RECD for Foundries: Planning Around Heat, Dust and Heavy Equipment

Every industry has its tough environments, and a foundry is near the top of the list. The air shimmers above the melt shop. Fine sand settles on every horizontal surface. Forklifts carry ladles, scrap and castings across yards that were never designed for the traffic they now see. Overhead, EOT cranes move tonnes of metal in arcs that do not care what is underneath.

Fitting a retrofit emission control device into that setting is not difficult engineering, but it is unforgiving engineering. Heat, dust and heavy equipment each push on the project in their own way, and a plan that ignores any one of them tends to fail within a season. This guide organises the planning of an RECD for foundries around those three pressures, with a hazard register you can fill in for your own site, followed by sections on layout, timing and long-term care.

What the DG Set Actually Does in a Foundry

Before looking at hazards, be clear about what your generator protects. In most induction furnace foundries, the furnace itself draws far more power than a typical DG set can supply, so melting stops during a grid failure. The DG set protects something just as important: the equipment that keeps a stopped furnace safe and the plant ready to restart.

Typical loads on a foundry DG include:

• Furnace cooling water pumps for the induction coil and power pack. A coil holding molten metal without cooling water can be badly damaged in a short time, so most furnace makers specify a reliable emergency cooling arrangement.
• EOT cranes, so that a ladle in mid-pour or a crucible that must be emptied can be handled safely.
• Cupola blowers and charging equipment, in foundries still running cupolas.
• Moulding machines, sand plant, shot blasting and fettling, where the set is large enough to keep secondary operations running.
• Compressors, dust collectors, lighting and the office.

That load list matters for RECD planning in two ways. First, the set is safety-critical: it cannot be out of service while metal is in a furnace. Second, its load pattern can swing from very light (pumps and lighting only during a stoppage) to heavy (moulding lines running), which affects how the diesel particulate filter cleans itself. We come back to both points below.

The Regulatory Backdrop for Foundry Clusters

Several major foundry clusters sit inside or close to the National Capital Region. Samalkha in Panipat district is a well-known cast iron cluster, and Faridabad, Ghaziabad and Sonipat host many more. The SAMEEEKSHA cluster profile of Samalkha foundries gives a useful picture of the technology and energy mix in a typical NCR foundry cluster.

Within NCR, CAQM Direction No. 76 linked the route for each DG to its capacity: sets rated 19 to 125 kW to dual fuel, sets of 125 to 800 kW to a choice between dual fuel and an RECD, and sets above 800 kW to an RECD. Foundries outside NCR, such as those in the Agra cluster near the Taj Trapezium Zone or in Rajkot, Kolhapur and Coimbatore, work under their own state and local requirements. Always confirm the current position with your SPCB. Our summary of DG set emission regulations and our note on what happens when a DG set is sealed for non-compliance show why the paperwork deserves attention.

The Foundry Hazard Register

The core of this guide is a simple register. For each of the three pressures, list what it does to the generator, what it does to the RECD and its installation, and what your plan will do about it. Here is a filled-in example you can adapt.

Pressure	Effect on DG set	Effect on RECD and installation	Planning response
Radiant and ambient heat	Higher intake air temperature, possible derating, radiator stress	Device and cladding add heat to an already hot room; electronics see high ambient	Locate away from melt shop walls, clad hot parts, ventilate, mount display in a cooler spot
Summer peaks	Coolant temperature alarms during long outages	Higher surface temperatures during commissioning and summer running	Plan fitment outside peak heat; verify cooling margin at full load
Sand and bentonite dust	Air filter loading, abrasive wear, dirty radiator	Dust on cladding, display and sensor tappings	Filtered louvres, sealed enclosures, cleaning schedule
Coal dust and resin sand fines	Same as above, plus combustible deposits	Combustible layer on hot surfaces	Keep hot surfaces clean; review hot work controls
Metal fume and shot blast dust	Fine particles in intake air	Deposits on sensors and connectors	Locate intakes away from fettling and shot blasting
Forklift and truck traffic	Impact on canopy and pipework	Impact on supports, exhaust run and device	Barriers, bollards, marked exclusion zone
EOT crane operations	Dropped loads, swinging hooks near DG bay	Load path over the device	Keep device outside crane envelope or protect it
Vibration from knockout and moulding	Loosening of fasteners	Fatigue at supports and flanges	Flexible bellows, isolated supports, periodic torque checks
Molten metal routes	Splash or spill risk	Device or cables in a ladle route	Never place equipment on or beside a ladle path

The register does two jobs. During design, it is a checklist for the vendor’s survey. After installation, it becomes the basis of your inspection routine.

Pressure One: Heat

Foundry heat has three sources: radiation from furnaces, ladles and freshly poured moulds; general ambient heat in a building full of hot metal; and the north Indian summer, which pushes outdoor temperatures well past 40°C for weeks.

Effects on the generator

Diesel engines are rated at a stated ambient temperature, and the engine maker publishes derating figures above it. A DG room built against the melt shop wall can run far hotter than outdoor air. Hot intake air carries less oxygen per cubic metre, so the engine has less air to burn its fuel, which tends to raise smoke and fuel consumption. The radiator also loses capacity as the gap between coolant and air temperatures shrinks. Our guide to common causes of generator overheating explains the mechanisms, and our summer maintenance tips cover seasonal preparation.

Effects on the RECD

An RECD itself runs hot, because it carries exhaust gas. Uninsulated, the device and its pipework radiate heat into the room, adding to the radiator’s burden. In a cool DG room this is a minor point. In a foundry DG room that is already hot, it can make the difference between a set that carries full load through a June outage and one that trips on high coolant temperature.

The device’s electronics, including the display and IoT unit, also have operating temperature limits. Mounting them on a wall that radiates heat from the melt shop is a poor choice.

Planning responses

1. Measure the room before design. Log DG room temperature over a few days in summer with the melt shop running. Share the readings with the vendor and the engine maker.
2. Clad all hot parts. Ask for insulated, metal-jacketed cladding over the RECD and exhaust line, with a target outer surface temperature recorded at commissioning.
3. Consider an outdoor location. If the room is already marginal, mounting the device outside, on a protected platform, removes its heat from the room entirely.
4. Improve ventilation. Check that hot air from the radiator is ducted out of the room and does not recirculate to the intake side.
5. Put the display somewhere cooler. A control room, an adjacent office or a shaded outside wall.

Pressure Two: Dust

Foundry dust is not one material. Green sand plants produce silica sand and bentonite fines. Coal dust is added to many green sand mixes. No-bake and core shops produce resin-coated sand fines. Shot blasting and fettling throw out metallic dust and abrasive. Melting produces fine metal oxide fume. Each behaves differently around a generator.

Effects on the generator

The air filter is the first line of defence. Abrasive silica that passes a damaged or poorly sealed filter can wear liners and rings quickly. A filter that loads up with fines restricts airflow, and an air-starved engine produces more smoke and more soot per hour, which ends up in the DPF. The radiator collects dust on its fins, reducing cooling capacity and adding to the heat problem above.

Our generator air filter maintenance guide is worth sharing with your maintenance team. In foundries, two-stage filtration with a pre-cleaner is often used for good reason.

Effects on the RECD and installation

Sand dust on the outside of the RECD is mainly a cleanliness and inspection issue. Coal dust and resin sand fines are different: they are combustible, and a layer on a hot surface can smoulder. Dust in backpressure tappings can give false readings, and fine dust inside a poorly sealed display enclosure shortens the life of electronics and connectors.

There is a people side too. Fitting crews working near sand plants and fettling shops are exposed to respirable crystalline silica. Your own safety rules for respiratory protective equipment should apply to the vendor’s team as well.

Planning responses

• Site the DG intake away from dust sources. Louvres facing the sand plant, shot blast room or fettling shop invite trouble. If relocation is not possible, fit filter panels on the louvres, sized so they do not restrict combustion and cooling air.
• Ask for sealed enclosures for the display, IoT unit and junction boxes, with a suitable ingress protection rating for a dusty site.
• Protect sensor tappings and ask the vendor how they should be cleared.
• Set a cleaning schedule with the set stopped and cool, using vacuum cleaning rather than compressed air, which only redistributes fines.
• Watch the trend data. If backpressure rises faster than expected, check the air filter before blaming the RECD.

Pressure Three: Heavy Equipment

A foundry yard is a working space for forklifts, tractor trolleys, dumpers, scrap trucks and, inside the building, EOT cranes and jib cranes. Equipment in that space gets hit. Exhaust pipework is especially vulnerable, because it often runs at a height where a forklift mast or a load can catch it.

Impact protection

Walk every route that vehicles take near the DG and the planned RECD position. Look for:

• Turning points where long loads swing
• Reversing areas where drivers have poor visibility
• Places where scrap or castings are stacked temporarily
• Exhaust pipes that cross a vehicle route at mast height

Then protect what you find. Concrete-filled steel bollards, guardrails and painted exclusion zones are inexpensive compared with a crushed exhaust line and a DG that cannot run during the next outage.

Crane envelopes

Map the crane hook coverage on the general arrangement drawing. If the RECD or exhaust run sits within a crane’s reach, either move it or install a protective frame, and add a rule that loads are not carried over it. Never place the device or its cables on or beside a ladle route. Molten metal spills happen, and anything in the path will be destroyed.

Vibration

Knockout grids, jolt-squeeze moulding machines, vibratory conveyors and heavy presses send vibration through floors and structures. An RECD mounted on a structure shared with that equipment will see it.

• Use flexible bellows between the engine and the rigid exhaust line, as you would on any installation, and check that the bellows are rated for the movement expected.
• Mount the RECD on its own support frame, isolated from structures carrying vibrating plant.
• Add torque checks of support and flange bolts to the maintenance plan, more often in the first few months.

Lifting the device into place

Larger RECDs are heavy and must be lifted into position. A foundry has cranes, and it is tempting to use the plant’s EOT crane. That can work if the device can be reached within the crane’s coverage and safe working load, and if a competent person plans the lift. Otherwise, bring a mobile crane or hydra for the day and plan its route through the yard so it does not cross active ladle or forklift paths.

Layout Options Compared

With the three pressures in mind, here is how common layout choices compare in a foundry.

Layout	Heat	Dust	Heavy equipment	Notes
Inside DG room, near the engine	Adds heat to the room	Shares room air with engine	Protected by room walls	Shortest exhaust run; good if room is cool and clean
Outside DG room on a wall bracket or platform	Heat released outdoors	Exposed to yard dust	Needs barriers if near traffic	Common best compromise
On the roof of the DG room	Heat released outdoors	Usually less dust settles	Away from vehicles; check crane reach	Longer run; access for inspection must be safe
At stack base in a fenced enclosure	Heat released outdoors	Depends on yard location	Easy to protect with fencing	Longer run; check backpressure carefully

Whatever the layout, the vendor must show that total exhaust backpressure stays within the engine maker’s limit. Our article on how exhaust backpressure affects a DG set explains why. If you are considering a smaller interim fix such as a taller stack, read whether increasing chimney height is an alternative to an RECD first.

The Load Pattern and the Filter

The DPF inside an RECD cleans itself by burning trapped soot when the exhaust is hot enough. That generally needs the engine to work at a decent fraction of its rating for a reasonable time.

Foundry DG sets show two very different patterns:

1. Stoppage mode. Melting has stopped because the grid is down. The DG carries cooling pumps, a crane on standby, lighting and the office. On a large set this may be only 15 to 25% of rating. Exhaust stays cool and soot accumulates.
2. Production mode. In foundries where the DG is large enough to run moulding, sand plant, shot blasting and fettling, load can be substantial and the exhaust runs hot.

If your set spends most of its outage hours in stoppage mode, the filter will need help. Options include running secondary operations on DG when it is safe to do so, scheduling periodic loaded runs, or asking the vendor about the right design for low-duty operation. Our post on whether an RECD suits a DG set that runs only occasionally and our guide on generator load factor and duty cycle go into more depth.

Engine condition matters more in a foundry than in many other settings, because dust and heat wear engines faster. A set that already smokes heavily will load any filter quickly. Our guide on whether to complete an engine overhaul before fitting an RECD helps you decide.

Timing the Retrofit Around Melting

Because the DG protects furnace cooling, the retrofit must happen when no metal is in any furnace that depends on it, or when an alternative cooling supply is proven and in place. That rules out most normal production days.

Good windows include:

• Furnace relining or major maintenance shutdowns. Furnaces are empty and cold, and maintenance teams are already on site.
• The weekly off day, where the foundry has one and the grid is stable. Confirm that no furnace will be charged until the DG is back in service.
• Planned holidays, keeping in mind that in NCR the Diwali period often overlaps with tighter GRAP stages.

Avoid fitment in May and June if possible. Heat stress for the crew is serious near a melt shop, and commissioning in peak heat makes it harder to separate a cooling problem from a normal summer reading.

Fitment itself often takes a day or two per set once fabrication is complete, but survey, design and fabrication happen beforehand. The RECD installation process sets out the sequence.

Hot work in a foundry

Foundries live with heat and sparks, which can make crews casual about hot work. Treat the exhaust retrofit like any other permit job: clear combustible dust, coal fines and oily residues from the area, keep extinguishers at hand, post a fire watch and check the area after work ends. Resin sand stores, oil-soaked floors under hydraulic equipment and fuel day tanks all deserve attention.

Commissioning Checks for a Foundry Site

Add these foundry-specific items to the vendor’s standard commissioning checklist:

• Full load test, or as close as the site allows, with room temperature, coolant temperature and exhaust temperature recorded together
• Measured backpressure compared with the engine maker’s limit
• Outer surface temperature of cladding at several points
• Display and IoT readings checked against local gauges
• Barriers and bollards in place before the area reopens to traffic
• Crane exclusion markings painted and communicated to crane operators
• Bolt torque recorded at supports and flanges, ready for later comparison
• Operator briefing on alarms, especially what a rising backpressure alarm means

Keep the commissioning report with your consent documents. Our guide on what happens during a pollution control board inspection explains what inspectors usually ask to see.

A Foundry Inspection Routine

Use your hazard register as the basis for routine checks. An illustrative schedule:

Check	Frequency	What to look for
Barriers, bollards and exclusion markings	Weekly	Damage, missing paint, stacked material inside the zone
Air filter restriction indicator	Every long run, at least weekly	Rising restriction, damaged seals
Radiator fin condition	Fortnightly	Dust build-up, bent fins
RECD and cladding surfaces	Fortnightly, set cool	Dust and coal fines, damaged cladding
Support and flange bolts	Monthly for three months, then quarterly	Loosening from vibration
Sensor tappings and connectors	Monthly	Blockage, dust ingress
Backpressure and temperature trends	Weekly review of IoT data	Steady rise, sudden jumps, low exhaust temperatures
Thermal survey of exhaust and device	Quarterly and before summer	Hot spots indicating damaged insulation

Combine these with your existing DG routine. The monthly maintenance checklist for diesel generators and our RECD maintenance guide cover the general items.

Two Illustrative Foundry Profiles

These are composite, illustrative examples, not real customers.

Cast iron foundry, Samalkha, 400 kVA

Two medium frequency induction furnaces, a green sand moulding line and a shot blasting unit. The 400 kVA set sits in a room against the melt shop wall, and summer readings show the room running far hotter than outside air. Forklifts carrying castings to fettling pass within a few metres.

Planning points: The RECD is mounted outdoors on a steel platform with a guardrail and bollards on the forklift side. The display is placed in the electrical room. Louvres facing the sand plant get filter panels. Stoppage-mode load is light, so the foundry runs shot blasting and fettling on DG during long outages where safe, and schedules a monthly loaded run. Fitment is planned for a furnace relining shutdown in March. The 400 kVA DG set RECD is the reference size.

Ductile iron and steel foundry, Faridabad, 1010 kVA

Larger foundry with several furnaces, an automatic moulding line, EOT cranes and a no-bake core shop. The 1010 kVA set (around 808 kW at 0.8 power factor) falls above 800 kW, the band where an RECD was the stated route under Direction 76.

Planning points: The device sits at the stack base inside a fenced enclosure outside the crane envelope. Vibration from the knockout grid reaches the DG building, so the RECD gets its own isolated foundation and an extended bellows section. Coal dust is not used here, but resin sand fines are, so cleaning of hot surfaces is fortnightly. The 1010 kVA DG set RECD is the reference model.

Frequently Asked Questions

Can an RECD survive the heat in a foundry DG room?

Yes, if it is planned for. Clad hot parts, ventilate the room properly, and mount electronics away from radiant heat. Where the room is already marginal, an outdoor location removes the device’s heat from the room.

Does foundry dust damage the RECD?

Sand dust mainly causes cleanliness and sensor issues. The bigger effect is indirect: dust loads the engine air filter, the engine runs rich and sends more soot to the DPF. Good intake filtration and regular cleaning are the answer.

Can the DG be taken out of service while furnaces are running?

Only if a proven alternative cooling supply is in place for the furnaces. In most foundries, fitment should happen during a relining shutdown, weekly off day or planned holiday with furnaces empty.

How do we protect the RECD from forklifts and cranes?

Walk vehicle and crane routes, then place the device outside them or protect it with bollards, guardrails and frames. Paint exclusion zones and brief drivers and crane operators.

Our foundry DG runs light during stoppages. Is that a problem?

Long light-load running slows filter regeneration. Run secondary operations on DG where safe, schedule loaded runs, and discuss low-duty options with the vendor.

Should we overhaul the engine first?

If the set smokes heavily, uses oil or has worn injectors, yes. A healthy engine reduces the soot load on the filter and extends maintenance intervals.

Plan for the Foundry You Actually Have

A foundry punishes equipment that was planned for a clean, quiet site. Start with the hazard register, place the device where heat, dust and traffic cannot reach it easily, and give it an inspection routine that matches the environment. Aceget designs and supplies CPCB type-approved RECDs for DG sets from 25 kVA to 2500 kVA, with IoT monitoring that helps you spot dust and load problems early. To arrange a survey of your foundry, get in touch with Aceget or review our full retrofit emission control device range.