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MEP Noise Impact Comparisons The tables below summarize the noise studies that were conducted for MEP's original Federal Energy Regulatory Commission (FERC) filin-, its amendment filing (where applicable) and the expansion filing For each of the three compressor stations. The data presented in these tables includes the existing measured ambient noise levels before the project started, the combined future noise levels (the currently existing levels plus the contribution of the proposed compressor stations as modeled in the original filin-, the amendment and the expansion) and the resultin- expected increase in noise over currently existin- conditions at the noise-sensitive areas (NSA) near each site. FF,RC limits compressor station noise (not counting currently existing leveis) to no greater than an Ld„ of 55 decibels (dBA), and the calcufated compressor station noise levels at each NSA location have been modeled to not exceed this limit. The 55 dBA limit is a level that the Environmental Protection Agency recommends for °`outdoor residential areas and farms and other outdoor areas where people spend widely varying amounts of time and other places in which quiet is a basis for use." The EPA considers this level as protective of the public health and welfare from the effects of environmental noise and notes that this criterion was developed without regard to technical or economic feasibiliry and contains a margin of safety. ln areas where the existing noise levefs are ciurently above 55 dBA, as is true for soine of Lhe iV1EP NSAs as shown below, the addition of another 55 dBA sound results in only minimal increases to future noise levels due to the logarithmic nature of decibel addition. This is one reason that FERC utilizes an absolute noise standard, so that there is a limit to how much noise can be increased. In fact, addinlg a 55 dBA sound to any sound that is already at 55 dBA or greater, will result in increases in noise of only 3 dE3A or less. Increases in noise of 3 dBA or less are considered to be barely perceptible. The Ld. is a measurement used by the FERC for evaluating compressor station noise. It is the avera-e of the noise occurring over a 24- hour period, but with a 10 dBA penalty for noise that is generated durinb the ni-ht. Noise levels from the compressor stations will be steady in level durin- all hours. Therefore, on a continuous 24-hour basis, the compressor stations are actually limited to a sound level of 49 dBA at any residence (this is the sound level that must be achieved during the post construction testing). MEP will ensure its operations do not exceed regulatory noise limits. While the increases in noise will be relatively small in most cases, it is likely that, depending on location, time of day, weather and levels of noise from other soLirces, some landowners within a half-mile of a compressor station will be able to hear it, at least at some times of day. Operational Noise Impact Results - Lamar Compressor Station (MEP 1) - NSA ErISLiTIb Ldn Noise Levels at Each Location (d BA) Ld„ When Existing Noise Levels are Combined with Project (dBA) Expected Increase (dBA) from Project Original Amended Expansion Original Amended Expansion NSA 1 57.6 58.6 N/A 58.7 1.0 N/A 1.1 NSA 2 56.4 56.6 N/A 56.6 02 N/A 0.2 NSA 3 54.4 55.4 N/A 55.6 1.0 N/A 1.2 NSA 4 47.4 49.0 N/A 49.1 1.6 N/A 1.7 NSA 5 63.9 63.9 N/A 64.0 0.0 N/A 0.1 NSA 6 55.4 55.8 N/A 55.8 0.4 N/A 0.4 NSA 7 57.6 58.2 N/A 583 0.6 N/A 0.7 NSA 8 57.6 59.1 N/A 59.3 1.5 N/A 1.7 NSA 9 57.6 58.9 N/A 58.9 1.3 N/A 13 NSA 10 59.8 60.1 N/A 60.2 0.3 N/A 0.4 - 000280