crater or star crack length > 5/32" is unacceptable.
Undercutting
Adjacent to cover pass
(EU) Adjacent to root pass
(IU)
Tungsten
Inclusions
Unacceptable if:
Accumulation of
Discontinuities
Excluding IPD, EU & IU
Unacceptable if:
1. Sum lengths of indications > 2" in any continuous 12" of weld.
2. Sum lengths of indication > 8% of weld length.
Pipe / Fitting Discontinuities
1. Any combination EU & IU length > 2" in any continuous 12" of weld.
2. Sum of EU & IU lengths in any combination > 1/6 of weld length.
Individual tungsten inclusions are be evaluated as rounded indications
(Porosity). Elongated or aligned tungsten inclusions are unacceptable.
Arc burns, long seam discontinuities and other discontinuities in the pipe or
fittings detected by RT shall be recordable.