Laboratory Products Focus
having the best reputation since it conducts strict inspections not only on the equipment, but also on the traceability of the production process.
As regards isolators, in Europe there is no standard to regulate their design and production, so that each manufacturer applies the quality and control systems it deems most suitable, meaning that their use for laboratory purposes is highly incipient and requires the user to have a high level of experience and only to deal with companies that have proven technical skills in this field.
Protection of the user, product, environment and maintenance personnel:
When the product to be handled inside the equipment is a hazardous chemical substance, such as, for example, cytostatic and cytotoxic drugs (substances that are cancerous or carcinogenic, mutagenic or toxic for reproduction), it is important to protect the operator as well as the service and maintenance personnel responsible for changing the filters of the equipment when required.
In these occasions, it is advisable to use a Class II Biological Safety Cabinet with a third filter stage under the work surface or a negative pressure isolator, also with its corresponding filter stage under the work surface. The two devices have negative pressure and laminar flow inside the work chamber. The only difference is that, while the cabinet sets up a protective barrier for the user by means of the air intake flow, the isolator places a physical glass barrier between the user and the sample. The two systems, according to best practices for laboratory work and equipment handling, are equally efficient and effective for protecting the user against the toxicity of the handled samples, and it is up to the user to select the type of device required for everyday work. It is important to consider that the user's ergonomics, access to the working material and cleaning are always much more limited in an isolator than in a biological safety cabinet, given the simple fact that the user has less mobility. It should also be stressed, as mentioned previously, that class II biological safety cabinets are regulated by a clearly defined European standard, while isolators are not.
isolators. If only one type of sample will be handled in the cabinet, laminar or turbulent flow can be selected.
Preference for a certified system
Class II Biological Safety Cabinet with third filtering stage for handling cytostatics
Biological safety cabinets are regulated by European Standard EN-12469. This standard describes the materials to be used to manufacture a cabinet, its design and production, as well as its requirements in terms of tightness, cleaning capacity or sterilisation capacity. It also describes the tests to be performed on the cabinets, from type testing to production, installation and maintenance tests (for example, assessment of the front opening latch, tightness of the casing, testing the filters after installation, speed of the laminar flow, extraction rate, luminosity, noise level). If, in addition, the cabinet is independently certified by a prestigious entity such as TÜV or LNE, this guarantees the quality and safety of the equipment. In the USA, standard NSF 49 has been in force since 1976.
At this respect to mention that only a third part well reported certification can guarantee the compliance of the standard.
European standard EN 12469 defines the following classification for biological safety cabinets:
Laboratory isolator with third filtering stage for handling cytostatics
How many samples will be handled simultaneously?
If the user of the device intends to handle several samples or products simultaneously, it is important to choose a device operating with sterile laminar flow, to minimise the risk of cross-contamination between samples. In these cases it is advisable to use class II biological safety cabinets or
For the isolators, there is no European standard to govern their design, production and methods for testing their key values, so that if the user requires certified equipment, an isolator is a more complex option which requires specific validation protocols approved at least by the user, the manufacturer and the body approving the laboratory.
It must be taken in account that EN- 12469 standards not only certifies compliance. Aditionally, certification companies as TÜV provides not only testing but treacability.
Table 2: The main characteristics of each cabinet class are defined in European standard EN 12469.
CLASS I II III
Front intake speed to protect the user
> 0.7 – 1.0 m/s ≥ 0.4 m/s
≥ 0.7 m/s with one glove outside
Vertical laminar flow speed to protect the product
Not applicable > 0.25 m/s – 0.50 m/s Not applicable
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