An open method for sustainable digital decisions
SDAF helps teams frame a consequential digital decision, compare functionally equivalent options across energy, carbon, lifecycle, circularity and cost, and turn the evidence into a transparent recommendation.
Open, vendor-neutral and designed to complement—not replace—established standards and specialist methods.
What SDAF means
SDAF is an open, vendor-neutral reference framework for making evidence-based, transparent and defensible sustainability decisions about digital systems.
It provides a structured, repeatable route from requirements and comparable evidence to a traceable, reviewable decision. Sustainability becomes part of architecture, procurement and lifecycle choices—not only something reported afterwards.
Leaders, architects, sustainability and finance teams, procurement, engineering, operations, risk, governance and assurance can use the same decision structure across projects, services, portfolios and supply chains.
SDAF does not prescribe a technology, supplier or calculation tool. It does not replace legislation, standards, certification schemes or specialist methods; it helps teams apply them coherently within a decision.
Start with the method
It makes the logic behind a sustainability claim visible: what is being compared, what is inside the boundary, which evidence supports the result and how uncertainty affects confidence.
State the intended outcome, functional unit, reference flow, system boundary and equivalent service before comparing options.
Comparable by designConsider operational energy, carbon, lifecycle effects, circularity and cost across the parts of the system that the decision can influence.
Lifecycle visibilityKeep actual data, derived values, benchmarks, assumptions and unknowns distinct so the result carries an honest level of confidence.
Evidence before claimsThe framework
A beginner can follow the sequence from the initial question to an assured recommendation. Experienced practitioners can go deeper into the eight-part framework, evidence trail and methodological controls.
Define the decision, purpose, ownership and sustainability intent.
Set the functional unit, boundaries, reference flow and equivalent service.
Compare energy, carbon, lifecycle, circularity and value using traceable inputs.
Translate the evidence into an owned technical recommendation and conditions.
Challenge confidence, sensitivity, completeness and reproducibility before release.
Purpose, principles, terminology, applicability and normative structure.
The controlled five-phase assessment lifecycle from Orient to Assure.
Boundaries, evidence quality, methods, uncertainty, confidence and traceability.
Evidence sufficiency, stability and the defensible decision record.
Lifecycle burdens and circularity benefits without double counting.
Oversight, independence, conformance and assurance requirements.
Roles, systems, controls, capability and operating cadence.
Controlled evidence exchange across organizations and methods.
Why I developed SDAF
I kept seeing the same gap: environmental consequences were being locked in through architecture, procurement and lifecycle choices long before they appeared in a sustainability report. Decisions were often based on isolated metrics, inconsistent boundaries or evidence that could not be compared or reproduced.
I developed SDAF to connect sustainability with the actual work of architecture—to create a common method across the digital stack and a shared language for technical, commercial, sustainability and governance teams. I released it openly so that others can use it, challenge it and help it mature.
Raymond du ToitCreator and steward of SDAF
How it works
The application does not pretend that incomplete information is precise. Unknown, assumed and benchmark values remain visible and reduce confidence—not the calculated impact itself.
Name the choice, owner, workload and equivalent outcome.
Use representative inputs or upload a multi-device inventory.
Separate measurements, operator data, supplier data, derived values, benchmarks and assumptions.
Issue a proposal report, then a final report after implementation and testing.
Apply SDAF
Use the guided six-step workflow for early solution evaluation or detailed estate comparisons. Model multiple sites, DR capacity, active and idle instances, product carbon footprints, acquisition choices, hardware retention, energy, Scope 2, TCO and simple ROI.
Assessment data is saved in your browser. No additional account or software licence is required.
Standards & evidence
SDAF distinguishes external accounting methods, standards-informed screening and SDAF-specific planning formulas. Sources, years, boundaries and suitability remain part of the assessment record.
Location-based and market-based results remain separate.
PUE terminology with facility-specific evidence preferred.
Context for lifecycle and product carbon footprint treatment.
Context for durability, recovery and circularity indicators.
Read & download
These links open the source documents in GitHub, so the website can provide a clear front door without creating duplicate or outdated copies. Zenodo remains the authoritative, citable record of Version 1.0.
Purpose, audience, application and organizational value.
Read on GitHub Five-minute orientationA concise introduction to SDAF and its principal components.
Read on GitHub For first-time usersPractical guidance for conducting a first SDAF assessment.
Start here Choose a pathwayNavigation routes for different roles, needs and interests.
Find your route Visual briefingA presentation-led overview for briefings and discussions.
View briefing Authoritative releaseThe fixed, citable Version 1.0 publication and full framework.
Open on ZenodoOpen framework · shared progress
SDAF is intended to grow through practical use, constructive challenge and shared learning. If you apply it, find a gap, want to run a pilot, contribute evidence or explore standards alignment, your perspective is welcome.
