Supply-Only vs Turnkey RECD Orders: Who Does What?

Quick answer: In a supply-only RECD order, the vendor delivers a certified device and its documents; everything that happens to it after it reaches your gate (exhaust modification, supports, installation, testing, compliance paperwork) is your responsibility or your contractor’s. In a turnkey order, often called SITC (supply, installation, testing and commissioning), one vendor takes responsibility for the whole job and hands you a working, tested system. Supply-only usually costs less on paper. Turnkey usually costs less in risk.

The rest of this article unpacks that answer: the three contract models buyers actually use, a task-by-task responsibility comparison, the gaps where problems tend to fall through, and five buyer scenarios that show which model fits whom.

Three Ways to Buy an RECD

Most guides describe two options. In practice there are three, and the middle one is often the most useful.

Model 1: Supply-only

The vendor manufactures or sources the device, ships it to your site, and provides the type approval certificate, datasheet and installation manual. Your own maintenance team, the generator dealer or a separate fabrication contractor installs it.

Model 2: Supply with supervision

The vendor supplies the device and sends an engineer to supervise installation by your contractor. The engineer checks layout, supports, alignment and connections, attends testing, and signs off that the installation follows the manufacturer’s requirements. Labour and materials for the exhaust work remain with you.

Model 3: Turnkey (SITC)

The vendor surveys the site, designs the layout, supplies the device and all materials, carries out every modification, tests the system, hands over documentation and stands behind the result. You provide access, utilities and a shutdown window.

Understanding how a retrofit normally unfolds helps when comparing these models. Our step-by-step RECD installation guide describes each stage.

Who Does What: Task-by-Task Comparison

The table below shows who typically owns each task under each model. Your contract can vary this, but if it is silent, these are the assumptions most vendors make.

Task	Supply-only	Supply + supervision	Turnkey (SITC)
Collecting generator and OEM exhaust data	Buyer	Buyer, vendor reviews	Vendor, buyer assists
Site survey and measurements	Buyer	Vendor engineer visits	Vendor
Device selection and sizing	Vendor, based on buyer’s data	Vendor	Vendor
Layout and support design	Buyer or buyer’s contractor	Vendor advises, contractor executes	Vendor
Back pressure calculation for complete system	Often nobody	Vendor	Vendor
Supply of device and certificate	Vendor	Vendor	Vendor
Supply of pipe, bends, bellows, steel, insulation	Buyer’s contractor	Buyer’s contractor	Vendor
Transport to site	Vendor (to gate)	Vendor (to gate)	Vendor (to final location)
Unloading and lifting into position	Buyer	Buyer’s contractor	Vendor
Dismantling existing exhaust	Buyer’s contractor	Buyer’s contractor	Vendor
Fabrication, welding and installation	Buyer’s contractor	Buyer’s contractor under supervision	Vendor
Hot work permits and site safety	Buyer and contractor	Buyer and contractor	Vendor, under buyer’s permit system
Pre- and post-installation testing	Buyer	Vendor attends	Vendor
Emission test coordination	Buyer	Buyer	Vendor (if specified)
As-built drawings and handover file	Buyer’s contractor	Shared	Vendor
Operator training	Vendor (manual only)	Vendor engineer	Vendor
Device warranty	Vendor (device only)	Vendor (device, conditional on supervised install)	Vendor (device and installation)
Workmanship warranty	Buyer’s contractor	Buyer’s contractor	Vendor
Single point of accountability	No	Partly	Yes

The final row is the one that matters most when something goes wrong.

What a Supply-Only Delivery Should Actually Contain

“Supply-only” does not mean “a box on a truck.” A properly specified supply-only order still gives the installer everything needed to fit the device correctly. If any of the following are missing, the buyer inherits risk that the vendor should carry.

• The device itself, with a nameplate showing model, serial number and flow direction.
• A copy of the type approval certificate and test report covering the engine power band. Check it using our guide on how to read an RECD test certificate.
• A dimensioned general arrangement drawing with flange sizes, overall length, weight and centre of gravity.
• Maximum allowable forces and moments on the device flanges, so the installer can design supports that do not strain the device.
• Predicted pressure drop across the device at the engine’s rated exhaust flow.
• Installation instructions, including orientation limits, minimum straight lengths if any, and recommended bellows positions.
• A commissioning checklist that the installer can complete and return.
• Maintenance instructions and the warranty card, with conditions clearly stated.

Ask for this list in the RFQ and make it a condition of payment. A vendor who cannot provide these documents for a supply-only order is unlikely to support you if something goes wrong later.

Where Problems Fall Through the Gaps

Splitting a job between parties creates interfaces. Each interface is a place where both parties can reasonably say “that was not my job.” In RECD retrofits, five gaps cause most of the trouble.

Gap 1: Back pressure across the whole system

The vendor guarantees the pressure drop across the device. The installer controls the length of pipe, number of bends and diameter changes. Nobody owns the total. If the installed system exceeds the engine’s limit, the vendor blames the pipework and the installer blames the device. Under turnkey, one party owns the full calculation. Read how exhaust back pressure affects a DG set to understand why this gap is so costly.

Gap 2: Support and stress on the engine

A device and its pipework are heavy and expand when hot. If supports are poorly designed, weight and thermal stress pass into the turbocharger or manifold. In supply-only, the vendor rarely sees the support design. Guidance on avoiding this: flexible bellows in an RECD exhaust system and wall-mounted vs floor-supported RECD support layout.

Gap 3: Warranty conditions

Many device warranties are conditional on correct installation. If an installer the vendor never met fits the device, a later failure can lead to an argument over whether installation caused it. Ask vendors to state their warranty conditions for supply-only orders in writing.

Gap 4: Test failures

If the post-installation test shows excessive back pressure or leaks, who rectifies and who pays? In supply-only, the answer depends on diagnosis, and diagnosis takes time. In turnkey, the vendor rectifies.

Gap 5: Compliance paperwork

Pollution control boards may ask for the type approval certificate, installation report, test results and photographs. In supply-only, the buyer assembles the file from multiple sources. Our environmental compliance checklist for generator owners shows what inspectors commonly look for, and what happens during a pollution control board inspection explains the process.

Comparing the Models Side by Side

Factor	Supply-only	Supply + supervision	Turnkey
Upfront price	Lowest	Moderate	Highest
Buyer’s management effort	High	Medium	Low
Need for in-house engineering skill	High	Medium	Low
Risk of scope gaps	High	Medium	Low
Speed of dispute resolution	Slow	Moderate	Fast
Control over contractor choice	Full	Full	Limited
Flexibility to use existing contractors	High	High	Low
Suitability for complex layouts	Low	Medium	High
Ease of compliance documentation	Hard	Moderate	Easy

Upfront price is only one line. When buyers compare the total cost, including their own staff time, the cost of delays and the risk of rework, the gap often narrows or reverses. Our article on RECD cost in India breaks down what typically sits inside a turnkey price.

The Hidden Costs of Supply-Only

When a supply-only quote looks attractive, add these items before comparing:

• Fabrication contractor: labour, welding, pipe, bends, bellows, steel and insulation.
• Lifting equipment: crane or chain block hire, and scaffolding.
• Engineering time: someone has to design the layout and supports and check back pressure.
• Testing: instruments, a load bank if needed, and staff time.
• Coordination: your staff managing two or more parties.
• Rework risk: a contingency for correcting problems found at testing.
• Downtime: longer shutdowns if parties are not synchronised.

If your organisation already has a capable maintenance team, some of these costs are absorbed. If not, they become real expenditure.

Worked Example: One Generator, Three Contracts

Consider a 380 kVA generator in a commercial building basement. The exhaust runs about 15 metres to an external shaft, with four bends. The building’s facility team includes one electrical supervisor but no mechanical engineer.

Under supply-only, the facility team receives the device and documents, then hires a local fabrication contractor. The contractor quotes for pipework and supports but has never calculated exhaust back pressure. The team asks the vendor, who supplies the device pressure drop but declines to comment on the pipework. Installation takes three days instead of two because the device has to be manoeuvred through a narrow basement corridor that nobody checked. At testing, back pressure is close to the OEM limit. The contractor adds a larger-diameter section to reduce it, which takes another day and an additional invoice.

Under supply with supervision, the vendor’s engineer visits before fabrication, spots the access problem, and recommends a split delivery. The engineer reviews the contractor’s pipe layout, suggests replacing two short-radius bends with long-radius ones, and attends testing. Back pressure is comfortably within limits on the first run. The facility team still manages the contractor and pays for materials separately.

Under turnkey, the vendor surveys the site, designs the layout including bends and supports, prefabricates pipe sections off-site, and plans lifting through the basement in advance. The facility team arranges the shutdown and permits, witnesses testing and receives a single handover file. The quoted price is the highest of the three, but there are no extra invoices and no internal engineering time.

None of these outcomes is inevitable. A strong contractor can make supply-only work smoothly, and a weak turnkey vendor can still make mistakes. The example simply shows where the effort and risk sit under each arrangement. Specific site challenges like this one are covered in our guide to basement DG room installations.

Five Buyer Scenarios: Which Model Fits?

Scenario 1: A housing society with one 250 kVA generator

The managing committee has no in-house engineer and relies on an annual maintenance contractor. Residents want minimal disruption and clear accountability.

Best fit: Turnkey. The committee lacks the capacity to manage interfaces, and one accountable vendor simplifies decisions. See our RECD purchase planning guide for RWAs.

Scenario 2: A manufacturing plant with a strong maintenance department

The plant has qualified mechanical engineers, an in-house fabrication shop and experience with exhaust systems. It runs four generators and wants to control scheduling around production.

Best fit: Supply with supervision. The plant can do the physical work efficiently, while vendor supervision protects warranty and ensures correct installation. Related: RECDs for auto component factories.

Scenario 3: A hospital with critical backup loads

Downtime must be planned around patient care, with temporary backup arranged. Infection control and safety rules restrict hot work.

Best fit: Turnkey, with a detailed method statement and phased shutdowns. One party controls the critical sequence. See RECDs for hospitals.

Scenario 4: A retail chain with generators at many locations

The chain has a central facilities team and local contractors in each city. Layouts vary widely.

Best fit: Mixed. Turnkey for complex sites, such as rooftops and basements; supply with supervision for simple ground-level installations where a trusted local contractor is available. A framework agreement with standard rates keeps it manageable. See RECDs for shopping malls.

Scenario 5: A public sector organisation issuing a formal tender

Procurement rules require competitive bidding, defined scope and single-point responsibility for performance.

Best fit: Turnkey (SITC). Most public sector RECD tenders on GeM are structured as supply, installation, testing and commissioning, because it gives a single accountable contractor and a clear acceptance point.

Decision Checklist

Answer these questions honestly. The more “no” answers, the stronger the case for turnkey.

• Do we have an engineer who can design exhaust layouts and supports?
• Can we calculate total system back pressure?
• Do we have a reliable fabrication contractor experienced with exhaust work?
• Can we coordinate the vendor, contractor and testing in one shutdown window?
• Are we comfortable assembling compliance documentation ourselves?
• Will the vendor honour the device warranty if our contractor installs it?
• Is the installation layout simple (ground level, short exhaust run, good access)?

Contract Clauses to Include for Each Model

For supply-only orders

• Vendor confirms device sizing based on data provided, and states assumptions.
• Vendor provides installation drawings, recommended support arrangement and maximum allowable loads on device flanges.
• Vendor states predicted pressure drop across the device at rated flow.
• Warranty conditions for installation by others are stated in writing.
• Vendor provides telephone or remote support during installation.

For supply with supervision

• Number of supervision visits and their timing (layout approval, mid-installation, testing).
• Supervisor’s authority to stop work that deviates from requirements.
• Supervisor signs a completion certificate confirming correct installation.
• Warranty applies in full once the supervisor signs off.
• Responsibility for rectification if the supervisor approves defective work.

For turnkey orders

• Complete scope, with a deemed-inclusion clause for items necessary to deliver a working system.
• Performance guarantees for back pressure and other measurable parameters.
• Acceptance test procedure and pass criteria.
• Single warranty covering device and workmanship.
• Handover documentation list.

For detailed guidance on dividing tasks in any of these models, see our article on defining customer and installer responsibilities in an RECD project.

Questions to Ask a Vendor Before Choosing a Model

Before committing, ask each shortlisted vendor the same questions. Their answers reveal how well each model will work with them specifically.

1. Do you offer all three models, and what is the price difference between them for my site?
2. For supply-only, what installation documentation do you provide, and what are your warranty conditions for installation by others?
3. For supervision, how many visits are included, and what happens if additional visits are needed?
4. For turnkey, do you use your own installation teams or subcontractors? If subcontractors, who supervises them?
5. Who calculates total exhaust back pressure under each model?
6. Who arranges and pays for post-installation emission testing?
7. What is your response time for warranty claims, and does it differ between models?
8. Can you share references from customers who used each model?

Vendors who answer clearly and consistently are usually easier to work with, whatever model you choose. Our guide to choosing among CPCB-approved RECD vendors covers broader vendor assessment.

Common Misconceptions About Turnkey and Supply-Only

“Turnkey means I have no responsibilities.” Not true. The buyer still provides access, permits, the shutdown window, test load and, in many cases, temporary backup power. Our article on customer and installer responsibilities lists them in detail.

“Supply-only is fine because the device is certified.” Certification covers the device as tested. It does not cover how your contractor installs it, how much back pressure your pipework adds, or whether supports stress the engine. The regulatory requirements set by the Central Pollution Control Board concern the outcome at the generator, not just the device on paper.

“Our generator dealer can install anything.” Dealers are experts on engines and alternators, but exhaust aftertreatment retrofits involve different skills. Check their experience before assuming.

“Turnkey vendors overcharge for installation.” Sometimes, but the price also covers design, coordination and risk. Compare against the full cost of doing it yourself, not just a fabricator’s labour rate.

Can You Switch Models Mid-Project?

It is possible but rarely smooth. A common situation is a buyer who orders supply-only, then struggles to find a contractor and asks the vendor to install. The vendor will usually want to survey the site again and may question work already done. If there is a real chance you will need installation help, ask for turnkey and supervision prices at the RFQ stage, even if you intend to order supply-only. Our guide to writing a technical RFQ for an RECD project shows how to request alternative prices.

Impact on Timelines

• Supply-only: device lead time, plus time to find and brief a contractor, plus installation. Coordination can add weeks.
• Supply with supervision: similar, but supervision visits must be scheduled.
• Turnkey: the vendor plans fabrication in parallel with device manufacture, often shortening the overall programme.

Typical durations are discussed in RECD installation timeline: what to expect. If you are working against air-quality restrictions in Delhi NCR, review how GRAP restrictions affect businesses using DG sets.

Frequently Asked Questions

Is turnkey always more expensive?

The quoted price is usually higher because it includes work that supply-only leaves to you. After adding your contractor, materials, lifting, testing and staff time, the difference is often smaller than it first appears.

Does supply-only affect the device warranty?

It can. Many vendors offer full warranty only if installation follows their instructions, and some require their own supervision. Ask for the warranty terms for installation by others in writing before ordering.

Can our generator AMC contractor install the RECD?

Possibly, if they have experience with exhaust fabrication and the vendor approves their method. Supply with supervision is a good way to use your existing contractor while protecting the warranty. See how to negotiate an AMC contract for your generator.

Who arranges the emission test?

Under supply-only, usually the buyer. Under turnkey, the vendor if the contract says so. Always state it explicitly. For background on testing, see does a smokeless DG set still need particulate measurement.

What is the safest choice for a first-time buyer?

For most first-time buyers without in-house exhaust expertise, turnkey is the safest choice, because it gives one accountable party for the outcome.

Bottom Line

Supply-only, supply with supervision and turnkey are not good or bad in themselves. Each suits a different level of in-house capability and risk appetite. The key is to choose deliberately, put the division of responsibility in writing, and make sure someone owns the gaps between device and installation.

If you are weighing these options for a specific generator, browse Aceget’s retrofit emission control devices, review our certifications, and talk to our team about which delivery model fits your site.