Limit value (technology)

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Limit ( English critical limit ) is in the technology and in the legal system of a unit specified reading a technical size , which must not be exceeded or its reaching a state change triggers.

General

Limit values ​​are intended in particular to serve health protection and occupational safety . The legal term “limit value” is often used in laws , but none of these laws offer a legal definition ; Nor is it an originally legal term. In terms of environmental law, limit values ​​are precisely defined concentrations of pollutants which must not be exceeded or which, if exceeded, result in predefined consequences. Measurement results within the limit values are to be tolerated and accepted. Limit values ​​therefore mark the boundary between harmful and non-harmful environmental risks; they represent a justifiable limit risk . In measurement , control and regulation technology the limit value is the value of the input variable of a limit signal element at which the binary output signal changes in the limit signal element.

Definition

The definition of limit values ​​is based on the findings of Paracelsus , for whom all things were poison and the dose alone determines whether a thing is not poison. This means that the intensity of biological effects is determined by the level and duration of exposure , but below this dose no effects are to be expected. This “ineffective” or at least harmless dose is the limit value.

species

The individual areas of law contain a large number of limit values. These include:

Biological limit value

The biological limit value is specified in accordance with Section 2 (9) GefStoffV for the concentration of a substance , its metabolite or a stress indicator in the biological material of an employee . The limit value concept contained in the GefStoffV knows not only the workplace limit value but also the maximum workplace concentration . According to Section 2 (8) GefStoffV, the occupational exposure limit value is the limit value for the time-weighted average concentration of a substance in the air at the workplace in relation to a given reference period.

Immission control law

From the pollution control laws are emission standards , the emission limit value and the exposure limit value known. The immission limit value is a value that limits the immission and is legally binding . Significant are the impairments caused by vapors , pressure , vibrations , gases , noises , smells , noise , smoke , soot , rays or heat that have spread into the ground , the air or the water ( Section 3 UmweltHG ). The noise protection is particularly emphasized by the national noise protection ordinances. They provide for the limit values ​​measured in the auxiliary unit of measurement decibel (A) (dBA) for commercial areas , mixed areas and residential areas . The limit value of the room volume in purely residential areas ( § 3 BauNVO ) is a sound pressure level of 50 dB (A) during the day and 35 dB (A) during the night , measured in the "reception room".

Nuclear power plants

Essential process variables such as coolant pressure , cooling temperature or reactor output are continuously monitored in nuclear power plants by safety systems that intervene as soon as these variables deviate significantly from their normal values ​​and exceed predetermined limit values.

Air pollution control

The legal basis for air pollution control are the international agreements and EU directives implemented in German law . The first limit values ​​for air pollution control were found in the Directive 80/779 / EEC for sulfur dioxide and airborne dust , which has since been repealed , Directive 82/884 / EEC for lead , Directive 85/203 / EEC for nitrogen dioxide , and Directive 88/436 / EEC for exhaust gases (see also exhaust gas standard ) or Directive 92/72 / EEC for ozone . Directive 2000/69 / EC for benzene and carbon monoxide , Directive 2001/81 / EC for other air pollutants , Directive 2008/50 / EC on air quality and clean air for Europe or Directive 2004/107 / EC on , among others, are still valid Arsenic , cadmium , mercury , nickel and polycyclic aromatic hydrocarbons in the air.

Radiation protection

In radiation protection , the dose limit is a limit value, expressed in millisieverts per calendar year , for the maximum permissible exposure to ionizing radiation . According to Section 78 of the Radiation Protection Act (StrlSchG), the limit for the effective dose for occupationally exposed persons is 20 millisieverts per calendar year. If the limit value has been exceeded in the calendar year in violation of this, continued employment as an occupationally exposed person is only permitted in accordance with Section 73 of the Radiation Protection Ordinance if the person responsible for radiation protection ensures that the exposure in the following four calendar years is limited, taking into account the limit value exceeded, so that the The sum of the doses does not exceed five times the respective limit value.

Drinking water

In drinking water samples of 100 ml may enterococci not be present, inter alia, may chloroform the limit of 0.05 mg / l and chlorite 0.0005 mg / l not exceed, potassium 12 mg / l Nitrate 50 mg / l and sodium 200 mg / l. These and other limit values ​​can be found in Annexes 1 to 3 and 5 of the Drinking Water Ordinance .

example

With the two-position controller , when the limit value is reached, an automatic switching process takes place, which triggers a process that is supposed to bring the controlled variable back into the desired range.

Demarcation

A guide value differs from a limit value in that it should be adhered to ( target regulation ), while the limit value must be adhered to ( mandatory regulation ). A target value indicates a maximum value that can usually be achieved at a certain point in time. Like guide values, target values ​​are not binding.

Individual evidence

  1. ^ Klaus Hüttermann, Functions of Limit Values ​​in Environmental Law and Delimitation of the Term , 1993, p. 9 ff.
  2. ↑ Renate Mayntz, Decision-Making Processes in the Development of Environmental Standards , in: Die Verwaltung, 1990, p. 140
  3. ↑ Jan Seidel, Grenzwerte im Bodenenschutz , 2009, p. 42
  4. ↑ Markus Wagner (Ed.) Lexicon / Glossary: ​​Basics, Terms, Vocabulary Electronics , Volume 10, 2012, o. P.
  5. ↑ Helmut Greim, Grenzwert , in: Franz-Josef Dreyhaupt (Ed.), VDI-Lexikon Umwelttechnik , 1994, p. 587 f.
  6. ^ VDI-Gesellschaft Bautechnik (ed.) / Hans-Gustav Olshausen, VDI-Lexikon Bauingenieurwesen , 1997, p. 359
  7. ↑ Heimward Alheit / Hans Heiß, neighbor law from AZ , 1993, p. 209
  8. ↑ Ralph Gill, Grenzwert , in: Helmut Schaefer (Ed.), VDI-Lexikon Energietechnik, 1994, p. 659
  9. ^ VDI-Gesellschaft Bautechnik (ed.) / Hans-Gustav Olshausen, VDI-Lexikon Bauingenieurwesen , 1997, p. 359
  10. ↑ Marcus Schiltenwolf / Markus Schwarz, Lexikon - Assessment in Medicine , 2013, p. 141
  11. ↑ Rolf Seyfarth / Klaus Joachim Soiné, Kleines Lexikon zur Trinkwasserbeschacity , 2000, p. 32
  12. ↑ Rolf Seyfarth / Klaus Joachim Soiné, Small Lexicon on Drinking Water Quality , 2000, p. 16 f.
  13. ↑ Rolf Seyfarth / Klaus Joachim Soiné, Small Lexicon of Drinking Water Quality , 2000, p. 47
  14. ^ Alfred Böge, Vieweg Lexikon Technik , 1997, p. 174
  15. ↑ Rolf Seyfarth / Klaus Joachim Soiné, Small Lexicon on Drinking Water Quality , 2000, p. 78