Man comes across gases practically in its every environment – starting with home installations up to technical gases used in industry. The atmosphere man breathes comprises approximately 21% O2, 78% N2, and what is left includes additives. They might be of natural or artificial origin. In some particular cases, the level of the pollutants might reach so high to become a hazard for living organisms. Therefore, the necessity to use appliances detecting and measuring the above-mentioned substances occurs.

Division of volatile substances:

  • gases – gases in normal conditions,
  • opary – vapours – vapoured part of liquid substances,
  • mists,
  • dusts

For our use, gases can be also classified as follows:

  • flammable gases – we take measurements due to fire fighting reasons
  • toxic gases – we take measurement due to Health and Safety reasons (poisoning or oxygen displacement)
  • measurements due to technological reasons

An extract from the most important definitions regarded with geometry:

  • explosion hazard area: An area within which a gaseous explosive atmosphere might be created (potential hazard).
  • gaseous explosive atmosphere: A mixture of flammable substances as gas, vapour or mist with the air in atmosphere conditions in which , after ignition, burning process spreads around entire not burned mixture.
  • lower explosion limit (DGW): Volume concentration of flammable gas or vapour in the air, below which a gaseous explosive atmosphere might be created.
  • upper explosion limit (GGW):  Volume concentration of flammable gas or vapour in the air, above which a gaseous explosive atmosphere might be created.
  • temperature of self-ignition for gaseous explosive atmosphere: The lowest temperature of heated surface, when with specified conditions according to IEC 79-4, an ignition of flammable substance as gas, vapour or mist with the air may occur.
  • type of fire fighting construction: Defined preventive measures employed in electrical devices in order to prevent ignition of surrounding gaseous explosive atmosphere.
  • the highest allowable concentration (NDS): Approximate weighted value of concentration and its influence on a worker within 8-hours, typical week of work defined in the Labour Code should not affect it labour activity nor its health or his future generations’ health.
  • the highest allowable concentration of the moment (NDSCh): Approximate concentration value which does not influence worker’s health if present in the working area not longer than 15 minutes and not more often than 2 time a shift with minimum 1-hour intervals.
  • point highest allowable concentration (NDSP): The value of the concentration which due to its thread to worker’s health may not be exceeded in the work environment at any times.

The performance of projects usually start with design through delivery, assembly, start-up to post-warranty service.