I-Pile · Square Pile · Spun Pile Methodology Guideline & Illustrative Values | StactBD Thailand — April 2026
1 Mission
Stact is committed to driving carbon transparency in Thai construction — aligned with TGO and international standards — so that engineers, designers, and QS professionals can use Carbon Footprint data as a genuine input to structural and material decisions.
| ⚠ Notice: All figures in every table are illustrative values calculated from internationally referenced Emission Factors, for educational purposes only. Real projects must verify EF values from manufacturer EPDs or TGO CFP certificates. |
2 Framework: The 5-Component Carbon Stack
Per EN 15804 and TGO guidelines, the Carbon Footprint of 1 metre of precast pile spans five components:
| No. | Component | Scope | Share | Notes |
| 1 | Concrete | A1–A2 | ~55–70% | Dominant driver. Pile grades C35–C80 carry substantially more cement than standard ready-mix. |
| 2 | Prestressing wire | A1–A2 | ~15–25% | BOF prestressing wire. Unified EF 1.5 kgCO2e/kg used for all pile types. |
| 3 | Manufacturing process (pile factory) | A3 | ~5–10% | Steam curing + plant electricity + Spinning (Spun only). |
| 4 | Transport | A4 | ~1–5% | Diesel truck; depends on distance and pile mass per meter. |
| 5 | Pile driving | A5 | ~2–8% | Crane and hammer diesel; varies with soil and pile length. |
* Proportions are indicative; vary with pile size, transport distance, and soil conditions.
3 Calculation Methodology & Emission Factors
Core formula for Carbon Footprint of 1 meter of pile (boundary A1–A5):
| CO2e (kgCO2e/m) = [Vconc × EFconc] + [Vconc × EFfactory] + [Msteel × EFsteel] + A4 + A5 |
EFconc = concrete EF (A1-A3 batching level) and EFfactory = pile factory EF (A3 product level) are separate components — keep them distinct to avoid double-counting.
Key point: Concrete EF varies by grade; Spun Pile Factory A3 is higher per m³
Concrete grade differs significantly across pile types, resulting in different EFs. Additionally, Spun Pile Factory A3 is ~16% higher per m³ of concrete than I-Pile and Square Pile due to the spinning process. However, because the hollow cross-section uses less concrete per meter, the absolute Factory A3 per meter of pile is broadly similar across all types (~1–3 kgCO2e/m), driven more by pile size than pile type.
| Parameter | Source | Illustrative Value (kgCO2e) | Unit | Notes |
| Concrete — Square Pile (C35-C40) | ICE DB v3.0 | ~300 | m³ | A1-A3 concrete batching only; does not include pile factory operations |
| Concrete — I-Pile (C45-C50) | ICE DB v3.0 | ~340 | m³ | Higher cement content (~410 kg/m³) yields higher EF |
| Concrete — Spun Pile (C60-C80) | ICE DB v3.0 | ~360 | m³ | Highest cement content (~475 kg/m³), minimal FA due to low W/C ratio |
| Pile Factory A3 — I-Pile / Square | Plant energy | ~20 | m³ conc. | Steam curing (~10.7) + electricity (~9.5 kgCO2e/m³ concrete) |
| Pile Factory A3 — Spun Pile | Plant energy | ~24 | m³ conc. | Adds spinning process (~3.3) — ~16% higher per m³ than I/Square |
| Prestressing wire (all pile types) | ICE DB v3.0 | 1.5 | kg | Unified EF for all pile types (BOF virgin steel) |
| Diesel transport (A4) | TGO / IPCC | ~0.096 | t-km | Adjust for actual truck load factor |
Values are illustrative — always verify from manufacturer EPD.
4 Illustrative Carbon Footprint Estimates
| Code | Type | Concrete (kgCO2e/m) | Pile Factory A3 (kgCO2e/m) | Steel (kgCO2e/m) | Total A1–A3 (kgCO2e/m) [Illustrative] |
| IP-300 | I-Pile | 23.2 | 1.4 | 12.0 | ~37 |
| IP-400 | I-Pile | 44.8 | 2.7 | 23.3 | ~71 |
| SQ-250 | Square | 18.8 | 1.3 | 18.5 | ~39 |
| SQ-300 | Square | 27.0 | 1.8 | 26.5 | ~55 |
| SQ-400 | Square | 48.0 | 3.2 | 47.1 | ~98 |
| SP-300 | Spun | 16.3 | 1.1 | 6.4 | ~24 |
| SP-400 | Spun | 24.6 | 1.6 | 9.6 | ~36 |
| SP-500 | Spun | 36.0 | 2.4 | 14.1 | ~52 |
A4 (transport) = distance × mass per metre × ~0.096 kgCO2e/t-km | A5 (driving) = diesel (litres) × 2.68 kgCO2e/litre
5 Carbon Efficiency Index (CEI)
Comparing Carbon Footprint per meter across different pile sizes is not meaningful in isolation — larger piles use more carbon but carry more load. CEI normalizes carbon against load capacity, exactly as QS compare cost-per-ton:
| CEI = CO2e per pile (kgCO2e) ÷ Typical Load (tons) = kgCO2e / ton load capacity |
| Lower CEI = less carbon per unit of load capacity = higher carbon efficiency. Always use Typical Load from a project Geotechnical Report — figures in the table are illustrative for Bangkok at 21 m depth. |
| Code | Type | CO2e/m (kgCO2e) | CO2e/pile (kgCO2e) | Typical Load (tons) | CEI (kgCO2e / ton load capacity) [Illustrative — lower is better ↓] |
| IP-300 | I-Pile | 37 | 767 | 32.5 | 23.6 |
| IP-350 | I-Pile | 52 | 1,098 | 42.5 | 25.8 |
| IP-400 | I-Pile | 71 | 1,485 | 60.0 | 24.8 |
| SQ-250 | Square | 39 | 808 | 32.5 | 24.9 |
| SQ-300 | Square | 55 | 1,163 | 50.0 | 23.3 |
| SQ-350 | Square | 75 | 1,580 | 70.0 | 22.6 |
| SQ-400 | Square | 98 | 2,065 | 95.0 | 21.7 |
| SP-300 | Spun | 24 | 499 | 37.5 | 13.3 |
| SP-350 | Spun | 29 | 604 | 52.5 | 11.5 |
| SP-400 | Spun | 36 | 752 | 60.0 | 12.5 |
| SP-450 | Spun | 44 | 922 | 75.0 | 12.3 |
| SP-500 | Spun | 53 | 1,102 | 85.0 | 13.0 |
| CEI < 15 = High efficiency | CEI 15–24 = Good efficiency | CEI > 24 = Standard efficiency |
| Observation: Spun Piles achieve the lowest CEI (~11–13). Although Spun concrete EF and Factory A3 intensity are highest per m³, the hollow section reduces concrete volume per meter significantly, yielding superior carbon-per-ton-of-load-capacity. Project decisions must also weigh typical load, cost, transport, and Geotechnical constraints. |
Extending CEI to project-level decisions
- Total Foundation Carbon = pile count × CO2e per pile — compare across design alternatives
- Cost–Carbon Matrix: X = cost/ton load capacity, Y = CEI — best choice is lower-left
- Reducing Dead Load via BubbleDeck slabs directly reduces pile count and Total Foundation Carbon
6 Recommended Assessment Steps
- Define system boundary (A1–A3 or A1–A5) before starting
- Use concrete EF differentiated by actual grade — do not apply a single EF to all pile types
- Keep concrete batching EF and Pile Factory A3 separate — do not double-count
- For Spun Piles: Pile Factory A3 EF is ~16% higher per m³ concrete than I-Pile/Square
- Request EPD or TGO CFP data from the pile manufacturer — most accurate source
- Use CEI as a proportional comparison tool; always reference load from a Geotechnical Report
References
[1] ICE Database v3.0, University of Bath / Circular Ecology, 2019
[2] Kim, J. et al. Embodied Life Cycle GWP of PC and PHC Piles in Korea. Buildings 13(10), 2023
[3] Suriyanon, N. et al. Carbon Footprint Assessment of a Bore Pile Contractor: Thailand. 2025
[4] TGO. Electricity EF Scope 2 = 0.4750 kgCO2e/kWh, effective 1 January 2025
Published by StactBD Thailand — BubbleDeck System Engineer & Representative in Thailand | April 2026
