Noise - A Universal Complaint

Noise - A Universal Complaint

According to a recent Daily News poll, most New Yorkers cite NOISE as the most annoying feature of urban life(1). Furthermore, when the NYC Police Department instituted its quality of life telephone hotline in August, 1996, 43% of complaints received related to noise(2).

The noise that annoys New Yorkers comes in many forms from many places. Shrieking subways(3), thudding pile drivers(4), roaring boilers(5), noisy neighbors(6), raucous restaurants(7). Community meetings throughout the City regularly address the failure or refusal of City agencies to effectively respond to noise complaints.

Excessive Noise is Unhealthy

Excessive noise is hazardous to our physical and mental health(8). The body reacts to unwelcome noise of any intensity indirectly as it does to other intrusive stressful stimuli: elevated blood pressure, excessive secretion of hormones, changes in the rhythm of the heart. There is a growing body of literature that suggests that these physiological responses may lead to actual bodily damage in adults and in children(9). In addition, the frustration of not being able to limit distracting noise compounds the body's physiological responses. In some cases, noise drives people to commit homicide or suicide

If this is a sign of the times then Sound Control best be on everyone's mind

Reprinted from Associated Press Tuesday, December 20, 2011

Rise in home building suggests industry turnaround

Dec. 20, 2011, 1:46 p.m. EST

AP

WASHINGTON (AP) — A surge in apartment construction gave home builders more work in November. And permits, a gauge of future construction, rose largely because of a jump in apartment permits.
Some analysts say the gains, though coming off extremely low levels, suggest the depressed housing industry may have reached a turning point.
Economists now say 2011 will be the first year since the Great Recession began in 2007 that home construction will have helped the economy grow. Before this year, the industry endured two of the worst years ever.
"Homebuilding is through the worst and is now steadily improving," said Paul Diggle, a property economist at Capital Economics.
Builders broke ground on a seasonally adjusted annual rate of 685,000 homes in November, a 9.3 percent jump from October, the government said Tuesday. It's the highest level since April 2010.
Still, the rate is far below the 1.2 million homes that economists say would be built each year in a healthy housing market.
Construction of single-family homes rose 2.3 percent in November to a seasonally adjusted annual rate of 447,000. Apartment construction jumped 32 percent to a rate of 238,000 units. Single-family homes account for about 70 percent of homebuilding.
For the year, work is expected to have begun on 430,000 single-family homes and 185,000 apartments. Those figures remain far below the roughly 840,000 single-family homes and 360,000 apartments that would be started in a healthy economy.
Tuesday's home construction data, along with encouraging economic news out of Germany and Spain, helped fuel a huge rally on Wall Street. The Dow Jones industrial average jumped more than 300 points, or 2.7 percent, by mid-afternoon.
Patrick Newport and Michelle Valverde, U.S. economists at IHS Global Insight, said the better-than-expected figures show that the housing industry is "finally getting off the mat."
"It'll keep getting better through next year," said Jared Franz, an associate economist at T. Rowe Price.
Last year, builders began work on roughly 587,000 homes. That barely surpassed the 554,000 homes started in 2009, the worst year ever.
Though new homes represent just 20 percent of the overall home market, they have an outsize impact on the economy. Each home built creates an average of three jobs for a year and generates about $90,000 in taxes, according to the National Association of Home Builders.
Renting has become a preferred option for many Americans who lost their jobs during the recession and were forced to leave their houses. The surge in apartments has provided a lift to the beleaguered housing market but has not been enough to completely offset the loss of single-family homes.
Permits rose 5.7 percent last month to a seasonally adjusted annual rate of 681,000, boosted by a 16 percent jump in permits for apartment buildings, to 246,000.
Builders typically begin construction on single-family homes six months after getting a permit. With apartment projects, the lag time can be up to a year.
Over the past year, permits for apartment buildings with five or more units have surged more than 80 percent. Permits for single-family homes have risen much less: just 3.6 percent.
Demand for new homes is weak. Record-low mortgage rates and plunging home prices have done little to help.
The chief problem: Builders are struggling to compete with deeply discounted foreclosures and short sales. Short sales occur when lenders allow homes to be sold for less than what's owed on the mortgage. Few homes are selling.
After previous recessions, housing accounted for at least 15 percent of U.S. economic growth. Since the recession officially ended in June 2009, it has contributed just 4 percent.
In October, sales of new homes rose slightly, largely because builders cut their prices in the face of weak demand. Sales hit a six-month low in August. And this year is shaping up to be the worst since the government began keeping records a half-century ago.
Another reason sales have fallen is that previously occupied homes have become a better deal than new homes. The median price of a new home is about 30 percent higher than the median price for a re-sale. That's nearly twice the markup typical in a healthy housing market.
The homebuilders' trade group said this week that its survey of industry sentiment rose in December to 21, the highest level since May 2010. Still, any reading below 50 indicates negative sentiment about the housing market. The index hasn't reached 50 since April 2006, the peak of the housing boom.

Just how do you calculate STC ratings?

For those of you that want to know how to calculate STC, here it is:

Measure the transmission loss (TL) for the wall system from 125 Hz to 4 kHz and plot on a chart.  The STC for the wall is determined by superimposing a contour chart (not shown here) upon the TL curve such that (1) there is no more than a 8-dB deficiency between the TL and the STC contour at any 1/3-octave frequency (i.e., no test point may be more than 8 dB below the STC contour), and (2) the total deficiency between the STC contour and the TL curve (i.e., the value of the STC contour minus the value of the TL curve summed at all 1/3-octave frequencies from 125Hz to 4 kHz) must be less than or equal to 32 dB.  Once the curve has been adjusted to met these two criteria, then the STC value of the wall is equal to the TL value of the contour at 500 Hz.

Makes sense?  Not really!

Best way to say it is:  The more noise the wall system reduces – the higher the STC number.

Building Codes

In the case of construction of new (or remodeled) apartments, condominiums, hospitals and hotels, many U.S. states and cities have stringent building codes with requirements of acoustical analysis, in order to protect building occupants from exterior noise sources and sound generated within the building itself.^[8]. With regard to exterior noise, the codes usually require measurement of the exterior acoustic environment in order to determine the performance standard required for exterior building skin design. The architect can work with the acoustical scientist to arrive at the best cost-effective means of creating a quiet interior (normally 45 dBA). The most important elements of design of the building skin are usually: glazing (glass thickness, double pane design, etc.), roof material, caulking standards, chimney baffles, exterior door design, mail slots, attic ventilation ports and mounting of through the wall air conditioners. A special case of building skin design arises in the case of aircraft noise, where the FAA has funded extensive work in residential retrofit.
Regarding sound generated inside the building, there are two principal types of transmission. First, airborne sound travels through walls or floor/ceiling assemblies and can emanate from either human activities in adjacent living spaces or from mechanical noise within the building systems. Human activities might include voice, amplified sound systems or animal noise. Mechanical systems are elevator systems, boilers, refrigeration or air conditioning systems, generators and trash compactors. Since many of these sounds are inherently loud, the principle of regulation is to require the wall or ceiling assembly to meet certain performance standards (typically Sound Transmission Class of 50), which allows considerable attenuation of the sound level reaching occupants.
The second type of interior sound is called Impact Insulation Class (IIC) transmission. This effect arises not from airborne transmission, but rather from transmission of sound through the building itself. The most common perception of IIC noise is from footfall of occupants in living spaces above. This type of noise is somewhat more difficult to abate, but consideration must be given to isolating the floor assembly above or hanging the lower ceiling on resilient channel. Commonly a performance standard of IIC equal to 50 is specified in building codes. California has generally led the U.S. in widespread application of building code requirements for sound transmission; accordingly, the level of protection for building occupants has increased markedly in the last several decad