CWICR Unit Converter

Business Case

Problem Statement

Construction data comes in various unit systems:

• Metric vs Imperial measurements
• Different unit conventions by trade
• BIM quantities need normalization
• Regional standards differ

Solution

Comprehensive unit conversion for construction quantities, normalizing data for CWICR integration and analysis.

Business Value

• Accuracy - Eliminate unit conversion errors
• Consistency - Standardize across projects
• Integration - BIM to cost data alignment
• Global - Support international projects

Technical Implementation

import pandas as pd
import numpy as np
from typing import Dict, Any, List, Optional, Tuple, Union
from dataclasses import dataclass
from enum import Enum


class UnitCategory(Enum):
    """Categories of measurement units."""
    LENGTH = "length"
    AREA = "area"
    VOLUME = "volume"
    WEIGHT = "weight"
    TIME = "time"
    QUANTITY = "quantity"


class UnitSystem(Enum):
    """Unit systems."""
    METRIC = "metric"
    IMPERIAL = "imperial"
    MIXED = "mixed"


@dataclass
class UnitConversion:
    """Unit conversion result."""
    original_value: float
    original_unit: str
    converted_value: float
    target_unit: str
    conversion_factor: float
    category: UnitCategory


# Conversion factors to base units
# Base units: meter (length), m² (area), m³ (volume), kg (weight), hour (time)

CONVERSIONS = {
    # Length to meters
    'm': {'factor': 1.0, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'meter': {'factor': 1.0, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'meters': {'factor': 1.0, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'cm': {'factor': 0.01, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'mm': {'factor': 0.001, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'km': {'factor': 1000.0, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'ft': {'factor': 0.3048, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'feet': {'factor': 0.3048, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'foot': {'factor': 0.3048, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'in': {'factor': 0.0254, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'inch': {'factor': 0.0254, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'inches': {'factor': 0.0254, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'yd': {'factor': 0.9144, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'yard': {'factor': 0.9144, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'yards': {'factor': 0.9144, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'mi': {'factor': 1609.344, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'mile': {'factor': 1609.344, 'category': UnitCategory.LENGTH, 'base': 'm'},
    'lf': {'factor': 0.3048, 'category': UnitCategory.LENGTH, 'base': 'm'},  # Linear foot

    # Area to m²
    'm2': {'factor': 1.0, 'category': UnitCategory.AREA, 'base': 'm2'},
    'm²': {'factor': 1.0, 'category': UnitCategory.AREA, 'base': 'm2'},
    'sqm': {'factor': 1.0, 'category': UnitCategory.AREA, 'base': 'm2'},
    'cm2': {'factor': 0.0001, 'category': UnitCategory.AREA, 'base': 'm2'},
    'mm2': {'factor': 0.000001, 'category': UnitCategory.AREA, 'base': 'm2'},
    'ha': {'factor': 10000.0, 'category': UnitCategory.AREA, 'base': 'm2'},
    'hectare': {'factor': 10000.0, 'category': UnitCategory.AREA, 'base': 'm2'},
    'ft2': {'factor': 0.092903, 'category': UnitCategory.AREA, 'base': 'm2'},
    'sf': {'factor': 0.092903, 'category': UnitCategory.AREA, 'base': 'm2'},
    'sqft': {'factor': 0.092903, 'category': UnitCategory.AREA, 'base': 'm2'},
    'yd2': {'factor': 0.836127, 'category': UnitCategory.AREA, 'base': 'm2'},
    'sy': {'factor': 0.836127, 'category': UnitCategory.AREA, 'base': 'm2'},  # Square yard
    'acre': {'factor': 4046.86, 'category': UnitCategory.AREA, 'base': 'm2'},

    # Volume to m³
    'm3': {'factor': 1.0, 'category': UnitCategory.VOLUME, 'base': 'm3'},
    'm³': {'factor': 1.0, 'category': UnitCategory.VOLUME, 'base': 'm3'},
    'cbm': {'factor': 1.0, 'category': UnitCategory.VOLUME, 'base': 'm3'},
    'l': {'factor': 0.001, 'category': UnitCategory.VOLUME, 'base': 'm3'},
    'liter': {'factor': 0.001, 'category': UnitCategory.VOLUME, 'base': 'm3'},
    'litre': {'factor': 0.001, 'category': UnitCategory.VOLUME, 'base': 'm3'},
    'ml': {'factor': 0.000001, 'category': UnitCategory.VOLUME, 'base': 'm3'},
    'ft3': {'factor': 0.0283168, 'category': UnitCategory.VOLUME, 'base': 'm3'},
    'cf': {'factor': 0.0283168, 'category': UnitCategory.VOLUME, 'base': 'm3'},
    'cuft': {'factor': 0.0283168, 'category': UnitCategory.VOLUME, 'base': 'm3'},
    'yd3': {'factor': 0.764555, 'category': UnitCategory.VOLUME, 'base': 'm3'},
    'cy': {'factor': 0.764555, 'category': UnitCategory.VOLUME, 'base': 'm3'},  # Cubic yard
    'cuyd': {'factor': 0.764555, 'category': UnitCategory.VOLUME, 'base': 'm3'},
    'gal': {'factor': 0.00378541, 'category': UnitCategory.VOLUME, 'base': 'm3'},
    'gallon': {'factor': 0.00378541, 'category': UnitCategory.VOLUME, 'base': 'm3'},

    # Weight to kg
    'kg': {'factor': 1.0, 'category': UnitCategory.WEIGHT, 'base': 'kg'},
    'kilogram': {'factor': 1.0, 'category': UnitCategory.WEIGHT, 'base': 'kg'},
    'g': {'factor': 0.001, 'category': UnitCategory.WEIGHT, 'base': 'kg'},
    'gram': {'factor': 0.001, 'category': UnitCategory.WEIGHT, 'base': 'kg'},
    'mg': {'factor': 0.000001, 'category': UnitCategory.WEIGHT, 'base': 'kg'},
    't': {'factor': 1000.0, 'category': UnitCategory.WEIGHT, 'base': 'kg'},
    'ton': {'factor': 1000.0, 'category': UnitCategory.WEIGHT, 'base': 'kg'},  # Metric ton
    'tonne': {'factor': 1000.0, 'category': UnitCategory.WEIGHT, 'base': 'kg'},
    'mt': {'factor': 1000.0, 'category': UnitCategory.WEIGHT, 'base': 'kg'},
    'lb': {'factor': 0.453592, 'category': UnitCategory.WEIGHT, 'base': 'kg'},
    'lbs': {'factor': 0.453592, 'category': UnitCategory.WEIGHT, 'base': 'kg'},
    'pound': {'factor': 0.453592, 'category': UnitCategory.WEIGHT, 'base': 'kg'},
    'oz': {'factor': 0.0283495, 'category': UnitCategory.WEIGHT, 'base': 'kg'},
    'ounce': {'factor': 0.0283495, 'category': UnitCategory.WEIGHT, 'base': 'kg'},
    'st': {'factor': 907.185, 'category': UnitCategory.WEIGHT, 'base': 'kg'},  # Short ton (US)

    # Time to hours
    'hr': {'factor': 1.0, 'category': UnitCategory.TIME, 'base': 'hr'},
    'hour': {'factor': 1.0, 'category': UnitCategory.TIME, 'base': 'hr'},
    'hours': {'factor': 1.0, 'category': UnitCategory.TIME, 'base': 'hr'},
    'h': {'factor': 1.0, 'category': UnitCategory.TIME, 'base': 'hr'},
    'min': {'factor': 1/60, 'category': UnitCategory.TIME, 'base': 'hr'},
    'minute': {'factor': 1/60, 'category': UnitCategory.TIME, 'base': 'hr'},
    'day': {'factor': 8.0, 'category': UnitCategory.TIME, 'base': 'hr'},  # 8-hour workday
    'days': {'factor': 8.0, 'category': UnitCategory.TIME, 'base': 'hr'},
    'week': {'factor': 40.0, 'category': UnitCategory.TIME, 'base': 'hr'},  # 40-hour week

    # Quantity (no conversion, just counting)
    'ea': {'factor': 1.0, 'category': UnitCategory.QUANTITY, 'base': 'ea'},
    'each': {'factor': 1.0, 'category': UnitCategory.QUANTITY, 'base': 'ea'},
    'pc': {'factor': 1.0, 'category': UnitCategory.QUANTITY, 'base': 'ea'},
    'pcs': {'factor': 1.0, 'category': UnitCategory.QUANTITY, 'base': 'ea'},
    'piece': {'factor': 1.0, 'category': UnitCategory.QUANTITY, 'base': 'ea'},
    'pieces': {'factor': 1.0, 'category': UnitCategory.QUANTITY, 'base': 'ea'},
    'no': {'factor': 1.0, 'category': UnitCategory.QUANTITY, 'base': 'ea'},
    'nr': {'factor': 1.0, 'category': UnitCategory.QUANTITY, 'base': 'ea'},
    'set': {'factor': 1.0, 'category': UnitCategory.QUANTITY, 'base': 'ea'},
    'lot': {'factor': 1.0, 'category': UnitCategory.QUANTITY, 'base': 'ea'},
    'ls': {'factor': 1.0, 'category': UnitCategory.QUANTITY, 'base': 'ea'},  # Lump sum
}


class CWICRUnitConverter:
    """Convert between construction units."""

    def __init__(self):
        self.conversions = CONVERSIONS

    def normalize_unit(self, unit: str) -> str:
        """Normalize unit string for lookup."""
        return str(unit).lower().strip().replace(' ', '').replace('.', '')

    def get_unit_info(self, unit: str) -> Optional[Dict[str, Any]]:
        """Get conversion info for unit."""
        normalized = self.normalize_unit(unit)
        return self.conversions.get(normalized)

    def convert(self,
                value: float,
                from_unit: str,
                to_unit: str) -> UnitConversion:
        """Convert value between units."""

        from_info = self.get_unit_info(from_unit)
        to_info = self.get_unit_info(to_unit)

        if not from_info:
            raise ValueError(f"Unknown source unit: {from_unit}")
        if not to_info:
            raise ValueError(f"Unknown target unit: {to_unit}")

        if from_info['category'] != to_info['category']:
            raise ValueError(
                f"Cannot convert between {from_info['category'].value} and {to_info['category'].value}"
            )

        # Convert: source -> base -> target
        base_value = value * from_info['factor']
        converted_value = base_value / to_info['factor']
        conversion_factor = from_info['factor'] / to_info['factor']

        return UnitConversion(
            original_value=value,
            original_unit=from_unit,
            converted_value=round(converted_value, 6),
            target_unit=to_unit,
            conversion_factor=conversion_factor,
            category=from_info['category']
        )

    def to_metric(self, value: float, from_unit: str) -> UnitConversion:
        """Convert to standard metric unit."""

        info = self.get_unit_info(from_unit)
        if not info:
            raise ValueError(f"Unknown unit: {from_unit}")

        base_unit = info['base']
        return self.convert(value, from_unit, base_unit)

    def to_imperial(self, value: float, from_unit: str) -> UnitConversion:
        """Convert to common imperial unit."""

        info = self.get_unit_info(from_unit)
        if not info:
            raise ValueError(f"Unknown unit: {from_unit}")

        imperial_map = {
            'm': 'ft',
            'm2': 'sf',
            'm3': 'cy',
            'kg': 'lb',
            'hr': 'hr'
        }

        base = info['base']
        imperial_unit = imperial_map.get(base, base)

        return self.convert(value, from_unit, imperial_unit)

    def convert_dataframe(self,
                          df: pd.DataFrame,
                          value_column: str,
                          unit_column: str,
                          target_unit: str,
                          output_column: str = None) -> pd.DataFrame:
        """Convert units in DataFrame column."""

        result = df.copy()
        if output_column is None:
            output_column = f"{value_column}_converted"

        converted_values = []
        for _, row in df.iterrows():
            try:
                conversion = self.convert(
                    row[value_column],
                    row[unit_column],
                    target_unit
                )
                converted_values.append(conversion.converted_value)
            except ValueError:
                converted_values.append(None)

        result[output_column] = converted_values
        result[f'{output_column}_unit'] = target_unit

        return result

    def normalize_units(self,
                        df: pd.DataFrame,
                        value_column: str,
                        unit_column: str) -> pd.DataFrame:
        """Normalize all units to base metric units."""

        result = df.copy()
        normalized_values = []
        normalized_units = []

        for _, row in df.iterrows():
            try:
                conversion = self.to_metric(row[value_column], row[unit_column])
                normalized_values.append(conversion.converted_value)
                normalized_units.append(conversion.target_unit)
            except ValueError:
                normalized_values.append(row[value_column])
                normalized_units.append(row[unit_column])

        result[f'{value_column}_normalized'] = normalized_values
        result[f'{unit_column}_normalized'] = normalized_units

        return result


class ConstructionUnitHelper:
    """Helper for construction-specific unit operations."""

    def __init__(self):
        self.converter = CWICRUnitConverter()

    def calculate_area(self,
                       length: float, length_unit: str,
                       width: float, width_unit: str,
                       result_unit: str = 'm2') -> float:
        """Calculate area from length and width."""

        # Convert both to meters
        length_m = self.converter.convert(length, length_unit, 'm').converted_value
        width_m = self.converter.convert(width, width_unit, 'm').converted_value

        # Calculate area in m²
        area_m2 = length_m * width_m

        # Convert to requested unit
        return self.converter.convert(area_m2, 'm2', result_unit).converted_value

    def calculate_volume(self,
                         length: float, length_unit: str,
                         width: float, width_unit: str,
                         height: float, height_unit: str,
                         result_unit: str = 'm3') -> float:
        """Calculate volume from dimensions."""

        # Convert all to meters
        length_m = self.converter.convert(length, length_unit, 'm').converted_value
        width_m = self.converter.convert(width, width_unit, 'm').converted_value
        height_m = self.converter.convert(height, height_unit, 'm').converted_value

        # Calculate volume in m³
        volume_m3 = length_m * width_m * height_m

        # Convert to requested unit
        return self.converter.convert(volume_m3, 'm3', result_unit).converted_value

    def concrete_volume(self,
                        length_ft: float,
                        width_ft: float,
                        thickness_in: float) -> Dict[str, float]:
        """Calculate concrete volume (common US method)."""

        # Convert to meters
        length_m = self.converter.convert(length_ft, 'ft', 'm').converted_value
        width_m = self.converter.convert(width_ft, 'ft', 'm').converted_value
        thickness_m = self.converter.convert(thickness_in, 'in', 'm').converted_value

        volume_m3 = length_m * width_m * thickness_m
        volume_cy = self.converter.convert(volume_m3, 'm3', 'cy').converted_value

        return {
            'm3': round(volume_m3, 3),
            'cy': round(volume_cy, 2)
        }

    def rebar_weight(self,
                     length: float, length_unit: str,
                     bar_size: str) -> Dict[str, float]:
        """Calculate rebar weight from length and bar size."""

        # Rebar weight per meter (kg/m) - US bar sizes
        rebar_weights = {
            '#3': 0.561, '#4': 0.996, '#5': 1.556,
            '#6': 2.24, '#7': 3.049, '#8': 3.982,
            '#9': 5.06, '#10': 6.41, '#11': 7.91
        }

        weight_per_m = rebar_weights.get(bar_size, 1.0)
        length_m = self.converter.convert(length, length_unit, 'm').converted_value

        weight_kg = length_m * weight_per_m
        weight_lb = self.converter.convert(weight_kg, 'kg', 'lb').converted_value

        return {
            'kg': round(weight_kg, 2),
            'lb': round(weight_lb, 2),
            'ton': round(weight_kg / 1000, 4)
        }

Quick Start

# Initialize converter
converter = CWICRUnitConverter()

# Simple conversion
result = converter.convert(100, 'ft', 'm')
print(f"{result.original_value} {result.original_unit} = {result.converted_value} {result.target_unit}")

# Convert to metric
metric = converter.to_metric(1000, 'sf')
print(f"1000 sf = {metric.converted_value} m²")

# Convert DataFrame
df = pd.DataFrame({
    'quantity': [100, 50, 25],
    'unit': ['cy', 'm3', 'cf']
})
normalized = converter.normalize_units(df, 'quantity', 'unit')

Common Use Cases

1. Area Calculation

helper = ConstructionUnitHelper()
area = helper.calculate_area(
    length=50, length_unit='ft',
    width=30, width_unit='ft',
    result_unit='m2'
)
print(f"Area: {area} m²")

2. Concrete Volume

volume = helper.concrete_volume(
    length_ft=20,
    width_ft=10,
    thickness_in=6
)
print(f"Concrete: {volume['cy']} CY = {volume['m3']} m³")

3. Rebar Weight

weight = helper.rebar_weight(length=100, length_unit='m', bar_size='#5')
print(f"Rebar weight: {weight['kg']} kg")

4. Normalize BIM Quantities

bim_data = pd.read_excel("bim_quantities.xlsx")
normalized = converter.normalize_units(bim_data, 'Quantity', 'Unit')

Resources

• GitHub: OpenConstructionEstimate-DDC-CWICR
• DDC Book: Chapter 2.3 - Data Standardization