What is an IRMA?
The Independent Report on Metering Arrangements (IRMA) is a formal, independent technical report required by Ofgem to verify that an RHI-accredited heating system’s metering setup is fully compliant with the scheme regulations.
The IRMA serves as proof that your meters are installed correctly, accurately measure the eligible heat, and appropriately account for any deductions required by the RHI rules. It is a critical layer of compliance for complex systems and a necessary assurance for securing your 20-year tariff payments.
When is an IRMA Mandatory for RHI Participants?
While not required for all RHI installations (simple, sub-45kW systems with standard metering are often exempt), an IRMA becomes mandatory in several key scenarios, typically when the installation is complex or when deductions need to be verified.
An IRMA is required if your installation:
- Has a large capacity: The installation has a capacity of 1 $\text{MW}_{\text{th}}$ or above.
- Uses Steam: The installation uses steam as the heat transfer medium.
- Is a 'Multiple' Metering Arrangement: The installation is classified as having a 'multiple' metering arrangement for RHI payment purposes. This classification applies when:
- Heat is supplied to multiple buildings with differing heat uses.
- There is ineligible heat use (e.g., swimming pools, cooling systems, or non-qualifying processes).
- Heat is supplied from multiple heat sources (e.g., biomass boiler plus fossil fuel backup).
- Requires a Heat Loss Calculation (HLC) or High-Loss Assessment:
- The system was accredited before 29th September 2013 (requiring an HLC).
- The Heat Loss Assessment (HLA) for external pipework shows that losses are greater than 3% of the projected annual heat output.
- System Change or Amendment: An updated IRMA is required when a significant change is made to the heating system that affects the metering arrangement (e.g., adding a new building, changing the pipework layout, or replacing a meter other than a like-for-like replacement).
How much does an IRMA Cost?
This depends on certain factors, the main ones being location and size of the scheme. A typical price range will be £1,500 for local and small schemes, to £3,000 for remote and very large schemes.
The IRMA Verification Checklist
The IRMA is a detailed, prescriptive document that must follow the official Ofgem template. It requires a competent, independent engineer to perform a physical site inspection and a detailed document audit. The IRMA verifies the following critical components of your metering setup:
The IRMA Process and Treco's Support
Managing the IRMA process requires specialist knowledge of both RHI regulations and commercial heating system design.
1. Commissioning the Competent Person
The IRMA must be completed by a "competent person"—an independent, unbiased engineer who possesses the necessary qualifications and expertise in heating system design and RHI metering standards.
2. Site Visit and Audit
The engineer will attend the site to physically inspect the installation, compare the physical setup against the RHI schematic, and confirm all meter details, serial numbers, and installation methods.
3. Report Generation and Submission
The engineer prepares the final report using the Ofgem IRMA Template, detailing all findings, supporting evidence (photos, schematics, certificates), and any exceptions found. This final, signed report is then submitted to Ofgem as a mandatory part of your application or amendment.
Crucially, if an IRMA is required but not submitted, or if the submitted IRMA is rejected, Ofgem will likely suspend RHI payments until the compliance issue is rectified.
Our IRMA Management Service
Treco provides end-to-end support for the IRMA process:
- Pre-IRMA Design Review: We check your existing or planned metering arrangement against all RHI regulations to pre-emptively fix common errors.
- Documentation Assembly: We provide the compliant schematics, heat loss calculations (HLA/HLC), and technical data required by the IRMA author.
- Independent Coordination: We coordinate with a qualified, independent engineer to complete the site audit and produce the final, compliant report on your behalf.