Residential standby generators may not keep you safe or be important during a tornado, but when electrical power stations and electrical lines are knocked out and hundreds of thousands of homes are left without power, standby generators do make this difficult time more tolerable for as the system is repaired. Standby generators do not run all the time, but when they do run, most are typically loud and emit sound levels ranging from 65 – 100 plus decibels, which often times annoy neighbors who don't have generators and exceed most community noise ordinances.
Being without electrical power after a storm causes increased anxiety to those affected. Living near neighbors that operate loud standby generators without soundproofing will cause increased anxiety and tension during an already difficult situation. A generator enclosure is the generator's first line of defense against the elements. It’s important to not only keep it in good condition, but also important to have proper soundproofing materials built into your enclosure to absorb the noise and keep it to a tolerable level. Keeping your neighbors up with loud generator noise during power outages may make a normally nice neighbor not so pleasant.
USA - Tornado Alley of the World
According to Live Science.com, in terms of absolute tornado counts, the United States leads the list globally, with an average of more than 1,000 tornadoes recorded each year. A distant second is Canada, with around 100 per year. Eighty percent of tornadoes are EF0 and EF1 (T0 through T3) tornadoes. The rate of occurrence drops off quickly with increasing strength—less than 1 percent are violent tornadoes (EF4, T8 or stronger).Outside Tornado Alley, and North America in general, violent tornadoes are extremely rare.
Mother Nature Network.com website says that in the United States, tornado season tends to move northward from late winter to mid-summer. In Southern states, tornado season is typically from March to May. In the Southern Plains, it lasts from May to early June. On the Gulf Coast, tornadoes occur most often during the spring. And in the Northern Plains, Northern states and upper Midwest, peak season is in June or July.
The two regions with a disproportionately higher incidence of tornadoes are Florida and an area in the Midwest known as Tornado Alley, a large strip of land going north to south that covers the northern region of Texas, Oklahoma, Kansas, Nebraska, Iowa, the eastern edge of Colorado, southwest tip of South Dakota and the southern edge of Minnesota.
Florida’s high tornado frequency is the direct result of their daily thunderstorms coming from the ocean and the Gulf of Mexico, as well as the many tropical storms and hurricanes that affect the Florida peninsula.
In the Gulf Coast region, Dixie Alley refers to West Tennessee, West Kentucky, North Mississippi and North Alabama. These states experience a significantly later tornado season that occurs in the late fall from October through December.
Worst Tornado Outbreak Ever Recorded
The April 25–28, 2011 tornado outbreak was the largest tornado outbreak ever recorded. The outbreak affected the Southern, Midwestern, and Northeastern United States, leaving catastrophic destruction in its wake, especially across the state of Alabama. It produced destructive tornadoes in Alabama, Arkansas, Georgia, Mississippi, Tennessee, and Virginia, and affected many other areas throughout the Southern and Eastern United States. In total, 358 tornadoes were confirmed by the National Weather Service in 21 states from Texas to New York and in southern Canada. Widespread and destructive tornadoes occurred on each day of the outbreak, with April 27 being the most active day with a record of 205 tornadoes touching down that day. Four of the tornadoes were destructive enough to be rated EF5 on the Enhanced Fujita scale, which is the highest ranking possible; typically these tornadoes are only recorded about once each year or less. In total, 348 people were killed as a result of the outbreak.
Power Outages Are Common With Tornadoes
Many severe tornadoes bring destruction to property and to electrical systems in large cities and small communities. Despite the U.S. tornado warning program, which began in 1957, death tolls – even with a growing population – have steadily decreased. Even with today's technology, there's still no way to control where these violent and destructive tornadoes go and what they will hit.
Media reports estimated that during the Alabama tornado outbreak on April 27 an estunated 262,000 electric “customers” (individual homes and businesses) were without electrical power. The electric utility industry assumes 3-4 people per customer which translates to approximately 786,000 to 1.4 million people being temporarily without electricity temporarily for a prolonged period of time. It can take anywhere from a few days to as many as 10 days or longer sometimes, depending on the situation and the damage.
Standby Generators: Remember the Soundproofing
All we can do to combat severe storms is to be prepared before they strike. These storms can develop quickly. Electrical power outages in general are happening more and more frequently not only in the United States but across the world. Having a standby generator system in place can make power outages much less burdensome.
Today's modern digital economy runs on a clean, abundant, and reliable source of power. Issues related to quality and reliable supply of power is driving up demand for backup residential and commercial generators worldwide. Having a standby generator with an enclosure that is properly soundproofed provides a win-win situation for you and your neighbors.
Power outages trigger standby generator systems to automatically switch to generator power until local power is restored. Your backup power system, which typically runs on your home’s existing natural gas line or by diesel fuel, will start and switch power to your home within 10-20 seconds. In most cases, having a generator installed not only will pay for itself, but it will increase the value of your home by several thousand dollars. The excessive noise pollution caused by standby generators is usually an issue that is learned the hard way by generator owners.
So when you purchase your home standby generator, it's important not to forget about the controlling the noise it will make while running. Soundproofing your enclosure will give you the peace of mind that your neighbors won't be calling the authorities complaining about excessive noise coming from your generator at night. These complaints can lead to expensive fines and citations for violating noise ordinances.
Source: PR Web Press Release:
San Jose, CA (PRWEB) October 29, 2012 - Globally, the residential generators market is witnessing growth primarily due to an unprecedented increase in consumer demand for electricity in the residential sector. National grids in many countries worldwide are taking on increasing pressure due to growing electrification and urbanization. The result is the rise in the frequency and number of electricity grid failures leading to power outages. Such energy shortages are prevalent in more than 80 countries globally, indicative of the seriousness of the problem. The situation has been triggering demand for standby power and thereby for generators, both for commercial and residential usage. While power outages and changing lifestyles have their own place in the hierarchy of growth drivers, the growing affordability of generators is becoming a major factor pushing consumers towards purchasing generators. In the context, with continuous spell of falling prices, the affordability of standby generators has been a major factor driving overall sales in the segment through the past decade.
Technological developments with the promise of enhancing fuel efficiency and operation of gensets also go a long way in increasing sales. The residential Standby Generators market is expected to provide huge growth opportunities in future. Despite high growth in the recent past, the market is relatively unsaturated and is expected to witness rapid growth in future also. Environmental performance has of late become a major criterion for several consumers who are growing increasingly aware of the impact of their lifestyle on the environment. Present day generators are more environment-friendly due to the incorporation of technologies such as electronic governors, and automatic voltage regulation. Presently, few smart generators are even capable of being monitored through the Internet.
Energy generator systems such as electrical generators, including diesel generators, are poised to benefit from the escalation in demand for power, constant changes in the energy policies world over, and rapid technological developments in the power generation equipment sector. Developments in the environment for power generation and distribution are especially poised to spur demand for generators in general. Installation of new power generation plants and the routine replacement of energy generation equipment directly translates into additional demand for power generator sets. In developed markets like Europe, and North America, aging energy infrastructure will provide opportunities for equipment replacements, upgradations and modernization Also, given that the modern digital economy runs on a clean, abundant, and reliable source of power, issues related to quality and reliable supply of power will drive demand for backup generators. Unreliable and disruptive power slices away a whopping US$50 billion from the US economy alone each year and issues related to outages, brownouts, and blackouts will continue to create business opportunities for generators worldwide.
As stated by the new market research report on Residential Generators, Asia-Pacific represents the largest regional market worldwide, sustained by massive demand from evolving markets of China and India. The region is also poised to display the fastest compounded annual growth rate of 7.7% through 2018. The residential generators market in Asia evolved at a rapid pace over the last decade. Sustained and robust economic growth, rising household income, boom in real estate and huge infrastructure projects makes the region a promising manufacturing hub. The Indian power backup market is a fast growing and lucrative market primarily due to persistent power shortages in the country. In China, the demand for electricity in residential and commercial segments is rising in tandem with the growing economic activity. China presents tremendous opportunity for generation as well as consumption of electric power. The development of electric power industry in China is vital for the growth of the country’s economy, and is therefore expected to witness continued growth over the long-term.
Major players profiled in the report include Baldor Electric Company, Briggs & Stratton Power Products Group, Cummins, Inc., Eaton Corporation, Generac® Power Systems Inc., General Electric Company, Generators.ie, Honda Power Equipment, and Kohler Power System, among others.
The research report titled “Residential Generators: A Global Strategic Business Report” announced by Global Industry Analysts Inc., provides a comprehensive review of the residential generators markets, industry and product overview, key growth drivers, product introductions and innovations and profiles of major/niche global as well as regional market participants. The report provides annual sales estimates and projections for residential generators market for the years 2010 through 2018 in value terms (US$) for the following geographic markets – US, Europe, Asia-Pacific, and Rest of World. The report also analyzes the global residential generators market in terms of unit sales. The study presents a six-year (2004-2009) historic analysis for additional perspective.
For more details about this comprehensive market research report, please visit –
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Global Industry Analysts, Inc., (GIA) is a leading publisher of off-the-shelf market research. Founded in 1987, the company currently employs over 800 people worldwide. Annually, GIA publishes more than 1300 full-scale research reports and analyzes 40,000+ market and technology trends while monitoring more than 126,000 Companies worldwide. Serving over 9500 clients in 27 countries, GIA is recognized today, as one of the world's largest and reputed market research firms.
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Using sound absorbing viscoelastic polymer material on the inside walls of generator enclosures and surrounding your noisy generator with an acoustical soundproofing barrier will significantly quiet noise to legally acceptable and comfortable levels. Most generators are noisy and operate above acceptable community noise levels without soundproofing. They can disturb neighbors and passers-by and can disrupt normal activities going on in nearby homes and inside your business if not controlled.
Most cities and communities now have noise/nuisance ordinances and are increasingly levying fines upwards of $500 per offense if your generator is louder than 65/55 (daytime/nightime) decibels when measured "at the property boundary." In many areas, second offenses can range from $500 - $1,000 "per day" as every day counts as a separate violation. If you have a noisy generator at your home or business, the risk of getting these unpredictable fines outweighs the cost and time of installing proper sound abatement systems.
Normal everyday conversation generally occurs at approximately 60 decibels on a sound meter which is significantly less than the sound decibel levels that many generators put out. This can make even every day conversation more difficult if you are around a noisy generator. High levels of noise are also known to negatively impact productivity, moods and anxiety levels.
Reciprocating engine-powered generators, used to make electricity on a temporary basis, produce a good deal of noise and vibration. During a temporary loss of electrical power, generators help keep essential home appliances running, keep businesses operational, and provide electricity in places like the outdoors and in recreational vehicles.
Whether these generators run continuously as part of a primary power source or occasionally in standby circumstances during emergencies or special needs situations, their noise levels usually need to be reduced to comply with local, state and federal noise or nuisance laws and ordinances in place to address noises described as "excessive, unreasonable, or repetitive in terms of volume so as to disturb the peace, quiet and comfort, and be offensive to the reasonable person of normal auditory sensitivity residing in or occupying a residential area."
Basic Types of Generators
Typical Residential and Non-Residential Sounds Levels in Many Communities
In many communities in North America, Europe and even other parts of the world, themaximum allowable sound levels, “measured at the nearest receiving property line,” within a similar range of the following:
Residential receiving properties (mixed-use zones are considered residential)
• 65 dBA during daytime hours for
• 55 dBA during nighttime hours
Nonresidential receiving property
• 67 dBA during daytime hours
• 62 dBA during nighttime hours
Click here to read specifics about a common noise ordinance:
Sources of generator set noise
An engine-generator is the combination of an electrical generator and an engine mounted together to form a single piece of equipment. This combination is also called an engine-generator set or a “gen-set.” In many contexts, the engine is taken for granted and the combined unit is simply called a generator.
Like any motor, a generator motor creates a lot of heat and needs a cooling system to prevent overheating. Standby generators can be either air-cooled or liquid-cooled. The major difference is that air-cooled systems are louder and not quite as effective. Liquid cooled systems are quieter and more dependable – and also more expensive to purchase and to maintain.
The decibel (often listed as dba) rating on a generator, is a number that is given that explains the noise level generated by the engine running. Some noisy generators can reach sound levels ranging from 80-100-plus decibels, which at 100 plus decibels translates to the noise of a jack hammer at 10 meters (32.8 feet); 110 decibels is the noise equivalent of a plane taking off at a 10 meters; 115 decibels translates to a jet’s screeching whistle at 10 meters, and is also the threshold of noise-induced pain. Sustained noise levels above this can cause hearing damage in short a short amount of time. Sustained noise at 100 dB can cause long term health problems. A higher quality and less noisy generator is going to be in the 70’s decibel rating while a really good generator will be in the 60’s decibels range.
According to a Cummings White Paper by Senior Acoustics Specialist Dennis Aaberg, generator set (residential and commercial generators) noise is produced by six major sources:
• Engine noise – This is mainly caused by mechanical and combustion forces and typically ranges from 100 dB(A) to 121 dB(A), measured at one meter, depending on the size of the engine.
• Cooling fan noise – This results from the sound of air being moved at high speed across the engine and through the radiator. Its level ranges from 100 dB(A) to 105 (A) dB at one meter.
• Alternator noise – This is caused by cooling air and brush friction and ranges from approximately 80 dB(A) to 90 dB(A) at one meter.
• Induction noise – This is caused by fluctuations in current in the alternator windings that give rise to mechanical noise that ranges from 80 dB(A) to 90 dB(A) at one meter.
• Engine exhaust – Without an exhaust silencer, this ranges from 120 dB(A) to 130 dB(A) or more and is usually reduced by a minimum of 15 dB(A) with a standard silencer.
• Structural/mechanical noise – This is caused by mechanical vibration of various structural parts and components that is radiated as sound.
Noise from “portable” generators comes primarily from two sources, the engine block and the exhaust system. With an air cooled engine there is little you can do about blocking noise. Some engines can have a larger muffler attached or make other changes to the exhaust system. Merely mounting exhaust pipe vertically will noticeably reduce noise.
Reducing Noise “Inside” the Generator Enclosure
With the growth of standby, prime and peaking power installations in densely populated areas, it’s become important to focus attention on understanding how generator noise is propagated and controlled.
Typically, there are two main methods for controlling the airborne noise in a power generator:
• Blocking airborne noise via a weighted barrier
• Absorbing airborne noise via acoustical absorbing insulation.
Aaberg’s white paper expands on this claim. It recommends that standby generator enclosures incorporate the following types of materials for best results and often with cost and performance improvements as compared to more traditional solutions:
• Flexible non-lead barriers (like Acoustiblok) in weights ranging from 1/4" lbs./ft2 to 2 lbs./ft2
• Faced acoustical foams in thicknesses ranging from 1/4" to 2" and with numerous facings, including reflective and reinforced facings
• Decoupled barrier composites and barrier/absorber composites in a range of barrier weights, decoupler thicknesses and absorption layer thicknesses faced with numerous films
• Damping composites comprising a damping layer to manage structureborne vibration
• Combined with acoustical foam layers to absorb airborne noise.
Significant noise control can be achieved by lining the generator’s sheet metal enclosure with a weighted barrier, or a decoupled weighted barrier (composite of barrier over decoupling foam) to help block noise. Ideally, at least 90 percent of the enclosure should be lined. For optimal effect the enclosure openings must be minimized.
Absorption reduces airborne noise due to mechanical sound energy by converting it into low grade heat energy. As air is pushed into the absorbing material by the sound pressure wave, viscous forces dissipate the mechanical sound energy as heat.
Most power generation equipment requires several openings in the metal enclosure – for air intake, exhaust and heat release. These openings are generally detrimental to the performance of barriers and decoupled barriers as they can allow noise to escape unhindered. By incorporating acoustical absorbers as a lining for louvers or by creating a path for airflow, noise can be absorbed before it escapes the enclosure.
In recent years, a wide range of elastomer innovations, like Acoustiblok, have been created that can be utilized in designing next generation gen-set enclosures. These materials must meet multiple design objectives including noise frequencies, operating temperature range and operating environment including thermal management, contaminant resistance and maintenance considerations.
Reducing Noise “Outside” the Generator
In a residential setting, the simplest type of noise control for generators or other gas or propane-powered engines is a noise barrier placed around it. Outdoor sound curtains or sound curtain noise barrier walls are an effective method of reducing noise generated by equipment, pumps, generators or other processes that are outside and are exposed to the elements.
It is important to take into account the source height of the generator, which can be fairly high, and to consider the height of the receiver if the impacted site has multiple floors.To be effective, a barrier wall must at least block the line-of-sight from the source to the receiver.
Sound barriers will make a substantial difference in the noise exposure levels from generators if the proper materials are used. They can reduce the sound by about 12-15 decibels, which is significant because a 10 decibel decrease in sound results in half the sound heard to the human ear. The more distance between the generator and your house or building, the better. Not all materials will work. It is important to do your research.
There are other soundproofing product solutions such as sound panels. Some soundproofing companies, like Acoustiblok, Inc. manufacture all-weather sound panels that are different from other conventional acoustical sound panels. In addition to being able to stand up to the most extreme environments, they not only absorb virtually all sound but they also contain a layer of noise absorbing viscoelastic material which provides exceptional noise blockage.
The sound absorbency of the panels brings down substantially the acoustical energy around the generator and by eliminating all sound reflections in the area, while the viscoelastic material in the panel allows it to also be an excellent sound barrier.
With increasing focus on noise in our communities, it's important to take a proactive approach to solving your generator noise issues by using lab tested and proven acoustical soundproofing materials.
READ MORE: Related Information
Acoustiblok quiets generators and noisy motors
United States Noise Pollution and Abatement Act (Noise Control Act)