How engineering work is really done and licensed: project phases, calculation packages, specs and submittals, codes and standards, QA/QC, the FE and PE, and ethics.

Engineering Practice & Licensure

## 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

1. *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.
2. *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.
3. *DD:* equipment is selected, pipe routes coordinated, and calculation packages written and checked.
4. *CD:* the drawings and specifications are completed, checked and sealed; the permit application goes in.
5. *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.


Map the phases of an engineering project, from feasibility to closeout, and the deliverables and roles in each.

How engineering projects run

Construction Documents BREAKDOWN | Schematic Design to Bidding

## Why this matters

On a real project, a calculation is not a scrap of paper that gives you a number. It is a **record**: evidence that the design meets its criteria, which a checker reviews, a licensed engineer relies on when sealing drawings, and which may be read years later after a failure, a renovation or a dispute. A calculation that cannot be followed by someone else is, for practical purposes, a calculation that was never done.

## The core idea: a calc package anyone can check

Firms have their own templates, but a good calculation package almost always contains:

1. **Cover sheet:** project, calc number and title, revision, originator, checker, approver and dates.
2. **Purpose and scope:** what is being calculated and what is not ("gravity design of beam B3; lateral loads by others").
3. **Design criteria and references:** the governing codes and standards **with edition**, client criteria, and the basis of design.
4. **Assumptions:** support conditions, material grades, load sources. Mark any that must be confirmed later ("assumed; to be verified by survey").
5. **Inputs, with sources:** every number has a source (a drawing, a vendor data sheet, a code table, a previous calc).
6. **Method:** the formula or software used, and why it applies.
7. **Calculations with units** at every step.
8. **Results and conclusion:** a short summary table: demand, capacity, ratio, OK or not.
9. **Revision log:** what changed in each revision and why.

## Units at every step

Most calculation errors that reach a checker are unit errors: kN mixed with N, mm⁴ with m⁴, kip-ft with kN·m. Two habits prevent them:

- **Convert to one consistent system first** (for example SI base units: N, m, Pa) and convert results back only for reporting.
- **Write units on every line** and check that they cancel. If you expect metres and get N·m, something is wrong.

Useful conversions to know: 1 GPa = 10⁹ Pa; 1 mm⁴ = 10⁻¹² m⁴; 1 kip = 4.448 kN; 1 ft = 0.3048 m; so 1 kip-ft = 1.356 kN·m; 1 psf = 47.88 Pa.

In Python, unit libraries such as **pint** attach units to numbers and raise an error if you add metres to newtons. In spreadsheets and Mathcad-style tools, keep a units column next to every value.

## Worked example: a textbook beam check

This is a classroom exercise to show the format, not a design. A simply supported steel beam spans L = 6.0 m and carries a uniform service load w = 10 kN/m. Take E = 200 GPa and I = 80 × 10⁶ mm⁴.

**Convert to SI base units:**

```text
w = 10 kN/m        = 10 000 N/m
L = 6.0 m
E = 200 GPa        = 200 × 10^9 Pa
I = 80 × 10^6 mm^4 = 80 × 10^6 × 10^-12 m^4 = 8.0 × 10^-5 m^4
```

**Reactions and moment** (standard simply supported beam formulas):

```text
R     = w L / 2   = 10 000 × 6.0 / 2   = 30 000 N    = 30.0 kN
M_max = w L^2 / 8 = 10 000 × 36 / 8    = 45 000 N·m  = 45.0 kN·m
```

**Midspan deflection:**

```text
δ = 5 w L^4 / (384 E I)
  = 5 × 10 000 × 1296 / (384 × 200 × 10^9 × 8.0 × 10^-5)
  = 6.48 × 10^7 / 6.144 × 10^9
  = 0.01055 m = 10.5 mm
```

Unit check: (N/m × m⁴) / (Pa × m⁴) = (N·m³) / (N/m² × m⁴) = m. Good.

**Serviceability check** against a deflection limit of L/360 (a limit commonly used for floor live load; the governing code and the project criteria set the limit for each case):

```text
allowable = 6000 mm / 360 = 16.7 mm
ratio     = 10.5 / 16.7   = 0.63   -> OK
```

A real beam design would also need the governing load combinations, strength checks for bending and shear to the applicable steel standard, lateral-torsional buckling, connections and vibration, all under the review of a licensed engineer. This example shows only how to set out and check a calculation.

## Writing calcs in Python

A script or notebook can be a fine calc package if it reads like one: a docstring header with calc number and revision, named inputs with sources in comments, one function per formula, units in every variable name or comment, and a printed results table. Because it is code, it can be re-run when an input changes, and the checker can test it with known cases (for example a hand-calculated example from a textbook).

## Common mistakes

- **Numbers without sources.** "w = 10 kN/m" from where? Cite it.
- **Mixed units.** mm and m in the same formula.
- **Hidden assumptions.** Pinned supports assumed but never stated.
- **No conclusion.** The reader should not have to hunt for "OK" or "not OK".
- **Editing a checked calc without a new revision.** Any change after checking needs a revision and a re-check.

## Quick recap

- A calc package is a record someone else must be able to follow and check.
- Include criteria with editions, assumptions, sourced inputs, method, units, results and a revision log.
- Convert to consistent units first and check that units cancel.
- Code-based calcs are welcome if they are readable, tested and versioned; real designs still need licensed review.

## Try it

Open the **Do** tab and finish a small Python calc package: convert the inputs, compute the deflection and write the check.


Write a calculation package someone else can check: criteria, assumptions, sourced inputs, consistent units and a clear conclusion.

Calculation packages

How To Use Dimensional Analysis To Find The Units of a Variable

Build a checklist from the spec excerpt: one row per measurable requirement (type, flow and head, casing pressure, impeller, seal, motor voltage, phase, frequency, efficiency, speed, enclosure, required documents).

Compare the submittal with each row and mark it Compliant, Non-compliant or Not shown.

Check the performance point: does 40 gpm at 38 ft meet 40 gpm at 35 ft? Note anything you would ask the contractor to confirm about the selection.

Write one specific comment for each non-compliant or missing item, citing the spec paragraph and stating the requirement (for example "2.1.C: casing rating at least 175 psi; submitted 125 psi.").

Choose a review action (No exceptions taken, Make corrections noted, Revise and resubmit, or Rejected) and write one sentence explaining why.

List one item you would route to another discipline (for example the motor voltage to the electrical engineer) and why.

Compare your result with a classmate or with the reading: you should have found problems with the casing rating, the motor voltage, the speed and the missing installation instructions.

## Why this matters

Drawings show *where* things go and how big they are. **Specifications** say *what quality* they must be and *how* they are installed. **Submittals** are the contractor's proof of what they actually intend to buy and build. Submittal review is one of the most frequent tasks given to early-career engineers, and it is where many mismatches (the wrong voltage motor, a weaker concrete mix, a breaker with too low an interrupting rating) are caught before they reach the site.

## The core idea: specs define requirements, submittals prove compliance

### How specifications are organised

In North America most building and infrastructure specifications follow the Construction Specifications Institute's **MasterFormat**, which groups work into numbered divisions, for example:

| division | content |
|---|---|
| 03 | Concrete |
| 05 | Metals |
| 22 | Plumbing |
| 23 | Heating, Ventilating and Air Conditioning (HVAC) |
| 26 | Electrical |

Each **section** (for example `23 21 23` for hydronic pumps) usually has three parts:

1. **Part 1 General:** scope, references to standards, **submittal requirements**, quality assurance, warranty.
2. **Part 2 Products:** the performance and material requirements, and acceptable manufacturers.
3. **Part 3 Execution:** installation, testing, start-up and cleaning.

Specifications use mandatory language ("shall") for requirements. They cite standards (ASTM, UL, NEMA, AWWA and others) rather than repeating them.

### What a submittal contains

- **Product data:** manufacturer catalogue sheets with the selected model, options and ratings marked.
- **Shop drawings:** drawings made by the fabricator or contractor showing exactly how an item will be made or installed (steel connections, rebar placement, panel layouts).
- **Samples:** physical finishes or materials.
- **Certificates and test reports:** mill certificates, factory test results, listings.

The contractor reviews and stamps the submittal first, then sends it to the design team.

## How an engineer reviews a submittal

1. **Find the governing requirements:** the spec section, the drawings and schedules, and any addenda or approved changes.
2. **Build a checklist** of every measurable requirement: performance, ratings, materials, dimensions, standards, options, warranty, required documents.
3. **Compare line by line.** Mark each item as compliant, non-compliant, or not shown.
4. **Check coordination:** does it fit the space, match the electrical supply, connect to the adjacent systems?
5. **Write clear comments,** each tied to a spec paragraph ("23 21 23, 2.2.C requires 208 V, 3-phase; submitted motor is 230 V, single-phase.").
6. **Choose an action.** Typical stamps are *No exceptions taken*, *Make corrections noted*, *Revise and resubmit* and *Rejected*. Wording varies by firm and contract.

The review is usually for **general conformance with the design intent**. It does not relieve the contractor of responsibility for dimensions, quantities, fabrication and means and methods. Firms phrase their review stamps carefully for exactly this reason: follow your firm's wording and procedure.

## Worked example

The specification requires: "Pump shall deliver 30 gpm at 45 ft total dynamic head. Motor shall be 208 V, 3-phase, 60 Hz, maximum 1,800 rpm nominal speed."

The submitted data sheet shows a pump curve passing through 30 gpm at 46 ft, and a motor rated 208-230/460 V, 3-phase, 60 Hz, 3,450 rpm.

- Flow and head: **compliant** (the operating point meets or slightly exceeds the requirement; check it is not far off the best-efficiency point).
- Voltage and phase: **compliant** (208 V, 3-phase is covered by the dual-voltage rating).
- Speed: **non-compliant** (3,450 rpm exceeds the 1,800 rpm maximum).

Action: *Revise and resubmit* with the comment "Spec 2.2.C: maximum nominal speed 1,800 rpm. Submit a 1,800 rpm (4-pole) motor selection with a matching pump curve."

## RFIs and substitutions

- A **request for information (RFI)** is the contractor's formal question about unclear or conflicting documents. Answer in writing, citing the documents; if the answer changes scope or cost, it goes through the change process.
- A **substitution request** proposes a product different from the specified ones. The contractor must show it is equal; the engineer is not obliged to accept it.

## Common mistakes

- **Reviewing only the highlighted model.** Options and accessories hidden in the small print often do not comply.
- **Vague comments.** "Check motor" helps nobody; cite the paragraph and state the requirement.
- **Approving outside your discipline.** Route structural supports, electrical feeders and controls to the right reviewers.
- **Redesigning in the review.** The review checks compliance; design changes need a formal change.
- **Missing the clock.** Contracts set review periods; late reviews delay the job.

## Quick recap

- Specs (MasterFormat divisions, Parts 1 to 3) define quality; submittals show what the contractor will supply.
- Review against a checklist built from the spec, drawings and addenda, and cite paragraphs in every comment.
- Choose a clear action and follow your firm's review-stamp wording and procedure.
- RFIs answer questions; substitutions must be shown to be equal.

## Try it

Open the **Do** tab and review a short sample submittal against a spec excerpt, then choose the review action.


Read a specification section and review a contractor's submittal against it, with clear comments and a review action.

Specs and submittals

How To Do Construction Submittals

Map project phases and deliverables, write a checked calculation package, and review submittals against specifications.