Archive for June, 2016

So why are you complaining?

Wednesday, June 15th, 2016

by Nick Miller

S'Martin- S'Mararten

Maybe one person’s noise is another person’s music. Train horns in the distance can have a kind of nostalgic sound, but people who live near a grade crossing may not think so. (Try a room on the back side of the Hampton Inn San Diego – Downtown. You might take your earplugs.) Find any newspaper article on the Internet about aircraft noise complaints, check the comments and you’ll find things like “These folks should have known they are buying near an airport,” or considerably snarkier. Which might be a reasonable remark except even knowing doesn’t translate to a real awareness of what living with loud aircraft overflights day-after-day is really like. Of course, what realtor or home owner is going to try to alert the prospective buyer to the reality of life near an airport?

Quite a few airports require that home buyers receive some sort of disclosure statement, but all the ones I know about are presented at the closing. A little late, don’t you think? The only possibly effective method I know of is attempted by DFW airport. They try to get realtors to send in home buyers, and DFW shows them large displays of where aircraft fly. Much better, I think, than telling the buyer their house is in a noise zone or is within some decibel value of a noise contour. Who’s going to understand that?

I feel quite certain that most people who buy a home in the near vicinity of a commercial air carrier airport (say within 1 to 5 miles, depending on specific location and the level of operations at the airport) are unaware of what it can be like to live there day-after-day, night-after-night. I find it quite interesting, however, that there is a predominant meme that posits house prices reflect the acceptability of aircraft noise (hedonic pricing method). In other words, people pay less for such homes because they discount the price since they will have to live with the noise. Using hedonic pricing assumes that the buyer decides what to pay because he knows what he’s buying. That’s fine for buying a 60-inch flat screen TV to replace a 20-inch flat screen. But I think it’s an inaccurate means of assigning a cost to noise, or “monetizing” aircraft noise so that it can be compared with other costs (e.g. air quality health effects) or benefits (e.g. accessibility to transportation) of living near an airport. Studies seem generally to show a reduction in house price of 10% to 12% per 10 dB increase in aircraft noise, beginning at some identified lower level where there is an assumed no effect of aircraft noise.

But does this method really reflect the “cost” of noise? Some argue that noise is a quality of life issue upon which no price can be placed – a problem common to many amenities, such as low crime rates, clean streets or green spaces. Another way of thinking about the cost of noise, if we must, is how community dislike of noise affects decision-making about airports. Think about the many years (decades even) that it takes to propose, approve, design and build a new runway or a runway lengthening. What are the costs of the many studies reported as drafts, revisions, and revisions of revisions and associated public meetings, to say nothing of the costs of delayed construction and travel delays due to insufficient air travel capacity?

Finally, here’s an incident I recall reading about, but can’t verify for certain. Someone living in Northeast Harbor, ME, didn’t like the sound he could hear of the local sewage treatment plant. He asked the town if they could quiet it, getting the reply that they didn’t have the money to modernize it. So he donated, I believe, $60,000 to help the town pay for the quieting. Whether accurately remembered or not, I believe the substance is correct, and this story suggests to me a possible short-coming of asking people how much they would be willing to pay for less noise. The answer probably depends on what resources they have available.

HMMH Assists FAA and Airports in Standardizing the Process for Determining Sound Insulation Program Eligibility

Tuesday, June 7th, 2016

by J. Eric Cox

HMMH has provided acoustical testing, design, and other consulting services to airports throughout the country that have implemented sound insulation programs in accordance with FAA Order 5100.38D Airport Improvement Program (AIP) Handbook. HMMH has most recently been conducting sound insulation measurements around several airports including:

  • T. F. Green State Airport (PVD) in Providence, Rhode Island
  • Tweed – New Haven Airport (HVN) in New Haven, Connecticut
  • Louisville International Airport (SDF) in Louisville, Kentucky (shown below)


Over the last several months, HMMH has also assisted the Federal Aviation Administration (FAA) and airport sponsors in standardizing the process for determining sound insulation program eligibility per current FAA requirements and criteria, which include that the average interior noise level for a residential building or educational facility must be 45 dB or greater.This work has included a recently completed Policy, Engineering, Analysis and Research Support (PEARS) study for the FAA Office of Environment and Energy regarding selection of appropriate aircraft noise spectra for use in determining outdoor-to-indoor building noise level reduction (NLR).

In addition, we have assisted several airport authorities (including Los Angeles World Airports and the Port of Seattle) in developing sound insulation program acoustical testing plans (ATP) for FAA review. This work has included providing additional information and supporting details related to the various methods that may be used to measure the exterior building façade sound level in the determination of NLR, each of which require a different adjustment to the measured level to account for the reflection of sound energy from the façade under test that is not transmitted through the exterior wall and instead travels back to the measurement microphone.

And as part of our on-going sound insulation testing work at Louisville International Airport, we have recently been evaluating noise mitigation program eligibility for several educational buildings and residential dormitories at the nearby University of Louisville Belknap Campus. This has required us to evaluate methods to compute daytime average sound levels (as required for educational facilities by FAA) that are consistent with the noise study, aircraft operations data, and analysis methods previously utilized to generate the Day-Night Average Sound Level (DNL) noise contours for the Noise Exposure Map (NEM).

Finally, I will be presenting a paper at the New England Noise-Con Revolution in Noise Control conference to be held in Providence, Rhode Island during June 13 – 15, 2016. This paper investigates the correlation between aircraft interior noise levels and various residential building construction features. The results of this analysis are then considered in the context of the current guidance provided in Appendix R of the FAA AIP handbook, which specifics a procedure to determine the eligibility of residences for sound insulation programs based on interior noise levels for categories of homes. Ultimately, we were unable to identify any specific building construction details which might result in truly effective categorizations of residential structures for this purpose since even the best possible approaches resulted in ranges of interior DNL noise levels that directly overlap and all of which span the 45 dB FAA criteria. An example presentation graphic is provided below comparing average interior DNL values for single family homes with total window assembly glazing thickness.

If you are interested and would like to learn more, please attend my Noise-Con presentation entitled “Investigation of Correlation between Aircraft Interior Noise Levels and Residential Building Construction Details” on Tuesday June 14, 2016 from 1:20 PM – 1:40 PM in Room 550 A/B of the Omni Providence Hotel during the “Building Acoustics Measurement and Modeling” conference session. Hope to see you there!