A multinational bank set up its back office at a prime location in Mumbai. As back-up power for the office, they installed three 1010 KVA Diesel Generator sets. The office is situated in a large commercial complex where several other buildings in the premises also housed offices having their own back-up generators.

The bank was in a declared commercial zone but was sharing a common compound wall with a residential complex. During commissioning of the generators, the noise was too loud and objectionable to the occupants of neighboring complex. They complained to the State Pollution Control Board (SPCB) which is the state authority that presides over such matters, who in turn instructed the multinational bank to reduced noise with immediate effect and deferred the bank from running their power generators at night till noise norms were complied with.

Thermosonics Private Limited was invited to study the case and propose a method to reduce noise and comply with norms as per SPCB. The analysis showed that the power generators were meeting requirements of noise norms of Industrial Zone, however they were installed right adjacent to a residential zone. The matter became further complicated as the 24×7 backup office could not be used by the bank, due to the restrictions imposed, in case of power failure. Detailed study revealed that as there were multiple generators within the commercial complex apart from the client’s unit, it was necessary to ensure that the noise levels were brought down below SPCB prescribed norms for residential zones.

Another issue was the exhaust gas from power generators that was built at a height of 7 meters from ground was also objectionable to the members of the residential complex. They feared that changing wind direction could sweep the flue gas towards them.

The following solutions were proposed by TPL with guaranteed attainable results: –

• A secondary modular acoustic enclosure with adequate forced ventilation installed enclosing all 3 power generators within.
• Exhaust gas ducts are taken to a height above the 11 storied residential complex.
• Pre and post acoustic installation, sound pressure level at residential complex to be measured in the presence of SPCB officials with their instruments to establish compliance.

The Bank was convinced with this approach and placed an order with Thermosonics Private Limited to execute the job within stipulated time. Noise measurements were taken in the presence of the officials from SPCB, the bank representatives and members of residential complex. The results were found acceptable to the SPCB officials as well as the residents of the complex. Following which a MOU document was prepared and signed by all officials to safeguard the bank from any future complaints from neighbors.