CO2 Carbon Footprint Calculator
Business Case
Problem Statement
Sustainability requirements demand carbon tracking:
- Need to quantify embodied carbon
- Material selection impact unclear
- Reporting requirements increasing
- No integration with BIM workflow
Solution
Calculate CO2 emissions from BIM quantities using EPD (Environmental Product Declaration) data and carbon coefficients.
Business Value
- Sustainability - Meet green building requirements
- Design optimization - Identify high-carbon elements
- Reporting - Automated carbon reports
- Decision support - Compare material alternatives
Technical Implementation
import pandas as pd
from datetime import datetime
from typing import Dict, Any, List, Optional, Tuple
from dataclasses import dataclass, field
from enum import Enum
class LifeCycleStage(Enum):
"""EN 15978 Life Cycle Stages."""
A1_A3 = "a1_a3" # Product stage
A4 = "a4" # Transport to site
A5 = "a5" # Construction
B1_B7 = "b1_b7" # Use stage
C1_C4 = "c1_c4" # End of life
D = "d" # Beyond system boundary
class MaterialCategory(Enum):
"""Material categories for carbon calculation."""
CONCRETE = "concrete"
STEEL = "steel"
TIMBER = "timber"
ALUMINUM = "aluminum"
GLASS = "glass"
BRICK = "brick"
INSULATION = "insulation"
GYPSUM = "gypsum"
OTHER = "other"
@dataclass
class CarbonCoefficient:
"""Carbon emission coefficient for a material."""
material: str
category: MaterialCategory
kgco2_per_unit: float # kg CO2e per unit
unit: str # kg, m3, m2, etc.
stage: LifeCycleStage
source: str # EPD reference
uncertainty: float = 0.1 # 10% default uncertainty
@dataclass
class CarbonResult:
"""Carbon calculation result for an element."""
element_id: str
element_name: str
material: str
category: MaterialCategory
quantity: float
unit: str
kgco2_per_unit: float
total_kgco2: float
stage: LifeCycleStage
level: str = ""
notes: str = ""
@dataclass
class CarbonSummary:
"""Carbon footprint summary."""
total_kgco2: float
total_tonco2: float
by_material: Dict[str, float]
by_category: Dict[str, float]
by_stage: Dict[str, float]
by_level: Dict[str, float]
element_count: int
gfa: float # Gross Floor Area
kgco2_per_m2: float
class CarbonCoefficientDatabase:
"""Database of carbon emission coefficients."""
def __init__(self):
self.coefficients: List[CarbonCoefficient] = []
self._load_default_coefficients()
def _load_default_coefficients(self):
"""Load standard carbon coefficients (EPD-based)."""
# Concrete products
self.add_coefficient(CarbonCoefficient(
material="Concrete C30/37", category=MaterialCategory.CONCRETE,
kgco2_per_unit=250, unit="m3", stage=LifeCycleStage.A1_A3,
source="Generic EPD - Concrete"
))
self.add_coefficient(CarbonCoefficient(
material="Concrete C40/50", category=MaterialCategory.CONCRETE,
kgco2_per_unit=300, unit="m3", stage=LifeCycleStage.A1_A3,
source="Generic EPD - High Strength Concrete"
))
self.add_coefficient(CarbonCoefficient(
material="Reinforcement Steel", category=MaterialCategory.STEEL,
kgco2_per_unit=1.99, unit="kg", stage=LifeCycleStage.A1_A3,
source="Generic EPD - Rebar"
))
# Steel products
self.add_coefficient(CarbonCoefficient(
material="Structural Steel", category=MaterialCategory.STEEL,
kgco2_per_unit=2.5, unit="kg", stage=LifeCycleStage.A1_A3,
source="Generic EPD - Structural Steel"
))
self.add_coefficient(CarbonCoefficient(
material="Steel Sheet", category=MaterialCategory.STEEL,
kgco2_per_unit=2.3, unit="kg", stage=LifeCycleStage.A1_A3,
source="Generic EPD - Sheet Metal"
))
# Timber products
self.add_coefficient(CarbonCoefficient(
material="Softwood Timber", category=MaterialCategory.TIMBER,
kgco2_per_unit=-500, unit="m3", stage=LifeCycleStage.A1_A3,
source="Generic EPD - CLT (carbon sequestration)"
))
self.add_coefficient(CarbonCoefficient(
material="Glulam", category=MaterialCategory.TIMBER,
kgco2_per_unit=-350, unit="m3", stage=LifeCycleStage.A1_A3,
source="Generic EPD - Glued Laminated Timber"
))
# Aluminum
self.add_coefficient(CarbonCoefficient(
material="Aluminum Profile", category=MaterialCategory.ALUMINUM,
kgco2_per_unit=8.0, unit="kg", stage=LifeCycleStage.A1_A3,
source="Generic EPD - Aluminum"
))
# Glass
self.add_coefficient(CarbonCoefficient(
material="Float Glass", category=MaterialCategory.GLASS,
kgco2_per_unit=15.0, unit="m2", stage=LifeCycleStage.A1_A3,
source="Generic EPD - Float Glass"
))
self.add_coefficient(CarbonCoefficient(
material="Double Glazing Unit", category=MaterialCategory.GLASS,
kgco2_per_unit=35.0, unit="m2", stage=LifeCycleStage.A1_A3,
source="Generic EPD - IGU"
))
# Masonry
self.add_coefficient(CarbonCoefficient(
material="Clay Brick", category=MaterialCategory.BRICK,
kgco2_per_unit=0.24, unit="kg", stage=LifeCycleStage.A1_A3,
source="Generic EPD - Clay Brick"
))
# Insulation
self.add_coefficient(CarbonCoefficient(
material="Mineral Wool", category=MaterialCategory.INSULATION,
kgco2_per_unit=1.2, unit="kg", stage=LifeCycleStage.A1_A3,
source="Generic EPD - Mineral Wool"
))
self.add_coefficient(CarbonCoefficient(
material="EPS Insulation", category=MaterialCategory.INSULATION,
kgco2_per_unit=3.5, unit="kg", stage=LifeCycleStage.A1_A3,
source="Generic EPD - EPS"
))
# Gypsum
self.add_coefficient(CarbonCoefficient(
material="Gypsum Board", category=MaterialCategory.GYPSUM,
kgco2_per_unit=2.8, unit="m2", stage=LifeCycleStage.A1_A3,
source="Generic EPD - Plasterboard"
))
def add_coefficient(self, coefficient: CarbonCoefficient):
"""Add carbon coefficient to database."""
self.coefficients.append(coefficient)
def find_coefficient(self, material_name: str,
stage: LifeCycleStage = LifeCycleStage.A1_A3) -> Optional[CarbonCoefficient]:
"""Find matching coefficient for material."""
material_lower = material_name.lower()
# Direct match
for coef in self.coefficients:
if coef.material.lower() == material_lower and coef.stage == stage:
return coef
# Partial match
for coef in self.coefficients:
if material_lower in coef.material.lower() or coef.material.lower() in material_lower:
if coef.stage == stage:
return coef
# Category match
category = self._guess_category(material_name)
for coef in self.coefficients:
if coef.category == category and coef.stage == stage:
return coef
return None
def _guess_category(self, material_name: str) -> MaterialCategory:
"""Guess material category from name."""
name_lower = material_name.lower()
if any(w in name_lower for w in ['concrete', 'cement', 'mortar']):
return MaterialCategory.CONCRETE
if any(w in name_lower for w in ['steel', 'iron', 'metal']):
return MaterialCategory.STEEL
if any(w in name_lower for w in ['wood', 'timber', 'lumber', 'plywood', 'clt']):
return MaterialCategory.TIMBER
if any(w in name_lower for w in ['aluminum', 'aluminium']):
return MaterialCategory.ALUMINUM
if any(w in name_lower for w in ['glass', 'glazing']):
return MaterialCategory.GLASS
if any(w in name_lower for w in ['brick', 'masonry', 'block']):
return MaterialCategory.BRICK
if any(w in name_lower for w in ['insulation', 'wool', 'foam', 'eps', 'xps']):
return MaterialCategory.INSULATION
if any(w in name_lower for w in ['gypsum', 'drywall', 'plaster']):
return MaterialCategory.GYPSUM
return MaterialCategory.OTHER
class CO2FootprintCalculator:
"""Calculate carbon footprint from BIM data."""
def __init__(self, coefficient_db: CarbonCoefficientDatabase = None):
self.db = coefficient_db or CarbonCoefficientDatabase()
self.results: List[CarbonResult] = []
self.warnings: List[str] = []
def calculate_element(self, element: Dict[str, Any],
stage: LifeCycleStage = LifeCycleStage.A1_A3) -> Optional[CarbonResult]:
"""Calculate carbon for single element."""
material = element.get('material', '')
if not material:
self.warnings.append(f"Element {element.get('element_id')} has no material")
return None
coefficient = self.db.find_coefficient(material, stage)
if not coefficient:
self.warnings.append(f"No coefficient found for material: {material}")
return None
# Get quantity in correct unit
quantity = self._get_quantity(element, coefficient.unit)
if quantity is None or quantity <= 0:
return None
total_kgco2 = quantity * coefficient.kgco2_per_unit
result = CarbonResult(
element_id=str(element.get('element_id', '')),
element_name=str(element.get('name', '')),
material=material,
category=coefficient.category,
quantity=quantity,
unit=coefficient.unit,
kgco2_per_unit=coefficient.kgco2_per_unit,
total_kgco2=total_kgco2,
stage=stage,
level=str(element.get('level', ''))
)
self.results.append(result)
return result
def _get_quantity(self, element: Dict[str, Any], unit: str) -> Optional[float]:
"""Get quantity in required unit."""
unit_lower = unit.lower()
if unit_lower == 'm3':
return float(element.get('volume', 0) or 0)
elif unit_lower == 'm2':
return float(element.get('area', 0) or 0)
elif unit_lower in ['kg', 'kilogram']:
# Try weight, then estimate from volume
weight = element.get('weight', 0)
if weight:
return float(weight)
# Estimate from volume with density
volume = element.get('volume', 0)
if volume:
density = self._estimate_density(element.get('material', ''))
return float(volume) * density
elif unit_lower in ['m', 'meter']:
return float(element.get('length', 0) or 0)
return None
def _estimate_density(self, material: str) -> float:
"""Estimate material density in kg/m3."""
material_lower = material.lower()
densities = {
'concrete': 2400,
'steel': 7850,
'timber': 500,
'aluminum': 2700,
'glass': 2500,
'brick': 1800,
'gypsum': 800
}
for key, density in densities.items():
if key in material_lower:
return density
return 1500 # Default density
def calculate_from_dataframe(self, df: pd.DataFrame,
stage: LifeCycleStage = LifeCycleStage.A1_A3) -> List[CarbonResult]:
"""Calculate carbon for all elements in DataFrame."""
self.results = []
self.warnings = []
for _, row in df.iterrows():
self.calculate_element(row.to_dict(), stage)
return self.results
def get_summary(self, gfa: float = 0) -> CarbonSummary:
"""Generate carbon footprint summary."""
by_material = {}
by_category = {}
by_stage = {}
by_level = {}
for result in self.results:
# By material
by_material[result.material] = by_material.get(result.material, 0) + result.total_kgco2
# By category
cat = result.category.value
by_category[cat] = by_category.get(cat, 0) + result.total_kgco2
# By stage
stg = result.stage.value
by_stage[stg] = by_stage.get(stg, 0) + result.total_kgco2
# By level
if result.level:
by_level[result.level] = by_level.get(result.level, 0) + result.total_kgco2
total_kgco2 = sum(r.total_kgco2 for r in self.results)
return CarbonSummary(
total_kgco2=round(total_kgco2, 2),
total_tonco2=round(total_kgco2 / 1000, 2),
by_material=by_material,
by_category=by_category,
by_stage=by_stage,
by_level=by_level,
element_count=len(self.results),
gfa=gfa,
kgco2_per_m2=round(total_kgco2 / gfa, 2) if gfa > 0 else 0
)
def export_results(self, output_path: str):
"""Export results to Excel."""
with pd.ExcelWriter(output_path, engine='openpyxl') as writer:
# Detailed results
results_df = pd.DataFrame([{
'Element ID': r.element_id,
'Element Name': r.element_name,
'Material': r.material,
'Category': r.category.value,
'Quantity': r.quantity,
'Unit': r.unit,
'kg CO2e/unit': r.kgco2_per_unit,
'Total kg CO2e': round(r.total_kgco2, 2),
'Level': r.level
} for r in self.results])
results_df.to_excel(writer, sheet_name='Details', index=False)
# Summary
summary = self.get_summary()
summary_df = pd.DataFrame([
{'Metric': 'Total kg CO2e', 'Value': summary.total_kgco2},
{'Metric': 'Total ton CO2e', 'Value': summary.total_tonco2},
{'Metric': 'Elements Analyzed', 'Value': summary.element_count}
])
summary_df.to_excel(writer, sheet_name='Summary', index=False)
return output_pathQuick Start
# Initialize calculator
calculator = CO2FootprintCalculator()
# Load BIM quantities
elements = pd.read_excel("bim_quantities.xlsx")
# Calculate carbon
results = calculator.calculate_from_dataframe(elements)
# Get summary
summary = calculator.get_summary(gfa=5000) # 5000 m2 GFA
print(f"Total: {summary.total_tonco2} ton CO2e")
print(f"Per m2: {summary.kgco2_per_m2} kg CO2e/m2")Common Use Cases
1. Material Comparison
# Compare concrete vs timber
concrete_elements = elements[elements['material'].str.contains('Concrete')]
timber_elements = elements[elements['material'].str.contains('Timber')]2. Target Compliance
TARGET_KGCO2_M2 = 500 # LEED/BREEAM target
if summary.kgco2_per_m2 > TARGET_KGCO2_M2:
print(f"Warning: Exceeds target by {summary.kgco2_per_m2 - TARGET_KGCO2_M2} kg/m2")3. Export Report
calculator.export_results("carbon_report.xlsx")Resources
- DDC Book: Chapter 3.3 - CO2 Estimation
- Reference: EN 15978, EPD databases