Five-Year Data Retention Under Article 6: What Records Should Companies Keep?

Prepared in British English as a practitioner Knowledge Card Package: answer, explanation, application, evidence, connections and publishing layer.

A figure such as "42,600 tCO2e" cannot be verified from the figure alone. A reviewer needs to know which facility, source streams, gases, period, activity records, factors, units, formulas, estimates and approvals produced it. If a value changes after filing, the company must also show which version was filed, why it changed and whether the authority was notified.

Retention therefore supports four distinct needs:

• reproduce the calculation;

• demonstrate that the reporting boundary was complete;

• respond to verification, inspection or authority questions; and

• preserve continuity when staff, systems, suppliers or methods change.

Figure 1. Five-year Article 6 retention architecture. Branded educational visual by London Reporting Academy.

The safest way to read Article 6(1)(c) is to distinguish two layers.

Statutory minimum

The Source must retain a record of measured emission quantities for five years from the date of each analysis and make the records accessible to authorised officers during that period.

Supporting evidence needed to make the record meaningful

The final measured quantity should be supported by the records that allow it to be reproduced and assessed. These supporting documents may also be required by an authority form, monitoring plan, verifier, permit, inspection or internal control policy.

Do not write that Article 6 expressly names every supporting document unless a current implementing instrument does so. State instead that the records are retained to support the legal record, periodic report and verification trail.

Layer 1 - legal, scope and reporting basis

Retain:

• Article 6 designation notice or applicable list;

• legal entity, branch, operator and facility details;

• permit and free-zone status;

• competent-authority correspondence;

• organisational and operational boundary memo;

• source, facility and emission-source register;

• reporting period and route confirmation;

• approved monitoring plan or methodology; and

• current forms and instructions.

This layer explains why the organisation reported and what the inventory covers.

Layer 2 - source data and operating records

Retain original or controlled copies of:

• fuel invoices, delivery notes and fuel-card records;

• utility invoices and meter exports;

• tank dips, stock movement and mass-balance records;

• production, throughput and operating-hour data;

• refrigerant purchase, recharge, recovery and disposal records;

• maintenance, leak and equipment logs;

• laboratory analyses and sampling records;

• calibration certificates and meter maintenance;

• waste, wastewater or process records where relevant;

• supplier statements and landlord data; and

• source-system extracts and query parameters.

Preserve the source record, not only a manually retyped summary.

Layer 3 - methodology and calculations

Retain:

• factor register and archived source publications;

• GWP set and gas mapping;

• calorific values, density and unit conversions;

• calculation workbooks and protected formula versions;

• scripts, code, data models and transformation logs;

• estimate and data-gap register;

• uncertainty and sensitivity analysis;

• allocation and consolidation logic;

• duplicate and completeness tests;

• recalculation and base-year policy where used; and

• methodology change log.

The archive should make calculations executable or reproducible even if the original preparer leaves.

Layer 4 - controls, approvals and verification

Retain:

• preparer and reviewer sign-offs;

• reconciliations to finance, operations and permits;

• variance analyses;

• access and change logs;

• internal audit or readiness findings;

• management representations;

• verifier proposal, scope and independence checks;

• evidence requests and responses;

• site-visit records;

• findings, corrections and closure evidence; and

• final verification statement or report.

Layer 5 - submission and correspondence

Retain:

• exact filed forms and attachments;

• read-only final package;

• file names and hashes;

• portal submission ID and timestamp;

• receipt, acknowledgement and status;

• authority questions and company responses;

• correction and resubmission packages;

• acceptance or closure record; and

• inspection document-provision log.

Article 6 refers to five years from the date of each analysis. This creates a rolling record rather than one simple annual deletion date.

For each analysis record, capture:

• analysis ID;

• analysis date;

• reporting period;

• relevant source and facility;

• minimum retention date;

• longer-retention basis, if any;

• legal-hold status; and

• disposal approval.

Illustrative example. A laboratory analysis dated 18 February 2026 has a minimum Article 6 retention date of 18 February 2031, subject to any longer requirement. A year-end calculation approved on 20 March 2027 has its own date. A corrected analysis should not erase the original or restart the clock invisibly; retain both and document the relationship.

The schedule should be approved by legal, records management, IT security and the climate-reporting owner.

Never overwrite a filed workbook or report. Use a version structure such as:

• Draft working versions;

• Inventory freeze version;

• Verification-adjusted version;

• Filed version;

• Corrected / resubmitted version; and

• Restated comparative version.

Each version should record the author, reviewer, date, reason, changed cells or data, effect on emissions, authority notification and approval. Use stable source IDs and factor IDs so that differences can be traced.

A change log should distinguish:

• error correction;

• late actual data replacing an estimate;

• factor or GWP update;

• boundary or structural change;

• method improvement; and

• operational emissions reduction.

This prevents a methodological change being misrepresented as performance.

Figure 2. Secure retention lifecycle. Branded educational visual by London Reporting Academy.

A record can be retained for five years and still fail if it is altered, inaccessible or stripped of context. Apply the following lifecycle.

Capture

Collect from the authoritative system or signed source. Record owner, date, system, query and extraction parameters. Avoid screenshots where a structured export is available.

Validate

Check completeness, format, malware, duplicate files and readability. Confirm that scans are legible and spreadsheets open without broken links.

Freeze

Create the approved version. Apply a hash, immutable identifier or write restriction. Store the data snapshot used by the calculation.

Control access

Use role-based access, least privilege, multi-factor authentication and separate write / approval rights. Restrict commercially sensitive, personal or privileged evidence.

Back up and test

Maintain backups in accordance with the organisation's resilience policy. Test restoration rather than assuming the backup works. Avoid a single cloud account or individual laptop as the only copy.

Hold or dispose

At the end of the retention period, check legal holds, inspections, disputes, verifier matters, contracts and other laws. Disposal should be authorised, logged and secure. Do not delete related source, calculation and submission records separately if doing so destroys the evidence chain.

Classify records at least as:

• public or published;

• internal;

• confidential commercial;

• personal data;

• legally privileged; and

• regulator / verifier restricted.

The filing team should know what must be submitted, what is retained for inspection and what requires legal review before disclosure. Article 6 access by authorised officers does not justify unrestricted internal access or casual transfer to third parties.

Prepare an index that allows authorised records to be located quickly without handing over unrelated information. The index should show:

• record ID and description;

• source / facility and period;

• file path or records-system reference;

• owner and access approver;

• confidentiality class;

• retention date;

• linked calculation or filing; and

• whether the record has been provided to an authority.

Maintain a document-provision log during inspection: request, authority, date, record, version, provider and any limitation or follow-up.

Illustrative scenario - not company data. A company reports refrigerant emissions based on a maintenance log showing 120 kg recharged. After filing, the service provider confirms that 20 kg related to a different facility.

The company does not edit the filed workbook. It preserves:

• the original service log and filed calculation;

• the provider's correction;

• the boundary and materiality assessment;

• the corrected calculation and review;

• the authority notification or resubmission record; and

• the final closure status.

Both the original and corrected analyses receive retention dates. The incident is also linked to a remediation action requiring facility IDs on future maintenance records.