What is the meaning of the As-built stamp on pipeline construction drawings?

The last edit to this post was made by The wise are enlightened on 2011-9-20 at 09:58. The main functions of a pipeline single-line diagram are as follows: 1. For thermal steam pipelines, stress calculations are required; therefore, a systematic diagram in single-line form must be provided to the pipeline engineering team； 2. The fittings for large-diameter pipes are relatively large in size; using a single-line diagram for material calculation yields more accurate results, which helps to save on costs ； 3. For construction, a single-line diagram allows for advance material cutting and pipeline prefabrication. Single-line diagrams are easy to read, simple to construct, and convenient for providing technical instructions ； 4. Single-line diagrams can clearly show all the fittings and valves along the pipelines, making it easy to keep track of the materials used; all materials are readily visible, ensuring accurate ordering ； 5. With a single-line diagram, the construction speed can be increased, improving work efficiency.

During the construction process, it is possible to discover some unreasonable aspects in the construction drawings, such as improper layout of pipelines, or situations where insufficient space exists for certain pipelines due to the addition of insulation material, requiring changes in their route. Adjustments are made to the pipeline routes based on actual needs. After completion of construction, certain changes to the drawings must be made according to the actual conditions on site; generally, these changes are made directly on the original blueprints, with the modified areas marked as as-built drawings, which are then archived for future reference. In other words, as-built drawings represent the layout of all pipelines and equipment at the site after construction is complete. LS has explained very clearly the purpose of the single-line diagrams: in actual construction, pipeline installation is carried out according to the blueprints, as single-line diagrams are merely axonometric views that indicate direction only, and their main use is for tracking materials and welding points

Reply to 3# yuanyongan: Thank you. Does \"blueprint\" refer to the original construction drawings that we take to the site? The drawing that was kept in a pressure testing bag after completion?

A blueprint refers to the original construction drawing for a project site. When changes are needed during construction, a request for approval of those changes is sent to the design firm. In China, design firms generally do not make changes directly on the original drawings; such firms almost no longer exist these days. However, they will confirm the requests for changes submitted by you. The drawings that need to be kept after completion are those on which you made the changes – you must affix a stamp from your company indicating that changes were made (I can’t remember exactly what kind of stamp it is), and also number them along with the corresponding request form for easy reference in the future. Each modified blueprint should be stamped with your company’s completion stamp for storage

For some projects in the past (and, of course, most of those projects were also small-scale), the design institute would only provide the plan views of the pipes; it was usually the construction party that created the hand-drawn single-line diagrams on site (to facilitate material cutting, counting of welds, and preparing documents for pressure testing, etc.). At present, some of the larger design institutes in China have adopted modeling software such as PDS or PDMS, which allows for the extraction of pipeline schematic diagrams and relevant data on pipeline materials directly from the models. However, a single-line diagram is not a mandatory design document (thus, it is usually provided in white format rather than in blueprint form); as part of the handover documents, markings are generally made on the pipeline layout in the blueprint, which is then stamped with the as-built seal, along with signatures from relevant personnel from the construction and supervision units. For large-scale projects these days, the client usually requests that the design firm prepare an official as-built drawing at the end (of course, this comes at an additional cost, as it is not part of the design fees).

Reply to 6# cage_zhao: Thank you, Cage-Zhao. Now I understand what blueprints are. Before, people would draw schematic diagrams manually based on the actual site conditions to facilitate construction, material cutting, and the preparation of pressure testing kits… Now, modeling software like PDMS saves us a lot of work, but it also reduces our ability to think and act independently.