DG Room Isolation
A generator that draws complaints is not an opinion problem. It is a number, written into regulation, that can be measured and evidenced.
What the rules actually ask for
Two separate things, and people routinely confuse them.
The set itself: Indian norms require diesel generator sets to be fitted with an acoustic enclosure, with a noise limit measured at one metre from the enclosure surface and a minimum insertion loss the enclosure has to deliver.
The site: the Noise Pollution (Regulation and Control) Rules set ambient limits at the boundary, different for residential, commercial, industrial and silence zones, and different again at night. Night is almost always the figure that decides a complaint.
An enclosure can pass and a site can still fail, if the exhaust, the intake louvre or the structural path was not dealt with. We measure both.
A complete enclosure system
- Spring mounts and anti-vibration pads under the set, so the slab stops carrying it
- Mass loaded vinyl inner barrier where mass is needed without thickness
- Composite board and stone wool wall and ceiling system
- Exhaust and intake silencers — usually the loudest thing left after the walls are done
- Acoustic louvres with splitters, so the set still gets its air
- Acoustic access doors with compression seals
- Post-treatment measurement and a written report for your records
If you already have a notice
Tell us at first contact. It changes the order we work in: we measure immediately, establish what the actual gap to the limit is, and deal with the largest single contributor first so there is measurable movement quickly, rather than waiting for the whole scheme.
| Untreated DG room | 95–110 dB(A) |
| Residential ambient, night | 45 dB(A) |
| Residential ambient, day | 55 dB(A) |
| Commercial ambient, day | 65 dB(A) |
| Achievable reduction | 35–60 dB |
| Set sizes handled | 10 kVA – 2000 kVA |
Ambient figures are the limits set by the Noise Pollution (Regulation and Control) Rules. Limits for the set itself are measured at one metre from the enclosure. We confirm the applicable figures for your zone at audit stage.
Asked before you ask.
Is an acoustic enclosure mandatory for a DG set?
For diesel generator sets, Indian norms require an acoustic enclosure and set a noise limit measured at one metre from the enclosure, with a minimum insertion loss the enclosure has to deliver. Separately, the Noise Pollution (Regulation and Control) Rules set ambient limits for residential, commercial, industrial and silence zones, day and night.
In practice that means two questions: does the enclosure perform, and is the ambient level at the boundary within limits. We measure both and give you the post-treatment report.
Can you work in a building that is already occupied?
Yes, and most of our commercial work is exactly that. Plant rooms, DG yards and party walls are normally dealt with while the building keeps running — sequenced around working hours, with dust control and access agreed in advance. Tell us the constraint at audit stage and it goes into the programme rather than becoming a surprise later.
Do you give a report after the work is done?
Yes. We measure again after installation and hand over the readings with the as-built detail. It is the only honest way to sell acoustic work: the claim made at the start should be checkable at the end.
What do STC, IIC, NC and RT60 actually mean?
STC is how well a wall, floor or ceiling blocks airborne sound — speech, TV, traffic. IIC is the same idea for impact: footsteps, a dropped chair. NC describes how quiet a finished room is when nothing is happening in it, which is what makes a cinema feel expensive. RT60 is how long sound takes to die away inside the room.
A wall can have a high STC and the room can still sound wrong. They are different numbers, solved by different work, and a proposal that only mentions one of them is incomplete.
Request a compliance check.
We measure at the set and at the boundary, compare both against the limits that apply to your zone, and put the gap in writing.
- We call you back within one working day to understand the problem.
- We visit and measure — baseline dB levels and frequency profile, at no charge.
- You get a written proposal with performance targets, materials and costs, itemised.
Hyderabad, Telangana – 500033