Installing a Retrofit Emission Control Device on a diesel generator is not simply a matter of attaching a box to the exhaust pipe. A successful retrofit requires technical assessment, correct sizing, exhaust integration, commissioning and proper documentation.

For businesses operating existing diesel generators, understanding the installation process can make it easier to plan shutdowns, coordinate with vendors and avoid expensive modifications later.

An RECD installation normally begins well before the equipment reaches the site. The generator specifications, exhaust arrangement, operating pattern and available installation space all need to be reviewed before the final system is fabricated.

RECD Installation Process guideFor a detailed step-by-step reference, the explains how a typical retrofit project progresses from pre-installation assessment to final handover.

1. Start With a DG Set Assessment

The first stage is understanding the generator on which the RECD will be installed.

The installer generally needs information such as:

Generator capacity
Engine manufacturer and model
Engine serial number
Manufacturing year
Exhaust pipe diameter
Existing silencer arrangement
Exhaust routing
Available installation space
Typical generator load
Operating hours
Existing emission-control equipment

This information is important because an RECD cannot be selected solely according to the generator's kVA rating.

The exhaust flow, temperature and backpressure characteristics of the engine also influence system selection.

2. Conduct a Site Survey

A physical site survey can identify installation challenges that may not be visible from photographs or basic specifications.

During the survey, the installation team can examine the existing exhaust line, mounting possibilities, structural supports, access routes and available service space.

Enclosed or soundproof DG sets may require additional planning because the emission-control device and associated pipework have to fit within the existing arrangement.

The survey also helps determine whether modifications to the exhaust line, supports or enclosure will be necessary.

A proper survey at the beginning can prevent fabrication errors and unnecessary downtime later.

3. Select the Appropriate RECD

After the technical information has been collected, the suitable RECD configuration can be determined.

The device should be compatible with the generator's exhaust flow and operating conditions. The system should also be designed so that exhaust backpressure remains within the permissible range specified for the engine.

This is particularly important because adding equipment to an exhaust system naturally introduces additional resistance.

CPCB's official RECD procedureThe provides technical requirements concerning retrofitted after-treatment devices, including particulate-matter reduction and type-approval/Conformity of Production requirements for RECD suppliers.

Therefore, buyers should verify the relevant approval and testing documentation rather than selecting an RECD based only on a supplier's marketing description.

4. Finalise the Exhaust Layout

Once the equipment has been selected, the installation layout can be finalised.

The design may need to account for:

Inlet and outlet connections
Exhaust pipe diameter
Flanges and flexible connections
Mounting brackets
Structural supports
Sensor locations
Controller position
Service access
Insulation
Chimney connection

The objective is to integrate the RECD into the existing exhaust system without creating unnecessary restrictions or making future maintenance difficult.

Service access should be considered at this stage rather than after the unit has already been installed.

5. Fabrication of the System

Many RECD installations require fabrication or modification of exhaust components according to the specific generator arrangement.

This can include custom pipe sections, mounting brackets, supports, flanges or other connection components.

The reason is simple: two generators with the same rated capacity can still have different physical exhaust configurations.

The fabricated components therefore need to match the actual site dimensions and approved layout.

This is one reason a professional RECD installation should not be treated as a completely standardised, one-size-fits-all job.

6. Prepare the Site Before Installation

The generator may need to be taken offline during physical installation.

Before the installation team arrives, the facility should therefore confirm:

Shutdown availability
Backup power arrangements
Site access
Work permits
Safety requirements
Lifting arrangements, where required
Hot-work permissions
Required tools and utilities
Access to the DG room or enclosure

For facilities where the DG is critical to operations, the shutdown window should be coordinated carefully.

Hospitals, data centres, industrial plants and telecom sites may need additional contingency planning because even a short generator outage can affect operations.

7. Safely Shut Down and Cool the Generator

The installation itself begins only after the generator has been safely shut down and isolated.

Exhaust components can remain extremely hot after the generator stops. The system therefore needs sufficient cooling time before technicians begin removing or modifying exhaust components.

Safety procedures should also be followed throughout the work, particularly where welding, cutting or other hot work is involved.

The exact procedure will depend on the facility's safety system and the installation scope.

8. Integrate the RECD Into the Exhaust Line

The next stage involves physically connecting the RECD to the existing exhaust system.

Depending on the site arrangement, this may involve removing an existing pipe section, using existing flanged connections or installing modified pipework.

The device should be securely supported so that its weight is not unnecessarily transferred to components that were not designed to carry it.

Connections should be properly sealed to minimise exhaust leakage.

Incorrect alignment, weak supports or poorly sealed joints can create problems during commissioning and later operation.

9. Install Sensors and Controls

Depending on the RECD design, sensors and control equipment may also need to be installed.

These can include monitoring components for parameters such as:

Exhaust temperature
Differential pressure
Filter loading
System condition
Regeneration status

The controller and associated wiring should be installed in an appropriate location where it can be accessed by operating and maintenance personnel.

Correct sensor positioning is important because inaccurate measurements can lead to incorrect system operation or unnecessary alarms.

10. Check Exhaust Backpressure

Backpressure is one of the most important technical parameters after installation.

The addition of an RECD changes the resistance within the exhaust system. Excessive backpressure can negatively affect engine performance and should therefore be checked during commissioning.

The installation team should verify the measured value against the engine manufacturer's permissible limits.

If the reading is higher than expected, the cause should be investigated before the system is handed over.

Possible factors can include incorrect sizing, restricted pipework, excessive bends, a blocked component or another installation issue.

11. Conduct the Initial Generator Run

After physical installation and safety checks are complete, the generator can be restarted.

The initial operating run allows technicians to check the system under actual conditions.

During this stage, the team may observe:

Exhaust temperature
Backpressure
Exhaust leakage
Unusual vibration
Abnormal noise
Sensor readings
Controller alarms
General system behaviour

Where appropriate, the generator can be observed at different operating loads to understand how the system behaves under realistic conditions.

This stage is important because a physically correct installation still needs to demonstrate stable operation.

12. Complete Commissioning and Testing

Commissioning confirms that the installed RECD is functioning as intended.

The commissioning process can include recording relevant operating parameters and checking the installation against the approved technical configuration.

Testing requirements depend on the applicable regulatory framework, system type and project scope.

The CPCB procedure also emphasises testing and compliance requirements for RECD systems, including applicable particulate-matter reduction requirements and supplier type approval.

For this reason, owners should ask the supplier exactly what testing and documentation will be provided as part of the project.

13. Collect the Installation Documents

The installation should end with a proper documentation handover.

Depending on the project, useful documents can include:

RECD type-approval documentation
Relevant test certificates
Installation report
Commissioning report
Generator details
Recorded backpressure values
Operating instructions
Maintenance schedule
Warranty documentation
Sensor/controller information

Keeping these records together can make future inspections and maintenance much easier.

Digital copies should also be retained so the documents are not lost if the physical file is misplaced.

14. Plan the First Maintenance Inspection

An RECD should not be treated as a fit-and-forget component.

The owner should understand what needs to be inspected and at what operating interval.

Depending on the system, maintenance may involve checking filter condition, differential pressure, sensors, exhaust connections, regeneration behaviour and other components.

The maintenance schedule should ideally be agreed with the supplier during commissioning rather than waiting until the first warning or abnormal reading appears.

Common RECD Installation Mistakes

Several avoidable mistakes can make an otherwise straightforward retrofit more complicated.

Using Incorrect Generator Information

If the engine model or capacity information supplied to the vendor is incorrect, the selected system may not be properly matched to the generator.

Skipping the Site Survey

Fabricating equipment without accurate exhaust measurements can result in connection and mounting problems during installation.

Ignoring Backpressure

An emission-control device should not be evaluated only by its pollution-reduction capability. Its effect on exhaust restriction must also be considered.

Poor Support Arrangement

The RECD and modified exhaust components need adequate structural support. Poor support can lead to vibration, stress and premature damage.

Forgetting Service Access

Installing the device in a location that is difficult to reach can make future maintenance unnecessarily complicated.

Treating Documentation as an Afterthought

A physically installed device without the appropriate technical and testing records can create difficulties during future verification.

How Long Does RECD Installation Take?

The actual installation period depends on generator size, exhaust configuration, number of DG sets, site accessibility and whether enclosure modifications are required.

A straightforward installation may be completed relatively quickly, while larger or more complicated projects can require additional time.

fabrication time and generator downtimeIt is important to distinguish between . Much of the fabrication work can take place before the generator is taken offline.

Planning the shutdown window separately can therefore help reduce operational disruption.

Final Checklist Before Handover

Before accepting the completed installation, the facility team should verify:

RECD model and specifications
Generator compatibility
Exhaust connections
Structural supports
Sensor installation
Controller operation
Exhaust leakage
Backpressure readings
Initial operating performance
Test documentation
Installation report
Maintenance instructions
Warranty details

Once these points have been checked, the facility has a much stronger basis for managing the RECD throughout its operating life.

Conclusion

RECD installation is an engineering process rather than a simple exhaust-pipe modification. The quality of the final result depends heavily on what happens before installation day: accurate generator information, site assessment, correct equipment selection and proper exhaust planning.

The physical installation must then be followed by backpressure checks, commissioning, documentation and a maintenance plan.

RECD for DG setFor businesses looking for a , taking time to evaluate the complete installation process can help reduce downtime, avoid compatibility issues and make long-term emission-control management easier.

RECD Installation for DG Sets: What Happens From Site Survey to Commissioning

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