TL;DR
This as built manufacturing upgrade case study follows a Victorian food-processing plant that planned to retrofit a new high-speed packaging line into a 1980s building with drawings no one trusted. ISS captured the existing process hall with terrestrial laser scanning and total station control, delivering a georeferenced point cloud and as-built model accurate to better than +/- 3 mm — which exposed three structural clashes before steel was fabricated. The upgrade was installed inside its shutdown window with zero foundation rework.
Key takeaways
- A two-day laser scan of a 1,400 m2 process hall produced a +/- 3 mm as-built point cloud, replacing 1980s drawings that were out by up to 180 mm in places.
- Comparing the as-built model against the supplier's 3D line model found three hard clashes — a roof purlin, a stormwater downpipe, and an existing cable ladder — before any steel was cut.
- Surveying to a GDA2020 / MGA2020 Zone 55 control network on AHD levels meant the as-built tied cleanly into the wider site model and future works.
- Total project survey cost was about AUD 14,500; the avoided foundation and steel rework was quoted by the head contractor at more than AUD 90,000.
- The packaging line was installed and commissioned inside a 9-day Christmas shutdown with no survey-driven delays.
Table of contents
- The client and the upgrade
- The challenge
- ISS approach
- Equipment and standards
- What the survey found
- The result
- The outcome for the client
- Frequently asked questions
- Request a quote
The client and the upgrade
The client was a mid-sized food and beverage manufacturer operating a ready-meals plant in Melbourne's south-east industrial belt around Dandenong South. The core building dated from the mid-1980s and had been extended and re-fitted at least four times. A capital project board had approved a new high-speed tray-sealing and case-packing line to lift throughput by roughly 35 per cent, with the new line threading through an existing process hall alongside live refrigeration and services.
The head contractor's project engineer had a problem that will be familiar to anyone who has run a brownfield retrofit: the supplier's new line was designed in 3D to millimetre tolerances, but the building it had to fit into was documented only by a folder of marked-up 2D drawings, several of which contradicted each other. Before committing to fabrication, the project team needed a single, trustworthy as-built record of the space. That is where this as built manufacturing upgrade case study begins.
The challenge
Three pressures collided on this job.
The drawings could not be trusted. Forty years of undocumented modifications meant the as-designed drawings bore little resemblance to reality. Spot checks during the site walk-down found a structural column roughly 140 mm from its drawn position and a main process drain at an invert level that did not match any plan on file. Designing a tightly-toleranced line against that data was a guaranteed source of clashes and field rework.
The building stayed live until the last minute. The plant could not stop for a survey. Refrigeration, hygiene zoning, and continuous production meant any data capture had to happen around operations, with strictly limited access to the ceiling void and service runs above the line route.
The install window was fixed and short. The new line had to be craned in, set out, and mechanically completed during a single 9-day Christmas shutdown. There was no float for discovering a clash on day two and waiting on a re-fabricated bracket. Every interference had to be found and resolved on the drawing board, weeks ahead.
The combination — untrusted geometry, an operating plant, and an immovable shutdown — is exactly the scenario where an accurate as-built survey pays for itself many times over.
ISS approach
ISS scoped the work as a control-based 3D laser scanning survey of the process hall and the full route the new line would occupy, from incoming product infeed to the case-packer discharge.
1. Control first. Before any scanning, the ISS surveyor established a closed control network through the hall using a total station, observing a braced traverse and reducing it onto the existing site control. Targets were fixed to columns and walls so every scan setup and any future works would share one datum. Control is the difference between a pretty point cloud and a survey you can build from.
2. Scan around production. Over two shifts, the hall was captured from 46 scanner setups, deliberately overlapping so registration did not rely on geometry alone. Scanning was sequenced around hygiene and production constraints — the team worked the high-traffic infeed area during a planning-day downtime and captured the ceiling void and service runs from a scissor lift during a scheduled maintenance afternoon.
3. Register and verify. Scans were registered to the control targets, not just cloud-to-cloud, so absolute accuracy was demonstrable rather than assumed. The registered cloud was checked against independent total station spot points; residuals stayed inside +/- 3 mm across the hall.
4. Model and clash-check. ISS extracted an as-built model of the structure, slab, and existing services along the line route and issued it with the registered point cloud. The supplier's 3D line model was then overlaid against the real geometry to hunt for interferences.
Equipment and standards
| Item | Detail |
|---|---|
| Laser scanner | Leica RTC360 terrestrial scanner, ~1.9 mm 3D point accuracy at 10 m |
| Control instrument | Leica TS16 1" total station (closed traverse) |
| Levelling | Digital level for slab and drainage invert levels on AHD |
| Datum | GDA2020 / MGA2020 Zone 55, levels on AHD (Australian Height Datum) |
| Registration | Target-based registration verified against independent total station points |
| Deliverables | E57 and RCP point cloud, as-built 3D model, 2D as-built CAD, deviation/clash report |
Holding the survey on GDA2020 / MGA2020 Zone 55 with levels on AHD mattered for more than tidiness: it meant the as-built dropped straight into the client's broader site model and will serve the next stage of works without re-survey. Scanning accuracy was specified and verified against the project tolerance rather than quoted from a brochure — a discipline ISS applies on every 3D laser scanning job. Field work was conducted under ISS site inductions, a job-specific SWMS, and the plant's hygiene and working-at-heights requirements; no confined-space entry was needed because the scanner reached the ceiling void from the lift.
What the survey found
The verified as-built model immediately earned its fee. Overlaying the supplier's line model against real geometry surfaced three hard clashes that the 2D drawings had completely hidden:
- A roof purlin sat roughly 90 mm into the envelope reserved for the case-packer's upper guarding — a collision that would have stopped the crane lift on shutdown day one.
- A stormwater downpipe, never shown on the structural drawings, ran straight through the planned infeed conveyor support line.
- An existing cable ladder clipped the maintenance access zone on the tray-sealer, which would have failed the electrical clearance check at commissioning.
Just as importantly, the survey pinned down the things the line had to land on. Slab levels under the new line varied by up to 22 mm across the footprint — well outside the supplier's +/- 5 mm levelness requirement for the sealer — so grout-pack thicknesses were designed in advance rather than improvised on site. The drainage invert that had not matched any drawing was measured precisely, allowing the new washdown falls to be set correctly the first time.
The result
With the clashes resolved on the drawing board, the head contractor reissued the line layout and the steel detailer fabricated brackets and supports to the corrected geometry. The roof purlin clash was cleared by a redesigned guarding bracket; the downpipe was re-routed during a pre-shutdown service isolation; the cable ladder was relocated 120 mm in the same window.
When the 9-day shutdown arrived, the new packaging line was craned in, set out from the same control network ISS had established, and mechanically completed with no foundation rework and no clash-driven stand-downs. The grout packs cut to the surveyed slab levels brought the sealer inside its +/- 5 mm tolerance on the first set, and the line was handed to commissioning on schedule.
| Metric | Outcome |
|---|---|
| As-built accuracy achieved | Better than +/- 3 mm across the hall |
| Pre-fabrication clashes found | 3 hard clashes, all resolved before steel was cut |
| Survey cost | ~AUD 14,500 |
| Rework avoided (head contractor estimate) | > AUD 90,000 |
| Shutdown delays attributable to survey | Zero |
The outcome for the client
The numbers tell the headline story — roughly six times the survey fee saved in avoided rework — but the durable value was the data itself. The client now holds a verified, georeferenced as-built point cloud and model of the process hall on GDA2020 and AHD. That record has already been reused to plan a refrigeration upgrade and a mezzanine office fit-out without a second mobilisation, and it forms the spatial spine of the plant's emerging digital asset record.
For a brownfield manufacturing upgrade, the lesson generalises well: the cost of an accurate as-built is small and known; the cost of trusting forty-year-old drawings is large and discovered at the worst possible moment, mid-shutdown.
Frequently asked questions
Why not just use the existing drawings for the upgrade design?
Because in most older plants the drawings no longer match reality. Decades of undocumented modifications mean columns move, services appear, and levels drift. On this project, spot checks found errors up to 180 mm — more than enough to cause clashes on a millimetre-toleranced line. An as-built survey replaces guesswork with measured geometry.
How accurate was the as-built and how do you prove it?
The registered point cloud held better than +/- 3 mm across the hall. ISS proves accuracy rather than assuming it: scans were registered to a total station control network, then checked against independent spot points, and the residuals were reported. Accuracy is specified against your tolerance and verified, not quoted from a scanner datasheet.
Could the survey be done without stopping production?
Largely, yes. Laser scanning is non-contact, so most of the hall was captured around live operations. Only the ceiling void and a few high-traffic zones needed brief access during planning-day downtime and a scheduled maintenance afternoon. ISS sequences scanning to fit hygiene, safety, and production constraints.
What standards and datum do you work to?
This survey was held on GDA2020 / MGA2020 Zone 55 with levels on AHD, so the as-built ties cleanly into the wider site model and future works. As-built deliverables were prepared consistent with AS 1100 drawing conventions, and field work followed a job-specific SWMS and the plant's site rules.
What did the client actually receive?
A georeferenced E57 and RCP point cloud, an as-built 3D model of the structure and services along the line route, 2D as-built CAD, and a deviation and clash report identifying the interferences against the supplier's line model. The data has since been reused for two further projects without re-survey.
Request a quote
If you are planning a manufacturing upgrade, retrofit, or equipment replacement into an existing building, find the clashes before you cut steel — not on shutdown day. ISS provides control-based laser scanning, as-built modelling, and dimensional control for plants across Australia, with deliverables that drop straight into your engineering workflow. Call ISS on 0407 057 015 or request a quote, send us your drawings and project scope, and we will recommend the most efficient way to de-risk your upgrade.
Industrial Spatial Solutions — Precision surveying for Australian industry. Call 0407 057 015 or request a quote.
Related: As-built and engineering surveys | Mechanical surveys | Manufacturing and processing surveys