22.214.171.124 Ventilation systems
Laboratories must be equipped with technical facilities that ensure adequate ventilation at all times. It must be possible to heat incoming air if necessary and introduce it without causing a draft. Exhaust air may be routed entirely or partially via fume hoods, provided they are still able to operate at full capacity. An air exchange of 25 m³/h per m² of laboratory floor area may be reduced or natural ventilation may be used if the hazard assessment indicates that this is an adequate and effective solution in the long term for the work to be performed. In laboratories with an air exchange below the normally required 25 m³/h per m², work involving hazards such as flammable liquids or other hazardous materials that are volatile, generate dust or form aerosols must be kept to an absolute minimum unless other types of additional protective measures are taken. Such restrictions on use for laboratories are to be documented and the proprietor is to inform all those in positions of responsibility, including those who subsequently assume such positions. Laboratories with air exchange levels below the required value during working hours are to be marked at the entrance with “Achtung: Reduzierter Luftwechsel” [Warning: Reduced air exchange]. In specific cases, the hazard assessment may also indicate that a higher air exchange level is required. It must be ensured that exhaust air containing dangerous quantities or concentrations of hazardous materials cannot get back into work areas. Doors must be kept closed in order to maintain proper ventilation and it must be ensured that they are not left standing open.
All ventilation plans and layouts must fulfi l the requirements listed in the standard VDI 2051 “Air-conditioning – Laboratories” (VDI Ventilation Code of Practice) of the Association of German Engineers (VDI) and the German standard DIN 1946-7 “Ventilation and air conditioning – Part 7: Ventilation systems in laboratories”.
Incoming and outgoing air must be routed so as to take in the entire laboratory area. Designing or installing the system incorrectly may result in “short-circuits” in the flow of air that miss out parts of the laboratory. Unless specified otherwise in the hazard assessment, the quantity of introduced air must reach at least 25 m³/(m²h) (related to the main usable floor space, or, as specified in the new standard, usable floor space); given a ceiling height of 3 m, this is approximately equivalent to an eightfold exchange of air. For fume hoods, see also DIN EN 14175 “Fume cupboards” and Section 6.3.1. Regular maintenance and cleaning of the ventilation system prevents the development of hygiene issues through microbial contamination. If it is concluded in the hazard assessment that these measures are sufficient and effective for the designated activities in the long term, the quantity of air exchanged may be reduced, for example, or natural ventilation may be used. However, this is not advisable if changes in use cannot be reliably foreseen (for example in research laboratories).
For further details on ventilation, see also the DGUV Information 213-857 “Laborabzüge – Bauarten und sicherer Betrieb”.