For a DG-set owner, knowing how to read RECD test certificate documentation can make it much easier to verify whether a proposed Retrofitted Emission Control Device is actually suitable for the intended generator. An RECD certificate may look like a technical form filled with model numbers, engine information, test results, and certification references, but each section serves a practical purpose.
The Central Pollution Control Board (CPCB) has published a dedicated RECD procedure for applicable in-use diesel-operated generator-set engines up to 800 kW gross mechanical power. Its certificate template identifies the manufacturer, RECD family, individual RECD model, engine application range, PM reduction efficiency, applicable emissions stage, and certificate validity, among other details. Understanding these fields helps buyers avoid a common mistake: assuming that a certificate for one RECD automatically proves suitability for every DG set.
Start With the Certificate Heading
The first thing to examine is the actual type of certificate. CPCB's published template refers to a “Certificate of Type Approval/Extension/Conformity of Production” for RECD compliance with diesel power-generating-set engines up to 800 kW gross mechanical power.
This heading immediately tells you what kind of document you are reading. Type Approval relates to the approved RECD configuration, while extension and conformity-of-production references relate to subsequent certification activities covered by the CPCB procedure. A buyer should therefore avoid treating every document labelled “test certificate” as identical. The document's title, certificate number, report references, and certification purpose should be read together.
Find the Certificate Number and Issue Date
Near the beginning of the CPCB template are fields for the Type Approval/CoP Certificate Number and the certificate issue date. These details are important for traceability.
The certificate number allows the supplier, manufacturer, testing agency, or facility owner to identify the exact certification record. The issue date provides a reference point when determining whether the document corresponds to the product currently being offered. Do not rely only on a scanned certificate showing a company logo. The identifying number and date should be visible and consistent with the supplier's supporting documentation.
Confirm the Manufacturer's Identity
The certificate template contains the manufacturer's name and address and identifies the manufacturing plant. It also records the manufacturer's trade name or mark. This is useful because the company selling the RECD may not always be the same entity named on the certification document.
When checking an offer, compare the manufacturer shown on the certificate with the manufacturer, importer, or supplier named in the quotation. Any difference should be explained clearly. For procurement teams, this simple cross-check can prevent confusion over whether the supplied equipment is actually the certified product or a different product being represented under the same commercial brand.
Look Closely at the RECD Family
One of the most important fields is the RECD family designation. CPCB's certificate template has separate entries for the RECD family and the individual RECD type/model designation. It also allows multiple RECD types to be listed within a family. This distinction matters because a manufacturer may have several related models under a common family, but that does not necessarily mean all models have identical applications.
When reading the certificate, locate the family designation first and then identify the exact type/model being offered to your facility. Do not stop after seeing the family name. The actual model or type designation should be matched against the supplier's quotation and the physical product documentation.
Identify the Exact RECD Type or Model
The RECD type/model designation is one of the most useful pieces of information for a buyer. CPCB's template specifically provides space for the RECD type/model designation and identifying part numbers.
This information creates a direct connection between the certificate and the device being installed. Suppose a supplier provides a certificate for a family of RECD products but quotes a specific model for a 500 kVA generator. The buyer should verify that the quoted model is actually one of the certified types covered by the certificate.
Part numbers should also be compared where available. A mismatch between the certificate and the quotation is a reason to request clarification before the purchase order is finalized.
Check the RECD Category and Class
The CPCB template includes fields for RECD category, such as domestic or imported, and the class of RECD. It also provides a field for the type identification of the RECD. These entries can look less important than the engine and performance information, but they help establish exactly what product configuration has been certified.
The type-identification marking and its location are also included in the template. This can help a buyer connect the paperwork with the physical equipment delivered to the site. When the RECD arrives, the facility should check whether the identification marking on the equipment corresponds to the documentation supplied.
The Most Important Section: Engine Application
For many buyers, the engine/application range is the most important field on the certificate. CPCB's template specifically includes “Engine/Engine Family for which the RECD is intended (application range).” This field should be compared with the actual generator engine installed at the facility.
The generator owner should verify the exact engine manufacturer, model, gross mechanical power, and other relevant technical characteristics and then compare those details with the application information shown in the certification documents. This is especially important because CPCB's published RECD framework is based on applicable in-use diesel genset engines and their gross mechanical power rather than simply treating all generators with similar kVA ratings as interchangeable. The current CPCB manufacturer list also presents different certified application ranges for different RECD manufacturers.
Don't Confuse kVA With Mechanical Power
A DG set is commonly identified by its electrical rating in kVA, but the RECD certification framework uses gross mechanical power in kW as a key technical reference. CPCB's current published RECD procedure covers applicable in-use diesel genset engines up to 800 kW gross mechanical power.
CPCB's RECD agency information also explicitly notes that, during Type Approval testing, the RECD and engine combination are tested for mechanical gross power in kW and that the corresponding kVA rating should be checked against the data plates on the in-use engine and DG set. Therefore, if a supplier tells you that a certificate applies simply because your generator is “500 kVA,” ask for the underlying engine application information as well.
Examine the PM Reduction Efficiency
The certificate template includes a specific field for PM Reduction Efficiency of the RECD. This is an important performance field, but it needs to be interpreted in context. The figure belongs to the certified RECD configuration and testing framework. It should not automatically be treated as a guaranteed real-world result for every possible engine or installation.
The correct question is not merely “What percentage is shown?” It is also “For which RECD model and which engine/application was this performance established?” Where the supplier provides a separate test report, the buyer should review it alongside the certificate rather than relying on a headline performance number in a brochure.
Check the Applicable Emissions Regulation or Stage
Another certificate field identifies the regulation and stage for which the RECD is designed to be fitted to an engine. This field can be particularly useful when dealing with older and newer engine configurations.
A facility should compare the stage identified in the certification with the engine's applicable emissions information. The purpose is not to make a compliance assumption from the stage name alone, but to establish whether the certified RECD configuration corresponds to the generator under consideration. Where the terminology is unclear, the supplier should provide an explanation supported by the underlying documentation.
Understand Certificate Validity
The CPCB certificate template includes a validity statement specifying that the certificate remains valid up to a stated date, subject to conformity-of-production requirements by the specified date. This is one of the easiest fields to overlook.
A buyer should check the validity date rather than assuming that a certificate remains current indefinitely. The conformity-of-production condition is also important because the certification framework includes ongoing production verification. For procurement in 2026, it is especially important to verify that the certificate being relied upon corresponds to the current product and relevant certification status.
Read the Test Report Together With the Certificate
A certificate alone may not contain every technical detail needed for a procurement decision. CPCB's RECD documentation includes a detailed test-report format covering engine information, RECD identification, emission measurements, PM-related calculations, smoke, specific fuel consumption, regeneration characteristics, exhaust back pressure, and other performance information.
The certificate tells you what configuration has been certified, while the supporting test report can provide the technical evidence behind that certification. For that reason, a serious buyer should request both documents where applicable.
Examine Exhaust Back Pressure Results
Exhaust back pressure is another field worth reviewing. The CPCB test-report framework includes an exhaust back-pressure requirement as part of the RECD evaluation.
This matters because the RECD becomes part of the engine's exhaust system after installation. The certificate and test report should therefore be considered alongside the actual exhaust configuration at the site. A physically compatible device is not automatically a technically acceptable installation if the completed exhaust arrangement does not satisfy the relevant requirements.
Look for Regeneration Information
Where the RECD technology uses regeneration, the test documentation should be examined for regeneration-related information. CPCB's test-report framework includes regeneration characteristics and related technical information.
For operators, this is more than a laboratory detail. The regeneration strategy can influence how the system needs to be operated, monitored, and maintained. The exact requirements depend on the selected RECD technology, so the supplier's operating instructions should be reviewed together with the certification documents.
Verify the Certification Agency
The certification agency is another important identity check. CPCB publishes information on RECD certification agencies and certified manufacturers. Its published agency information includes agencies such as ARAI and ICAT for specified RECD applications and explains that the corresponding kVA rating should be verified against the engine and DG-set data plates.
The certification agency named in the supplied documentation should therefore be consistent with the certification record being presented. Do not assume that a company-issued “certificate” has the same status as documentation associated with the applicable certification framework.
Compare the Certificate With the Physical RECD
Once the equipment reaches the site, the certificate should not remain inside a file cabinet while the installation proceeds. Compare the physical product's manufacturer marking, model/type designation, identifying part number, and type-identification information with the certification documentation. CPCB's template specifically provides fields for these identifiers.
This is a practical quality-control step. If the product delivered to the facility cannot be clearly linked to the certified documentation, the discrepancy should be resolved before commissioning.
How a Buyer Should Work With an RECD Supplier
A professional RECD supplier for DG sets should be able to walk the buyer through the certificate rather than simply sending a PDF and describing the product as “CPCB approved.” The supplier should explain which model is being supplied, which engine application it covers, which certification document supports the product, what the PM reduction figure represents, and whether the certificate remains valid.
The supplier should also be able to connect the certificate with the installation documentation, commissioning records, operating instructions, and maintenance information. This creates a much stronger documentation chain from the certified product to the equipment actually installed at the facility.
A Simple Certificate-Reading Example
Imagine a facility operating a diesel generator whose engine documentation identifies a particular manufacturer, model, and gross mechanical power. The supplier proposes an RECD and provides a certificate. The facility should first identify the certificate number and date, then verify the manufacturer. Next, it should locate the RECD family, exact type/model, part numbers, and engine application range.
The facility can then examine the PM reduction efficiency, emissions-stage field, certificate validity, and supporting test-report data such as back pressure and regeneration. Finally, once the RECD is delivered, the model and identification markings should be compared with the certificate. That sequence makes the certificate useful as a verification document instead of treating it as a marketing attachment.
Why Current Verification Matters in 2026
The CPCB manufacturer list currently available on its website is dated 09 May 2025 and identifies certified RECD manufacturers together with their applicable in-use diesel genset engine power ranges and certification agencies. For a procurement decision in 2026, buyers should check whether CPCB has issued a newer list, revised procedure, or other applicable direction.
CPCB's official website continues to publish regulatory material and indicates a website update dated 01 January 2026. This is why an older certificate, supplier brochure, or third-party article should not be assumed to represent the complete current compliance position.
Conclusion
Learning how to read RECD test certificate documentation gives DG-set owners a much stronger basis for evaluating retrofit emission-control equipment. The most important fields are not necessarily the most visually prominent ones. Certificate number and date establish traceability. Manufacturer and plant information establish product identity. RECD family, type/model, and part numbers connect the certificate to the actual equipment. Most importantly, the engine/application range establishes whether the certified RECD is intended for the generator under consideration. The PM reduction efficiency, emissions stage, validity statement, test results, regeneration information, and exhaust back-pressure data provide additional technical context. That combination of document verification and technical matching provides a much more reliable basis for an RECD procurement decision than the phrase “CPCB approved” alone.
Frequently Asked Questions
What is the most important information on an RECD test certificate?
The engine/application range and the exact RECD type/model are among the most important fields because they help establish whether the certified device corresponds to the intended generator. The certificate also identifies the manufacturer, family, part numbers, PM reduction efficiency, and validity.
Should I check the RECD family or the exact model?
Both should be checked, but the exact RECD type/model and identifying part number are particularly important when matching the certificate to the equipment being purchased.
Does an RECD certificate based on kW automatically cover a DG set with a similar kVA rating?
No. CPCB documentation distinguishes mechanical gross power in kW from the corresponding DG-set kVA rating and calls for the rating to be verified against the engine and DG-set data plates.
Why should I check the certificate validity date?
The certificate template includes a stated validity period and a conformity-of-production condition, so buyers should verify the status of the certificate being relied upon.
Does an RECD test certificate by itself prove complete site compliance?
No. The certificate relates to the certified RECD configuration. Overall compliance can also depend on correct installation, operation and maintenance, the specific DG set, location, consent conditions, and current requirements of the relevant authorities.