Glossar

Acoustics

  • Impact noise level
  • The impact noise level L is that noise, which arises in a room when it is tapped with a standardized tapping machine in a room adjacent the ceiling or stairs.
  • Sound level difference D
  • The sound level difference D is the difference between the sound level L1 in the source room and the sound level L2 the receiving room D = L1 - L2 (in dB).
  • Sound power level
  • Sound energy per second, which emits a noise source, It is most commonly given as a sound power level, which is based on an output of 0.000 000 000 001 watts. The sound power level corresponding to the measured sound pressure level at 28 cm distance a in all directions evenly radiating point-shaped sound source.
  • sound-sound pressure level.
  • Sound - Sound pressure level Subsonic refers to mechanical vibrations in an elastic medium. For the physics of sound is a disturbance of the air pressure (p), which spreads like a water wave. When sound is air pressure fluctuations that can be measured by means of a microphone in Pascal (Pa). Audible the range of 0.00002 Pa (threshold of hearing) to 100 Pa (pain threshold). Since this series of numbers are very unwieldy, using a logarithmic scale, the decibel (dB). 0 dB corresponds to the threshold of hearing, 140 dB of pain threshold. The sound level L (in dB) is a measure of the energy or sound intensity contained in the sound. Due to the logarithmic measurement system an increase of the sound level by 10 dB represents an increase on the 10 times the sound pressure. A doubling of the sound intensity increased the level by 3 dB. Two equally loud noise sources causing thus an increase of 3 dB SPL than just one of them. So the sum of two noises with 0 dB is a noise with 3 dB (0dB + 0dB = 3 dB). Only a level change of 10 dB is perceived by the human ear as a doubling of the volume. However, this represents an increase as the traffic by 90% - that is, 50 cars are as twice as loud perceived as 5 cars. Doubling the distance from a source which is small compared to the distance, resulting in a gain reduction by 6 dB.
  • Sound insulated –value R
  • Sound reduction index R The sound reduction index R results from a test and measurement is used for the identification of sound insulation of a component. R is frequency-dependent and is calculated from the sound level difference D in consideration of the surface S of the separating member and the absorption area A in the receiving room. “Rw“ designates the quality of a component perpendicular to its propagation direction.
  • Sound insulated ventilator
  • Ventilation unit for effective reduction of external noise sources which particular by strong traffic noise (road traffic, rail traffic, air traffic, industrial noise, neighborhood noise etc.) are caused. In particular, sound absorbing are designed as outer wall passage or air vent for free assembly on outside walls or in combination with windows for decentralized use as wall fan with a preferred arrangement In addition to the demand- supply of fresh air in loaded insulation objects such as residential buildings, office and administration buildings etc. the sound insulated ventilator also regulates the EnEV (German energy efficiency law/norm) hygienic air exchange and thus receives , sustained by preventing excessive humidity , at the same time the building structure .
  • Acoustic absorption
  • When a sound wave on a soft, deformable or porous body meets and is wholly or partially absorbed, we speak of sound absorption. In relation to a space is created by e.g. . The loss of sound energy in the reflection at the boundary surfaces of a room or to the objects or persons in a room. The loss arises while primarily by converting sound into heat. Where the sound partly in neighboring rooms or (z. B. through open doors) to the outside (transmission), it will be lost for the room
  • Resultant sound reduction Rw, res
  • The resultant sound reduction index Rw , res is obtained (consisting of n partial areas) when a component of the resultant sound reduction activity’s Ri of the individual sub-areas .
  • Reverberation time
  • The reverberation time is the most important for the acoustics measured variable. It is defined as the time within which the acoustic energy has fallen in a room after the switching off of the sound production by 60dB
  • Middle sound isolation value Rm
  • The median reduction value Rm is the arithmetic mean of the sound insulation measurements over a frequency range of 100 - 3150 Hz at (16 thirds) . Within this frequency range the human ear is most sensitive, and the volume proportion of common-mode noise on the wall back is greatest.
  • Airborne sound insulation
  • The airborne sound insulation describes sound insulation between rooms. The sound insulation is calculated by combining Multiple sound pressure level and reverb time measurements. The investigated frequency range is typically from 50 Hz to 5 kHz. The measured airborne sound insulation is frequency-dependent and can be converted into a single number sound reduction index to characterize the acoustic performance.
  • Airborne noise
  • Airborne noise consists of the progressive movement of mass particles (vibrations) and is transmitted in the form of sound waves at the speed of sound (340m/s). The differing frequencies (the number of changes in pressure per second) generate characteristic tones. For example, whistling has a high frequency, compared to the low frequency generated by a growl of distant thunder. Frequencies are measured in Hertz (Hz). The audible range of a healthy young person extends from approx. 20 Hz to approx. 20 kHz (20,000 Hz).
  • Noise-effects
  • The physical reactions to noise below 85 dB (A) love for temporary action in the field of human adaptability. Regular noise exposure can reduce the social, emotional or physical well-being, lead to illness or even hearing loss. A distinction is made : - Harassment (for example, communication disorders) - Health (hearing loss , stress related illnesses , insomnia) As health impairing the noise impact research looks at continuous loads from 60 to 65 dB (A). With noise levels from 40 dB (A), the sleep stages can change. The refreshing atmosphere of sleep is perceived by most people already from 25 to 30 dB (A) when be disturbed. Stress-related diseases, particularly cardiovascular disease occurred in studies of the effect of road traffic noise on a day averaging levels 65-70 dB (A) increased to. Hearing damage can (according to UBA.) occur in: - Individual sound events> 135 dB (eg explosion) - High sound pressure levels> 120 dB for a few minutes - Prolonged noise levels 85-89 dB
  • Noise
  • Noise is a variety of sound. It means any unwanted sound. Sounds, particularly loud ones that disturb people or make it difficult to hear wanted sounds, are noise. For example, conversations of other people may be called noise by people not involved in any of them; any unwanted sound such as domesticated dogs barking, neighbor’s playing loud music, portable mechanical saws, road traffic sounds, or a distant aircraft in quiet countryside, is called noise. Acoustic noise can be anything from quiet but annoying to loud and harmful. At one extreme users of public transport sometimes complain about the faint and tinny sounds emanating from the headphones or earbuds of somebody listening to a portable audio player; at the other the sound of very loud music, a jet engine at close quarters, etc. can cause irreversible hearing damage. At intermediate levels there are a range of deleterious health effects from noise.
  • Structure-borne noise
  • Structure-borne noise is transmitted through solid structures, such as steel, wood, concrete, stone etc. This includes for example impact sound and part of the noise generated by the technical machinery installed in a building. The unit of measurement for describing sound is the decibel ("dB").
  • Pollution limits
  • In the current defined rules as specified rating levels peak level in bedrooms, in the neighborhood, at work, etc. The rules include TA sound , VDI 2058 page 1 , UVV VBG 121 noise and implementing.
  • Frequency
  • Frequency is the number of complete cycles per second in alternating current direction. The standard unit of frequency is the hertz, abbreviated Hz. If a current completes one cycle per second, then the frequency is 1 Hz; 60 cycles per second equals 60 Hz (the standard alternating-current utility frequency in some countries). Larger units of frequency include the kilohertz (kHz) representing thousands (1,000's) of cycles per second, the megahertz (MHz) representing millions (1,000,000's) of cycles per second, and the gigahertz (GHz) representing billions (1,000,000,000's) of cycles per second.
  • Aircraft noise
  • The currently valid “Aircraft Noise Act” from 1971 has until energy equivalent continues sound of 67 dB (A) limitations of building use to be accepted. These values are significantly outdated perceptions of the noise impact research. The Federal Environment Agency has proposed in a study on aircraft noise effects following noise exposure areas that should be considered when new or extensions : For aircraft noise levels of 55 dB (A) at daytime and 45 dB (A) at night the limit is reached to considerable harassment. For aircraft noise levels of 60 dB (A) at daytime and 50 dB (A) at night are to be feared from preventive medical point of view health impairments. For aircraft noise levels above 65 dB (A) at daytime and 55 dB (A ) at night time health problems in the form of cardiovascular diseases can be expected.
  • Continuous sound level
  • With a continuous sound is dying average sound exposure in a place defined. In strong fluctuating volumes (e.g. road or air traffic) a so-called averaging levels or energy equivalent continuous noise Leq) taken as time average level for assessing noise .
  • Evaluated sound level Rw
  • Denotes a single number, the sound insulation of components. To assess the sound insulation, the frequency-dependent reference curve for the sound reduction index by as much as dB upwards (better) or down (worse) is shifted. The higher the sound reduction index Rw, the better the sound insulation of the component (window, wall, etc.).
  • Evaluated norm sound difference; Dn,w
  • If a single number for the identification of sound insulation of components , in which a reference to a test surface S (ceiling or wall) would not be possible or fraught with errors , for example, when transferring between not lying directly adjacent rooms (diagonal transmission) or at too small measuring surface. The evaluation of the normalized level difference Dn is analogous to evaluate the sound reduction index R. The weighted standard – value norm acoustics is a common process variable for the evaluation of sound absorbing ventilators.
  • Sound rating level
  • The sound rating level is related to certain periods, corrected averaging level. It is used mostly for comparison with exposure values . An evaluation of the noise is very difficult, because noise is assessed individually very different. A loud rock concert with about 120 dB is considered by one pleasant and the other as a highly disturbing. Rail noise is often less bothersome than aircraft noise. If numerous people interviewed, the responses are similar to the noise of a distribution around a mean value. The sound rating level (Lr) is a measure of the noise exposure with correction factors for influences that are particularly troublesome. In the calculation of the continuous sound level, surcharges for information content, time of day and situations included.
  • Acoustics
  • Acoustics is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound.
  • Equivalent sound absorption area A
  • Acoustics is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound.
  • A-evaluated noise level
  • A-evaluating is only really valid for relatively quiet sounds and for pure tones as it is based on the 40-phon Fletcher–Munson curves which represented an early determination of the equal-loudness contour for human hearing.

Glass architecture

  • U-value
  • The U-value is the unit of measurement for determining the heat loss of a component. The U - value indicates the amount of heat passing through 1m2 of a component at a temperature difference of 1 Kelvin per unit time. The lower the U-value of an element of a building's fabric, the more slowly heat is able to transmit through it, and so the better it performs as an insulator.
  • LT-value
  • The light transmission of a glazing is the percentage of solar radiation in the range of visible light, which is transmitted from the outside to inwards. The LT- value is dependent on the glass thickness and the composition of the glass batch as well as of possible coatings. The higher the LT value the more light penetrates into the room.
  • g-value
  • The g value indicates how much of the total incident solar radiation passes through the glazing into the room. The higher the value, the more solar heat you feel in the room. Typically g-values will range between 0.2 and 0.7, with solar control glazing having a g-value of less than 0.5.

Humidity problems

  • Health threat due to mildew
  • The mildew damages or caused not only the buildings, it has also extremely high health risk. The spores of the fungi are among the most important indoor allergens and may trigger a wide variety of allergic reactions allergic skin irritations and flu-like symptoms of severe fatigue and dizziness to can cause asthma. In Germany alone, there are about 4 million mildew allergies. A sensible humidity control is important in order to avoid mildew . As a solution, in particular lends itself to the use of fans with an automatic humidity control.
  • Structural damage from mildew
  • How much water can be absorbing the air, depends on its thermal temperature: Thermal (warm) air can hold more water than colder. The colder air cannot absorb as much water and there is condensate formation occurs at high relative air humidity, cooling the warm room air, for example, on cooler places on the wall, the degree of saturation decreases. These moist places provide ideal living conditions for the mildew. For prevention of moisture damage (mildew problem at wall) a controlled supply of fresh and dry outside air and discharge the spent and moist air is necessary. With the fully sealed construction envelope often combines a problem: Could the humid air, whose attack has not changed over time, looking at older and fully sealed construction buildings their way out, so skip this way with sealed buildings. Simultaneously, the building must be planned so that the necessary for the purpose of health and heating minimum air exchange is ensured, i.e. is performed sufficiently fresh air into the building. Also for the construction physics necessary air exchange rate of 0.5 h-1 window have changed their central role today. By thermal insulation measures as required by the “Energy Saving Ordinance” by using “high quality materials” and expert workmanship and by minimizing unwanted leakage values of the outer walls controlled, permanent ventilation is becoming increasingly important for the construction hygiene. The DIN 1946, as another known quantity in this context, deems an exchange of air 20-30 m3 per hour and person when necessary.

Technical construction terms

  • Window lintel
  • The upper horizontal boundary/zoning of a door or window framing is called fall.
  • Windows- / door reveal
  • As the reveal is defined as the inner, vertical cross-sectional area of window or door apertures at the masonry. Usually windows- / door reveal are plastered; The corners are usually reinforced by corner angle. In ventilated facades, the reveal may be made in accordance with the facade cladding also made of aluminum, natural stone or other material panels.
  • Knee wall
  • Knee wall is the walled up from the ceiling plane in the area of the eaves wall, on which rests the roof structure. The higher the knee wall (Flap tile), the more floor space under the sloping ceilings are available. In Germany was jamb wall on the long side runs often unflustered in wood.
  • Jamb wall
  • Jamb wall is the room space between the outer knee wall. Usually is (usually solid) and the inner jamb wall (usually plasterboard) referred. This space cannot be used for residential purposes, it offers the ideal storage space or for accommodating supply technical components (e.g. laying of pipes)

Ventilation

  • Energy saving with air conditioning
  • There are many factors that determine the heating energy requirements of a house - from the thermal insulation of the walls to the quality of the heating system up to the individual consumer behavior. In older buildings it often leads to unpleasant drafts leaky windows to a subjective overestimation of air exchange proportion of the total heat losses. For non- renovated (old buildings) buildings that were built up in the early seventies, go 65-80 % of the heat (transmission) by airtight components such as walls, roofs, glass etc. lost (!). Only 20 - 35 % of the heating needs at the expense of ventilation.
  • Thight sealed building construction
  • In today's low-energy and passive houses used commercially reasonable thermal insulation measures are carried out. These homes are so well insulated that the ventilation heat requirement accounts for up to two thirds of the total heat loss. In order to provide reliable protection against moisture damage, the controlled ventilation is standard on low-energy houses an indispensable concept of this design. Thus the physical building space and hygienic minimum air exchange rates can be secured and the ventilation heat losses are suppressed with the use of ventilation systems with heat recovery to a third of total energy consumption.