MCC - Qualifications

Qualifications

Qualifications


QUALIFICATIONS OF HORIZONTAL OR VERTICAL LAMINAR AIRFLOW CABINETS

Controls enable us to know the particulate class in the enclosure, validate the particle efficiency of the supply filter, measure the supply airflow and velocity, and to verify the laminarity of the flow.

I) REFERENCE GUIDELINES :

  • U.S FEDERAL STANDARD 209EEN 1822-1: NF
  • IN 1822-1 (classification index: X 44.014.1) = very high-efficiency Air filters and air filters with very low(weak) penetration (HEPA and ULPA) - Left 1: Classification, tries(essays) of performance and marking.
  • IN 14 644: classification(ranking) of the cleanliness of the air, the measures, the tries(essays) and the methods.
  • RECOMMENDATIONS ASPEC // RULES(RULERS) OF CERTIFICATION AFNOR(FRENCH NATIONAL ORGANIZATION FOR STANDARDIZATION) // NF MARK - PSM .

II) Description of the various flows

1) Horizontal Laminar Flow

Unidirectional horizontal flow which only protects the experiment. The operator can perform experiments inside the post under sterile air flow. The air blown through the absolute filter is pre-filtered to protect it.

2) Vertical Laminar Flow

Unidirectional vertical laminar flow which only protects the experiment. The operator can perform experiments inside the post under sterile air flow.

There are technical differences between these types:

(1) Total recycling: Absence of extraction and air blown through the absolute filter comes from resumption before the worktop.
(2) Pressure / total flow: the air blown through the absolute filter is pre-filtered (similar to horizontal flow).The air flows and drains into the front opening and/or on the back of the worktop.

III) METHODS

1) Measurement of airflow rate: Supply speed

Supply air velocity through HEPA filters is measured using a hot wire anemometer. The individual speed values are measured according to the mapping (see diagram below): at the level of the work area (level of the protective glass) and 10 cm from the HEPA filters grid. A velocity map is established to verify the laminarity of the air flow: values must not deviate by more than 20% from the mean value.

Example for a PSM of 1.20 m wide:
L = width of the interior volume
l = depth of the interior volume
n = number of points on the width
N = number of points on the depth

The ideal speed of supply of the absolute filters is 0.45 m/s. In all cases, the speed must be between 0.35 to 0.55 m/s.
The supply flow is calculated based on the size of the absolute filter.

Materials used: TESTO 425 / / 0560 4251 / / No. 02311980/202
TESTO 425 / / 0560 4251 / / NO. 02322474/202
DEGREE C - HACH / / AVS1012D2D205M / / NO. 1205-1056361-005

2) Determination of the particulate class:

Air, through the main HEPA filter and in accordance with the requirements of the class H14 of EN 1822-1, should be classified as ISO 5 in compliance with the ISO EN 14644 standard (class 100 M3.5 according to Federal Standard 209 E).

Used equipment (laser particle counter):

CLIMET-MODEL CI 450 - N ° 056170.
PUTS ONE-MODEL 3313 - N ° 031001079
HACH - MODEL - 3423 N ° 1012532007

Sampling per minute rate: 28.3 litres up to 50 litres.
Measurements made at 10 cm from the absolute filter to detect leaks, and at the level of the work area which will determine the particulate class of the enclosure.
Each sample measures the number of particles with the following diameters, 0.3 µm, 0.5 µm, 1 µm, and 5 µm.
The number of points corresponds to the standard AFNOR or FS-209 E (ex: 12 points for a filter of 1220 x 610 mm): cf diagram of §1.

3) Integrity test of the air filtration system (optional):

The sealing of the high efficiency particulate air (HEPA) filters in the biological safety cabinet is evaluated by emitting an aerosol upstream and by measuring its diffusion downstream. The used aerosol is the EMERY.
100% of the photometer calibration is performed upstream of the HEPA filter.

Particles which have not been captured are measured by scanning the surface of each filter and sealing joints using the iso-kinetic probe of the photometer.

Any concentration of aerosol downstream of HEPA filters, greater than 0.01% compared to upstream is considered to be leaks.

Used equipment: LINEAR PHOTOMETER BC 400 No. 3242.

IV) Temperature, humidity, sound, lighting & Ultraviolet (UV) radiation level measurements.

. Temperature and humidity measurement is performed through the sampling probe incorporated the CLIMET CI 450 particle counter or the HACH MODEL above 3423.
These values are given for information purposes. Measurements are carried out at the center of the work space.
. The sound level of the BSC in operation must be less than or equal to 64 dB. This level is measured at center of the work space, and 30 cm from the front at a height of 38 cm from the work area.
. Electroluminescence must be greater than or equal to 750 Lux. Measured at the center of the work space.
Luxmeter of sensitivity between 0 & 3,000 Lux is used.
. Ultraviolet radiation must be greater than or equal to 500 µW/cm2. Measured at 10 cm from the UV tube and at the level of the work area. The DM - 254 X radiometer measures ultraviolet radiation of short wavelength (between 220 & 280 nanometers) in a measurement range from 0 to 19,999 µW/cm2.