What Are Acoustic Enclosures?
Acoustic enclosures are purpose-built noise control structures that enclose a noise-generating piece of equipment — a diesel generator (DG set), pump, compressor, chiller, or industrial machine — to reduce the noise emitted to the surrounding environment. They work by combining sound transmission loss (mass law) and sound absorption (porous materials) to achieve a target insertion loss (IL) measured in decibels.
In India, the demand for acoustic enclosures has been driven by CPCB's mandatory noise limits for DG sets (75 dB(A) at 1 m), increasing urbanisation placing industrial equipment adjacent to residential areas, and growing awareness of occupational noise exposure limits (85 dB(A) per IS:3483).
If you are a facility manager, MEP contractor, or procurement officer looking for acoustic enclosure manufacturers in India, this guide will help you specify correctly and evaluate suppliers effectively.
Applications of Acoustic Enclosures in India
| Application | Equipment | Typical IL Required | Regulatory Standard |
|---|---|---|---|
| DG set enclosure | Diesel generators (15 kVA – 3000 kVA) | 20–35 dB | CPCB DG Set Noise Rules 2002 |
| Pump room enclosure | High-pressure pumps, booster sets | 15–25 dB | NBC 2016, local municipal limits |
| Compressor enclosure | Air compressors, screw compressors | 20–30 dB | OSHA / Factory Act noise limits |
| Chiller acoustic hood | Centrifugal / screw chillers | 10–20 dB | ECBC 2017, green building credits |
| Industrial machine enclosure | CNC, press, stamping, grinding | 15–30 dB | IS:3483, Factories Act |
| Transformer acoustic enclosure | Distribution transformers | 10–18 dB | IS:2026, utility company specs |
CPCB Compliance Requirements for DG Sets
The Central Pollution Control Board (CPCB) issued the Noise Pollution (Regulation and Control) Rules 2000 and the DG Set Noise Standards 2002, which require:
- All DG sets rated above 5 kVA must be acoustically enclosed
- Noise level must not exceed 75 dB(A) at 1 metre from the enclosure surface
- The enclosure must have adequate ventilation to prevent engine overheating (airflow ≥ 6 air changes per hour inside the enclosure)
- Anti-vibration mounts must be used between the engine/alternator skid and the floor
- Exhaust silencer with minimum 25 dB attenuation must be installed on the exhaust stack
A typical open DG set generates 95–105 dB(A) at 1 metre. To meet the 75 dB(A) limit, the enclosure must achieve a minimum insertion loss of 20–30 dB. Most quality acoustic enclosures achieve 25–35 dB IL.
7-Point Vendor Evaluation Checklist
Ask for a third-party test report showing actual insertion loss in dB(A) for the panel construction being quoted. Be sceptical of vendors who only provide "up to X dB" claims without supporting test data.
An acoustic enclosure that suffocates the engine is useless. The manufacturer must provide ventilation calculations showing adequate air changes per hour for the generator's heat rejection rate (kW). This requires thermodynamic analysis, not guesswork.
The acoustic panel should specify: outer material (aluminium or GI), infill (mineral wool / rockwool, density ≥80 kg/m³, thickness ≥50 mm), and inner liner (perforated aluminium or GI, ≥22% perforation). Demand the panel datasheet.
Maintenance access is critical. Verify that access doors are acoustically treated (double-seals, acoustic fill), large enough for engine service (oil filter, coolant, battery access), and securely latched with acoustic gasket perimeter seals.
The exhaust silencer and stack must be integrated into the enclosure design with flexible couplings, thermal insulation on exhaust pipes inside the enclosure, and proper penetration seals where the stack exits the enclosure.
Anti-vibration mounts between the DG skid and the floor are mandatory for CPCB compliance. Ensure the manufacturer provides AVM sizing calculations based on the DG set's operating speed (RPM) and mass.
The best manufacturers offer post-installation noise measurement at 1 m and confirm compliance with CPCB limits as part of the commissioning process. This gives you documented evidence of compliance for regulatory inspections.
Types of Acoustic Enclosures
Canopy-type enclosures enclose the DG set on all sides (4 walls + roof) and are suitable for outdoor DG sets up to ~500 kVA. They are factory-fabricated and delivered as modular panels for on-site assembly.
Room-type enclosures convert an existing plant room or construct a new acoustic room around large DG sets (500 kVA and above). The walls, roof, doors, and ventilation openings are all acoustically treated. This offers higher insertion loss (30+ dB) and easier maintenance access.
Partial enclosures target specific noise sources (e.g., cooling fan housing, alternator end cap) when full enclosure is not practical due to space or access constraints.
Sample Specification Clause
Why KBG Group for Acoustic Enclosures
KBG Group manufactures acoustic enclosures and noise control solutions from their Bengaluru facility, with in-house design, fabrication, and quality teams. Their enclosures have been installed across 500+ sites in India.
Key sectors served:
- Data centres — DG set canopy enclosures for Tier III and Tier IV facilities in Bengaluru, Hyderabad, and Mumbai
- Hospitals — Room-type acoustic enclosures for critical power DG sets (noise-sensitive environment)
- Commercial buildings — Canopy enclosures for rooftop and basement DG sets
- Industrial facilities — Compressor and pump room acoustic treatments for SEZ and manufacturing plants
- Metro rail — Tunnel ventilation fan acoustic enclosures for BMRCL and DMRC projects
Get a CPCB-Compliant Acoustic Enclosure Quote
Share your DG set specs and site details. Our team will provide an acoustic assessment and indicative quotation within 48 hours.
Request Acoustic Assessment →Indicative Pricing Guide
| Enclosure Type | DG Set Range | Indicative Cost |
|---|---|---|
| Standard canopy (GI outer) | 15–125 kVA | Rs. 50,000 – 1,50,000 |
| Premium canopy (aluminium outer) | 15–500 kVA | Rs. 80,000 – 3,00,000 |
| Room enclosure (modular panels) | 500–2000 kVA | Rs. 3,00,000 – 12,00,000 |
| Pump room acoustic treatment | per room area | Rs. 2,500 – 5,000 per m² |
| Industrial machine enclosure | per project | Rs. 1,50,000 – 8,00,000 |
Prices are indicative and vary with site conditions, DG set size, target IL, and material specification. Contact KBG Group for a project-specific quotation. GST applicable.
Frequently Asked Questions
Who makes acoustic enclosures for DG sets in India?
KBG Group is a specialist acoustic enclosure manufacturer in India, with 500+ installations across data centres, hospitals, commercial buildings, and industrial facilities. All DG set enclosures are designed to comply with CPCB noise standards (≤75 dB(A) at 1 m).
What CPCB noise limit applies to DG sets?
CPCB requires that all DG sets above 5 kVA must not emit more than 75 dB(A) at 1 metre from the enclosure during daytime operation. Violation can result in closure notices and penalties. KBG Group's enclosures are designed to achieve this with 5 dB margin.
What insertion loss do I need for a DG set enclosure?
A typical open DG set generates 95–105 dB(A) at 1 m. To meet the 75 dB(A) CPCB limit, you need 20–30 dB insertion loss. KBG Group's standard aluminium canopy enclosures achieve 25–35 dB IL, providing comfortable CPCB compliance margin.
Will an acoustic enclosure overheat my DG set?
Not if it's properly designed. KBG Group's enclosures incorporate acoustically attenuated ventilation louvres (their own manufactured product) with airflow calculated to handle the DG set's full heat rejection. Thermal analysis is provided with every enclosure proposal.
What is the price of an acoustic enclosure for a 250 kVA DG set?
An aluminium canopy enclosure for a 250 kVA DG set typically costs Rs. 1,50,000 – 2,50,000 supply and install (excluding DG set, foundation, and exhaust stack). Contact KBG Group with your DG set model and site details for an accurate quote.