Phase 7 · Pass the examination
Embodied carbon in the examination
The A1–A3 calculation the Institution asks for, where it appears in each paper, and how much depth is expected.
Who this is for:Candidates at any stage
One formula, applied to the elements you have designed — and since January 2024 sustainability is a key feature of every question on every paper.
The method the Institution gives
Institution of Structural Engineers
- Approximate A1–A3 carbon footprints for key elements can be assessed by a straightforward calculation of element mass multiplied by the embodied carbon factor (ECF) of the material.
- Embodied carbon (kgCO₂e) = mass (kg) × embodied carbon factor (kgCO₂e/kg)
- Candidates may refer to the Institution's How to Calculate Embodied Carbon for methodology and ECF values.
- Industry-average ECF values are recommended, but other suitable values may be used.
- Candidates are encouraged to use the Institution's free online embodied carbon basics course in preparation.
- Sustainability in every question
- From January 2024The Institution altered the exam content so that sustainability is a key feature of all questions. Only documents carrying '2024' in the version number describe the current paper.
From Exam Guidance and Instructions — Chartered Membership Examination, Institution of Structural Engineers.
Where it appears
Carbon is not a separate section. It is folded into the calculations:
- On the Chartered paper, section 2c asks for the form, size and approximate A1–A3 carbon footprints of all the principal structural elements.
- On the Incorporated paper, section 2c asks the same.
- On the supplementary paper, part c asks for it on two principal elements.
At scheme stage, in section 1a, the instructions are clear that you are not expected to extend to carbon comparisons — what is expected there is that you demonstrate approaches which minimise material through structural efficiency, and take up any reuse opportunity the question offers.
That distinction is worth holding onto under time pressure. Scheme stage: material efficiency and reuse, argued. Calculation stage: numbers.
Doing it quickly and defensibly
Because the method is mass × factor, the work is really in getting the mass, which you already have from sizing the element.
- 01Volume from your own sizing — you have the section and the length.
- 02Mass — volume × density. Carry the densities you use most into the exam in your folder.
- 03Multiply by the ECF for the material and, where it matters, the grade or the recycled content assumption.
- 04State the source of the factor and any assumption behind it.
Round sensibly and say that you have. An approximate footprint stated to four significant figures invites a question about what you think you know.
Preparation worth doing beforehand
Have a short, ordered sheet in your folder with the industry-average factors for the materials you are likely to use — concrete at the grades you use, reinforcement, structural steel, timber, masonry — with densities alongside. The arithmetic is then a minute per element instead of a hunt.
The Institution's own free course and its How to Calculate Embodied Carbon document are the intended preparation, and using its recommended industry-average values is the safest choice in an exam where you cannot check anything online.
The calculation, element by element
- 01
Take the volume from your own sizing
You already have the section and the length from the design calculation, so no new work is needed.
- 02
Convert to mass
Volume times density. Carry the densities you use most into the exam in your folder, so this is arithmetic rather than a search.
- 03
Multiply by the embodied carbon factor
For the material and, where it matters, the grade or the recycled-content assumption you are making.
- 04
State the source and the assumption
Which factor you used and where it came from. Industry-average values are recommended, and saying so is part of the answer.
- 05
Round, and say that you have
It is an approximate A1–A3 footprint. Quoting it to four significant figures invites a question about what you think you know.
In your folder before the exam
6 items · saved in this browser only
Ticked locally in this browser. The Institution's own guidance and its free embodied carbon course are the intended preparation.
Embodied carbon workspace
Mass times embodied carbon factor, element by element — the method the Institution gives. You supply the factors; none is stored here.
Embodied carbon (kgCO₂e) = mass (kg) × embodied carbon factor (kgCO₂e/kg)
Add the principal structural elements you have sized. Volume comes from your own calculation; density and the carbon factor come from your own sources.
Queensferry holds no embodied carbon factors. Take yours from the Institution’s own guidance, which recommends industry-average values, and state the source in your answer.
Everything here is stored in this browser only. Nothing is uploaded, nothing is analysed, and clearing your browser data will delete it — so export anything you want to keep.
Related pages and tools
- CalculationsWhich elements to design, how far to check each, and how to keep a calculation package legible under time pressure.
- AppraisalWeighing two schemes against criteria drawn from the brief, with sustainability as a key criterion.
- Chartered examThe five sections, what each is worth, and what the examiners say they are looking for in each.
- SustainabilityThat sustainability has changed something you actually did — a quantity, a material, a decision to reuse rather than replace — and that you can talk about the whole life of the structure rather than only its construction.