Introduction
This document is intended to give some information about the differences between some standards for biological safety cabinets, from an European perspective. The most commonly referenced standards for biological safety cabinets are the European EN 12469, the American NSF 49 and the GMP guidelines[1]. However, there are significant differences between the standards on i.e. the following subjects
- Inflow velocity
- Downflow velocity
- Classes of cabinets
- Number of particles allowed
Differences
Type of cabinets
Biological safety cabinets according the European EN 12469 are classified in three classes:
- Class I are cabinets with one opening at the front and provide personnel and environmental protection but no product protection.
- Class II are cabinets with one opening at the front and provide personnel and environmental protection and also product protection.
- Class III cabinets have a fully closed working area (i.e. like glove boxes) and operators are separated by a physical barrier.
The class II cabinet can have either 2 or 3 HEPA filters.
Additionally, the NSF 49 has more detailed types for the class II cabinets: A1, A2, B1, B2 and C1
Inflow and downflow velocities
For Europe almost all cabinets which are type tested will still have an inflow and downflow corresponding with the informative annex from the EN 12469:2000. However, in 2026 a new version of the EN 12.469 will be release where the inflow and downflow are now longer specified in the standard but have to correspond with the type test results as stated in the manual.
EN 12.469 annex H (till 2025):
| Class | Mean inflow velocity | Mean downflow velocity |
| I | ≥0.70 m/s – 1,0 m/s | N.A. |
| II | ≥0.4 m/s | 0,25 m/s – 0,50 m/s |
| III | ≥0.70 m/s with one glove off | N.A |
As a result of this most class II cabinets in Europe still have a type teste with an inflow of 0,45 – 0.50 m/s and a downflow of 0.28 -0.32m/s
NSF 49
The NSF 49 is has similar values for the inflow and downflow with exception of the Class II A1
| Class | Mean inflow velocity | Mean downflow velocity |
| A1 | 75 ft/min (0.38m/s) | 50 to 80 ft/min (0.25 – 0.40m/s) |
| A2 | 100 ft/min (0.51m/s) | 50 to 80 ft/min (0.25 – 0.40m/s) |
| B1 | 100 ft/min (0.51m/s) | 50 to 80 ft/min (0.25 – 0.40m/s) |
| B2 | 100 ft/min (0.51m/s) | 50 to 80 ft/min (0.25 – 0.40m/s) |
| C1 | 100 ft/min (0.51m/s) | 50 to 80 ft/min (0.25 – 0.40m/s) |
* A2 class cabinets are typically comparable to modern day EN 12.469 class II cabinets
GMP Annex A
The GMP does not specify specific values for biological safety cabinets, but uses classes for cleanroom classification. Typically a biological safety cabinet is expected to be a Grade A class. This Grade A has the following guidelines on velocities:
| Class | Mean inflow velocity | Mean downflow velocity |
| Grade A zone | 0.45 m/s ± 20% | 0.36 – 0.54 m/s |
The minimum downflow velocity is in this guideline considerably higher than the minimum requirement in both the EN 12469 and NSF 49. Given the common downflow values used for the type test in Europe this then means that most BSC’s do not have a type test according the GMP specifications.
If these higher downflow velocities are required the performance should be covered by a corresponding type test. It should never be assumed that non-verified (i.e. not type tested) values are given the same performance as the design values or original used type test values.
Particles
For the number of particles there are multiple standards referring to the number of particles in cleanrooms. For example
- ISO 14644-1
- US FED STD 209E
- BS 5295
- GMP Annex A
In Europe the ISO 14664-1 and GMP Annex A are the most relevant ones. Typically BSC’s correspond with ISO Class 5 or GMP Grade A.
According to Annex A of the GMP guideline for Grade A zones, particle monitoring should be undertaken for the full duration of critical processing, including equipment assembly, expect where justified by contaminants in the process that would damage the particle counter of present a hazard, e.g. live organisms and radiological hazard. The Grade A zone should be monitored in such a frequency and with suitable sample size that all interventions, transient events and any system deterioration would be captured and alarms triggered if alert limits are exceeded (pp.3-4)
Summary / GMP specifications
Most biological safety cabinets sold on the European market are specified by the manufacturer to fulfil the requirements given in the EN 12469. It is advisable to have this is demonstrated by a certificate from an independent recognized party such as for example the TüV Nord or any equivalent party.
But when the BSC shall comply with the GMP guidelines it has to be verified if the following applies:
- Type test certificate available for the requested velocities
- 51 m/s +/- 20% inflow
- 36 – 0.54m/s downflow)
- Test port available for continuous particle count monitoring
- Alarm status monitoring (also for exhaust when applicable)
[1] Biological safety cabinets for cytostatic and other CMR substances are not covered. Mainly because there is no European standard for these type of products. Most European parties refer to a German National standard for cytostatic work.
