In the operation of welding, the pipes are lined up so that they are welded in the extremities and, for this, are necessary that the welding machines are carried throughout the passage. During this process, the workers are displayed to the noises emitted for the tractor that carries the machines, for the noise emitted for the retroescavadeira that raise the pipes it lines up and them, for the sanders that rectify laces of weld and for the proper weld machines. After the welding of the pipes in its extremities, the area is displayed causing its oxidation, that is removed through the jateamento for, after that, to be coated by a blanket of protection against corrosion. The high level of noise is generated during the jateamento for the compressor, the escavadeira, for agricultural tractor that carries all the equipment and for the equipment of jateamento properly said. As the passage of the Cacimbas-Bar gas-line of the Stream he is very extensive, the pertinent activities to its construction constantly changed of place, becoming thus a itinerante workmanship. Due to this mobility, the measurements of noise had not been carried through always in the same local but, yes as the team if dislocated throughout the stretch. Therefore, the measurements in those stretches had been prevented where it could occur interference of the external way in the measurement, as for example in next places them highways, where the vehicles mainly of great transport emit a level of significant noise, in places next to plants or close to noisy activities that could influence directly in the values of the measured sound pressure levels. In such a way, it was looked to evaluate the noises emitted only and so only for the specific equipment of the evaluated activity and without the interference of external sources. main emitting sources of noise, of the activities of welding and jateamento, are listed in Table 01, together with the NPS emitted for each one..