Session 4 Q&A
We had 110 questions in total across the Q&A panel and the chat. I narrowed it down to 45 key questions that cover the construction materials, methods, and final bootcamp logistics.
I categorised the questions according to the following topics:
- Bootcamp Exam, Certification & Logistics
- Construction Methods: The “5R” Framework & Circularity
- Concrete, Cement & Geopolymers
- Steel & Metals: Decarbonization & Recycling
- Bio-Based Materials & Case Study (EcoCocon)
- LCA Methodology: Energy, Refrigerants & Allocation
- Software Features & Reporting
1. Bootcamp Exam, Certification & Logistics
(Questions 1–8)
1. When and where is the exam?
The exam is available now (opened Thursday) on the One Click LCA Academy (academy.oneclicklca.com). You will find it in the “Construction LCA Bootcamp - Autumn 2025” course curriculum.
2. What is the format of the exam?
It consists of 25 multiple-choice questions.
3. Is there a time limit or limit on attempts?
You can take the quiz as many times as needed to pass. All questions are related to the topics discussed in the four sessions.
4. How long do we have to complete it?
The exam window is open until December 27, 2025 (4 weeks from the start).
5. Do I get a separate certificate for the EPD Bootcamp?
Yes. If you completed the EPD Bootcamp, there is a separate exam and certificate for that course.
6. Can I import materials in Portuguese/Spanish (or other languages)?
You can import the file, but the automatic mapping will likely fail for Portuguese because the software recognizes only supported languages (we currently support 11, including Spanish). You will need to manually map your “Betão” or “Hormigón” to “Concrete” in the database during the import process.
7. Until when can we access the recording and slides?
You have access to the recordings and slides on the Academy until the next bootcamp is published, provided you are enrolled in the course.
8. How much does the software cost after the trial?
Pricing depends on your region and license type (Business vs. Enterprise). You can contact sales@oneclicklca.com or check the website for quote requests. Academic licenses for students remain free for non-commercial thesis work.
2. Construction Methods: The “5R” Framework & Circularity
(Questions 9–14)
9. Which life-cycle stages cover “Refurbishment”?
- Module B5 (Refurbishment): Covers planned renovations (e.g., replacing a facade).
- Module B4 (Replacement): Covers individual element swaps (e.g., a window breaks).
- New Project: If you are doing a massive renovation of an existing asset, you often model it as a “New” project where the retained structure has A1-A3 = 0, and you only model the new materials added (A1-A5).
10. What is “Design for Disassembly” (DfD) in seismic areas?
It is challenging. High-seismic areas (like New Zealand or Japan) often require rigid, cast-in-place connections for safety, which makes disassembly harder compared to bolted timber/steel connections. However, research into post-tensioned timber and modular steel systems is advancing DfD even in seismic zones.
11. Can we really recycle concrete?
Yes, but usually as downcycling (crushed aggregate for road base). True recycling (separating cement paste from aggregate to make new cement) is technically possible but energy-intensive and not yet widely scalable.
12. How does “Modular” construction compare to “On-site” in terms of carbon?’
- A1-A3 (Product): Modular can be slightly higher due to heavier frames (for lifting).
- A5 (Construction): Modular is significantly lower (less waste, fewer site impacts).
- End of Life: Modular has much higher reuse potential (Module D).
13. What is the “5R” Framework mentioned?
Refurbish, Reduce, Replace, Reuse, and Require. It is a hierarchy of actions to lower embodied carbon, starting with “Do we need to build new?” (Refurbish/Reuse) before moving to material choices (Reduce/Replace).
14. Is there a global database for recyclable materials?
Not a single global one. Materials Passports (like Madaster) are emerging to track recyclable materials in specific buildings, and One Click LCA’s “Materials Compass” can filter for materials with high recycled content.
3. Concrete, Cement & Geopolymers
(Questions 15–19)
15. What are the options to replace cement? Common SCMs (Supplementary Cementitious Materials) include:
- Fly Ash (coal byproduct)
- Slag / GGBS (steel byproduct)
- Silica Fume
- Calcined Clay (LC3)
- Limestone powder
16. Are there datasets for Geopolymers / Alkali-Activated Materials?
Yes. The One Click LCA database includes EPDs for geopolymer concretes. These typically show much lower carbon (A1-A3) but you must check availability in your local market.
17. What is the trade-off between Carbonation and Steel Corrosion?
Concrete naturally absorbs CO2 (carbonation), which is a “negative emission.” However, carbonation lowers the pH of concrete, which can lead to the corrosion of steel reinforcement. Low-carbon concretes (with less clinker) may carbonize faster, so cover depth and durability must be carefully engineered.
18. How does LC3 (Limestone Calcined Clay Cement) compare to OPC?
LC3 can reduce CO2 emissions by up to 40% compared to Ordinary Portland Cement (OPC) because calcining clay requires lower temperatures (approx. 800°C) than making clinker (1450°C).
19. Can we do dynamic LCA (carbon over time)?
One Click LCA provides “Period” charts (in Expert licenses) that show when emissions occur (e.g., a spike at Year 30 for window replacement). This helps visualize the “Carbon Cashflow” of the building.
4. Steel & Metals: Decarbonization & Recycling
(Questions 20–24)
20. What is “Zero Carbon Steel”?
This typically refers to steel produced using Hydrogen in the Direct Reduced Iron (DRI) process, powered by renewable energy, instead of coal/coke in a Blast Furnace. Commercial availability is expected to scale in the late 2020s.
21. What is the cut-off for steel recycling rates?
Steel can theoretically be recycled infinitely without loss of properties. However, in LCA, we usually assume a recovery rate (e.g., 90-95%) and a recycling loss (e.g., 5%) for the remelting process.
22. How do we account for Hydrogen gas in EAF steel?
If Hydrogen is used as a fuel/reductant, its impact depends on how it was made (Green H2 from renewables vs. Grey H2 from gas). This would be captured in the Module A3 (Manufacturing) energy inputs of the steel EPD.
23. Is Stainless Steel worse than Carbon Steel?
Generally, yes (per kg). Stainless steel contains alloying elements like Chromium and Nickel, which have high extraction footprints. However, Stainless Steel requires no coating and lasts longer, so it might be better over a full life cycle in corrosive environments.
24. Where can we find more on the “Zero Carbon Steel” trials?
Major producers like SSAB (Hybrit), ArcelorMittal, and H2 Green Steel publish regular updates on their pilot projects in Sweden and Europe.
5. Bio-Based Materials & Case Study (EcoCocon)
(Questions 25–30)
25. How does the EcoCocon (Straw Panel) system handle fire safety?
Compressed straw contains very little oxygen. When exposed to fire, the surface chars (like heavy timber), protecting the core. It has passed standard fire resistance tests (e.g., RE120).
26. What about termites and humidity?
- Humidity: The panels are vapor-permeable (“breathable”) but must be protected from liquid water (rain) by a facade/cladding, just like any timber frame.
- Termites: Physical barriers and proper detailing are used, similar to standard timber construction protocols.
27. What is the End of Life for straw panels?
They are fully biodegradable. They can be composted (returning carbon to the soil) or incinerated for energy. If composted, the sequestered carbon is released slowly; if incinerated, it is released immediately (but counts as biogenic).
28. How long is the lifespan of a straw building?
If kept dry, straw lasts indefinitely. There are straw-bale houses in the US and Europe that are over 100 years old and still in good condition.
29. Are there datasets for Rice Husk Ash?
Yes, Rice Husk Ash is a high-silica bio-based material used as a cement replacement or insulation. Datasets exist, but availability varies by region (common in Asia).
30. What hinders the widespread adoption of bio-based materials?
Key barriers include:
- Perception: (e.g., “Fire risk” myths).
- Insurance/Regulation: Building codes can be slower to adapt to non-standard materials.
- Supply Chain: Scaling up from niche to industrial production.
6. LCA Methodology: Energy, Refrigerants & Allocation
(Questions 31–36)
31. How do we report “Guarantees of Origin” (GOs) for green energy?
If a manufacturer buys GOs but is connected to the grid:
- Market-based approach: They can report lower carbon in A3.
- Location-based approach: They report the average grid mix.
- In EPDs: This must be explicitly stated. Some program operators allow GOs, others require the physical grid mix.
32. How do Data Centers account for refrigerants?
Refrigerants (for cooling servers) are a massive hotspot.
- Leakage: Modeled in Module B1 or B6.
- Global Warming Potential: Many older refrigerants (HFCs) have GWPs of 1000-2000x CO2.
- Solution: Newer refrigerants (HFOs) or natural cooling have much lower impacts.
33. What is the impact of deforestation?
Deforestation is tracked under “Land Use Change” (LUC) emissions in EN 15804+A2. If wood comes from unsustainable sources (forest carbon stock decreases), a high LUC penalty is added to the carbon footprint.
34. Can One Click LCA simulate “Dynamic” LCA?
The core tool uses static characterization factors (standard LCA). However, the Period/Life-Cycle graphs allow you to see the timing of emissions, which is the first step toward understanding dynamic impacts (e.g., when the carbon hits the atmosphere).
35. Is there a checklist for material thresholds (e.g., kgCO2/m² targets)?
Yes. Organizations like LETI, RIBA, and Carbon Heroes provide benchmarks (e.g., “Target < 500 kgCO2e/m² for an A-rated building”). You can use the “Carbon Heroes” benchmark tool in the software to see where your materials sit on the curve.
36. Do we account for “Sufficiency” (reducing demand)?
Yes, this is the “Refurbish/Reduce” part of the 5R framework. The most sustainable building is the one you don’t build. LCA helps quantify the savings of not building new floor area.
7. Software Features & Reporting
(Questions 37–45)
37. How do we show reports to clients?
- PDF/Word Report: Best for formal submissions (generated via “More Actions”).
- Online Results Page: Good for interactive workshops (showing hotspots live).
- Sankey Diagrams (and others): Excellent for visualizing “where the carbon is coming from” for non-technical clients.
38. Can I use Carbon Designer 3D for a 2-3 story dwelling?
Yes. You can edit the number of floors in the CD3D parameters. If the specific geometry is complex (e.g., split levels), you can generate the different shapes first and then manually adjust the quantities in the main query.
39. Can I import my own material list from Excel?
Yes. You can copy-paste your Bill of Materials (BoQ) into the “Import Excel” template. The tool will try to map your items to EPDs.
40. Will there be an auditing process for our LCAs?
In the bootcamp? No. The exam tests your knowledge, but we do not manually audit your practice models. In real life? Usually. Certification schemes (BREEAM, LEED, Green Star) either require third-party verification of your LCA, or allocate additional credits if you pursue third party verification..
41. What is better for the UK: BREEAM or LEED?
- BREEAM is the dominant UK standard and aligns better with UK planning/regulations.’
- LEED is globally recognized and favored by international tenants (US corporates).
- For Carbon/Energy specifically, both have rigorous credits. BREEAM is generally more tailored to the UK grid and material supply chain.
42. How do we update our knowledge after the bootcamp?
- Community: Join the One Click LCA Community.
- Webinars: We host regular “Winter/Spring” bootcamps and expert webinars.
- Newsletter: Subscribe to the OCL newsletter for regulatory updates (EPBD, etc.).
43. Is there a trial version for academics?
Yes. We offer free licenses for students and researchers for non-commercial thesis work. You can apply on the One Click LCA website under “Student License.”
44. Why does London have a different scheme (GLA) than BREEAM?
The Greater London Authority (GLA) has specific planning policies (London Plan) that mandate Whole Life Carbon assessments for all referable schemes. It is a regulatory requirement for planning permission, whereas BREEAM is a voluntary certification (though often required by planning too).
45. Can I use One Click LCA for ICF (Insulated Concrete Forms)?
Yes. You can model ICF by combining Concrete (Core) and Insulation (EPS formwork) materials. You can find both in the database.