The plant is built twice.
The first time on paper.
Before a foundation is poured, the whole plant exists as a design basis, a mass balance, a P&ID and a set of drawings that a site can build from. That is the part of the job we are actually good at — and the part that decides whether the plant runs at rate in its first month or its third year.
Everything starts with one document.
The design basis is a short document — usually six to ten pages — that fixes what the plant must do and what it must do it with. Every drawing after it is a consequence.
We write it together with the client before any drawing is started. It records the product and grade, target output and shift pattern, raw material assay and source, site conditions, utilities, discharge limits and the standards the plant must meet. It is signed by both parties. When a question comes up in month seven — and it always does — the answer is in that document, not in somebody's memory of a meeting.
| Subject | What the basis fixes | Who provides |
|---|---|---|
| Product | Grade, Al2O3 content, solid or liquid, packaging | Client |
| Capacity | Tonnes per year, batches per day, shift pattern, design margin | Client + GARUN |
| Raw material | Alumina source, acid concentration, assay, impurities, delivery form | Client |
| Site | Location, dimensions, plot plan, soil bearing capacity, flood level | Client |
| Utilities | Power (kV, kVA), steam (pressure, t/h), water, compressed air, drainage | Client + GARUN |
| Emissions | Stack limits for HCl and particulates, noise, effluent limits | Client / authority |
| Standards | Pressure, structural, electrical and safety codes to be applied | Client + GARUN |
Where the client cannot supply a figure, we state the assumption in writing and flag it as a design risk. Assumptions that stay hidden are what turn into variation orders.
Four stages, four sets of drawings.
Each stage ends with a defined deliverable and a client approval gate. Nothing moves to the next stage until the previous one is signed off — which is how a project stays on schedule instead of unravelling in the last month.
Concept & feasibility
Week 1-2Route selection, capacity model and a plot plan. We compare the acid route against alternatives on capital, operating cost and product quality.
- Design basis
- Block flow diagram
- Capacity & cost model
- Plot plan option study
Basic engineering
Week 3-6The process is frozen here. Mass and heat balance, PFD, equipment list and datasheets that are firm enough to send out for quotation.
- Mass & heat balance
- PFD
- Equipment list & datasheets
- Utility summary
Detailed engineering
Week 6-14Every drawing the site builds from, produced from a 3D model and clash-checked before release. Vendor data is incorporated, not assumed.
- P&ID & GA
- Foundation loads
- Piping isometrics
- Electrical & control
As-built & handover
At commissioningDrawings corrected to what was installed, with test records and the O&M manual, bound into a handover set the client can operate from.
- As-built register
- Test records
- O&M manual
- Spare parts list
What 200 sheets actually contain.
A drawing set is not a pile of paper — it is an indexed, revision-controlled package in which every sheet has a number, a purpose and a status.
| GR-PFD-001 | Process flow diagramEvery stream with flow, temperature, pressure and composition; the basis for the mass balance and the utility summary. | A1 / PDF |
| GR-PID-010…019 | Piping & instrumentation diagramsLine numbering, instrument tags, control loops, interlock philosophy. One sheet per process area, not one for the whole plant. | A1 / DWG |
| GR-GA-101/102 | General arrangement — plan and sectionsEquipment layout with maintenance access, operator routes, escape routes and future expansion space shown. | A1 / DWG |
| GR-EQ-201…212 | Equipment general arrangement drawingsOne per equipment tag: dimensions, nozzle schedule, support loads, lining and insulation. The drawing a fabricator builds from. | A1 / DWG |
| GR-FD-301/302 | Foundation layout and load tableAnchor bolt layouts, embedded plates, static and dynamic loads, grout details. What the civil contractor needs, in the form they need it. | A1 / DWG |
| GR-ST-401 | Structural steel and platform scheduleBeam sizes, connection details, handrail and access platforms for elevated equipment. | A1 / DWG |
| GR-PI-501…5xx | Piping isometricsOne per line: spool breakdown, bill of materials, weld numbering, support locations. This is what makes site piping quick. | A3 / DWG |
| GR-EL-601/602 | Single-line diagram and cable scheduleLoad list, breaker sizing, cable routes, earthing. Issued with the motor list so the client can order cable locally. | A1 / DWG |
| GR-IC-701 | Instrument index and loop drawingsTag, service, range, alarm and trip settings, loop diagram for each control loop. | A3 / PDF |
| GR-SP-801 | Equipment datasheetsOne per tag: duty, materials, design conditions, connections, inspection requirements. | A4 / PDF |
| GR-AB-001 | As-built registerRevision index against the issued-for-construction set, with every change recorded and every red-line markup closed out. | A4 / PDF |
The register above is the core. A live project also carries utility distribution, insulation and painting schedules, lifting plans for heavy vessels, a safety and hazard review record, and the commissioning procedures — typically another forty to sixty sheets.
How a drawing gets approved.
Four review points, each with a defined deliverable and a fixed comment period. This is the discipline that keeps a design honest.
- 01
30% review — layout and process
PFD, plot plan, equipment list and the first GA. The client confirms the process route and the space allocation before anything is detailed. Comment period: 5 working days.
- 02
60% review — mechanical and civil
Equipment GA drawings, foundation loads and the structural concept. The civil contractor can start here, which is usually the real schedule constraint.
- 03
90% review — everything else
P&ID complete, piping isometrics, electrical and instrumentation. This is the last point at which a change costs engineering time rather than steel.
- 04
IFC release — issued for construction
Signed, stamped and released to site. Every later change becomes a revision with a cost and schedule consequence, recorded in the register.
Internally every discipline drawing passes a check by a second engineer before it reaches the client. Calculations are filed with the drawing they support, so the reason for a 1,500 mm nozzle elevation is traceable three years later.
Modelled, clash-checked, then drawn.
We build the plant as a 3D model first. Drawings are cut from the model, which means the plan, the section and the isometric cannot disagree with each other.
The model is used for three things beyond drawing production: clash detection between pipework, steel and equipment; extracting accurate bills of material so the procurement list matches the design; and walking the client through the plant before it exists. On overseas projects that last point saves an enormous amount of correspondence.
- Clash check at 60% and again at 90%, with every collision resolved or accepted in writing
- Nozzle orientation agreed with the vessel fabricator before the GA is released — not after the vessel is built
- Maintenance envelopes drawn into the model: can the dryer drum be changed, can the impeller be lifted out
- Neutral model export (STEP or IFC) available if the client wants to coordinate with their own civil and structural design
Who actually draws it.
A project team of five to eight people, led by one process engineer who stays with the job from the first call to the as-built set.
Process engineer
Owns the design basis, the mass and heat balance and the P&ID. The single point of technical accountability for the whole plant.
Mechanical draughting
Equipment GA drawings, nozzle schedules, lining and insulation details, fabrication drawings released to the workshop.
Layout and foundations
Plot plan, foundation loads, anchor layouts, steel and platform schedules, co-ordinated with the client's civil contractor.
Electrical and instrumentation
Load list, single-line diagram, cable schedule, instrument index, control philosophy and interlock schedule.
Piping is detailed by the same team that produced the GA, which is why the isometrics and the layout agree. On a turnkey project the site supervision comes from this team as well — the person answering the site query has usually drawn the sheet in question.
What you receive, in what format.
| Deliverable | Content | Format |
|---|---|---|
| Design basis | Capacity, materials, utilities, standards, assumptions | |
| Mass & heat balance | Stream table, utility consumption, yield | XLS / PDF |
| PFD & P&ID | Process flow, line and instrument numbering, control loops | DWG / PDF |
| General arrangement | Plan, sections, maintenance access, expansion space | DWG / PDF |
| Equipment drawings | GA per tag, nozzle schedule, support loads | DWG / PDF |
| Civil package | Foundation layout, load table, anchor and embedded plates | DWG / PDF |
| Piping package | Isometrics, support schedule, bill of materials | DWG / PDF |
| Electrical package | Load list, single-line diagram, cable and earthing schedule | DWG / PDF |
| Instrument package | Index, datasheets, loop drawings, interlock schedule | PDF / XLS |
| 3D model | Clash-checked plant model | STEP / IFC on request |
| O&M manual | Operating sequence, troubleshooting, spares, maintenance plan | |
| As-built register | Revision index and closed-out red-line markups |
Drawings are issued in English as standard. Metric dimensions; imperial conversion on request.