Research project interference factors: Movement in the laboratory

Movement in the laboratory

Movement in the laboratory

Dynamic interference and its impact

Research project interference factors: Movement in the laboratory


Research for a safer laboratory:

Safety cabinets (SC) are for many biotechnological and pharmaceutical laboratories a very importance protective device, to ensure the safe handling of hazardous substances or dangerous biological agents. The protective functions in the way of personnel, product and cross-contamination protection make up the most important properties of this safety cabinet. 

Experimental setupThese protection functions are tested to the currently valid standards using the microbiological test method - in an empty laboratory. Any impact which personnel may have while working in the laboratory are therefore not taken into account.
However, a person generates unwanted air currents with a every movement and so easily becomes an "interference factor" to laboratory safety.

As part of a multi-annual research project, Berner International has tested the impact of these "movements" on the protective functions of safety cabinets.  

The following movements can generate a disturbance in the laboratory:

- The person in front of the safety cabinet

- Movements near the aperture

- A moving person in front of the safety cabinet  (e.g. the assistant handing cytotoxic preparations to the user)

- Opening and closing of doors near safety cabinets





As shown in the animation, a moving person generates various air currents.
This generates a negative pressure behind their back, which leads to an increased air current  in this area (as shown in yellow).






To test the effect which movements have on the safety of a laboratory, safety cabinets from different manufacturers were set to their individual operating points in accordance with their specifications respect of laminar and air inflow velocities.

Dynamic interference factorsAs in larger laboratories with several safety cabinets the air flow velocities of the safety cabinets are often reduced to save energy, or to lower the noise levels. The air currents of inflow and downflow were then reduced further, leading up to the complete loss of protection. In this way, the very different ways of reduction, depending on the type of safety cabinet was obvidentcould be demonstrated.

In case of the interference factor "human", the greatest negative impact on the protective functions of an SC are the "arm movements in the workspace opening of the SC" and the "moving person in front of the SC".

 Results and consequences:

1. The air currents of safety cabinets must only be reduced within the performance limits of the SC.  For the relevant data from the manufacturer is to be obtained.

2. Fast arm movments (especially pumping movements) in front of the work space opening should be avoided.

3. During the "critical phase" of drug preparation (during which actual hazardous substances may be released) there should be no further staff ( eg. someone handing vials) present in the vicinity of the safety cabinet.

4. On light of these findings, the requirements on the testing of the protection functions of  safety cabinets in accordance with DIN EN 12469, needs to be re-examined.