Whole Life Carbon

Tangible calculates carbon impacts across the full building lifecycle, assuming a 60-year building life. This page documents the calculation method for each module.

Tangible’s whole-building lifecycle carbon approach is aligned with the National Whole Building Life Cycle Assessment (wbLCA) guidelines. EPD data used in Tangible is structured to be consistent with ISO 21930 (environmental product declarations for construction products), and the LCA process documented here follows EN 15978 (sustainability of construction works — assessment of environmental performance of buildings).

Overview

Module	Title	Approach
A1–A3	Product	EPD value
A4	Transport	Weight/volume of material and distance traveled
A5	Construction	Construction emission factor + on-site material waste
B1	In-use	EPD value
B2	Maintenance	EPD value
B3	Repair	Ignored (assigned to B4)
B4	Replacement	Calculated from material service life
B5	Refurbishment	Ignored (assigned to B4)
B6	Operational Energy	Building type and location estimate
C1	Deconstruction	Demolition emission factor
C2	Transport	Weight and default distance to processing
C3	Waste Processing	EPD value
C4	Disposal	EPD value

A1–A3: Manufacturing

Impacts pulled directly from EPDs. Includes raw material extraction, transport to factory, and manufacturing.

A1\text{–}A3 = \text{EPD Impact} \times \text{Product Quantity}

For insulation (impacts reported per m²·RSI):

A1\text{–}A3_{\text{insulation}} = \text{EPD Impact} \times \text{Product Quantity} \times \frac{R\text{-Value}}{5.678}

A4: Transportation

Calculated using material weight/volume and ASHRAE 240P transport emission factors.

Default factors (manufacturing location unknown):

Source	Factor	Unit
Local ready-mix concrete	`14.79`	`kg CO2e / m³`
Regional (same state/province)	`0.1422`	`kg CO2e / kg`
National (Americas)	`0.2833`	`kg CO2e / kg`
European → Eastern US/Canada	`0.5060`	`kg CO2e / kg`
European → Western US/Canada	`0.3649`	`kg CO2e / kg`
Asian → Eastern US/Canada	`0.5512`	`kg CO2e / kg`
Asian → Western US/Canada	`0.4090`	`kg CO2e / kg`
Other	`0.5512`	`kg CO2e / kg`

Product-specific factors (manufacturing location known, North America):

Straight-line distance × 1.4 routing factor. Return trip factor (RF): 1.0 for concrete trucks, 0.5 for trips ≤ 800 km, 0.0 for trips > 800 km.

Mode	Factor	`RF`
Concrete mixing truck	`0.3095 kg CO2e / m³-km`	1.0
Truck	`0.0001171 kg CO2e / kg-km`	0.5 / 0.0

A4_{\text{default concrete}} = \text{Emission Factor} * \text{Product Volume}

A4_{\text{default}} = \text{Emission Factor} * \text{Product Weight}

A4_{\text{specific concrete}} = \text{Emission Factor} * \text{Product Volume} * (\text{Distance} * 1.4) * (1 + RF)

A4_{\text{specific}} = \text{Emission Factor} * \text{Product Weight} * (\text{Distance} * 1.4) * (1 + RF)

A5: Construction

Construction factor of 40 kg CO2e / m² per ASHRAE 240P, distributed to products by their share of total project mass.

On-site wastage rates:

Category	Rate
Gypsum Board, Plywood, Sheathing	15%
Metal, Wood Framing, Shotcrete, Paint	10%
Siding, Tiles	8%
Rebar	3%
Curtain Wall, Glass	1%
Other	5%

A5 = \text{Construction Factor} + \text{Material Waste}

\text{Material Waste} = \text{Waste Rate} \times (GWP_{A1\text{–}A4} + GWP_{C2\text{–}C4})

B1: In-use

EPD value if available; otherwise 0 kg CO2e. Insulation scaled by R-Value.

B2: Maintenance

EPD value if available; otherwise 0 kg CO2e. If the EPD assumes a service life other than 60 years, Tangible prorates:

B2 = \frac{B2_{\text{EPD}}}{\text{EPD Service Life}} \times 60 \text{ years}

B4: Replacement

Assumes 60-year building life. All replacements are like-for-like (B3/B5 ignored). Default service lives from ASHRAE 240P:

Material Type	Default Service Life
Enclosure glass, roofing, gypsum board, doors	30 years
Services (MEP, low voltage)	30 years
Interior finishes (paint, carpet, laminate, flooring)	10 years
Other	60 years

B4 = \left[\frac{60}{\text{Service Life}} - 1\right] \times (GWP_{A1\text{–}A5} + GWP_{C1\text{–}C4})

B6: Operational energy

Estimated from building type and location over 60 years. Default EUI per Energy Star:

Asset Type	Site Energy EUI (`kBtu / m²`)
Education	`907.4`
Healthcare	`2,522.0`
Hospitality	`678.1`
Industrial	`244.3`
Multifamily	`641.5`
Office	`569.4`
Retail	`553.3`
Data Center	PUE `1.82`, IT Power `5 MW`, Utilization `30%`

Users can override EUI in Project Details. Total operational energy uses Tangible's default gross floor area (excluding parking).

Fuel mix: Defaults to electricity vs. natural gas split based on asset type and location per Energy Star.

US electricity — NREL Cambium mid-case decarbonization scenario (year-by-year through 2050, flat after 2050).
Canada electricity — Canada's Energy Future 2021 and ECCC Data Catalogue.
Natural gas — 0.05311 kg CO2e / kBtu per EPA.

C1: Deconstruction

30% of A5 = 12 kg CO2e / m², distributed by product mass share.

C2: Transport to EOL

Truck transport, 32 km to landfill/processing (EPA WARM), at 0.0001171 kg CO2e / kg-km.

C3/C4: End of Life

EPD values if available, otherwise:

Material	C3 (`kg CO2e / tonne`)	C4 (`kg CO2e / tonne`)
Concrete	`2.08`	`0.00`
Metal	`0.66`	`1.29`
Wood	`0.00`	`24.94`
Other	`0.00`	`18.78`