DG set pollution control RECD systemA can play an important role in controlling particulate emissions from eligible in-use diesel generator engines. But when an organization is evaluating an RECD, the question should not simply be whether a device is available in the market. A more important question is whether the particular device is appropriately documented, tested, certified, and suitable for the generator on which it will be installed.

For this reason, CPCB-related certification matters when selecting a retrofit emission-control device. CPCB has established a system and procedure for compliance testing of Retrofit Emission Control Devices (RECDs) intended for in-use diesel-operated internal-combustion engines used in genset applications up to 800 kW gross mechanical power. The procedure includes requirements relating to emission limits, certification, test equipment, and testing procedures. Understanding what certification means and what it does not mean helps generator owners make more informed decisions.

Why Emission Control Matters for DG Sets

Diesel generators are widely used when reliable electrical power is required.

They provide backup or supplementary electricity for:

Hospitals
Manufacturing facilities
Commercial buildings
Data centres
Hotels
Educational institutions
Construction sites
Telecom infrastructure
Residential complexes
Industrial facilities

Although operating hours can vary considerably, the exhaust from a diesel engine contains pollutants that need to be managed according to applicable environmental requirements.

Particulate matter is one of the key emission concerns addressed by the CPCB RECD framework.

Rather than replacing an entire generator, a retrofit approach can provide a way to add emission-control technology to an existing eligible engine.

What Is a RECD?

Retrofit Emission Control DeviceRECD means .

The term “retrofit” indicates that the device is intended to be applied to an existing engine rather than being incorporated into the engine at the original manufacturing stage.

An RECD is integrated with the generator's exhaust system and is designed to reduce particulate emissions within its applicable technical and certified scope.

However, not every commercially available emission-control device should automatically be considered suitable for every diesel generator.

The engine, power range, product model, certification information, and installation conditions all need to be evaluated.

Why Certification Matters

Certification provides an important layer of technical verification.

CPCB's RECD testing framework includes performance testing of the engine with and without the retrofit device and evaluates areas such as particulate emissions, regulated pollutants, smoke, exhaust back pressure, specific fuel consumption, regeneration characteristics where applicable, and compatibility-related requirements.

This matters because an emission-control device cannot be evaluated only by its physical appearance.

Two devices may look similar externally but have different:

Internal technology
Filtration characteristics
Operating requirements
Regeneration strategies
Monitoring systems
Back-pressure characteristics
Application ranges

Testing provides a structured way to evaluate these technical characteristics.

Certification Is Product-Specific

specific product and applicationOne of the most important points for generator owners is that certification should be considered in relation to the .

A supplier may say:

“Our RECD is CPCB approved.”

That statement should lead to further questions.

Ask for:

Manufacturer name
RECD model
Part number
Certification details
Certification/test agency
Applicable engine range
Applicable power range
Relevant test documentation

CPCB's published test-report format itself calls for information such as the manufacturer, base engine, engine model, rated power, RECD family, RECD type/model, identifying part numbers, test procedure reference, performance results, and the engine types for which the device is qualified.

This demonstrates why a generic certification statement is not enough for proper technical evaluation.

Engine Compatibility Comes First

A certified RECD is not automatically suitable for every DG set.

Before selecting a product, identify the engine's:

Manufacturer
Model
Serial number
Gross mechanical power
Rated speed
Emission category or applicable phase
Existing exhaust configuration

CPCB's published RECD procedure is specifically scoped to in-use diesel engines up to 800 kW gross mechanical power for genset applications.

Therefore, buyers should establish whether their generator falls within the applicable scope before proceeding.

Why Gross Mechanical Power Matters

Generator owners often describe their machines using kVA.

However, RECD technical documentation can identify the engine using gross mechanical power.

This distinction is important during product selection.

For example, a facility may describe its generator as a “500 kVA DG set,” while the RECD supplier needs the engine's technical specifications to determine the appropriate application.

The safest approach is to provide the supplier with the engine nameplate and technical documentation.

What Does CPCB Testing Evaluate?

CPCB's published RECD test-report format shows that evaluation can cover multiple technical areas.

These include:

Particulate Matter

The RECD's effect on particulate emissions is a central part of the testing framework.

Regulated Pollutants

The testing framework includes measurement of pollutants such as CO, HC and NOx.

Smoke

Exhaust smoke is also included in the specified test procedures.

Exhaust Back Pressure

The retrofit system should be evaluated for its effect on exhaust back pressure.

Specific Fuel Consumption

Fuel-consumption performance is also included within the testing framework.

Regeneration

Where applicable, regeneration characteristics and strategy are evaluated.

Engine Compatibility

The documentation identifies the engine types for which the tested RECD is qualified.

This is why certification should be treated as a technical matter rather than simply a marketing label.

CPCB Certification and Installation Are Different Things

Even a properly documented RECD still needs correct installation.

Certification of a product does not mean that every installation will automatically be correct.

The installation team should consider:

Exhaust pipe dimensions
Mounting arrangements
Available space
Structural support
Electrical connections
Sensor positioning
Controller location
Maintenance access
Exhaust back pressure

A poorly planned installation can create technical problems even when the selected equipment is appropriate.

Why Exhaust Back Pressure Matters

When a retrofit device is introduced into an existing exhaust system, it can affect exhaust flow.

This is why exhaust back pressure is included in the CPCB RECD testing framework.

Before installation, the technical team should therefore review the engine manufacturer's applicable limits and the RECD manufacturer's installation requirements.

The objective is to ensure that the retrofit does not create an unsuitable exhaust condition for the engine.

Certification Helps Buyers Avoid Unsupported Claims

The RECD market can contain products presented with broad environmental claims.

A buyer should be cautious about statements such as:

“100% CPCB compliant”
“Works with every DG set”
“Universal RECD”
“No maintenance required”
“Guaranteed compliance for every site”

Such statements should not be accepted without appropriate technical documentation.

Environmental compliance can depend on the specific equipment, installation, operating conditions, applicable requirements, and regulatory authority.

A properly documented product provides a stronger basis for evaluation.

What Should a Generator Owner Verify?

Before purchasing an RECD, create a documentation file containing:

Product Details

Product name
Model
Part number
Manufacturer
Product datasheet

Certification Details

Certification/test agency
Certificate or test-report reference
Applicable engine range
Applicable power range
Relevant testing procedure

Installation Details

Exhaust requirements
Mounting requirements
Electrical requirements
Sensor/controller requirements
Back-pressure considerations

Service Details

Warranty
Maintenance schedule
Spare parts
Technical support

This documentation can make future inspections, maintenance, and technical reviews easier.

Is “CPCB Approved” the Same as “CPCB Compliant”?

These phrases should not automatically be treated as interchangeable.

The buyer should determine exactly what the supplier means by the claim.

Ask:

Which product was tested?

For which engine?

At what power range?

Under which CPCB procedure?

Which certification/test agency performed the evaluation?

What does the certification actually cover?

These questions help distinguish a documented certification claim from general advertising language.

The Role of the RECD Controller

Many modern retrofit systems can incorporate controllers and sensors.

Depending on the product, these components may support:

System monitoring
Alarm indication
Fault detection
Sensor monitoring
Operating-status information
Diagnostic functions

The exact features vary by manufacturer and technology.

Therefore, when purchasing an RECD, ask whether the controller is part of the standard system or an optional component.

Why Genuine Documentation Matters

A genuine product should be accompanied by documentation that allows the buyer to understand what is actually being supplied.

Important documents may include:

Technical datasheet
Installation instructions
Certification/test documentation
Product identification
Warranty information
Maintenance instructions

Documentation also helps service personnel identify the correct replacement components later.

What Is an RECD Device as per CPCB Norms?

RECD device as per CPCB normsWhen searching for an , the correct approach is to verify the exact product and its documented application.

CPCB's published test-report format requires detailed information about the tested base engine and RECD, including the engine model, rated power, RECD model, identifying part numbers, performance results, and the engine types for which the device is qualified.

Therefore, buyers should not select a device simply because its advertisement contains the words “CPCB” and “RECD.”

Instead, verify:

Product identity
Engine compatibility
Power range
Certification/test documentation
Installation requirements
Applicable current regulatory requirements

Certification Does Not Replace Maintenance

An RECD should not be considered a fit-and-forget product.

The generator itself must continue to be maintained according to the engine manufacturer's recommendations.

Depending on the RECD technology, maintenance may involve:

Inspection
Sensor checks
Controller diagnostics
Cleaning
Regeneration-related procedures
Component replacement
Exhaust inspection

The exact schedule should come from the manufacturer.

A poorly maintained engine can also affect exhaust conditions and the overall operation of the emission-control system.

When Should You Be Especially Careful?

Extra verification is advisable when:

The supplier cannot provide a model number
Certification documents are unavailable
The engine details were never requested
The supplier claims universal compatibility
Installation requirements are unclear
Warranty conditions are vague
Maintenance requirements are not documented
The quotation contains only a single unexplained price

A professional supplier should be able to explain the technical basis for its recommendation.

How Certification Benefits Facility Owners

Proper documentation can provide several practical advantages.

Better Product Selection

The buyer can determine whether the device is intended for the particular engine.

Better Technical Confidence

Testing information provides a basis for understanding product performance.

Easier Maintenance

Clear product identification helps service teams work with the correct equipment.

Better Record Keeping

Certification and installation records can be retained with the generator's environmental documentation.

Reduced Procurement Risk

Detailed documentation makes it easier to distinguish a technically supported product from an unsupported market claim.

Frequently Asked Questions

Does every DG set require an RECD?

RECD applicability depends on the applicable regulatory requirements and the characteristics of the generator. The CPCB RECD procedure itself covers eligible in-use diesel engines up to 800 kW gross mechanical power. Always verify the current requirements applicable to your specific installation.

Is an RECD only about particulate matter?

The CPCB RECD framework is principally aimed at PM reduction, while its testing documentation also considers other regulated pollutants, smoke, fuel consumption, back pressure, and other technical requirements.

Can one certified RECD be installed on any DG set?

No. The product's documented application range and compatibility with the particular engine must be verified.

Does certification eliminate the need for proper installation?

No. Correct engineering, installation, commissioning, and maintenance remain important.

What documents should I request from an RECD supplier?

At minimum, request the product datasheet, exact model/part number, applicable engine range, certification/test information, installation requirements, warranty terms, and maintenance instructions.

Final Thoughts

properly documented, technically suitable, and appropriately installed emission-control system for the specific DG setCertification matters because an RECD is not simply another exhaust accessory. It is an emission-control technology that must be evaluated against specific technical and application requirements. CPCB's published framework provides a defined process for evaluating RECDs for eligible in-use diesel genset engines up to 800 kW gross mechanical power. Its testing documentation demonstrates the importance of factors such as PM performance, regulated pollutants, smoke, exhaust back pressure, fuel consumption, regeneration characteristics where applicable, and engine applicability. Check the manufacturer, model, engine range, power range, certification information, installation requirements, warranty, and maintenance support. Also verify the latest applicable CPCB requirements and any requirements imposed by the relevant State Pollution Control Board or local authority. The goal is not merely to purchase an RECD with a certification claim. The goal is to select a .

Why Every DG Set Needs a Pollution Control RECD System — CPCB Norms Explained

Everything Generator Owners Need to Know About the Rules Driving This Requirement