The requirements of the quality and shape of a working diagram of radiation of panoramic X-ray apparatus is analyzed in the article. The analysis is given when using them with a standard 100 mm wide of radiography roll film for of circular welds at building pipelines. The results of an experimental investigations of these diagrams for thin- and thick-wall pipes are given. The conclusions are made about the need to change the geometry of targets of panoramic X-ray tubes at radiography of welds on pipes with small diameters. Keywords: radiography, panoramic X-ray tube, directivity diagram, inspection of circular welds.