Previous chapters have covered those defects and losses in strength that may be described as arising from metallurgical effects. This chapter covers those defects that may be described as defects of geometry, their causes and the non-destructive testing techniques that may be used to detect them. Many of these defects are caused by the welder, because of either a lack of care or a lack of skill, and emphasise the need for adequate training. Similarly, if non-destructive testing is to be correctly performed and defects accurately identified and sized, well-trained and experienced nondestructive evaluation (NDE) operatives are needed. A simple and inexpensive non-destructive examination technique that is sometimes overlooked is that of a thorough visual examination by a suitably trained and experienced welding inspector. Such an examination will identify many defects, particularly those of shape as listed in Section 11.2 below.