ImmersaEngineering / Design & document review
An independent read of the package before it is issued.
Calculations, datasheets, flowsheets, P&IDs, specifications and safety cases reviewed together and independently of whoever produced them. Returned marked up, with findings ranked by consequence and the reasoning attached, so that each one can be argued with rather than merely accepted.
What it covers
The package, and the joins between its parts.
Most serious findings are not errors inside a document. They sit between two documents that are each internally consistent and disagree with one another. A package review is aimed at those joins as much as at the contents.
The calculations
The numbers that fix equipment size, duty and cost. An error here is cheapest to catch early and most expensive to discover after procurement.
- Process sizing and rating calculations, independently checked
- Mass and energy balances
- Hydraulic calculations: single-phase, two-phase, compressible and gravity flow
- Heat transfer and exchanger sizing and rating
- Relief scenario screening, relief load determination and relief device sizing
- Process simulation review and validation, steady-state and dynamic
The documents that carry them
The design basis, flowsheets, datasheets and specifications the project is executed against. A defensible number in an ambiguous document still causes the wrong equipment to be bought.
- Process design basis and design philosophy documents
- Flowsheets — BFD, PFD, MFD, UFD
- Equipment datasheets and technical specifications
- P&IDs and the control philosophy behind them
- Utility system design — cooling water, steam, nitrogen, instrument air, vacuum
- Materials selection and process compatibility
The joins
Where responsibility passes from one document, discipline or contractor to another, and each side assumes the other has it.
- Interface assumptions between disciplines
- Consistency between the design basis and what the calculations actually assume
- Consistency between datasheets and the flowsheet duty they are meant to satisfy
- Vendor documents against the specification they were bid to
How it is delivered
Ranked by consequence, not by page order.
A package review returns findings ordered by what they cost if left, not by where they happen to appear in the document set. Items examined and found sound are recorded too, so the absence of a finding means something.
What arrives
The document set, at whatever revision it currently stands, together with the decision the review is meant to support — a gate, a purchase, a handover.
Reviewing against the decision rather than in the abstract is what keeps the findings useful.
What comes back
A revision-controlled report: findings ranked by consequence, each traced to the specific document and revision it arises from, with the reasoning attached and the assumptions stated.
Rev 1 records the client and contractor response against every finding, and that record stays with the client.
Typical findings
What a package review turns up.
Illustrative and non-attributable. Each is invented; no engagement lies behind any of them.
- A column specified on a feed assay that excluded trace heavies. At the measured assay the bottoms ran hotter than design, pushing the reboiler past its duty and capping throughput before the unit reached nameplate.
- A two-phase line sized on a single-phase correlation. The flow regime at turndown was never checked. Predicted pressure drop was low by a factor that would have starved the downstream separator.
- A heat exchanger rated at clean conditions only. No fouling allowance appeared in the basis. The duty was achievable on day one and at no point after the first campaign.
- Two documents that were each correct. The design basis and the datasheet described different operating envelopes. Neither was wrong in isolation; the equipment could only satisfy one of them.
Invented for illustration. Nothing arising from a real engagement is reused, retold or cited as a credential.
See the deliverable
Read one before you commission one.
The specimen is exactly this deliverable: an independent review of a solvent recovery column and its relief system, seventeen pages, six findings ranked by consequence.
It carries the assumptions relied on, a sensitivity table, the items examined and found sound alongside those that were not, the residual risk that remains after the recommended actions, and a passage setting out where the conclusion could be wrong. Every page is marked SPECIMEN; the facility, the client and the findings are invented.
Have a design package reviewed before it is issued.
A short description of the problem, the document set or the decision is enough to confirm suitability, propose a structure and give an indicative cost. A mutual non-disclosure agreement is executed before technical detail is exchanged.
Discuss a requirement