Your Home Naturally,cool

Keeping cool indoors when it is hot outdoors is a problem. The sun beating down on your home causes indoor temperatures to rise to uncomfortable levels. Air conditioning provides some relief. But the initial costs of installing an air conditioner and the electricity costs to run it can be high.

In addition, conventional air conditioners use refrigerants made of chlorine compounds, suspected contributors to the depletion of the ozone layer and global warming. But there are alternatives to air conditioning. This article provides some common sense suggestions and low-cost retrofit options to help you "keep your cool" and save electricity.

Staying Cool

An alternative way to maintain a cool house or reduce air conditioning use is natural (or passive) cooling. Passive cooling uses non-mechanical methods to maintain a comfortable indoor temperature.

The most effective method to cool your home is to keep the heat from building up in the first place. The primary source of heat buildup (i.e., gain) is sunlight absorbed by your house through the roof, walls, and windows. Secondary sources are heat-generating appliances in the home and air leakage. Specific methods to prevent heat gain include reflecting heat (i.e., sunlight) away from your house, blocking the heat, removing built-up heat, and reducing or eliminating heat generating sources in your home.

Reflecting Heat Away

Dull, dark-colored home exteriors absorb 70% to 90% of the radiant energy form the sun that strikes the home's surfaces. Some of this absorbed energy is then transferred into your home by way of conduction, resulting in heat gain. In contrast, light-colored surfaces effectively reflect most of the heat away from your home. The most effective method to cool your home is to keep the heat from building up in the first place.

Installing a radiant barrier

Radiant barriers are easy to install. It does not matter which way the shiny surface faces - up or down. But you must install it on the underside of your roof - not horizontally over the ceiling. and the barrier must face an airspace.

For your own comfort while in the attic, install the radiant barrier on a cool, cloudy day. Use plywood walk boards or wooden planks over the ceiling joists for support. Caution: Do not step between the ceiling joists, or you may fall through the ceiling. Staple the foil to the bottom or side of the rafters, draping it from rafter to rafter. Do not worry about a tight fit or small tears in the fabric; radiant transfer is not affected by air movement. The staples should be no more than 2 to 3 inches (5 to 8 centimeters) apart to prevent air circulation from loosening or detaching the radiant barrier. Use a caulking gun to apply a thin bead of construction adhesive to the rafters along the seams of the foil barrier. This will make the installation permanent.

Roofs

About a third of the unwanted heat that builds up in your home comes in through the roof. This is hard to control with traditional roofing materials. For example, unlike most light colored surfaces, even white asphalt and fiberglass shingles absorb 70% of the solar radiation. One good solution is to apply a reflective coating to your existing roof. Two standard roofing coatings are available at your local hardware store or lumberyard. They have both waterproof and reflective properties and are marketed primarily for mobile homes and recreational vehicles. One coating is white latex that you can apply over many common roofing materials, such as asphalt and fiberglass shingles, tar paper, and metal. most manufacturers offer a 5-year warranty.

A second coating is asphalt based and contains glass fibers and aluminum particles. You can apply it to most metal and asphalt roofs. Because it has a tacky surface, it attracts dust, which reduces its reflective somewhat. Another way to reflect heat is to install a radiant barrier on the underside of your roof. A radiant barrier is simply a sheet of aluminum foil with a paper backing. When installed correctly, a radiant barrier can reduce heat gains through your ceiling by about 25%.  Radiant-barrier materials cost between $0.13 per square foot ($1.44 per square meter) for a single-layer product with a kraft-paper backing and $0.30 per square foot ($3.33 per square meter) for a vented multiflora product with a fiber- reinforced backing. The latter product doubles as insulation.

Walls

Wall color is not as important as roof color, but does affect heat gain somewhat. white exterior walls absorb less heat than dark walls. and light, bright walls increase the longevity of siding, particularly on the east, west, and south sides of the house.

Windows

Roughly 40% of the unwanted heat that builds up in your home comes in through windows. Reflective window coatings are one way to reflect heat away from your home. These coatings are plastic sheets treated with dyes or thin layers of metal. Besides keeping your house cooler, these reflective coatings cut glare and reduce fading of furniture, draperies, and carpeting. Two main types of coatings include sun-control films and combination films. Sun-control films are best for warmer climates because they can reflect as much as 80% of the incoming sunlight. Many of these films are tinted, however, and tend to reduce light transmission as much as they reduce heat, thereby darkening the room. Combination films allow some light into a room but they also let some heat in and prevent interior heat from escaping. These films are best for climates that have both hot and cold seasons. Investigate the different film options carefully to select the film that best meets your needs. Note: do not place reflective coatings on south-facing windows if you want to take advantage of heat gain during the winter. The coatings are applied to the interior surface of the window.

Although you can apply the films yourself, it is a good idea to have a professional install the coatings, particularly if you have several large windows. This will ensure a more durable installation and a more aesthetically pleasing look.

Landscaping is a natural and beautiful way to shade your home and block the sun.

Blocking the Heat

Two excellent methods to block heat are insulation and shading. Insulation helps keep your home comfortable and saves money on mechanical cooling systems such as air conditioners and electric fans. Shading devices block the sun's rays and absorb or reflect the solar heat.

Insulation

Weatherization measures - such as insulating, weather stripping, and caulking - help seal and protect your house against the summer heat in addition to keeping out the winter cold. For more information on weatherizing your home, see our weather stripping article The attic is a good place to start insulating because it is a major source of heat gain. Adequately insulating the attic protects the upper floors of a house. Recommended attic insulation levels depend on where you live and the type of heating system you use. for most climates, you want a minimum of R-30. In climates with extremely cold winters, you may want as much as R-49. again, check the DOE fact sheet insulation on how to determine the ideal level of insulation for your climate.

Wall insulation is not as important for cooling as attic insulation because outdoor temperatures are not as hot as attic temperatures. also, floor insulation has little or no effect on cooling.

Although unintentional infiltration of out-side air is not a major contributor to inside temperature, it is still a good idea to keep it out. Outside air can infiltrate your home around poorly sealed doors, windows, electrical outlets, and through openings in foundations and exterior walls. Thorough caulking and weather stripping will control most of these air leaks.

Shading

Shading your home can reduce indoor temperatures by as much as 20 degrees F (11 degrees C).

 

Landscaping

Landscaping is a natural and beautiful way to shade your home and block the sun. A well-placed tree, bush, or vine can deliver effective shade and add to the aesthetic value of your property. When designing your landscaping, use plants native to your area that survive with minimal care. Trees that lose their leaves in the fall (i.e., deciduous) help cut cooling energy costs the most. when selectively placed around a house, they provide excellent protection from the summer sun and permit winter sunlight to reach and warm your house. The height, growth rate, branch spread, and shape are all factors to consider in choosing a tree.

Vines are a quick way to provide shading and cooling. grown on trellises, vines can shade windows or the whole side of a house. Ask your local nursery which vine is best suited to your climate and needs. Besides providing shade, trees and vines create a cool microclimate that dramatically reduces the temperature (by as much as (9øf []5øc]) in the surrounding area. During photosynthesis, large amounts of water vapor escape through the leaves, cooling the passing air. and the generally dark and coarse leaves absorb solar radiation. You might also consider low ground cover such as grass, small plants, and bushes.a grass-covered lawn is usually 10øf (6øc) cooler than bare ground in the summer. If you are in an arid or semiarid climate, consider native ground covers that require little water. For more information on landscaping, see the erec fact sheet landscaping for energy efficiency

Planning Your Planting

Placement of vegetation is important when landscaping your home. The following are suggestions to help you gain the most from vegetation:

• Plant trees on the northeast-southeast and the northwest southwest sides of your house. Unless you live in a climate where it is hot year-round, do not plant trees directly to the south. Even the bare branches of mature deciduous trees can significantly reduce the amount of sun reaching your house in the winter.
  
  
• Plant trees and shrubs so they can direct breezes. Do not place a dense line of evergreen trees where they will block the flow of cool air around or through them. * Set trellises away from your house to allow air to circulate and keep the vines from attaching to your house's facade and damaging its exterior. Placing vegetation too close to your house can trap heat and make the air around your house even warmer. * Do not plant trees or large bushes where their roots can damage septic tanks, sewer lines, underground wires, or your house's foundation. * Make sure the plants you choose can withstand local weather extremes.

Shading Devices

Both exterior and interior shades control heat gain. Exterior shades are generally more effective than interior shades because they block sunlight before it enters windows. When deciding which devices to use and where to use them, consider whether you are willing to open and close them daily or just put them up for the hottest season. You also want to know how they will affect ventilation. Exterior shading devices include awnings, lovers, shutters, rolling shutters and shades, and solar screens. Awnings are very effective because the block direct sunlight. They are usually made of fabric or metal and are attached above the window and extend down and out.

A properly installed awning can reduce heat gain up to 65% on southern windows and 77% on eastern windows. A light-colored awning does double duty by also reflecting sunlight. Maintaining a gap between the top of the awning and the side of the house helps vent accumulated heat from under a solid- surface awning. If you live in a climate with cold winters, you will want to remove awnings for winter storage, or by retractable ones, to take advantage of winter heat gain.

Roughly 40% of the unwanted heat that builds up in your home comes in through windows. The amount of drop (how far down the awing comes) depends on which side of your house the window is on. An east or west window needs a drop of 65% to 75% of the window height. A south-facing window only needs a drop of 45% to 60% for the same amount of shade. A pleasing angle to the eye for mounting and awning is 45ø. Make sure the awning does not project into the path of foot traffic unless it is at least 6 feet 8 inches (2 meters) from the ground. One disadvantage of awnings is that they can block views, particularly on the east and west sides. However, slatted awnings do allow limited viewing through the top parts of windows.

Louvers are attractive because their adjustable slats control the level of sunlight slats control the level of sunlight entering your home and, depending on the design, can be adjusted from inside or outside your house. The slats can be vertical or horizontal. Louvers remain fixed and are attached to the exteriors of window frames.

Shutters are movable wooden or metal covering that, when closed, keep sunlight out. Shutters are either solid or slatted with fixed or adjustable slats. Besides reducing heat gain, they can provide privacy and security. Some shutters help insulate windows when it is cold outside. Rolling shutters have a series of horizontal slats that run down along a track. Rolling shades use a fabric. these are the most expensive shading options, but the work well and can provide security. many exterior rolling shutters or shades can be conveniently controlled from the inside. One disadvantage is that when fully extended, the block all light.
Solar screens resemble standard window screens except they keep direct sunlight from entering the window, cut glare, and block light without blocking the view or elimination air flow. They also provide privacy by restricting the view of the interior from outside your house. Solar screens come in a variety of colors and screening materials to compliment any home. Although do-it-yourself kits are available, these screens will not last as long as professionally built screens.

Although interior shading is not as effective as exterior shading, it is worthwhile if none of the previously mentioned techniques are possible. There are several ways to block the sun's heat from inside your house.

Draperies and curtains made of tightly woven, light-colored, opaque fabrics reflect more of the sun's rays than they let through. The tighter the curtain is against the wall around the window, the better it will prevent heat gain. Two layers of draperies improve the effectiveness of the draperies' insulation when it is either hot or cold outside. Venetian blinds, although not as effective as draperies, can be adjusted to let in some light and air while reflecting the sun's heat. Some newer blinds are coated with reflective finishes. To be effective, the reflective surfaces must face the outdoors. Some interior cellular (honeycombed) shades also come with reflective mylar coatings. But they block natural light and restrict air flow. Opaque roller shades are effective when fully drawn but also block light and restrict air flow. Ventilated attics are about 30 degrees F (18 degrees C) cooler than unventilated attics.

Removing Built-Up Heat

Nothing feels better on a hot day than a cool breeze. Encouraging cool air to enter your house forces warm air out, keeping your house comfortably cool. However, this strategy only works when the inside temperature is higher than the outside temperature. Natural ventilation maintains indoor temperatures close to outdoor temperatures close to outdoor temperatures and helps remove heat from your home. But only ventilated during the coolest parts of the day or night, and seal off your house from the hot sun and air during the hottest parts of the day.

The climate you live in determines the best ventilation strategy. In areas with cool nights and very hot days, let the night air in to cool your house. A well-insulated house will gain only 1 degree F (0.6 degree C). By the time the interior heats up, and the outside air should be cooler and can be allowed indoors. In climates with day time breezes, open windows on the side from where the breeze is coming and on the opposite side of the house. Keep interior doors open to encourage whole house ventilation. If your location lacks consistent breezes, create them by opening the windows at the lowest and highest points in your house. This natural "thermosiphoning," or "chimney," effect can be taken a step further by adding a clerestory or a vented skylight.

In hot, humid climates where temperature swings between day and night are mall, ventilate when humidity is not excessive. Ventilating your attic greatly reduces the amount of accumulated heat, which eventually works its way into the main part of your house. Ventilated attics are about 30 degrees F (18 degrees C) cooler than unventilated attics. Properly sized and placed louvers and roof vents help prevent moisture buildup and overheating in your attic.

Often-overlooked sources of interior heat gain are lights and household appliances, such as ovens, dishwashers, and dryers. Because most of the energy that incandescent lamps use is given off as heat, use them only when necessary. Take advantage of daylight to illuminate your house. and consider switching to compact fluorescent lamps. These use about 75% less energy than incandescent lamps, and emit 90% less heat for the same amount of light.

New, energy efficient appliances generate less heat and use less energy. Many household appliances generate a lot of heat. When possible, use them in the morning or late evening when you can better tolerate the extra heat. Consider cooking on an outside barbecue grill or use a microwave oven, which does not generate as much heat and uses less energy than a gas or electric range.

Washers, dryers, dishwashers, and water heaters also generate large amounts of heat and humidity. To gain the most benefit, seal off your laundry room and water heater from the rest of the house. New, energy efficient appliances generate less heat and use less energy. When it is time to purchase new appliances, make sure the are energy efficient.

All refrigerators, dishwashers, and dryers display an energy guide label indicating the annual estimated cost for operating the appliance or a standardized energy efficiency ratio. Compare appliances and buy the most efficient models for your needs.
Using any or all of these strategies will help keep you cool. even if you use air conditioning, many of these strategies, may not be enough. sometimes you need to supplement natural cooling with mechanical devices. fans and evaporative coolers can supplement your cooling strategies and cost less to install and run than air conditioners.

Ceiling fans make you feel cooler. their effect is equivalent to lowering the air temperature by about 4 degrees F (2 degrees C). Evaporative coolers use about one-fourth the energy of conventional air conditioners. Many utility companies offer rebates and other cost incentives when you purchase or install energy saving products, such as insulation and energy efficient lighting and appliances. Contact your local utility company to see what it offers in the way of incentives.

Ventilation

Indoor Air Quality and Ventilation

Indoor Air Quality (IAQ) is an increasingly important issue in the work environment. The study of indoor air quality and pollutant levels within office environments is a complex problem. The complexity of studying and measuring the quality of office environments arises from various factors including:

• Office building floor plans are frequently changing to accommodate increasingly more employees and reorganization.
• Office buildings frequently undergo building renovations such as installation of new carpet, modular office partitions and free-standing offices, and painting.
• Many of the apparent health symptoms are vague and common to both the office and home environment.
• Guidelines or standards for permissible personal exposure limits to pollutants within office buildings are very limited.

Many times odors are associated with chemical contaminants from inside or outside the office space, or from the building fabric. This is particularly noticeable following building renovation or installation of new carpeting. Out-gassing from such things as paints, adhesives, sealants, office furniture, carpeting, and vinyl wall coverings is the source of a variety of irritant compounds. In most cases, these chemical contaminants can be measured at levels above ambient (normal background) but far below any existing occupational evaluation criteria.

NIOSH has conducted hundreds of building studies which indicate that the most likely sources of this problem are - poor ventilation, poor thermal conditions, too high or low humidity, emissions from office machines, copiers and other building contaminants and poor ergonomic layout of workstations.

Overview of Ventilation Design

Relative Humidity	Winter Temperature Range	Summer Temperature Range
30%	68.5 - 76.0 F	74.0 - 80.0 F
40%	68.5 - 75.5 F	73.5 - 79.5 F
50%	68.5 - 74.5 F	73.0 - 79.0 F
60%	68.0 - 74.0 F	72.5 - 78.0 F
Note: Relative humidity above 50% is not recommended because it can promote mold growth.

Indoor Air Pollution

An inadequately ventilated office environment or a poorly designed ventilation system can lead to the build up of a variety of indoor air pollutants. Air pollutants can originate within the building or be drawn in from outdoors. Examples of sources that originate outside a building include:

• pollen, dust and fungal spores
• general vehicle exhaust
• odors from dumpsters
• re-entrained exhaust from the building itself or from neighboring buildings

Examples of sources that originate from within the building include:

• building components and furnishings
• smoking
• maintenance or remodeling activities (painting, etc.)
• housekeeping activities
• unsanitary conditions (standing water from clogged drains or dry traps) and water damage
• emissions from office equipment or special use areas (print shops, laboratories, or food preparation areas)

Controls to Prevent Indoor Air Pollution

The following recommendations and guidelines are useful in preventing indoor air quality problems:

• HVAC systems should receive periodic cleaning and filters should be changed on a regular basis on all ventilation systems.
• The ventilation system should introduce an adequate supply of fresh outside air into the office and capture and vent point air pollutant sources to the outside.
• Office machinery should be operated in well-ventilated areas. Most office machinery does not require local exhaust ventilation in areas that are already provided with 7-10 air changes per hour. Photocopiers should be placed away from workstations. Workers should vary work tasks to avoid using machines excessively.
• Office equipment should be cleaned/maintained according to the manufacturer's recommendations. Properly maintained equipment will not generate unhealthy levels of pollutants.
• Special attention should be given to operations that may generate air contaminants (such as painting, pesticide spraying, and heavy cleaning). Provisions for adequate ventilation must be made during these operations or other procedures, such as performing work off-hours or removing employees from the immediate area, utilized.

Evaluation

Monoblock centrifugal pump

Monoblock centrifugal pumps are widely used in a variety of applications. In many applications the role of monoblock centrifugal pump is critical and condition monitoring is essential. Vibration based continuous monitoring and analysis using machine learning approaches are gaining momentum. Particularly artificial neural networks, fuzzy logic were employed for continuous monitoring and fault diagnosis. This paper presents the use of C4.5 decision tree algorithm for fault diagnosis through statistical feature extracted from vibration signals of good and faulty conditions.

New evidence mechanical factors

New evidence identifies mechanical factors that limit human running speeds

Jamaican sprinter Usain Bolt's record-setting performances have unleashed a wave of interest in the ultimate limits to human running speed. A new study published in the Journal of Applied Physiology offers intriguing insights into the biology and perhaps even the future of human running speed.

The newly published evidence identifies the critical variable imposing the biological limit to running speed, and offers an enticing view of how the biological limits might be pushed back beyond the nearly 28 miles per hour speeds achieved by Bolt to speeds of perhaps 35 or even 40 miles per hour.

The new paper, "The biological limits to running speed are imposed from the ground up," was authored by Peter Weyand of Southern Methodist University; Rosalind Sandell and Danille Prime, both formerly of Rice University; and Matthew Bundle of the University of Wyoming.

"The prevailing view that speed is limited by the force with which the limbs can strike the running surface is an eminently reasonable one," said Weyand, associate professor of applied physiology and biomechanics at SMU in Dallas.

"If one considers that elite sprinters can apply peak forces of 800 to 1,000 pounds with a single limb during each sprinting step, it's easy to believe that runners are probably operating at or near the force limits of their muscles and limbs," he said. "However, our new data clearly show that this is not the case. Despite how large the running forces can be, we found that the limbs are capable of applying much greater ground forces than those present during top-speed forward running."

In contrast to a force limit, what the researchers found was that the critical biological limit is imposed by time -- specifically, the very brief periods of time available to apply force to the ground while sprinting. In elite sprinters, foot-ground contact times are less than one-tenth of one second, and peak ground forces occur within less than one-twentieth of one second of the first instant of foot-ground contact.

The researchers took advantage of several experimental tools to arrive at the new conclusions. They used a high-speed treadmill capable of attaining speeds greater than 40 miles per hour and of acquiring precise measurements of the forces applied to the surface with each footfall. They also had subjects' perform at high speeds in different gaits. In addition to completing traditional top-speed forward running tests, subjects hopped on one leg and ran backward to their fastest possible speeds on the treadmill.

The unconventional tests were strategically selected to test the prevailing beliefs about mechanical factors that limit human running speeds -- specifically, the idea that the speed limit is imposed by how forcefully a runner's limbs can strike the ground.

However, the researchers found that the ground forces applied while hopping on one leg at top speed exceeded those applied during top-speed forward running by 30 percent or more, and that the forces generated by the active muscles within the limb were roughly 1.5 to 2 times greater in the one-legged hopping gait.

The time limit conclusion was supported by the agreement of the minimum foot-ground contact times observed during top-speed backward and forward running. Although top backward vs. forward speeds were substantially slower, as expected, the minimum periods of foot-ground contact at top backward and forward speeds were essentially identical.

According to Matthew Bundle, an assistant professor of biomechanics at the University of Wyoming, "The very close agreement in the briefest periods of foot-ground contact at top speed in these two very different gaits points to a biological limit on how quickly the active muscle fibers can generate the forces necessary to get the runner back up off the ground during each step."

The researchers said the new work shows that running speed limits are set by the contractile speed limits of the muscle fibers themselves, with fiber contractile speeds setting the limit on how quickly the runner's limb can apply force to the running surface.

"Our simple projections indicate that muscle contractile speeds that would allow for maximal or near-maximal forces would permit running speeds of 35 to 40 miles per hour and conceivably faster," Bundle said.

Mechanical Engineers Are More Focused on Sustainable Design

The first annual sustainable design-trend watch survey jointly commissioned by the American Society Mechanical Engineers and autodesk  found that two-thirds of respondents have worked on designing sustainable products.

The survey of ASME members is the first research conducted to understand the factors and impacts of sustainable design on mechanical engineers and their manufacturing businesses in industries including automotive and transportation, industrial machinery, consumer products and energy. Sustainable engineering refers to the design and manufacture of a volume of goods and services while using Earth’s resources more efficiently and producing less waste.

A key trend highlighted by the survey is that more than half of the practicing engineers responding reported they expect to increase their use of sustainable design practices in the next year. Primary design concerns focused on using less energy, reducing emissions and complying with environmental and regulatory standards. Additionally, a separate survey of ASME student members found that half of the respondents have encountered sustainable design practices in their studies and are extremely interested in green and sustainable information and causes.

“Engineers have to understand the impact of their decisions on built and natural systems,” says ASME Executive Director Thomas G. Loughlin. “They must be skillful at collaborating closely with colleagues in an increasingly interdisciplinary work environment to meet efficiency and resources goals impacting our only Earth.”

The results of the survey confirm that designing with sustainability in mind is now a primary aim of mechanical engineers, says Robert “Buzz” Kross, senior vice president, manufacturing industry goup at Autodesk.

Mechanical Engineering Priorities Trending Toward Renewable Materials
 

Along with creating designs that use less energy, reduce emissions and comply with regulatory standards, respondents also indicated that design priorities include using renewable, recyclable and recycled materials, reducing material waste in manufacturing and improving manufacturing processes to use fewer resources.

However, cost is a major consideration when deciding to factor sustainability into developing a new product, according to the survey. One-third of the professional engineer respondents indicated that they would consider sustainable technologies for new products only if they are cost-competitive.

 

Survey Methodology and Demographics
 

The online survey of 50,000 ASME professionals and 18,000 ASME student members was conducted over a two-week period in December. The questionnaire covered 16 questions and generated nearly 3,500 respondents in the U.S. Approximately 60% of the practicing engineers responding to the survey have careers spanning more than 20 years, with more than 25% focusing on the design and development of products, systems or equipment. Nearly 20% of the respondents work in the energy and power industry, and more than 10%, respectively, work in professional services and in manufacturing fields.

Mechanical ventilation.

Basic concepts in mechanical ventilation.

Mechanical ventilatory support is a major component of the clinical management of critically ill patients admitted into intensive care. Closely linked with the developments within critical care medicine, the use of ventilatory support has been increasing since the polio epidemics in the 1950s (Lassen 1953). Initially used to provide controlled mandatory ventilation, today with advances in technology, most mechanical ventilators are triggered by the patient, increasing the awareness of the complexity of patient/ventilator interaction (Tobin 1994). Though ventilator appearance and design may have changed quite significantly and the variety of options for support extensive, the basic concepts of mechanical ventilatory support of the critically ill patient remains unchanged. This paper aims to outline these concepts so as to gain a better understanding of mechanical ventilatory support.

Muscular Tension and Body Posture in Relation to Voice Handicap and Voice Quality in Teachers with Persistent Voice Complaints

Muscular Tension and Body Posture in Relation to Voice Handicap and Voice Quality in Teachers with Persistent Voice Complaints

 

The aim of this study was to investigate the relationship between extrinsic laryngeal muscular hypertonicity and deviant body posture on the one hand and voice handicap and voice quality on the other hand in teachers with persistent voice complaints and a history of voice-related absenteeism. The study group consisted of 25 female teachers. A voice therapist assessed extrinsic laryngeal muscular tension and a physical therapist assessed body posture. The assessed parameters were clustered in categories. The parameters in the different categories represent the same function. Further a tension/posture index was created, which is the summation of the different parameters. The different parameters and the index were related to the Voice Handicap Index (VHI) and the Dysphonia Severity Index (DSI). The scores of the VHI and the individual parameters differ significantly except for the posterior weight bearing and tension of the sternocleidomastoid muscle. There was also a significant difference between the individual parameters and the DSI, except for tension of the cricothyroid muscle and posterior weight bearing. The score of the tension/posture index correlates significantly with both the VHI and the DSI. In a linear regression analysis, the combination of hypertonicity of the sternocleidomastoid, the geniohyoid muscles and posterior weight bearing is the most important predictor for a high voice handicap. The combination of hypertonicity of the geniohyoid muscle, posterior weight bearing, high position of the hyoid bone, hypertonicity of the cricothyroid muscle and anteroposition of the head is the most important predictor for a low DSI score. The results of this study show the higher the score of the index, the higher the score of the voice handicap and the worse the voice quality is. Moreover, the results are indicative for the importance of assessment of muscular tension and body posture in the diagnosis of voice disorders.