Can RECD Installation Support a Green Building Assessment?

A green building file is a long list of claims, each backed by a drawing, a test report or a log. Sooner or later, someone asks whether the retrofit emission control device on the diesel generators can earn anything. This guide answers that question for the RECD green building case, criteria family by criteria family.

The honest answer, up front: an RECD can support documentation for criteria dealing with compliance with pollution norms, outdoor air quality, indoor air quality protection and site or construction management. It rarely earns points on its own. Whether it contributes at all depends on the rating system, the version your project is registered under, and how well the evidence is organised. Installing an RECD does not guarantee any credit, point or rating outcome.

What follows is a map. Rather than walking through one rating system clause by clause, we sort the RECD evidence you are likely to hold into the six types of criteria that green rating systems tend to contain, and show what assessors usually look for in each.

A short primer on IGBC, GRIHA and LEED in India

Three systems account for most green building assessments in India. Each publishes its own rating systems, reference guides and addenda, and each revises them. Always work from the version your project is registered under.

IGBC. The Indian Green Building Council is part of the Confederation of Indian Industry (CII) and is headquartered in Hyderabad. It runs a large family of rating systems across residential, commercial, industrial, built environment and net zero categories, including Green New Buildings and Green Existing Buildings. In the published Green New Buildings rating system (version 3.0 with addenda), DG sets appear in a few places we could verify: “DG sets or Back-up systems” are listed among the systems to be covered by the post-occupancy performance audit plan under the commissioning mandatory requirement, and power backup systems are listed among loads for energy sub-metering.

GRIHA. GRIHA was developed by TERI and is administered by the GRIHA Council. The Ministry of New and Renewable Energy adopted it in 2007 as the national rating system for green buildings. GRIHA V.2019 includes a construction management criterion titled “Air and Soil Pollution Control” and an “Indoor Air Quality” criterion, and a newer Version 6 has also been released. The GRIHA help centre has clarified, for example, that the rating does not require BEE star-rated DG sets, and that projects must submit an air quality test report during operation even where specific fine-particle filters are not installed.

LEED. LEED is administered by the US Green Building Council and is used on many Indian commercial projects, particularly for multinational tenants. In LEED v4, the indoor environmental quality prerequisite “Minimum indoor air quality performance” points mechanically ventilated projects to ASHRAE Standard 62.1-2010, Sections 4 to 7. Section 5 of that standard deals with, among other things, the location of outdoor air intakes relative to contaminant sources such as exhaust outlets.

None of these systems, in the sources we checked, awards a specific point for “fitting an RECD”. That is the starting point for everything below.

How to read the rating-system map

Every criterion family below follows the same three questions:

• What assessors typically want. The kind of evidence that satisfies the criterion intent.
• What RECD evidence helps. Documents that genuinely support the claim.
• What does not count. Common submissions that add bulk but not proof.

The families are not tied to one system. A “construction-phase pollution” criterion exists in some form in most systems; the exact wording, points and whether it is mandatory differ. Treat this as a filing structure for your evidence, and then check each item against your project’s reference guide.

Family 1: mandatory compliance and legal obligations

Most rating systems expect the building to meet applicable national and local laws as a baseline. IGBC’s draft version 4 of Green New Buildings, for example, refers to national standards and codes including CPCB and SPCB guidelines. For DG sets in India, that baseline means the generator and its emission control arrangement must satisfy the consent conditions issued by your State Pollution Control Board, the emission norms applicable to the engine, and, in Delhi NCR, the directions issued by the Commission for Air Quality Management.

What assessors typically want

A clear statement that each DG set is legally permitted to operate, backed by the consent document and evidence that the conditions are being met. Assessors are not regulators, but they will not accept a credit claim built on equipment that is out of compliance.

What RECD evidence helps

• The RECD’s type approval certificate, issued after testing by a recognised agency such as ARAI or ICAT under the CPCB procedure for retrofit devices on in-use DG engines up to 800 kW gross mechanical power. Our guide on reading an RECD test certificate line by line explains what each field means.
• A record matching the certificate to the specific engine model and rating on site. A certificate for a different engine family proves little.
• The SPCB consent to operate, showing the DG sets and any RECD-related conditions.
• In NCR, a note on how the sets are operated during GRAP stages, linked to the relevant directions. Our overview of GRAP rules for DG sets in Delhi NCR gives the background.

What does not count

A vendor brochure, a generic “CPCB approved” sticker, or a letter saying the device “meets all norms” without a certificate number. If you need to check a claim, our walkthrough on verifying that an RECD is CPCB tested for your DG set sets out the steps. For the wider legal picture, see our page on DG set emission regulations in India.

Family 2: outdoor air pollution and site emissions

Some rating systems include criteria about limiting the building’s contribution to local outdoor air pollution, or about outdoor air quality at the site. Wording varies widely: some focus on construction dust, some on combustion equipment, some on ambient monitoring.

What assessors typically want

Evidence that combustion sources on site are controlled, that exhaust is discharged in a way that disperses properly, and, where the criterion asks for it, ambient or stack measurements.

What RECD evidence helps

• Before-and-after particulate test reports from an accredited laboratory, carried out at matched load with the sampling location recorded.
• Stack height and discharge arrangement drawings that show compliance with SPCB consent conditions.
• A short narrative explaining what the RECD controls (particulate matter, and where it has an oxidation catalyst, carbon monoxide and hydrocarbons) and what it does not (total NOx, CO2).

What does not count

Handheld AQI monitor readings taken near the stack, or smoke photos “before and after”. These are not measurements an assessor can rely on. A particulate reduction percentage quoted without the test conditions is weak evidence. The sibling post on which RECD case study results a buyer should trust applies equally to green rating submissions.

Family 3: indoor air quality and protection from exhaust re-entry

This is where DG sets matter most to green rating assessors, and where the RECD is most often misunderstood. Indoor air quality criteria usually require ventilation that meets a recognised standard, and that standard normally governs where outdoor air intakes sit relative to exhaust outlets.

What assessors typically want

Drawings showing every fresh air intake, operable window zone and DG exhaust outlet, with measured or calculated separation distances meeting the method specified by the rating system. In LEED v4, that route runs through ASHRAE 62.1-2010; ASHRAE’s published interpretations confirm that designers may use the standard’s separation distance table or its calculation appendix. IGBC and GRIHA have their own indoor air quality criteria, and the specific requirements should be read from the current reference guide.

What RECD evidence helps

• The RECD general arrangement drawing showing where the treated exhaust discharges, and confirming that the stack outlet location was not changed by the retrofit.
• A separation check, signed by the MEP consultant, for each intake near the DG exhaust path. Our review of RECD installation near fresh air intakes covers how to do this.
• Post-occupancy indoor air quality test reports, where the rating system asks for them.

What does not count, and a safety point

An RECD does not change the required separation distance. Exhaust from a DG set with an RECD still contains carbon monoxide, nitrogen oxides and heat, and the RECD does not remove all of them. Do not argue that treated exhaust can sit closer to an intake.

The same applies to indoor operation. An RECD never makes it safe to run a DG set indoors or to discharge its exhaust into an occupied or semi-enclosed space. Exhaust must go outdoors through a properly designed stack, following the engine maker’s guidance, local building and fire codes and SPCB stack-height conditions. The sibling post on whether an RECD makes a DG safe to operate indoors explains why in detail.

Family 4: construction-phase DG use

Building sites run DG sets for months before grid power arrives. GRIHA V.2019, for instance, includes a construction management criterion on air and soil pollution control, and IGBC’s construction-related mandatory requirements list measures such as dust suppression. Whether DG emissions are specifically assessed depends on the system and version.

What assessors typically want

A construction environmental management plan that names pollution sources, the controls applied and the records kept. Where DG sets are in use, assessors usually want to see that they are compliant and that their use is logged.

What RECD evidence helps

• A list of every DG set on site (owned and hired), with its rating, emission control status and consent position.
• RECD certificates for hired sets, collected from the rental contractor at mobilisation.
• Monthly run-hour logs, showing when temporary power was replaced by grid supply.
• Records of how sets were managed during GRAP stages, if the site is in NCR.

Our post on RECDs for construction projects with changing power demand covers how to keep the device matched to the engine.

What does not count

A single certificate filed at the start of a two-year build, with no record of which sets actually ran.

Family 5: energy, DG run hours and alternatives

Energy criteria are usually the biggest block of points in any green rating. DG sets rarely help here, because diesel generation is expensive and carbon-intensive per unit. Where they appear, it is through metering, minimising run hours or replacing diesel with cleaner backup.

What assessors typically want

Sub-metered DG energy, annual run hours, fuel consumption, and, where the project claims it, evidence of renewable or storage alternatives that reduce diesel use. IGBC Green New Buildings, for example, lists power backup systems among the loads for energy sub-metering.

What RECD evidence helps

Very little directly. The RECD is not an energy-saving device. It does not reduce fuel consumption or CO2, and its added back-pressure can raise fuel use very slightly. If anyone on the team plans to present an RECD as a carbon reduction, read our analysis of whether an RECD reduces CO2 emissions first.

What the RECD file can contribute is clean run-hour data. If the device logs operating hours, or your RECD service records track them, those figures can corroborate the DG energy meter.

Alternatives worth documenting alongside

Projects chasing energy points usually do better by cutting DG hours: rooftop solar, battery energy storage for short outages, or converting sets to run partly on gas. If dual-fuel is on the table, our comparison of an RECD versus a dual-fuel kit explains how the two address different problems. Any of these can be documented together with the RECD, but each claim needs its own evidence.

What does not count

Statements that the RECD “improves efficiency” or “reduces the carbon footprint”. These invite scrutiny and weaken the rest of the file.

Family 6: operations, maintenance and performance verification

Ratings for existing or operational buildings, and the post-occupancy parts of new-building ratings, care about whether systems keep working. IGBC’s commissioning requirement, which names DG sets or backup systems among the systems to be covered by the post-occupancy audit plan, is one example.

What assessors typically want

An operations and maintenance plan, maintenance records, and evidence that performance was checked periodically after handover.

What RECD evidence helps

• The RECD maintenance schedule and service reports, including cleaning or ash-removal dates and any differential pressure or temperature readings if the device has those sensors.
• Periodic emission test reports, where your consent conditions require them.
• Operator training records and a simple log of alarms and corrective actions.

Our RECD maintenance guide lists what a good service routine includes. If your organisation runs an environmental management system, the same records can sit inside it; the sibling post on including an RECD project in an ISO 14001 environmental programme shows how.

What does not count

A maintenance contract with no completed service reports. A contract shows intent; a stamped service report shows performance.

The RECD green building evidence pack

Pull the documents together into one folder, organised by criteria family, before the assessor asks. This table is a starting point; adjust it to your rating system and version.

Document	Supports which criteria family	Who usually provides it
RECD type approval certificate (ARAI/ICAT test basis)	1 Compliance, 2 Outdoor emissions	RECD supplier
Engine-to-certificate match sheet (model, rating, serial)	1 Compliance	RECD supplier with facility team
SPCB consent to operate, showing DG sets	1 Compliance	Owner / facility team
Stack height and discharge drawing	1 Compliance, 2 Outdoor, 3 IAQ	MEP consultant
RECD general arrangement drawing	3 IAQ, 6 O&M	RECD supplier
Intake-to-exhaust separation check	3 IAQ	MEP consultant
Before-and-after particulate test report (accredited lab)	2 Outdoor emissions	Testing laboratory, commissioned by owner
Construction-phase DG register and run-hour logs	4 Construction	Main contractor
DG sub-meter readings and annual run hours	5 Energy	Facility team / BMS
RECD service reports and maintenance schedule	6 O&M	RECD service provider
Operator training record	6 O&M	RECD supplier / facility team
GRAP-period operating log (NCR projects)	1 Compliance, 4 Construction	Facility team / contractor

ESG teams can reuse many of these records, though their metrics differ; see the sibling post on which metrics to use when reporting RECD outcomes in ESG disclosures.

Pitfalls that weaken an RECD submission

These are the problems that most often turn RECD evidence from an asset into a liability.

1. Claiming CO2 reduction. A particulate filter or oxidation catalyst does not reduce CO2. Any line in the narrative implying it does gives the assessor a reason to question everything else.
2. Claiming NOx reduction. Filters and oxidation catalysts leave total NOx essentially unchanged; some catalysed designs shift part of the NO to NO2. Only claim NOx reduction if a technology that actually reduces NOx is installed and tested.
3. No stack height evidence. A certificate for the device says nothing about whether the stack meets your consent conditions. Assessors increasingly ask for the drawing.
4. Certificate does not match the engine. If the engine was replaced or uprated after the RECD was certified, the file is broken.
5. No maintenance records. An RECD that has not been serviced for two years cannot be presented as a working control.
6. Moving the stack outlet during retrofit without re-checking intakes. A small change in outlet position can bring exhaust closer to an air handler intake.

When to bring the RECD into the rating file

Timing matters. The cost of fixing an evidence gap rises sharply after handover.

Project stage	RECD actions for the rating file
Concept and registration	Decide which rating system and version; list DG-related criteria; note whether DG sets will be new or existing
Design development	Locate DG sets, stacks and fresh air intakes together; run the separation check; specify the RECD in the MEP tender
Procurement	Require the type approval certificate, engine match sheet and GA drawing as tender deliverables
Construction	Maintain the site DG register; collect certificates for hired sets; log run hours monthly
Commissioning	Witness RECD installation; file the commissioning report; run before-and-after particulate tests if required
Handover	Transfer manuals, service schedule and training records to the facility team
Occupancy and recertification	Keep service reports, run-hour logs and periodic test reports for operational or existing-building ratings

Bringing the RECD into design development is the simplest way to build a strong RECD green building file.

Illustrative example: a 12-storey office with two 1010 kVA sets

The following example is illustrative. The building, figures and distances are invented to show method, not to represent any real project or rating requirement.

A 12-storey office building in Gurugram has two 1010 kVA DG sets on a podium-level plant yard, with stacks rising to above roof level. The developer is pursuing a green rating for a new commercial building. Both sets are fitted with RECDs.

A note on scope: the CPCB RECD procedure covers in-use DG engines up to 800 kW gross mechanical power. A 1010 kVA set produces around 808 kW of electrical output at 0.8 power factor (1010 × 0.8 = 808), so its engine’s gross mechanical power will typically be higher than that. Sets of this size can therefore fall outside the procedure’s scope, and the project team must confirm with the SPCB and the supplier which compliance route applies before relying on any certificate. For sizing reference, see the RECD page for 1010 kVA DG sets.

Evidence checklist status

Evidence item	Family	Status	Action
Compliance route confirmation for each set	1	Pending	Written confirmation from supplier and SPCB query
SPCB consent to operate	1	Available	File copy in pack
Stack height drawing	1, 2, 3	Available	Confirm as-built matches drawing
RECD GA drawings, both sets	3, 6	Available	None
Intake separation check	3	Partly complete	One intake fails; see below
Before-and-after particulate tests	2	Planned	Book accredited lab at matched load
DG sub-meter readings	5	Available	Export 12 months from BMS
RECD service reports	6	1 of 2 sets	Chase missing report for Set B
Operator training record	6	Missing	Arrange refresher session and record it

Run hours and DG energy share

The BMS shows the following for the past 12 months:

• Set A: 212 hours
• Set B: 188 hours
• Total: 212 + 188 = 400 hours
• Average per set: 400 ÷ 2 = 200 hours

Average load during runs was about 450 kW per running set. DG energy supplied is approximately 400 hours × 450 kW = 1,80,000 kWh. Total building consumption for the year was 42,00,000 kWh, so the DG share is 1,80,000 ÷ 42,00,000 = 0.0429, or about 4.3%.

At an illustrative specific fuel consumption of 0.27 litres per kWh, diesel used is 1,80,000 × 0.27 = 48,600 litres.

The RECD changes none of these numbers. The team reports them under energy criteria as DG performance, and separately reports the RECD under compliance and outdoor emissions. If the developer wants to reduce the 4.3% share, the levers are solar, storage or reduced outages, not the RECD.

Intake distance check

The MEP consultant identifies two fresh air intakes near the DG stack outlets. The rating system specifies a method for intake separation; call the minimum the system’s specified distance, D. For this illustration, assume the consultant’s calculation for this exhaust type and arrangement gives D = 10.0 m. This is a placeholder, not a value taken from any standard.

Intake	Measured separation	Specified distance D	Margin	Result
AHU-3 roof intake	14.5 m	10.0 m	14.5 − 10.0 = +4.5 m	Meets
AHU-5 terrace intake	7.8 m	10.0 m	7.8 − 10.0 = −2.2 m	Does not meet

The RECD does not rescue AHU-5. The options are to relocate the intake by at least 2.2 m further away, extend or redirect the stack outlet (subject to the consent conditions and structural checks), or use the system’s calculation method if it allows credit for discharge velocity or direction. The RECD documentation stays in the file under families 1, 2 and 6, but the intake problem has to be solved by design.

FAQ

Does installing an RECD earn IGBC or GRIHA points?

Not by itself, in the rating documents we reviewed. An RECD can support evidence for criteria on compliance, outdoor emissions, indoor air quality and operations, but points depend on the system, version and complete evidence. Check the current reference guide for your project.

Is a DG set with an RECD allowed closer to a fresh air intake?

No. Separation is set by the rating system’s referenced standard and good design practice. The RECD does not remove CO, NOx or heat completely, so the specified distance still applies.

Can we report the RECD as a carbon reduction in our green building file?

No. An RECD does not reduce CO2. Report it as a particulate control and compliance measure. Carbon reductions come from burning less diesel.

What if our DG sets are larger than 800 kW?

The CPCB RECD procedure covers in-use DG engines up to 800 kW gross mechanical power. For larger engines, ask your SPCB and supplier which compliance route applies, and document the answer in the rating file.

Do hired DG sets during construction need RECD documentation?

If the rating system asks for construction-phase pollution control, assessors will usually want to see that every set on site, including hired ones, was compliant. Collect certificates at mobilisation and keep the site DG register updated.

Who should own the RECD evidence pack?

The sustainability consultant usually compiles it, but the facility team should own it after handover, because operational and existing-building ratings depend on continued records.

Building a Rating File With Aceget

Aceget supplies CPCB type-approved retrofit emission control devices for DG sets from 25 kVA to 2500 kVA. Aceget’s product page describes a silicon carbide ceramic filter with a precious-metal coating and an oxidation catalyst stage, with particulate reduction of up to around 96% depending on DG condition and fuel. For green building projects, we can provide the type approval documents, engine match details, GA drawings and service records your consultant needs, and help confirm the right compliance route for each set. Explore our retrofit emission control device range, review our certifications, or contact our team to start assembling your RECD evidence pack.

Related Reading

• How to Include an RECD Project in an ISO 14001 Environmental Programme
• Reporting RECD Outcomes in ESG Disclosures: Which Metrics Should You Use?
• Reading an RECD Case Study: Which Results Should a Buyer Trust?
• Reviewing RECD Installation Near Fresh Air Intakes
• How to Get a Pollution NOC for a DG Set
• What Is an RECD and How Does It Work?