Noise and Vibration Assessment

used to provide the highest level of protection. All of these limits have been used successfully, andcompliance to these limits has not been known to result in appreciable structural damage. Allvibration limits referred to herein apply on the ground level and take into account the response ofstructural elements (i.e. walls and floors) to ground-borne excitation.The majority of project construction activities would employ open-trench construction methods toinstall the new backbone pipeline, distribution lines, cross-connections, and customer serviceconnections. After the pipelines are installed, the trench and pavement would be restored. Finally,the existing pipelines and connections would be abandoned.Activities with the potential of generating perceptible vibration levels would include the removal ofpavement and soil, shoring, and the compacting of backfill after the new pipeline is installed. Theproposed project would, at times, bring construction activities within about 25 feet of sensitive landuses along the project alignment. Table 6 summarizes typical vibration levels associated withvarying pieces of construction equipment at a distance of 25 feet.Equipment anticipated during project construction would include: backhoes, excavators, cranes,dump trucks, front end loaders, asphalt pavement grinders, boiler trucks, bypass pipes, asphaltpavers, concrete trucks and various passenger vehicles. Neither vibratory or impact pile driving areproposed as part of the construction of the project.A review of the proposed equipment and the vibration level data provided in Table 5 indicates thatvibration levels generated by the majority of proposed equipment would be equal to or below the 0.2in/sec PPV criteria used to assess the potential for cosmetic damage to buildings of normalconventional construction. Vibration levels from dropping heavy equipment (clam shovel drop) orthe operation of a vibratory roller at a distance of 25 feet could slightly exceed the 0.2 in/sec PPVcriteria. Theoretically, these potential exceedances could be up to one one-hundredth of an inch persecond PPV (0.01 in/sec PPV). However, at a distance of 26 feet, the levels are calculated to be lessthan the 0.2 in/sec PPV criteria. Sporadic events such as dropping of heavy objects, and the use ofvibratory rollers within 25 feet of residences should be avoided to the extent possible. The impactresulting from the project would be considered less-than-significant as vibration levels would notexceed the 0.2 in/sec PPV criteria established to evaluate the risk for cosmetic or structural damageto buildings. Vibration levels generated by construction activities would be perceptible indoors andmay be considered annoying. However, planned construction hours are during the daytime, limitingthe possibility of annoyance during typical periods of sleep or rest, and would only affect a particularresidence for a brief period of time as construction activities occur in areas immediately adjoining theresidence.12