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Noise Abatement
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Glossary of Terms

Having to do with hearing or sound.

Avigation Easement

A legal document acknowledging the existence of Bradley International Airport, its aircraft operations and environmental impacts (including noise) above a particular residential property; in exchange for the benefit of sound insulation for the residential dwelling.  The Avigation Easement is jointly signed by the homeowner(s) and the Airport, or designee, as acknowledgement of this fact and then recorded on the property deed.

Bid Package

A group of houses assembled together into one construction contract.


The result of high humidity (moisture in the air) that produces a “fog” when it hits a colder surface such as a glass window.

Day-Night Level (DNL)

The measure of sound levels over a 24-hour period, taking into account quiet periods as well as periods when aircraft are flying over. For flights that occur after 10 p.m. and before 7 a.m., these events are counted twice. The DNL noise exposure contours in East Granby, Suffield, Windsor, and Windsor Locks are DNL 65 up to DNL 70.

Decibel (dB)

The decibel (dB) is the unit of measure used to represent the change in sound pressure that is detected by the human ear. Since the range between the slightest and greatest sounds that we hear is extremely large, the decibel uses the logarithmic scale to compress this range to a more meaningful range with zero dB representing the threshold of hearing. Most sounds we experience in our day-to-day lives vary between 30 dB (the noise experienced in a typical bedroom at night) and 100 dB (the noise experienced inside a nightclub).  The chart below illustrates different levels of sound as measured in decibels, or dBA, a scale that accurately presents sound as humans perceive it.


Describes whether a home is qualified for participation in the Residential Sound Insulation Program by being located in designated treatment areas as defined by the Part 150 Noise Compatibility Program for Bradley International Airport.

Homeowner Participation Agreement

The Homeowner Participation Agreement is an agreement between the homeowner and Bradley International Airport authorizing sound insulation treatments at a given property.  The execution of the Agreement is required before construction can begin.


"Noise" generally refers to sound that in unwanted.  Loud music may be a wonderful "sound" to someone, but "noise" to another person.  Unwanted sound interferes with our normal day-to-day activities such as sleeping, conversation, or listening to television or radio.

Noise Compatibility Program (NCP)

Also known as Noise Compatibility Plan, this document outlines activities that are undertaken by airports to reduce the noise impacts on neighborhoods surrounding those active commercial airports.  NCP activities typically include a mix of strategies such as property acquisition or sound insulation, and changes in flight operations.

Noise Level Reduction (NLR)

Noise level reduction is measured in decibels, and is defined as a constant numerical value between the interior noise level and the exterior noise level. This measurement is taken before and after acoustical treatment to determine the overall improvement in noise level reduction. This value will be used to compare the post-construction interior noise levels in the home to the FAA goal of 45 DNL.

Noise Paths

Constructions within homes, such as doors, windows, and vents, and/or lightly constructed wall and ceiling assemblies where environmental noise can travel through or infiltrate.

Part 150 Study

A study which results in a plan to address aircraft noise and land use compatibility in the communities surrounding an airport. The Bradley International Airport has recently completed an update of its Noise Exposure Maps for its Part 150 study and has received federal funding for sound insulating eligible residential homes based on these land use measures.  "Part 150" refers to the particular section of the Code of Federal Regulations that describes the Federal Aviation Administration requirements for this study.


RSIP is an acronym for Residential Sound Insulation Program.

RSIP Field Team

Personnel such as engineers, architects, and program managers who will go into each home to gather information and make noise reduction treatment recommendations.

RSIP Project Representative

A full-time construction management individual who observes the work of the contractor and ensures that the contractor's work conforms to the bid documents.


The professionals hired by Bradley International Airport to complete the sound insulation of homes in East Granby, Suffield, Windsor, and Windsor Locks.

Sound Insulation

Sound Insulation refers to the acoustical treatments which reduce noise inside the home.  Since sound follows the path of least resistance, the most critical areas in sound insulating a home are penetrations in the home's exterior surfaces such as doors, windows and roof vents, including window air-conditioners.  Treatments can include replacing or supplementing windows and doors, installation of attic insulation, caulking and sealing.

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