Example of state defned noise levels Noise can come from more sources than the actual drilling rig V ehicles moving in and out of the site are often the cause of noise increase 2 Noise fr om the hydraulic fracking pr ocess Shale gas extraction can continue at each drilling site for many years but it is the initial construction drilling and hydraulic fracturing process that creates the main environmental impact Initial construction of the well takes approximately 23 weeks Noise is caused by the construction activity but also from frequent movement of heavy plant and vehicles in and out of the site Once the well has been constructed drilling commences and may last up to 30 days depending on well depth The drilling process is noisy and usually continues 24 hours a day and throughout the night when surrounding communities are most sensitive to noise Extensive measures are taken around the drilling site to reduce noise which can include for example a sound wall or curtain to reduce noise levels in neighbouring communities After drilling is complete the hydraulic fracking process directs a high pressure water mixture into the well to fracture the rock and release gas Fracking can take between 35 days and is usually limited to daylight hours Fracking does create noise but usually at a lower level than that from drilling Once the well is capped everything is removed from the drilling pad and gas is drawn from the pipeline using compressors These create some noise which is usually successfully managed by housing the compressors in sound isolating enclosures However there has been noise disturbance reported where they are located close to residences Applicable Noise Legislation In the United States noise impact from drilling can be regulated at a state level or ef fected through legislation at the City or municipality level through specifc modifcation of general noise ordinances An example at the state level is the Colorado Oil and Gas Conservation Commission which was established as part of the Colorado department of natural resources It aims to foster the responsible development of the state s oil and natural gas resources Their noise regulations stipulate maximum permissible levels depending on land use ranging from 55dB for residential agricultural and rural to 80dB for industrial land use Levels are more stringent during night time During daytime the regulations permit an exceedance of up to 10dB of these limits providing it does not last more than 15 minutes in any one hour period In addition periodic impulsive or shrill noises have dif ferent level limits Complex legislation such as this presents a huge challenge to drilling companies needing to demonstrate compliance Local legislation typically requires city or parish noise ordinances to be modifed These address a wide range of community noise disturbances from amplifed sound power tools and setting of f freworks Additional requirements to address noise from oil and gas wells may include Limiting drilling operations to daylight hours during weekdays only Limiting heavy vehicle movement Ambient noise level test requiring continuous noise monitoring for 24 to 72 hours prior to works commencing to gain a valid background noise measurement Continuous monitoring during the drilling and fracking process at any nearby sensitive receptors such as schools hospitals and churches If complaints are received immediate continuous monitoring for 24 or 72 hour period to take place within 24 hours of the notifcation of complaint