Map the phases of an engineering project, from feasibility to closeout, and the deliverables and roles in each.
Why this matters
As a student you solve problems that arrive fully defined. At work, an engineering project starts as a vague need ("we need a bigger pump station", "the new line needs a control panel") and takes months or years to become something built. Knowing the phases, who does what, and which documents each phase produces lets you contribute from your first week, ask sensible questions and understand why a "small change" late in a project can be so expensive.
The core idea: decisions narrow phase by phase
Every project moves from many options and little detail to one option and full detail. Early decisions are cheap to change and have the most influence on cost; late changes are expensive because drawings, orders and construction depend on them.
Building and infrastructure projects
Civil, structural, mechanical (building services) and electrical engineers on buildings and infrastructure usually work in these phases (names vary by firm and contract):
| phase | purpose | typical deliverables |
|---|---|---|
| Planning / feasibility | Is the project viable? Which options exist? | studies, site investigation, rough cost, basis of design |
| Schematic design (SD) | Choose the concept and main systems | layouts, system sizing, outline specifications, cost estimate |
| Design development (DD) | Fix sizes, routes and equipment | developed drawings, calculation packages, coordinated layouts |
| Construction documents (CD) | Describe everything needed to build | full drawing set, specifications, final calcs, sealed by the engineer of record |
| Bidding / procurement | Select a contractor | addenda, answers to bidder questions |
| Construction administration (CA) | Make sure what is built matches the design intent | submittal reviews, RFI responses, site observation reports |
| Closeout | Hand over | record drawings, operation and maintenance manuals, commissioning reports |
Teams often talk in percentages: a "30% set" is roughly the end of schematic design, "60%" is design development and "90%" is a near-final set going through final checking before it is issued for construction.
Product and machine projects
Mechanical and electrical engineers designing products or equipment follow a similar narrowing path with different names: requirements, concept design, preliminary design review (PDR), detailed design, critical design review (CDR), prototype build and test, verification and validation, and release to production. The deliverables are requirements documents, CAD models and drawings, analyses, test plans and reports, and a bill of materials.
Who is involved
- Owner / client: pays for the project and sets the requirements.
- Engineer of record (EOR): the licensed engineer responsible for a discipline's design; their seal on the documents carries legal responsibility.
- Designers and engineers-in-training: do much of the calculation, modelling and drafting under the EOR's supervision.
- Contractor and subcontractors: build it, and submit shop drawings and product data showing how.
- Authority having jurisdiction (AHJ): the building department, utility or regulator that issues permits and inspects.
Delivery methods change the flow
- Design-bid-build: the owner hires a designer, completes the design, then bids it to contractors. Clear roles; slower.
- Design-build: one contract covers design and construction. Faster and fewer hand-offs; the owner has less direct control of design decisions.
- Construction manager at risk (CMAR): a construction manager joins during design to advise on cost and buildability, then builds for a guaranteed maximum price.
Worked example: a small pump station upgrade
- Feasibility: a civil engineer compares three options (new pumps in the existing building, a new building, or a package station) with rough costs. The owner picks option one.
- SD: mechanical sizes the pumps from flow and head requirements; electrical confirms the service can carry the new motors; structural checks that the floor can take the equipment.
- DD: equipment is selected, pipe routes coordinated, and calculation packages written and checked.
- CD: the drawings and specifications are completed, checked and sealed; the permit application goes in.
- CA: the contractor submits pump data sheets; the engineer reviews them against the specification, answers RFIs and visits the site.
A change of pump model in step 2 costs an afternoon. The same change after the pumps are ordered costs weeks and real money.
Common mistakes
- Detailing too early. Drawing bolt holes before the concept is agreed wastes effort that will be redone.
- Missing the basis of design. Without written design criteria, nobody can check whether the design meets them.
- Poor coordination. A duct and a beam occupying the same space, found on site instead of in DD.
- Treating CA as an afterthought. Many problems are caught, or missed, in submittal review.
Quick recap
- Projects narrow from options to detail: feasibility, SD, DD, CD, bidding, CA and closeout (or PDR and CDR for products).
- Each phase has defined deliverables; percentages (30/60/90) describe progress.
- The engineer of record seals the final documents and carries responsibility for them.
- Changes get more expensive the later they happen.
Try it
Open the Do tab and take the quiz to match phases with their deliverables and roles.