Diesel generators are widely used in commercial buildings, hospitals, factories, and industrial facilities to provide reliable backup power. However, their exhaust emissions can contribute to air pollution, making effective emission-control systems an important consideration. A Retrofit Emission Control Device (RECD) can help reduce targeted pollutants from existing diesel generator sets when properly selected, installed, and maintained.

For businesses using RECD technology, understanding the test certificate is essential. The certificate and supporting documents provide information about the tested equipment, emission performance, testing procedure, and applicable approval scope. Knowing how to interpret these details helps facility managers, procurement teams, and maintenance professionals make informed decisions.

What Is an RECD Test Certificate?

An RECD test certificate or associated laboratory report documents the testing and performance of an emission-control device under specified conditions. Depending on the document, it may include manufacturer details, model identification, testing methods, emission measurements, and the test outcome.

It is important to understand that a laboratory test report, a type-approval document, and an installation certificate are not necessarily the same document. Each serves a different purpose.

A test report records laboratory findings, while a type-approval document establishes the approval scope for a particular product or model. Installation documentation connects the supplied device with the generator at a particular site.

Businesses should review the complete documentation package rather than relying solely on a supplier's brochure or a single performance claim.

Aceget's article on how to read an RECD test certificateFor a more detailed guide, visit.

Why Is It Important to Read the Certificate Correctly?

Understanding an RECD certificate helps businesses determine whether the documentation corresponds to the equipment they intend to purchase or have already installed.

Incorrectly interpreting a certificate can create confusion about approved generator capacities, emission-reduction claims, and the applicability of test results.

The main benefits of reviewing the certificate include:

Improved documentation checks: Identify the manufacturer, model, and relevant report references.
Better understanding of performance: Review the pollutants measured and the reported reduction in emissions.
Informed purchasing decisions: Compare technical information with the supplier's claims.
Compliance preparation: Maintain relevant records for inspections and environmental audits.
Clearer communication: Ask manufacturers and service providers specific questions about missing or inconsistent information.

A certificate review supports compliance management, but it does not independently guarantee that a particular installation meets every applicable regulatory requirement.

Important Details to Check on an RECD Certificate

1. Manufacturer Name and RECD Model

Start by checking the manufacturer's name and the exact RECD model or type identification. These details establish which product the document concerns.

Compare the model information with the device identification plate, technical specification sheet, purchase documents, and installation records.

If the certificate refers to a different model, do not assume that the approval automatically applies to the supplied device. Ask the manufacturer or supplier to clarify the difference before accepting the documentation.

2. Generator Capacity and Application Range

Generator capacity is another important detail. RECD approvals and supporting reports may specify a particular application range or identify the engine configurations covered by the test.

Check whether the generator's rated capacity and technical configuration fall within the stated approval scope. Also review any applicable engine-model restrictions.

A similar-looking device or a generator with a nearby capacity rating should not automatically be considered covered by the same approval. Confirm the exact applicability with the manufacturer and relevant approval documents.

3. Testing Laboratory and Procedure

The certificate or report should identify the testing laboratory and the applicable testing procedure.

In India, the Central Pollution Control Board (CPCB) publishes a system procedure for emission compliance testing of retrofit emission-control devices for diesel generator engines up to 800 kW of gross mechanical power.

System and Procedure for Emission Compliance Testing of Retro-fit Emission Control Devices (RECD) for Diesel Power Generating Set EnginesThe relevant document is titled , reference PCLS/12/2021-22, revised on July 24, 2023.

official CPCB RECD testing procedureBusinesses can consult the to understand the prescribed testing framework.

Always confirm the laboratory's recognition and the applicable procedure for the particular certificate being reviewed.

4. Baseline and RECD-Fitted Emission Results

One of the most informative sections of a test report is the comparison between emissions before and after fitting the RECD.

The baseline result represents the emissions measured without the device under the specified test conditions. The RECD-fitted result records emissions with the device installed under the relevant test conditions.

These measurements help demonstrate the device's performance during testing.

Depending on the test scope, the report may include particulate matter (PM), nitrogen oxides (NOx), carbon monoxide (CO), hydrocarbons (HC), smoke, and other relevant parameters.

Not every RECD necessarily reduces all pollutants to the same degree. Therefore, check which pollutants were actually measured and which results are reported.

5. Emission-Reduction Percentage

Suppliers often advertise RECD performance using a percentage reduction figure. To understand this figure, examine the underlying measurements rather than considering the percentage alone.

The reduction can be calculated using the following formula:

[

\text{Reduction (%)}=

\frac{B-A}{B}\times100

]

Here, (B) represents the baseline emission value and (A) represents the emission value measured with the RECD fitted.

For example, if baseline particulate matter emissions are 1.0 g/kWh and the measured value after fitting the device is 0.2 g/kWh, the reduction is 80%.

This is an illustrative calculation, not a claim about the performance of any specific RECD model. Actual results must be interpreted according to the report's test method, measurements, adjustments, and applicable acceptance criteria.

6. Test Date and Report Identification

Check the test date, report number, certificate reference, and other identification details.

These references help distinguish one laboratory report from another and make it easier to request clarification from the issuing organization.

If the document specifies a validity period, approval period, or re-verification requirement, review those details carefully. Do not assume that every certificate has the same validity conditions.

Where a document refers to a separate type-approval certificate, obtain that supporting document and check whether its scope matches the tested RECD model.

Common Mistakes to Avoid

Even a detailed certificate can be misunderstood if its information is reviewed without considering the complete testing and approval context.

Focusing only on the reduction percentage: A high percentage is not enough on its own. Review the baseline readings, final readings, pollutants measured, and relevant acceptance criteria.

Ignoring the application range: A report for one model or engine configuration may not cover another. Check the actual approval scope.

Confusing testing with approval: A laboratory report and a type-approval document serve different purposes. Confirm that the required approval documentation is available.

Overlooking supporting pages: Annexures and technical schedules may contain important emission readings, engine specifications, and application details.

Assuming laboratory results guarantee site performance: Actual performance can vary with engine condition, load, installation quality, fuel characteristics, and maintenance. Laboratory results should not be treated as a guarantee of identical results under every operating condition.

Maintaining RECD Documentation at Your Facility

Good documentation practices help businesses manage emission-control equipment throughout its service life.

Keep the relevant test report, applicable type-approval documents, purchase invoice, installation records, service history, and maintenance reports together. Ensure that the documents can be matched to the RECD actually installed on the generator.

Facility managers should also record inspections, servicing, repairs, and any changes to the generator or emission-control system that could affect performance.

If a certificate contains unclear information or a mismatch, contact the supplier or manufacturer for clarification. Where necessary, seek confirmation from the issuing laboratory or relevant regulatory authority.

Central Pollution Control BoardFor regulatory reference, businesses can consult the and the applicable State Pollution Control Board or other competent authority.

Conclusion

Reading an RECD test certificate correctly helps businesses understand what has been tested, which equipment the report covers, and how emission-control performance has been documented.

The most important areas to review are manufacturer and model identification, generator application range, testing procedure, baseline and RECD-fitted emission measurements, reduction calculations, and supporting approval details.

By reviewing these elements together, businesses can evaluate supplier claims more carefully, maintain better records, and identify questions that need clarification before purchasing or accepting an installation.

A systematic approach to certificate review supports responsible emission-control management and helps facilities make better-informed decisions about their diesel generator equipment.

How to Understand an RECD Test Certificate for Diesel Generators

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