From issued-for-construction
to first pallet.
The drawings leave the office and the plant becomes somebody's problem on site. This page is about that part — who does what, in what order, and what has to be true before we call a plant handed over.
The order things actually happen in.
A plant is not delivered on a date, it is delivered by a sequence. Each step below has a defined output that the next step depends on.
- T0
Contract and kick-off
Scope, schedule, drawing register and communication protocol agreed. The client names one project manager with authority to approve drawings — projects with two approvers are the ones that slip.
- T0 + 2 weeks
Design basis signed
Process route, capacity, raw material, utilities and standards fixed in writing. Nothing is detailed before this document exists.
- T0 + 6–14 weeks
Detailed design and procurement
P&ID, GA, foundation loads and equipment drawings issued through the 30%, 60% and 90% review gates. Long-lead items — drums, towers, lined vessels — are ordered at 60%.
- T0 + 14–34 weeks
Fabrication and trial assembly
Built in our workshop against the released drawings, trial-assembled, inspected and photographed. Client or third-party inspection is welcome at any stage.
- T0 + 30–40 weeks
Shipping and site preparation
Packing list, loading plan, sea freight. In parallel the client completes foundations to our load table — the most common schedule risk on an overseas project.
- Site week 1–2
Receiving and erection
Site survey against the GA, setting-out, equipment placement, alignment and grouting. Our supervisor checks datum and anchor positions before any vessel is set.
- Site week 3–8
Piping, electrical and insulation
Isometrics drive the piping; the cable schedule drives the electrical work. Both are issued early enough for the local contractor to buy materials locally.
- Site week 8–11
Commissioning
Hydro-test, flushing, instrument loop check, interlock test, then cold and hot commissioning on water before any acid is introduced.
- Site week 11–14
Trial run and performance test
Continuous run at design rate, product sampled and analysed against the specification, utilities measured against the design figures.
- Handover
As-built set and training
Drawings corrected to installed condition, test records compiled, operators trained, and the as-built register signed by both parties.
What we test before we leave.
Commissioning is not switching on. It is a list of checks, each with an acceptance criterion, signed off as it is completed.
| Check | Acceptance criterion | Record |
|---|---|---|
| Hydrostatic test | Held at 1.5× design pressure, no drop over 30 min | Test sheet |
| Rotation and alignment | Agitators and drives within 0.1 mm coupling alignment | Alignment log |
| Instrument loop check | Every loop driven end to end, alarm and trip verified | Loop folder |
| Interlock test | Each interlock simulated and confirmed at the panel | Cause & effect |
| Water run | Full line run on water, no leak, pumps at design duty | Run log |
| Scrubber performance | Outlet HCl ≤ 10 mg/m³ at design gas flow | Stack test |
| Dryer performance | Output and moisture within 5% of design | Shift record |
| Product quality | Al2O3, basicity and insolubles within spec | COA |
| Bagging accuracy | Ten consecutive bags within ±0.2% | Weigh log |
| Operator competence | Shift team runs the plant unaided for 24 h | Training record |
What you keep.
The plant is the visible deliverable. The documents are the ones that decide how the next ten years go.
- As-built drawing set, every sheet re-issued at revision AB with red-line markups closed
- Equipment test records: material certificates, weld maps, lining spark test, pressure test where applicable
- O&M manual: operating sequence, start-up and shutdown, troubleshooting by symptom, maintenance schedule
- Spare parts list with recommended first-year and two-year stock, and the supplier for each part
- Commissioning report and the performance test results, signed by both parties
- Training record naming each operator and the modules completed
What clients ask about site work.
Who supervises erection?
A GARUN commissioning engineer, on site for the erection window — typically three to six weeks depending on line size. We supervise and check; the client's contractor performs the work. Where a turnkey contract covers installation, our own crew does it.
What if our contractor has never built a chemical plant?
Common, and manageable. We issue an erection sequence and method statements, hold a site briefing before work starts, and check datum and alignment at each stage. We would rather spend three extra days supervising than three weeks correcting.
How much local labour is needed?
For a 30,000 t/y line: roughly eight to twelve people for erection, four to six for piping, two electricians and two instrument technicians during commissioning.
Can commissioning happen in stages?
Yes, and often should. Reaction and settling can run and sell liquid product while the drying stage is still being erected, provided the design includes the split header from the start.
What happens if the performance test fails?
We stay and fix it. The test has defined acceptance criteria before it starts, so failure is a specific measurement, not a disagreement. Remedial work and a repeat test are at our cost within the warranty scope.