An ISO symbol used to represent a weld requirement consists of an arrow line, a multiple reference line, and the appropriate welding symbol or symbols, Figure 26.1.

The method for representing a symbol with the use of a multiple reference line is illustrated in Figure 26.2. For symmetrical welds, a single continuous reference line is used. In such cases, the dashed line is unneces­sary, Figure 26.3.

FIGURE 26.2 ■ Method of representing an ISO symbol for a weld that requires a dual reference line (solid and dashed).

The purpose of a dual reference line is to be able to readily identify to which side of a joint the welding symbol applies. When applied to the dashed line, it signifies the other side of the joint; when applied to the continuous ref­erence line, it signifies the arrow side of the joint. The dashed line may be drawn above or below the continuous line and is parallel to the continuous line, Figure 26.4.

In Figure 26.1, note that a tail is not included as an integral part of the symbol, and there is no term used to identify the total symbol (in the case of AWS symbology, it is identified as a “welding symbol”). In addition, whereas AWS basic symbols are identified as weld symbols,

ISO identifies its comparable elementary sym­bols as welding symbols. A comparison of ISO and AWS symbols is illustrated in Table 26.9.

Arrow Side, Other Side Significance

The arrow side, other side significance of a joint is the same for an ISO symbol and an AWS symbol. Examples are illustrated in Figure 26.5.

FIGURE 26.6(0, b) ■ Method for indicating which member of a joint is to be prepared.

Method for Indicating Which Member of a Joint Is to Be Prepared

An ISO symbol does not provide for the use of a broken arrow line to indicate which joint member of a groove weld is to be prepared. However, it is indicated by an unbroken arrow line as illustrated in Figure 26.6. When the direction of the arrow points toward the upper member of the joint, it indicates that the upper member is to be prepared, Figure 26.6(a). Conversely, when it points toward the lower member, it indicates that the lower member is to be prepared, Figure 26.6(b).