WORKSHOP DRAWINGS

As far as I know, drawing approval comes when the engineer/supervisor in charge of the project has no more changes to be made to the drawings. This will vary according to the company procedures, feedback from the client, the progress of the project, etc.

As-built drawings are for items that have already been made or built, and no drawing for the item exists, but is needed. Someone, usually a drafter or technician, has to take measurements of the object before the drawing can be made.

3Doug,

I agree with you but want to add a little more from my perspective in ISO factories.

Drawing approval usually takes place whenever you need to lock into the revision level process. At the simplest, that means before the drawing is sent to a vendor or to the manufacturing floor. If there is a Critical Ddesign Review involving the customer and/or other shops, the drawing may have to be approved at that time.

If the drawings are for a limited quantity, or for a pilot production, changes will be made at the production level as mistakes are caught. Those changes will typically be recorded on a single set of "as-built" red-lines with appropriate notes and approvals on the drawings. Those red-lines will then be preserved and turned into a proper "as-built" drawing.

The whole idea is that, if you know the date a piece was manfacured, you know all the details.

In addition to the above, the approval processes and business procedures will vary with engineering discipline.

To illustrate, while civil, structural and mechanical drawings sometimes require a high level of confidence before formal approval, so as to minimise any time-and-cost-of-rework implications, the same is not necessarily so of control system drawings, where simple modifications to wiring can be carried out during functional testing, if necessary. It is commonplace for drawings to be revved-up from the final "for construction" issue to the "as shipped" issue while the equipment is being packed ready for despatch.

During construction, various minor changes can occur and be marked by the construction office on the "as shipped" issues, which then return to the Drawing Office at a late stage in the commissioning process for up-revving to "as built".

An "as-built" drawing is especially valuable as a final record for a project, particularly if a problem arises and the location of the problem is some distance away. All parties can then discuss the problem over the drawing, and resolve it without all needing to travel to Site.

Remember the basic task of a drawing is to COMMUNICATE!

"A picture is worth 10³ words." That sort of thing.