A weld is indicated on a drawing by (1) a symbol (Fig. A1. 1a) and (2) an arrow connected at an angle to a reference line usually drawn parallel to the bottom of the drawing (Fig. A1. 1b). The side of the joint on which the arrow is placed is known as the ‘arrow side’ to differentiate it from the ‘other side’ (Fig. A1. 1c). If the weld symbol is placed below the reference line, the weld face is on the arrow-side of the joint, while if the symbol is above the reference line the weld face is on the other side of the joint (Fig. A1. 1c). Symbols on both sides of the reference line indicate welds to be made on both sides of the joint while if the symbol is across the reference line the weld is within the plane of the joint. A circle where arrow line meets reference line indicates that it should be a peripheral (all round) weld, while a blacked in flag at this point denotes an ‘on site’ weld (Fig. A1. 1d). Intermittent runs of welding are indicated by figures denoting the welded portions, and figures in brackets the non-welded portions, after the symbol (Fig. A1. 1e). A figure before the symbol for a fillet weld indicates the leg length. If the design throat thickness is to be included, the leg length is prefixed with the letter ‘b’ and the throat thickness with the letter ‘a’.