Preliminary Note

Abstact from VDI 3781 part 4 from July 2017


This standard serves to determine the minimum height of the outlets of exhaust gas discharge sys-tems that are used to discharge emissions from combustion systems, from installations that release organic solvents (e.g. installations not requiring a permit within the scope of 31. BImSchV (31st German Federal Immission Control Ordinance)) and from other pollutant-emitting installations.

From an air pollution control perspective, there is no difference in principle between the discharge condi-tions for exhaust gas from small and medium com-bustion systems in accordance with 1. BImSchV, for vapours of organic solvents from installations re-quiring a permit in accordance with 4. BImSchV under conditions of low emission mass flows, and for installations not requiring a permit. The provi-sions of VDI 2280 have, therefore, been incorpo-rated in VDI 3781 Part 4.

The minimum height determined in accordance with this standard meets the requirements for un-disturbed removal of exhaust gas with the free airflow and for adequate dilution of the exhaust gas, in order to prevent harmful environmental effects that are avoidable with the best available techniques, and minimise those that are unavoida-ble (cf. BImSchG (German Federal Immission Control Act)).

This standard does not apply to the chimneys of the following heating appliances:

  • gas appliances 1) with a nominal heat output up to 400 kW, operated with gases from the public gas grid or liquid gas
  • condensing oil boilers with a nominal heat out-put up to 400 kW, using oil type EL low-sul-phur in accordance with DIN 51603-1
  • forced-draught oil boilers with a nominal heat output up to 70 kW, using oil type EL low-sul-phur in accordance with DIN 51603-1

Reference: VDI / Source, Beuth / Guideline

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