The most expensive survey is the one nobody can open. A PAS 128 site visit that returns only a marked-up PDF forces every designer to digitise the same lines again, usually without the quality levels. Specify the file format in the instruction.
CAD is the civils default: 2D DWG or equivalent in the project coordinate system, layered by owner or type, with a quality-level attribute that survives a copy-paste into the drainage model. NJUG colours help humans. They do not replace QL labels.
GIS is the asset-owner default. Local authorities and framework contractors often live in a georeferenced stack. Issuing both from the same surveyed geometry is cheaper than running a second survey because someone forgot to ask.
Chamber cards and photographs belong with the model. A duct route that was visible in a cover should not exist only in a surveyor’s memory. Residual-risk notes belong there too: the GPR gap under the slab, the owner who never returned a plan, the assumed crossing you chose not to expose.
The CICES client guide treats presentation as part of the specification. So do we. Read underground utility mapping for how this practice issues files, and send your employer’s information requirements with the quote request if you already have a layer standard.
Coordinate systems are not a footnote. A beautiful DWG in the wrong grid will clash with the topographic survey by a constant that everyone will argue about for a week. Name OSGB36 / British National Grid or the project grid in the instruction. Attach the topo if it exists.
Attributes should survive export. If quality levels live only as text on a sheet and not as data on the segment, the first person who copies the line into another file will lose them. That is a deliverable defect, not a user error.
PDF remains useful as a viewing copy. It is a terrible sole deliverable. If a supplier says the model is “too complex for CAD”, ask what they think the drainage engineer is going to do with a picture.
Versioning belongs in the filename and in a revision cloud, not in an email subject that says “final2_reallyfinal”. When a trial hole upgrades a segment, issue a new revision. Future you will need to know which drawing the excavator held.
Plot styles should be boring. A rainbow of house colours that ignore NJUG or the client’s standard will be redrawn by the next person, and the quality levels will fall off in the redraw.
Issue a viewing PDF and the model together. Some people on the project will only ever open the PDF. They still need the key. The people who model drainage need the file that is not a picture.
If you cannot name the coordinate system, you are not ready to accept a deliverable. Ask. Then write it on the title block so the next consultant does not have to guess.
A usable PAS 128 file is one a stranger can open in six months and still see how each line was evidenced. If your current supplier cannot describe that file in a paragraph, you do not yet have a deliverable standard. Write one before the next instruction.
Take this into the brief
Agree the file test before anyone surveys: a stranger on the design team should open the CAD or GIS, see a quality level on a segment, and find the residual-risk note without telephoning the surveyor. If that test fails, you have a picture, not a deliverable.
British National Grid or the project grid should appear on the title block. Layer names should be dull. Revisions should be dated. Those three habits are how a PAS 128 file survives contact with the next consultant, which is the only audience that matters once the van has left.