3.14 Extent of Welding Denoted by Symbols
When the length of a weld is not specified in the symbol, the welded length is the one between abrupt
changes in the direction of welding.
The length of weld may also be designated by a dimensional length of hatching.
As its name implies, the all-around welding symbol specifies the weld all around the joint, regardless of
the number of planes involved.
The section on fillet welds reviews all of the above variations to the extent of welding, as covered by a
welding symbol with or without supporting dimensioning.
When intermittent welds are required in the length of a joint, they should be dimensioned by the
welding symbol in a manner as shown and thoroughly discussed in the section on fillet welds.
Groove welds are normally continuous for the full length of the joint, in which case no reference to
length is needed in the welding symbol.
3.15 Multiple Reference Lines
The very objective of the multiple reference line concept is to give the welding symbol the added
capability to specify the sequence of welding operations as well as to provide additional information
relative to the examination of welds or other operations.
Two or more reference lines are feasible. They should, however, be used with good judgment.
The rule that applies to sequencing is very clear. It states that the operation that is desired first is to be
shown on the reference line closest to the arrow. All subsequent operations are to follow the same
sequencing order as the pertinent reference lines move away from the arrow. The welding symbol
shown in Figure 3.34 explains this principle: