Green Mark 2021 vs. GMI: Comparing Whole Life Carbon Assessment (WLCA) Requirements
- Adapt D&B
- 4 days ago
- 4 min read
If you're planning a certification pathway in Singapore, one of the first practical questions is which BCA scheme actually applies to your project — Green Mark 2021 (GM:2021) for whole buildings, or Green Mark for Interiors (GMI) for tenanted spaces and fit-outs.
Both frameworks include carbon-focused sections built around Whole Life Carbon Assessment (WLCA) principles, but the scope, scoring structure, and terminology differ enough that mixing them up can cost you time and points during submission.
This post breaks down exactly how the two frameworks treat whole life carbon, so you can scope your Whole Life Carbon Assessment (WLCA) correctly from the start.
Which Scheme Applies to Your Project?
Green Mark 2021 (GM:2021) applies to whole buildings — new developments and existing buildings undergoing major retrofit or reassessment. It covers the base building: structure, façade, common M&E systems, and base-building operations.
Green Mark for Interiors (GMI) applies to tenanted interior spaces — offices, retail units, restaurants, laboratories, and supermarkets. It evaluates what a tenant controls within their leased space, independent of the base building's own Green Mark status (though GMI does reference the base building's rating in some scoring criteria).
If you're a developer certifying a new building, GM:2021 is your framework. If you're a tenant fitting out office space or a retail unit, GMI applies instead — and the two are scored on different criteria, point structures, and documentation requirements.
Whole Life Carbon Assessment (WLCA) Under Green Mark 2021
Under GM:2021, whole life carbon sits within the Whole Life Carbon (Cn) section — one of five sustainability sections, each worth up to 15 points, alongside Health & Wellbeing, Resilience, Maintainability, and Intelligence. Scoring 10 or more points in this section qualifies a project for a Whole Life Carbon exemplary-performance badge.
Key scoring criteria include:
CN1.1 Whole Life Carbon Assessment — up to 3 points for meeting minimum scope: Substructure and Superstructure across Product Stage (A1–A3), Construction Stage (A4–A5), Maintenance (B2), Replacement (B4), and Operational Energy (B6). New-build projects completing the full scope can earn up to 2 additional Innovation points.
CN1.1(ii) Embodied Carbon Computation — points awarded for calculating embodied carbon via BCA-recognised tools (Singapore Building Carbon Calculator or Building Embodied Carbon Calculator) and for achieving reductions against BCA's reference embodied carbon benchmarks — 1,000 kgCO₂e/m² for non-residential, 1,500 for residential, and 2,500 for industrial buildings.
CN1.2 2030 Transition Plan — points for publishing a net-zero carbon transition plan based on Scope 1 and Scope 2 emissions.
Whole Life Carbon Assessment (WLCA) Under Green Mark for Interiors
GMI structures its carbon criteria under the Low Carbon (CN) section, also worth 15 points as one of five sustainability sections (alongside Energy Efficiency, Health & Wellbeing, Environmental Stewardship, and Smart Integration), also with a badge available at 10+ points.
Key scoring criteria include:
Section 5.1 Embodied Carbon Computation — points for calculating upfront embodied carbon (A1–A5) of interior construction materials and mechanical/electrical equipment, using the Singapore Building Carbon Calculator, scaled by the number of material and equipment types assessed (≥3 materials for partial points, ≥7 for full points; similarly ≥3 or ≥5 equipment types).
Section 5.2 Carbon Inventory & Plan — points for Scope 1 and Scope 2 carbon reporting (5.2a) and for developing a sustainability/decarbonisation transition plan (5.2b). Notably, criteria 5.2a(i) and (ii) are a prerequisite to score under other Low Carbon criteria for Platinum and Platinum ZE ratings — meaning higher-tier GMI submissions need this reporting in place before other Low Carbon points can be claimed.
Section 5.3 Low Carbon Products and Practices — a broader set of criteria covering sustainable product procurement, conservation and reuse of existing finishes and furniture, and use of certified low-carbon materials.
Side-by-Side: Key Differences
GM:2021 | GMI | |
Applies to | Whole buildings | Tenanted interior spaces |
Carbon section name | Whole Life Carbon (Cn) | Low Carbon (CN) |
Section max points | 15 | 15 |
Badge threshold | 10+ points | 12 points |
Core embodied carbon tool | SBCC / BECC | SBCC |
Scope focus | Substructure & Superstructure | Interior construction materials & M&E equipment |
Notable prerequisite | None at Cn section level | Carbon reporting (5.2a) prerequisite for higher scoring at Platinum/Platinum ZE |
Transition plan criterion | CN1.2 (2030 Transition Plan) | Section 5.2b (decarbonisation plan) |
Why This Distinction Matters When Scoping Your WLCA
Because the two frameworks define scope, reference benchmarks, and prerequisite structures differently, a Whole Life Carbon Assessment (WLCA) built for a GM:2021 submission cannot simply be repurposed for a GMI submission on the same site, even if the underlying methodology (EN 15978 lifecycle modules, EN 15804-verified product data, RICS Whole Life Carbon Assessment for the Built Environment, 2nd Edition) is consistent across both.
This matters most in mixed-use scenarios — for example, a developer certifying the base building under GM:2021 while an anchor tenant separately pursues GMI for their fit-out. In these cases, the two assessments need to be scoped and coordinated carefully to avoid double-counting or gaps in coverage between what the base building assessment covers and what the interior assessment covers.
Getting Started
Whether you're certifying a whole building under GM:2021 or an interior fit-out under GMI, getting the scope of your Whole Life Carbon Assessment (WLCA) right from the outset — aligned to the correct framework's criteria, reference benchmarks, and prerequisite structure — saves significant rework at submission stage.
Adapt D&B manages Whole Life Carbon Assessments (WLCA) for both GM:2021 and GMI submissions in Singapore, ensuring your scope, data, and documentation match the specific framework your project falls under.
This article is for general informational purposes. Certification criteria referenced are current as of publication; please refer to BCA's official Green Mark 2021 and GMI certification standards for the latest requirements.
