Clean rooms
| Clean rooms and laboratories for industrial, scientific, pharmaceutical and electronics manufacturing applications. Clean rooms, laboratories and pharmaceutical/electronic manufacturing facilities frequently use cascade ventilation systems to maintain a sterile environment. |
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Pressure stabilisers are used to maintain a typical 15 Pascal differential between rooms. (For Cat 3 and Cat 4 laboratories higher differential pressures are normal.) For clean rooms and manufacturing facilities it is possible to work on the "10% rule". In positive pressure rooms the supply volume is worked out to provide the necessary air change rate, taking account of heat loads etc. Subtracting any door leakage and constant equipment extract from this figure gives the nett outflow, i.e. the amount of air to be removed from the room.
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It has been found from practical experimentation that 10% of this can be passed through pressure stabilisers to the next room and the balance extracted thus obviating the need for very large transfer volumes between rooms. In the case of large clean rooms with high supply rates it is possible to reduce the transfer to as little as 5% of the nett outflow. |
A similar scenario applies in negative pressure areas but in reverse. The Aercon ® Division of Power Utilities Group has assisted with the design and supplied the pressure control equipment for many clean rooms conforming to BS 5295 and meeting Medicines Inspectorate, Home Office and FDA requirements. We can also work to US FS 209E standard for FDA approved facilities, the EU GMP standard and ISO 14644-1.
Suitable equipment.
The Aercon ® LF range of Pressure stabilisers in standard, fire rated and smoke rated forms are suitable for these applications and can be provided with carbon steel bodies with white polyester coated finish or in Grades 304 or 316 stainless steel. 50LF variants are suitable for use with thin partitioning systems of 50 - 79mm thickness and for door mounting, while 80LF units can be used in 80 - 99mm partitioning sytems.
The premium range Type W Air Pressure Control Valves are also ideal for pharmaceutical applications.
The standard heavy duty polyester/epoxy coated carbon steel bodies offer excellent chemical resistance and Type W valves are also available in all Grade 304 or 316 stainless steel. All Type W valves can be removed from their wall sleeves for cleaning purposes without the need for tools.
Design and application service.
A free computer aided design and application service is available for clean room applications. |
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To take advantage of this, please forward a floor plan, indicating either by fax, or by e-mail (in a recognised CAD format, e.g .DXF or .DWG) and we will be delighted to provide a set of calculations showing where every litre of air comes from and goes to and how it gets there.
Comparison of Clean room standards and Air change rates.
Clean Room classification.
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Room
Classifications |
Class |
|
ISO 14644-1 |
Class 3 |
Class 4 |
Class 5 |
Class 6 |
Class 7 |
Class 8 |
|
US FS 209E |
1 |
10 |
100 |
1,000 |
10,000 |
100,000 |
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EU GMP |
- |
- |
A/B |
- |
C |
D |
|
BS 5295 |
C |
D |
E/F |
G/H |
J |
K |
Airflow and air change rates
|
Standard
ISO/US FS 209D |
Average Air Flow Velocity |
Air changes / hour |
|
3 (Class 1) |
0.305 - 0.457 m/s (60 - 90 ft/min) |
360 - 540 |
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4 (Class 10) |
0.254 - 0.457 m/s (50 - 90 ft/min) |
300 - 540 |
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5 (Class 100) |
0.203 - 0.406 m/s (40 - 80 ft/min) |
240 - 480 |
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6 (Class 1,000) |
0.127 - 0.203 m/s (25 - 40 ft/min) |
150 - 240 |
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7 (Class 10,000) |
0.051 - 0.076 m/s (10 - 15 ft/min) |
60 - 90 |
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8 (Class 100,000) |
0.005 - 0.041 m/s (1 - 8 ft/min) |
5 - 48 |
Typical applications
|
US FS 209E |
US FS 209D |
BS
5295 |
GMP |
Applications |
|
M 1.5 |
1 |
C |
- |
Electronics manufacture
(no people allowed) |
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M 2.5 |
- |
D |
- |
Electronics manufacture |
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M 3.5
|
100
|
E/F
|
A/B
|
Medicines and fluids
packing. Microbiological control rooms.
Protective disinfected
clothing worn |
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M 4.5 |
1000 |
G/H |
- |
Pharmaceuticals |
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M 5.5 |
10,000 |
I |
C |
Operating theatres, electronics production. |
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M 6.5 |
100,000 |
- |
D |
Tabletting |
GMP
(Good Manufacturing Practice) (January 1997) is used by EU member countries.
BS 5295
1989 The British Standard for clean rooms.
ISO 14644
1999/ISO 14644 : 2000 International Standard. US Federal Standard 209E
1992 - America's current FDA approved clean room standard.
US Federal Standard 209D 1988 was replaced by Edition E in 1992.The terms Class 100,000, 10,000, 1,000, 100, 10, & 1 refer to the maximum number of airborne particles per cubic foot equal to or larger than 0.5 microns in diameter based primarily on the average of all samples taken.