For a European industrial heat buyer, a pellet offer must fit the installed boiler as well as the budget. A low ash percentage alone does not establish that a new fuel will run without deposits or cleaning interruptions. Before committing to recurring deliveries, agree how boiler compatibility will be demonstrated.
1. Ask two separate questions about ash
ISO 18122:2022 measures ash content. ISO 21404:2020 addresses characteristic temperatures of ash melting behaviour. They answer different questions: how much residue is measured, and how the prepared ash behaves when heated.
For procurement, keep these as separate lines in the specification. Do not convert an ash percentage into an assumed melting temperature or treat a generic “low ash” statement as an operating guarantee. If the boiler supplier requires an ash melting report, a moisture or calorific-value report cannot fill that gap.
2. Start with the installed boiler's fuel envelope
Ask the boiler manufacturer or authorised service partner to identify the acceptable fuel specification for the exact model, grate and feed system. Share the proposed pellet specification and available laboratory reports before purchasing the trial quantity.
IEA Bioenergy Task 32 describes how combustion design and air distribution influence slagging. A laboratory result therefore needs an equipment-specific interpretation.
Ask for a written decision: suitable for a controlled trial, additional analysis needed, or outside the approved fuel envelope. Avoid a universal temperature threshold copied from another boiler. This guide is for fuel qualification; any operating adjustments belong to the qualified boiler team.
3. Make the laboratory request unambiguous
A useful request names the product and represented lot, the chosen test method and edition, and the intended boiler assessment. Ask the laboratory to report test conditions and all characteristic temperatures determined by the method, including any endpoint not reached within the test range.
| Request item | Purchasing purpose |
|---|---|
| Sample and lot identification | Connect the result to the fuel being evaluated |
| Ash preparation and test atmosphere | Allow the boiler specialist to interpret the result |
| Method, units and reported endpoints | Compare reports on the same basis |
| Deviations and measurement limitations | Identify what the report cannot establish |
Ask the laboratory and boiler specialist which additional analyses, if any, are needed. Do not order an expensive test panel without a decision it will support.
4. Agree a controlled trial before a supply commitment
Define the trial quantity, duration and permitted operating conditions with the boiler team. Choose a duration that can reveal the site's relevant deposit and cleaning behaviour; there is no single trial length suitable for every plant.
Record the starting condition and the reference fuel used for comparison. During the authorised trial, log fuel consumption, delivered heat where metered, alarms, cleaning interventions and interruptions. Inspect deposits only under the site's safe shutdown procedure. Keep photographs and observations tied to the same operating period and fuel lot.
Agree the pass, review and stop criteria beforehand. A fuel should not receive unrestricted approval merely because the first few hours produced heat.
5. Turn the trial into a clear purchasing decision
Record what has been approved: fuel specification, boiler configuration, operating range and evidence reviewed. State when a change requires reassessment. A trial on one installation is not blanket approval for every customer boiler.
Suggested enquiry wording: “Please provide available ash-content and ash-melting reports for the proposed fuel. Our boiler specialist will review compatibility before a controlled trial. We will agree trial criteria and the conditions for recurring supply in writing.”
The same workflow can support buyers in the EU, EEA, UK and Switzerland. Apply the installation's own permit and manufacturer requirements; approval at one site does not establish compliance elsewhere.
6. Prepare a focused Nord Panels enquiry
Nord Panels manufactures in Kazakhstan using exclusively Kazakhstan-sourced raw materials. Review the wood pellet product page for available product information and laboratory documents. Request the report needed for your application; this article does not claim a particular ash melting result or universal boiler approval.
Send the boiler model, destination, expected volume and the boiler specialist's information requirements through Nord Panels contacts. This gives the supplier a concrete basis for discussing evidence, samples and supply conditions.
Sources checked on 12 September 2026. Cover image is an illustrative laboratory scene.