The Olathe Compressor Station is operated by TransColorado Gas Transmission for the compression of natural gas for pipeline transmission. The station is located on a plateau in isolated Colorado scrubland, two miles from the nearest residences.
SCOPE OF WORK
Kinder Morgan, the owner of TransColorado Gas Transmission, contacted INNOVA to conduct a noise level audit at the station, and to make recommendations for mitigation of the noise that had been an on-going source of annoyance to nearby residents. While the Olathe Compressor Station complied with the Federal Energy Regulatory Commission’s (FERC’s) guidelines, Kinder Morgan was committed to identifying and solving the noise problem.
Noise level measurements were undertaken within and outside the walls of the station to confirm compliance. Day and night readings were made at five sites near the private residences adversely affected by the noise, and at various distances between the residences and the station.
Using meteorological information, INNOVA established a correlation between temperature, residents’ noise perception, and measured noise levels. The conclusion: due to atmospheric changes, noise levels―chiefly from the turbine exhaust stack―were noticeable at the residences at various times.
The final design, supply and installation work included replacement of the turbine exhaust muffler system, Genset exhaust systems, and lagging of yard piping.
While FERC noise limits applied, INNOVA, in consultation with Kinder Morgan, established noise limits for the station of 65 dBA at the property line.
Based on meteorological data and the acoustic survey findings, INNOVA identified five areas for sound abatement:
- Gas turbine stack
- Exhausts for the two Gensets
- Genset radiator coolers
- As optional components, the building itself and gas piping
UNIQUE PROJECT HURDLES
INNOVA faced three distinct challenges on the project: noise source identification, timing, and design requirements. Despite the station’s compliance, residents reported unusually high noise levels of a sudden and random nature. INNOVA’s initial challenge was simply identifying the level and source of the offending noise. The intermittent nature of the noise required an extended survey time. This extended acoustic survey period was particularly worrisome because the Colorado regulatory authorities required the problem to be solved within a certain timeframe. Given timing and cost concerns, replacing the existing foundation to support an additional 23,500 pounds for the new stack was not an option (the difference between the 6,500-pound weight of the old stack and the 30,000 pounds for the replacement stack). While the plant operated, as usual, INNOVA exposed the existing foundation and installed new, reinforced footing. A seven-day shutdown had been anticipated to install the noise control. Effective planning and co-ordination reduced the period to five days.
Acoustic surveys were undertaken in the spring and summer. Client approval for design, supply and installation work was received in September, and the project was successfully completed three weeks before the regulatory deadline. In a follow-up meeting, residents reported no issues with noise from the Olathe Compressor Station.