Pipeline flaw detection issues
Thread Content
The gas pipeline has two branches; one is D159 with a design pressure of 0.4 MPa, and the data sheet specifies that its flaw detection and pipe grade are GC2. Another pipe has its pressure reduced to 0.08 MPa by a pressure reducing valve; it has dimensions of D108x4, with a design pressure of 0.08 MPa as well. Its length is 500 meters. This pipe is not listed in the data sheet, but the design specifications state that all welds must be inspected for defects. Question: According to the catalog of special equipment, the second pipe does not fall under the category of pressure pipes and therefore does not require inspection; but is it necessary to perform flaw detection on this pipe?
According to the Catalogue of Special Equipment (2014), this pipe does not fall under the category of pressure pipes, so it is not required to undergo inspection or registration. However, the design documents for this pipe specify that all welds must be inspected, which indicates that it was designed in accordance with the regulations applicable to pressure pipes; therefore, special attention must be paid during its installation and use.
Whether a pipeline is inspected or not has absolutely nothing to do with whether it is a pressure pipeline that requires inspection! When the design documents require flaw detection, it must be carried out without any discussion
The design pressure is below 0.1 MPa, so it falls outside the scope of pressure pipelines; however, considering the medium, it belongs to SHB3 category, and 10% inspection is sufficient – 100% would be excessive
It is necessary to set the flaw detection ratio based on the properties of the material
Starting from the 345th floor, inspections are carried out in accordance with the requirements of the design drawings. Whether inspections are conducted during use is a separate matter from the construction process; construction must be carried out strictly in line with the drawings