ITP generator — precast erection

Half the hold points on precast are in a factory two hundred miles away — and the ITP that misses them finds out on the hardstanding.

Precast is the scope where the most valuable gate happens before anything reaches site. The corpus is explicit about it: a pre-dispatch review of the manufacturer’s checksheet, with no outstanding deviations on cover, finish defects, NCRs or technical queries, is a hold point before a unit leaves the factory. Miss it and the decision you are making on the hardstanding is repair, incorporate or reject — with a crane on standby.

The second thing precast ITPs routinely under-specify is bedding. The criteria are unusually exact, they involve two different strength requirements pulling in opposite directions, and the shim material is specified by what it must not be.

It is free and there is no sign-up. Type the scope, read the whole plan on screen. Where the tool has not been given your specification, project-specific criteria come back marked TBC — EVIDENCE REQUIRED with the document that would close them named. That is the correct answer, not a limitation politely worded — an ITP that quietly fills a tolerance with a typical value is worse than one that leaves the box open, because somebody signs the first one.

What controls precast erection

These are the documents an acceptance criterion on this scope has to agree with. A criterion that restates the activity and attaches a reference is doing half the job.

• BS EN 13369 and the product standards for the unit type — Common rules for precast concrete products.
• BS EN 1504-3 — Structural and non-structural repair — the material class for infilling lifting-anchor pockets.
• BS 8500 / BS EN 206 — The concrete itself, and the cube results required before transport and before installation.
• The lift plan and the lifting-anchor datasheets — Anchor inspection, and what may be lifted with what. A signature on a lift plan is often not a technical check — acceptance may confirm only that the plan is current. The engineering gate is the peer Appointed Person check.
• The accepted temporary works design for propping — Temporary stability between placing and permanent connection.

The inspection sequence, and where the gates fall

Hold points belong where the evidence stops being recoverable, and the test is always the same question: what becomes invisible next? On this scope that puts 8 of the 20 steps below at a hold point — the rest are witness points, surveillance, review or recorded inspection depending on your contract and on who is watching.

1. Material approvals — shims, bedding mortar, sealants, joint filler
2. Unit identification labelling verified
3. [H] Temporary works design for propping accepted
4. [H] Pre-dispatch review of the manufacturer’s checksheet — no outstanding deviations on cover, finish defects, NCRs or technical queries — The last point at which a non-conforming unit is the factory’s problem rather than yours.
5. [H] Cube results provided before transportation and before installation
6. Off-loading inspection; defective units set aside for a determination of repair, incorporate or reject
7. [H] Lifting-anchor inspection against the datasheets in the lift plan
8. Storage — laid flat, air-side face downward, on timbers, no faces touching the ground
9. [H] Levelling pad cast to design elevation, cured and surveyed
10. Bedding detail prepared — grout with prepared joint surface, nylon shims and compressible strip former, or shims only
11. Setting out and formation-level checks at the stated centres
12. Unit delivery and damage check
13. [H] Installation to line, gap and alignment tolerance
14. Temporary propping — two per element, anchored, permit to load
15. Bedding-mortar trial testing — flow cone, flow between glass plates, compressive strength, expansion, water absorption, elastic stability
16. Grouting, with every batch tested — flow cone and cubes
17. Lifting-anchor pockets infilled with a BS EN 1504-3 CE-marked material per the manufacturer’s repair procedure
18. [H] Prop removal on issue of a permit to load
19. Joint filler board and sealing — joint gap clean and dry, concrete masked so sealant does not adhere to exposed faces and the tape does not stain
20. [H] Full quality-assurance packs received, reviewed and correct

One rule that catches people and is not negotiable: hold points cascade upward. Where the client, the designer or a third party has identified an intervention as a hold point, it is a hold point in your column too. You cannot accept theirs and keep yours as a witness.

Acceptance criteria that survive a review

The acceptance-criteria column header in one real template is the whole test: what answer should we get if it is right? If the entry does not let a third party, months later, decide pass or fail from the record alone, it is not an acceptance criterion. These are from issued ITPs on this scope — not composed as illustrations:

• Front faces of adjacent panels shall not be out of line by more than 10 mm at any point; nominal 20 mm gap between adjacent parapet elements, ±10 mm.
• Bedding mortar compressive strength not less than 50 N/mm²; bedding material 28-day compressive strength not greater than 10 N/mm²; permanent metal shims not permitted — permanent levelling shims to be nylon, sized such that the induced compressive stress does not exceed 0.6 fck of the precast unit or the supporting structure.
• Levelling pad cast to design elevation with tolerance +0/−5 mm; minimum 12 hours cure before setting panels.
• Cube results provided before transportation and before installation, to demonstrate compliance and suitability to lift; lifting anchors inspected against the datasheets in the lift plan.
• Panels stored laid flat, air-side face downward, on timbers; no faces touching the ground; not stood on end; stacks of no more than five.

Against which, the ones that get marked every time: as per design · as specified in the material approval form · as per manufacturer’s instruction · document accepted · within accepted tolerances · acceptable to use · visual inspection · see notes. They fail for one reason: they defer the criterion to a document the inspector does not have on the deck, and they give the person signing nothing to be wrong about.

What comes back TBC on this scope, and where it comes from

The generator does not have your specification, so it will not invent these. It marks them and names the document that would close them:

• The alignment, gap and step tolerances for your unit type
• The bedding system — and both strength requirements, which are not the same number
• Propping duration and the release criterion
• The manufacturer’s repair procedure reference for anchor pockets
• Which QA pack documents the client requires, and when

Other scopes

• ITP generator — in-situ reinforced concrete
• ITP generator — earthworks and fill
• ITP generator — drainage
• ITP generator — formwork and falsework
• ITP generator — waterproofing

Why the generated draft is a draft, and stays one

Starting permanent works without an accepted ITP is a critical non-conformance in its own right, and proceeding through a hold point gets an NCR raised against you. Before this output is issued it needs the project references and drawing revisions, the criteria above completed from your specification, the responsible parties set against your own contract, the check-sheet numbering aligned — inspection item 4.12 on the ITP has to be item 4.12 on the check-sheet — and a named author, reviewer and approver.

So it says DRAFT — FOR COMPETENT REVIEW on its own title, and should keep saying it until a competent person has been through it against the specification.