Civil Engineering Reference
In-Depth Information
16 Non-destructive testing symbols - AWS
ANSI/AWS A2.4-98 includes a comprehensive system to indicate
the requirements for non-destructive testing (NDT) on a drawing, but
in ISO 2553: 1992 there is no reference to NDT.
The AWS letter designations for NDT are listed in
Table 16.1
.
Table 16.1
The AWS letter designations for non-destructive testing (NDT)
Type of test
Symbol
Acoustic emission
AET
Electromagnetic
ET
Leak
LT
Magnetic particle
MT
Neutron radiographic
NRT
Penetrant
PT
Proof
PRT
Radiographic
RT
Ultrasonic
UT
Visual
VT
A note of caution is necessary regarding the visual testing symbol
VT because many drawings, probably the majority, will be issued
without symbols for NDT. This should not be taken to imply that
visual inspection is not required. It is essential and should be
obvious that all welded components should be visually inspected as
a matter of routine.
An application of symbols for NDT is shown in
Fig. 16.1
in which
the symbols are placed on a reference line, as for weld symbols, with
an arrow line pointing to the welded joint.
VT + UT
RT + PT
16.1
Welding and non-destructive
testing (NDT) symbols for a branch to
cylinder weld and a cap to branch weld
(AWS).
It should be noted that, in contrast to the arrow for welding
symbols, the arrow for NDT always points to the weld to be tested
and never refers to a weld on the other side of the joint. If a double
