When do windows and doors in laboratories need to be kept closed?

In TRBA 100 “Protective measures for activities involving biological agents in laboratories”, a distinction must first be made between protection levels 1 and 2. In the Protection level 1: Windows and doors should be closed while working with biological agents (5.2.1 paragraph 5 TRBA 100), in the Protection level 2 means that windows and doors must be kept closed during activities involving biological substances (5.3 para. 10 TRBA 100). For protection level 2, this is specified again in the Biological Agents Ordinance (BioStoffV) itself, at least for the windows, in Annex II No. 20 (“Windows must be closed during the activity"). But what are the reasons why windows and doors should/must be closed during activities involving biological substances?

In biological materials laboratories, work is carried out with biological materials (microorganisms, cell cultures, and endoparasites, including their genetically modified forms and agents associated with transmissible spongiform encephalopathy) that can endanger humans through infections, infection-related acute or chronic diseases, toxin formation, or sensitizing effects. Closed windows during activities with biological materials help to keep these materials safe in the laboratory and to prevent their release into neighboring workrooms or the surrounding area. Furthermore, biological material laboratories are often equipped with special ventilation systems and/or microbiological safety cabinets (MSW). Open windows and doors, especially when opened simultaneously, can disrupt air filtration or the airflow of the MSW, increasing the risk of contamination of employees. In addition, closed windows and doors also prevent Unauthorized persons can get into the laboratory.

The BioStoffV not only regulates measures to protect the safety and health of employees from hazards arising from these activities, but also regulates measures to protect

1. Employees in work areas in which they may be endangered by activities (according to Section 2 Paragraph 7 of the BioStoffV) without carrying out these activities themselves, and
2. other persons, insofar as they may be endangered due to the use of biological substances by employees or by entrepreneurs without employees (Section 1 (1) of the BioStoffV).

Overall, closed windows and doors contribute to the security and Health protection in the laboratory and the surrounding area and that the risk of contamination and accidents is minimized.