Lifecycle Carbon Calculator for Construction

Overview

Calculate embodied carbon (EC) and lifecycle carbon emissions for construction materials, assemblies, and projects. Support sustainable design decisions and carbon reduction targets.

Business Case

Carbon calculation supports:

• Regulatory Compliance: Meet carbon reporting requirements
• Green Certifications: LEED, BREEAM, Living Building Challenge
• Design Optimization: Choose lower-carbon alternatives
• Sustainability Goals: Track progress toward net-zero

Technical Implementation

from dataclasses import dataclass, field
from typing import List, Dict, Any, Optional
from enum import Enum
import pandas as pd

class LifecycleStage(Enum):
    A1_A3 = "Product Stage (A1-A3)"  # Raw materials, transport, manufacturing
    A4 = "Transport to Site (A4)"
    A5 = "Construction (A5)"
    B1_B7 = "Use Stage (B1-B7)"  # Maintenance, repair, replacement
    C1_C4 = "End of Life (C1-C4)"  # Demolition, transport, disposal
    D = "Beyond Lifecycle (D)"  # Reuse, recycling potential

@dataclass
class MaterialCarbon:
    material_id: str
    name: str
    category: str
    unit: str
    carbon_a1_a3: float  # kgCO2e per unit
    carbon_a4: float
    carbon_a5: float
    carbon_b: float
    carbon_c: float
    carbon_d: float  # Usually negative (credit)
    density: float  # kg/m³ if applicable
    source: str
    epd_url: str = ""

@dataclass
class AssemblyCarbon:
    assembly_id: str
    name: str
    materials: List[Dict[str, Any]]
    total_carbon: float
    carbon_by_stage: Dict[str, float]

@dataclass
class ProjectCarbon:
    project_id: str
    name: str
    gross_area: float
    assemblies: List[AssemblyCarbon]
    total_embodied_carbon: float
    carbon_per_area: float
    carbon_by_stage: Dict[str, float]
    carbon_by_category: Dict[str, float]
    benchmark_comparison: Dict[str, Any]

class LifecycleCarbonCalculator:
    """Calculate lifecycle carbon for construction."""

    # Sample material carbon data (kgCO2e per unit)
    DEFAULT_MATERIALS = {
        'concrete_30mpa': MaterialCarbon(
            material_id='C30', name='Concrete 30MPa', category='Concrete',
            unit='m³', carbon_a1_a3=300, carbon_a4=5, carbon_a5=2,
            carbon_b=0, carbon_c=10, carbon_d=-20, density=2400,
            source='EPD Database'
        ),
        'concrete_40mpa': MaterialCarbon(
            material_id='C40', name='Concrete 40MPa', category='Concrete',
            unit='m³', carbon_a1_a3=350, carbon_a4=5, carbon_a5=2,
            carbon_b=0, carbon_c=10, carbon_d=-20, density=2400,
            source='EPD Database'
        ),
        'steel_rebar': MaterialCarbon(
            material_id='REBAR', name='Steel Reinforcing Bar', category='Steel',
            unit='kg', carbon_a1_a3=1.99, carbon_a4=0.05, carbon_a5=0.02,
            carbon_b=0, carbon_c=0.05, carbon_d=-0.5, density=7850,
            source='WorldSteel EPD'
        ),
        'steel_structural': MaterialCarbon(
            material_id='STEEL', name='Structural Steel', category='Steel',
            unit='kg', carbon_a1_a3=1.55, carbon_a4=0.05, carbon_a5=0.03,
            carbon_b=0, carbon_c=0.05, carbon_d=-0.8, density=7850,
            source='AISC EPD'
        ),
        'timber_clt': MaterialCarbon(
            material_id='CLT', name='Cross-Laminated Timber', category='Timber',
            unit='m³', carbon_a1_a3=-500, carbon_a4=10, carbon_a5=5,
            carbon_b=0, carbon_c=50, carbon_d=-100, density=500,
            source='AWC EPD'
        ),
        'gypsum_board': MaterialCarbon(
            material_id='GYP', name='Gypsum Board 12.5mm', category='Finishes',
            unit='m²', carbon_a1_a3=3.2, carbon_a4=0.2, carbon_a5=0.1,
            carbon_b=0, carbon_c=0.3, carbon_d=-0.1, density=10,
            source='EUROGYPSUM EPD'
        ),
        'insulation_mineral': MaterialCarbon(
            material_id='INS_MW', name='Mineral Wool Insulation', category='Insulation',
            unit='m³', carbon_a1_a3=45, carbon_a4=2, carbon_a5=1,
            carbon_b=0, carbon_c=5, carbon_d=-2, density=40,
            source='EURIMA EPD'
        ),
        'glass_double': MaterialCarbon(
            material_id='GLASS', name='Double Glazed Unit', category='Glazing',
            unit='m²', carbon_a1_a3=35, carbon_a4=1, carbon_a5=0.5,
            carbon_b=0, carbon_c=2, carbon_d=-5, density=25,
            source='Glass for Europe EPD'
        ),
        'aluminum': MaterialCarbon(
            material_id='ALU', name='Aluminum Profile', category='Metals',
            unit='kg', carbon_a1_a3=8.0, carbon_a4=0.1, carbon_a5=0.05,
            carbon_b=0, carbon_c=0.1, carbon_d=-4.0, density=2700,
            source='EAA EPD'
        ),
    }

    # Building type benchmarks (kgCO2e/m²)
    BENCHMARKS = {
        'Office': {'typical': 500, 'good': 350, 'best': 200},
        'Residential': {'typical': 400, 'good': 280, 'best': 150},
        'Retail': {'typical': 450, 'good': 320, 'best': 180},
        'Industrial': {'typical': 350, 'good': 250, 'best': 150},
        'Healthcare': {'typical': 700, 'good': 500, 'best': 350},
    }

    def __init__(self):
        self.materials: Dict[str, MaterialCarbon] = dict(self.DEFAULT_MATERIALS)
        self.assemblies: Dict[str, AssemblyCarbon] = {}

    def add_material(self, material: MaterialCarbon):
        """Add or update a material."""
        self.materials[material.material_id] = material

    def calculate_material_carbon(self, material_id: str, quantity: float,
                                   stages: List[LifecycleStage] = None) -> Dict:
        """Calculate carbon for a material quantity."""
        if material_id not in self.materials:
            raise ValueError(f"Unknown material: {material_id}")

        material = self.materials[material_id]

        if stages is None:
            stages = list(LifecycleStage)

        carbon_by_stage = {}
        total = 0

        for stage in stages:
            if stage == LifecycleStage.A1_A3:
                carbon = material.carbon_a1_a3 * quantity
            elif stage == LifecycleStage.A4:
                carbon = material.carbon_a4 * quantity
            elif stage == LifecycleStage.A5:
                carbon = material.carbon_a5 * quantity
            elif stage == LifecycleStage.B1_B7:
                carbon = material.carbon_b * quantity
            elif stage == LifecycleStage.C1_C4:
                carbon = material.carbon_c * quantity
            elif stage == LifecycleStage.D:
                carbon = material.carbon_d * quantity
            else:
                carbon = 0

            carbon_by_stage[stage.value] = carbon
            total += carbon

        return {
            'material_id': material_id,
            'material_name': material.name,
            'quantity': quantity,
            'unit': material.unit,
            'total_carbon': total,
            'carbon_by_stage': carbon_by_stage
        }

    def create_assembly(self, assembly_id: str, name: str,
                        components: List[Dict]) -> AssemblyCarbon:
        """Create an assembly from multiple materials."""
        total_carbon = 0
        carbon_by_stage = {stage.value: 0 for stage in LifecycleStage}
        material_details = []

        for comp in components:
            material_id = comp['material_id']
            quantity = comp['quantity']

            result = self.calculate_material_carbon(material_id, quantity)
            total_carbon += result['total_carbon']

            for stage, carbon in result['carbon_by_stage'].items():
                carbon_by_stage[stage] += carbon

            material_details.append({
                'material': result['material_name'],
                'quantity': quantity,
                'unit': result['unit'],
                'carbon': result['total_carbon']
            })

        assembly = AssemblyCarbon(
            assembly_id=assembly_id,
            name=name,