Skills

Process Flow Diagram and P&ID

6 weeks · 0 milestones

Produce a Process Flow Diagram (PFD) and a Piping and Instrumentation Diagram (P&ID) for a real or representative chemical or process engineering system to industry standard symbology (ISO 10628 or ANSI/ISA 5.1). The PFD must include: all major process equipment identified with equipment tags, all process streams with stream numbers linked to a stream data table (flowrate, composition, temperature, pressure), the major control loops shown in simplified form, and a process description narrative. The P&ID must include: all equipment with instrument and equipment tag numbers, all instrumentation (sensors, transmitters, indicators, controllers) with ISA function codes, all control loops with instrument tags and signal types, all valves (manual, automatic, check) with valve tags, and line specifications (pipe class, insulation, heat tracing where applicable). Preferred proof: a real PFD and P&ID from a project. Accessible alternative: DWSIM (which includes a PFD drawing environment and equipment library) for the PFD; for the P&ID, draw.io with ISA symbol libraries (free, available as community add-ons) or Lucidchart free tier with P&ID shapes. Proof artifacts: the PFD with stream data table (design artifact) and the P&ID with complete instrument and line annotations (documentation artifact). Verification: a process engineer reviews 'this high-pressure steam line — what line class would you specify, and where is your pressure relief?' — requiring specific reasoning from your own P&ID.

Part of: Engineering · Proves for: Engineers, UG

Milestone map

3 milestones

Select Process and Establish PFD Scope

1 week (2–3 hrs/week)

Choose a chemical or industrial process to document — a distillation unit, reactor system, utility package, or similar. Establish the PFD scope: which unit operations and streams are included, what the system boundary is. Plan the PFD structure: how many unit operations, how streams will flow left-to-right, and which streams need heat and material (H&M) balance data. A well-planned scope prevents the most common PFD error: missing streams or equipment that makes the balance tables inconsistent.

Proof required

Submit your PFD scope document: the process selected, a written description of what is included and excluded, a sketch of the planned PFD layout (hand-drawn is acceptable), and a list of all unit operations and major streams.

What gets checked

Scope document states explicitly what is included and excluded from the PFD boundary
Sketch shows planned layout with unit operations in boxes and streams as directed arrows — not text descriptions
At least five unit operations and eight streams are included — sufficient complexity for a meaningful P&ID in M3

Common mistakes

Choosing a single-unit process (one reactor, no separation) — too simple to produce a meaningful PFD or P&ID
Not planning the layout before drawing — mid-drawing rework is far more expensive than planning the layout on paper first

Resources

Foundationstart here

What a verifier looks for

Confirm scope document states the system boundary explicitly — not just 'the process'.
Confirm the layout sketch shows unit operations and streams — not a written description.
Confirm ≥5 unit operations and ≥8 streams are in scope.

You'll sign in first, then come straight back here.

Draw the PFD and Complete the Heat and Material Balance

3–4 weeks (4–5 hrs/week)

Draw the complete Process Flow Diagram using standard ISA or IEC chemical engineering symbols. Include all major equipment, process streams, utility connections, and stream identification numbers. Complete a heat and material (H&M) balance table documenting flow rate, composition, temperature, pressure, and enthalpy for each process stream. The H&M balance table is the data backbone of the PFD — without it the diagram is a schematic, not a process document.

Proof required

Submit your PFD drawing (PDF or high-resolution image) and H&M balance table: all streams with flow rate, composition, temperature, pressure, and enthalpy values, with data sources cited.

What gets checked

PFD uses standard symbols (ISA 5.1 or equivalent) and labels all equipment with tag numbers and stream with stream numbers
H&M balance table covers all process streams with all five parameters (flow, composition, temperature, pressure, enthalpy)
All H&M balance data cites its source — simulation output, thermodynamic data book, or cited calculation

Common mistakes

Drawing unit operations without stream numbers — unlabelled streams make the H&M balance table unusable
H&M balance table with estimated or missing values — every cell must have a real value or be explained as 'not applicable'

Powstik Guide

A PFD and a closed heat and material balance.

Steps

Number every stream on the PFD.
Give each stream flow, composition, T and P.
Check mass in equals mass out.
Check the heat balance per unit.

Template

| Stream | Flow | Composition | T | P |
|--------|------|-------------|---|---|
Mass closure: __%        Heat closure: __%

What gets sent back

Balance doesn't close.
Streams unnumbered.
Property sources not cited.

Resources

Foundationstart here

Depthgo deeper

What a verifier looks for

Confirm PFD uses consistent standard symbols and all equipment has tag numbers, all streams have stream numbers.
Confirm H&M balance table covers all process streams — no stream is undocumented.
Confirm H&M balance data sources are cited — simulation output, NIST, or calculation reference.

You'll sign in first, then come straight back here.

Develop the P&ID and Review for Operability

3–4 weeks (3–4 hrs/week)

Develop a Piping and Instrumentation Diagram (P&ID) from the PFD, adding all process piping, control loops, safety instrumentation (PSVs, emergency shut-down valves), and utility connections. Review the P&ID against an operability checklist: does every unit have a start-up bypass? Are all instrumentation loops complete (sensor → controller → final element)? Can the system be safely shut down? Have the P&ID reviewed by a chemical or process engineer.

Proof required

Submit your P&ID drawing (PDF or high-resolution image) and operability review record (≥500 words): checklist of operability issues found, changes made, reviewer name and role, ≥3 challenge questions and your responses.

What gets checked

P&ID adds control loops, safety devices, and piping details not shown on the PFD — it is not simply the PFD with pipe sizes added
Operability review identifies ≥2 specific issues and documents the changes made to address them
Reviewer has chemical or process engineering experience — peer review without domain expertise does not count

Common mistakes

Submitting a P&ID that is a copy of the PFD with pipe diameters added — a P&ID must show instrumentation, control loops, and safety devices
Reviewer without process engineering background — P&ID review requires domain expertise to identify control loop completeness and safety instrumentation gaps

Powstik Guide

A P&ID and a 500-word operability review.

Steps

Add instruments, valves and control loops.
Walk through start-up and shutdown.
Check isolation and relief points.
Record findings and fixes.

Template

| Checklist item | Finding | Fix |
|----------------|---------|-----|
Start-up/shutdown notes:

What gets sent back

Review under 500 words.
No control loops shown.
Findings without fixes.

Resources

Foundationstart here

Depthgo deeper

What a verifier looks for

Engineering Design Triad check: M1–M3 together produce a design artifact (PFD + P&ID drawings), an analysis artifact (H&M balance table with all streams), and a documentation artifact (operability review record + P&ID review) — confirm all three types are present.
Confirm P&ID adds instrumentation, control loops, and safety devices that are absent from the PFD — it must be a distinct document.
Confirm operability review identifies ≥2 specific issues and the changes made.
Confirm reviewer has chemical or process engineering experience.
The Proof Accessibility Rule applies — draw.io (free), DWSIM (free), NIST WebBook (free), and IChemE free resources are all accessible without commercial licence.

You'll sign in first, then come straight back here.

Part of

Chemical & Process Engineering →

Related outcomes

Milestone map

3 milestones

Select Process and Establish PFD Scope

1 week (2–3 hrs/week)

Proof required

What gets checked

Scope document states explicitly what is included and excluded from the PFD boundary
Sketch shows planned layout with unit operations in boxes and streams as directed arrows — not text descriptions
At least five unit operations and eight streams are included — sufficient complexity for a meaningful P&ID in M3

Common mistakes

Choosing a single-unit process (one reactor, no separation) — too simple to produce a meaningful PFD or P&ID
Not planning the layout before drawing — mid-drawing rework is far more expensive than planning the layout on paper first

Resources

Foundationstart here

What a verifier looks for

Confirm scope document states the system boundary explicitly — not just 'the process'.
Confirm the layout sketch shows unit operations and streams — not a written description.
Confirm ≥5 unit operations and ≥8 streams are in scope.

You'll sign in first, then come straight back here.

Draw the PFD and Complete the Heat and Material Balance

3–4 weeks (4–5 hrs/week)

Proof required

Submit your PFD drawing (PDF or high-resolution image) and H&M balance table: all streams with flow rate, composition, temperature, pressure, and enthalpy values, with data sources cited.

What gets checked

PFD uses standard symbols (ISA 5.1 or equivalent) and labels all equipment with tag numbers and stream with stream numbers
H&M balance table covers all process streams with all five parameters (flow, composition, temperature, pressure, enthalpy)
All H&M balance data cites its source — simulation output, thermodynamic data book, or cited calculation

Common mistakes

Drawing unit operations without stream numbers — unlabelled streams make the H&M balance table unusable
H&M balance table with estimated or missing values — every cell must have a real value or be explained as 'not applicable'

Powstik Guide

A PFD and a closed heat and material balance.

Steps

Number every stream on the PFD.
Give each stream flow, composition, T and P.
Check mass in equals mass out.
Check the heat balance per unit.

Template

| Stream | Flow | Composition | T | P |
|--------|------|-------------|---|---|
Mass closure: __%        Heat closure: __%

What gets sent back

Balance doesn't close.
Streams unnumbered.
Property sources not cited.

Resources

Foundationstart here

Depthgo deeper

What a verifier looks for

Confirm PFD uses consistent standard symbols and all equipment has tag numbers, all streams have stream numbers.
Confirm H&M balance table covers all process streams — no stream is undocumented.
Confirm H&M balance data sources are cited — simulation output, NIST, or calculation reference.

You'll sign in first, then come straight back here.

Develop the P&ID and Review for Operability

3–4 weeks (3–4 hrs/week)

Proof required

What gets checked

P&ID adds control loops, safety devices, and piping details not shown on the PFD — it is not simply the PFD with pipe sizes added
Operability review identifies ≥2 specific issues and documents the changes made to address them
Reviewer has chemical or process engineering experience — peer review without domain expertise does not count

Common mistakes

Submitting a P&ID that is a copy of the PFD with pipe diameters added — a P&ID must show instrumentation, control loops, and safety devices
Reviewer without process engineering background — P&ID review requires domain expertise to identify control loop completeness and safety instrumentation gaps

Powstik Guide

A P&ID and a 500-word operability review.

Steps

Add instruments, valves and control loops.
Walk through start-up and shutdown.
Check isolation and relief points.
Record findings and fixes.

Template

| Checklist item | Finding | Fix |
|----------------|---------|-----|
Start-up/shutdown notes:

What gets sent back

Review under 500 words.
No control loops shown.
Findings without fixes.

Resources

Foundationstart here

Depthgo deeper

What a verifier looks for

Engineering Design Triad check: M1–M3 together produce a design artifact (PFD + P&ID drawings), an analysis artifact (H&M balance table with all streams), and a documentation artifact (operability review record + P&ID review) — confirm all three types are present.
Confirm P&ID adds instrumentation, control loops, and safety devices that are absent from the PFD — it must be a distinct document.
Confirm operability review identifies ≥2 specific issues and the changes made.
Confirm reviewer has chemical or process engineering experience.
The Proof Accessibility Rule applies — draw.io (free), DWSIM (free), NIST WebBook (free), and IChemE free resources are all accessible without commercial licence.

You'll sign in first, then come straight back here.