Non-Tariff Barriers

Non-Tariff Measure

NTM classification

B7: Product quality, safety or performance requirements 

Date when the measure came into force

02 April 2001 

Publication where the measure is specified

Government Notice R93 (Government Gazette 22014) Of 2 February 2001 

Regulation where the measure is specified

Compulsory Specification For Microbiological Safety Cabinets (Classes I, II And III) 

Country/Region applying the measure

South Africa 

The rationale of the measure

1.1 This specification covers requirements for the construction, fittings and pre-installation and post- installation performance of class I, class li and class III microbiological safety cabinets (also known as biological safety cabinets) intended to protect the operator and the environment from hazardous microbiological materials and (if so required by the customer or user or both), organic toxins and non-corrosive volatile organic agents.

NOTE - Microbiological safety cabinets are not intended to provide protection against corrosive chemical or radioactive materials.

1 .2 The specification does not cover the actual design of a safety cabinet and in no way restricts new design, provided that a microbiological safety cabinet of a new design complies with the requirements for materials, reliability, performance and safety given in this specification.

NOTE - Microbiological safety cabinets of class I, class II and class III should not be confused with laminar flow
clean workstations that usually discharge horizontally and vertically towards the operator and that do not provide
protection for an operator, but can even increase exposure to airborne hazards. 

Coded list of objectives

X: For purposes n.e.s. 

Description of the measure

3 General requirements
3.1 Class
A cabinet shall be of one of the following classes:
a) class I: A partially enclosed cabinet that is so constructed that air flows inwards through the work- access aperture and away from the operator. The exhaust air is filtered through a HEPA-filter before being discharged from the cabinet.
WARNING — These cabinets shall not be used as, or confused with, fume cabinets which are intended for chemical procedures.
NOTE - Class I cabinets provide protection for personnel and the environment against ordinary or potentially hazardous microbiological agents, i.e. at risk levels associated with agents that cause disease in human beings, animals or plants, provided that the usual precautions in handling microbiological material are observed. The level of competence required of personnel who handle material in these cabinets should be that of personnel formally trained as microbiologists.
b) Class II: A partly enclosed cabinet that is so constructed that the air in the work space is flushed with a clean, HEPA-filtered, unidirectional downward flow of air, and the escape of particles from the work space is prevented by an inward flow of air through the work-access aperture The exhaust air is filtered through a HEPA-filter before being discharged from the cabinet.

Note- Class II cabinets provide protection for personnel, the environment and the product against ordinary or potentially hazardous microbiological agents, i.e. at risk levels associated with agents that cause disease in human beings animals or plants, provided that the usual precautions in handling microbiological materials are observed. The level of competence required of personnel who handle material in these cabinets should be that of personnel formally trained as microbiologists.
c) class III: A totally enclosed, ventilated cabinet of gastight construction that is so constructed that the operator is separated from the work space by a physical
barrier, and the work space is so flushed with HEPA-filtered air under negative pressure that the escape of articles from the work space is highly unlikely. The exhaust air is filtered through a HEPA-filter before being discharged from the cabinet to the outside atmosphere through an airtight duct.
NOTE - Class III cabinets provide protection for personnel and the environment against special and extremely hazardous microbiological agents, i.e. at risk levels associated with agents that are highly infectious or toxic to human beings, animals and plants, and that can cause dangerous disease, or at risk levels associated with agents that cause genetic mutations or that can have a synergistic effect with other materials. The cabinet also controls airborne contamination that might be detrimental to the work in the work space. The level of competence required of personnel who handle material in these cabinets should be that expected of personnel formally trained as microbiologists and who have also received proper training in the handling of extremely dangerous agents.

3.2 Dimensions

3.2.1 External dimensions
The overall dimensions of a cabinet, excluding the readily removable parts, shall be such that it can pass through a standard single doorway of nominal height and width 2,0 m and 0,78 m respectively.
3.2.2 Work space dimensions
In the case of class I and class II cabinets, the width of the work space shall not exceed 1 900 mm and the depth shall be in the range 500 mm to 700 mm. The height of the work space shall be at least 550 mm. The volume of the work space shall be not less than 0,2 m3 and not more than 0,75 m3

3.3 Outer shell (main structure) - Material and construction
3.3.1 General
3.3.1.1 A cabinet shall be constructed of glass or metal that is deemed to be corrosion resistant when tested in accordance with 6.11. If stainless steel is used, it shall be of at least AISI Grade 304 and the requirement for corrosion resistance shall not apply.
3.3.1 .2 There shall be no cracks and surface defects, including ineffective mating with gasket surfaces or other sealing devices. All structural joints that are not welded shall be sealed with a suitable sealant that is not liable to crack. The gasket or sealing material shall not be used as a structural material for any joint or connection of the cabinet or any of its panels.
3.3.2 Stability of the cabinet
When a free-standing cabinet is tested in accordance with 6.14, the rear bottom edge of the cabinet shall not lift off the surface on which it rests by more than 1,6 mm when a torque of 700 Nm is applied at the centre of the rear top edge. In the case of a cabinet installation that does not provide this degree of stability, provision shall be made for stabilizing the cabinet by appropriate means to ensure compliance.
3.3.3 Windows
Windows shall be of safety glazing material that complies with the performance requirements of SABS 1 263-1 1 986, Safety and security glazing materials for buildings - Part 1: Safety performance of glazing materials under human impact, as published by Government Notice No _ 1851 of 1 December 1995 or of other suitable materials that are resistant to ultraviolet rays and that perform at least as well as the safety glazing material.
3.3.4 Access panels
Removable access panels or covers shall be provided for the maintenance or removal (or both) of filters blowers motors, lighting, electrical components and plumbing. When access panels or covers are in place, their seals shall prevent leakage of contaminated air to the surrounding atmosphere.
Physical means to position and support large access panels or covers shall be provided to facilitate safe fitting and removal. Fastenings shall not compromise the integrity of the outer shell of cabinets. Fastenings of class III cabinets shall not penetrate the inner or outer shell. There shall be effective mating of the access panels or covers with the gasket surfaces.
NOTE - Access panels to contaminated zones should be removed only after the whole cabinet has been decontaminated.
3.3.5 Tracks and guides
All tracks and guides for doors, windows, access panels and covers shall be so constructed and installed as to minimize the collection of foreign matter and to facilitate cleaning.
3.3.6 Access points to the exhaust duct (class III cabinets)
Class III cabinets shall have access points to the exhaust duct to facilitate the measurement of airflow.
3.4 Work space — Material and construction
3.4.1 General
3.4.1 .1 The work space, excluding the viewing window, but including the work floor and its associated structures, the sump and grills, where applicable, shall be constructed entirely of a suitable metal that, when tested in accordance with 6.11 , is deemed to be corrosion resistant. If stainless steel is used, it shall be of at least AISI Grade 304 and the requirement for corrosion resistance shall not apply.
3.4.1.2 When an internal work surface (see 2.1 .10) is tested in accordance with 6.1 3 and the surface is compared with untreated areas, there shall be no visible effect other than a slight change of gloss or discoloration.
NOTE - The resistance of the surface to special chemical solutions which are intended to be used, should also be evaluated.
3.4.1 .3 The surfaces shall be smoothly finished and cleanable (see 2.1 .4), and shall be such that glare (see 2.1.7) from lighting (see 3.4.6.2) is avoided.
3.4.1 .4 In order to prevent penetration by microorganisms, all welds shall be ground flush and dressed. Joints, cracks and crevices in the work space shall be effectively sealed with a suitable sealant which is resistant to solvents and to normal disinfectants.
3.4.1.5 There shall be no sharp projections within the work space.
3.4.2 Internal corners and angles
All internal corners and angles in the work space shall be
a) free from cracks and crevices, and
b) designed to facilitate cleaning and disinfection.
3.4.3 Viewing window

The viewing window shall consist of transparent panel that complies with the requirements of 3.3.3 and that can be opened, m class I and class II cabinets only, to allow access to the workspace.
3.4.3.2 The viewing window shall form the front boundary of the clean air environment and shall not disrupt the laminar pattern of airflow.
3.4.3.3 Apart from being optically clear and not adversely affected by accepted cleaning methods the size, position and angle of the viewing window shall allow a clear and unobstructed view into the work space when the operator is seated centrally in front of the cabinet.

3 4.3.4 When a class II cabinet is tested in accordance with 6.5, all seals around the top and sides of the viewing window shall have a DOP aerosol penetration not exceeding 0,03 %.

3.4.4 Work-access aperture (class I and class II cabinets only)
The edges of the work-access aperture shall be so formed as to minimize air turbulence at the entry. The vertical dimension of the aperture shall be in the range 200 mm to 250 mm.

3.4.5 Work-access aperture cover (class I and class II cabinets only)

A cover to fit the work-access aperture shall be provided in order to seal the cabinet during decontamination.

3.4.6 Work space illumination
3.4.6.1 The work space shall be illuminated by fluorescent lamps. The lamps and accessories shall be outside the work space. Replacement and maintenance of the lamps and accessories shall be carried out from the outside of the cabinet without compromising the integrity of the work space.

3.4.6.2 The lamps shall be so positioned that their reflections do not impede the visibility through the window. The operator's eyes shall be shielded from direct radiation.

3.4.6.3 When determined in accordance with 6.2, the average illuminance at the work surface shall be at least 800 Ix (800 lumens per square metre). No single illuminance reading shall differ from the average illuminance by more than 20 %.
3.4.6.4 Ultraviolet lamps shall not be installed as integral parts of the cabinet.
3.4.7 Control gear
All control gear shall be accessible from the outside of the cabinet without the integrity of the plenums or biohazard safety barriers being affected. Control gear shall be so mounted and so sealed that there is no air leakage into the atmosphere, and that the control gear cannot become contaminated by contaminated air.

3.4.8 Screens
In class I and class II cabinets, one or more screens shall be provided on the return air manifold to prevent any loose material from being drawn from the work space into the motor blower or the HEPA-filter housings. The screen(s) shall register in position without the need for fastening. The finish of the screen(s) shall be smooth to facilitate cleaning and disinfection.

3.4.9 Gas fittings
3.4.9.1 If the work space of class I and class II cabinets has a supply of flammable gas (for example, for bunsen burners) this supply shall be controlled by means of a solenoid valve that will allow the flow of gas only when the motor blowers are switched on.
3.4.9.2 In order to reduce explosion hazard, the solenoid valve shall be such that it has to be manually reset after any interruption of the power supply.
3.7 Exhaust system

3.7.1 The cabinet shall be so constructed that the air contained in it may be
a) exhausted to the outside atmosphere, by a system that prevents air from flowing back into the cabinet, or

b) discharged back into the laboratory (class I and class II cabinets only).

3.7.2 If necessary, an additional airtight exhaust duct of a length as short as possible, but not exceeding 3 m, can be used.

3 7 3 If the use of a short duct is not possible, a separate, additional motor blower shall be fitted as near as possible to the outside discharge end of the external exhaust duct, and a thimble type collector (see figure 1) (class I and class II cabinets only) shall be used at the junction between the cabinet duct and the external exhaust duct. The external blower shall be set to ensure excess extraction at all times.
The external blower shall be electronically linked to the cabinet to disable the cabinet if the external blower is not operating correctly.

3.7.4 The air extraction system shall be capable of dealing with external wind conditions and duct resistances. Manufacturers shall specify maximum allowable external resistances to airflow.

3.7.5 To prevent air from flowing back into the cabinet, especially when the fan is switched off, the exhaust duct shall be fitted with an automatic anti-blowback system downstream of the exhaust filters. Anti-blowback valves shall be so constructed that the internal components are visible at all times and that the valve seats can be easily inspected and cleaned. Micro switches or other electrical components or controls shall be outside the duct.

3.8 Electrical services

3.8.1 Wiring
Electrical wiring shall be
a) insulated wiring that complies with SABS 1 507:1 990, Electrical cables with extruded solid dielectric insulation for fixed installations (300/500 Vtol 900/3 300 V), as published by Government Notice No. 1851 of 1 December 1995 and SABS 1574:1992, Electrical cables - Flexible cords and flexible cables, as published by Government Notice No. 1851 of 1 December 1995; or
b) aibber-insulated wiring that complies with SABS 1520-1:1990, Flexible electrical trailing cables for use in mines - Part 1: Low-voltage (640/1 100 V and 1 900/3 300 V) cables, as published by Government Notice No. 1 851 of 1 December 1 995 and SABS 1 520-2:1 990, Flexible electric trailing cables for use in mines - Part 2: High-voltage (3,8/6,6 kVto 19/33 kV) cables, as published by Government Notice No. 1851 of 1 December 1995, with the said SABS 1574 and with SABS 1576:1993, Electrical cables - Single core arc welding cable, as published by Government Notice No. 1851 of 1 December 1995.

Wiring that penetrates boundaries of contaminated areas shall be anchored and their points of entry shall have been made gastight, using non-porous sealants that are not liable to crack or to become porous, or other appropriate means. Electrical components and wiring, other than the blower motor(s) and the associated wiring, shall not be located within the contaminated air zones. All wiring and electrical components within the clean air area of the work space shall be so mechanically secured that no turbulence will be created. Adhesive tape shall not be used for fixing or looming.

3.8.2 Controls
A control enclosure and all controls shall form an integral part of the cabinet . The control enclosure shall contain a control panel. The enclosure shall have a cover that will allow unlimited access to the connections and wiring of the panel. A legible wiring diagram shall be permanently fixed to the cabinet. All operator-adjustable controls shall be clearly visible and easily accessible to the operator. All operation controls and electrical components within the control enclosure shall be identified by being suitably marked in a permanent manner.

3.9 Noise levels
When a cabinet is tested in accordance with 6.7, the noise emitted by the cabinet during operation shall not exceed 65 dB(A).
3.10 Vibration
When a cabinet is tested in accordance with 6.3, during the entire operation of the cabinet the vibration velocity in any plane of any work surface shall have an r.m.s. value of 10 Hz ± 1 Hz to 250 Hz ± 25 Hz, not exceeding 0,7 mm/s. 

Reference of the measure

Regulations 3.1 to 3.10 

Measure also domestic

Yes 

Products affected by the measure.

Description

Microbiological safety cabinets (classes I, II And III) 

Countries/Regions affected by the measure.

Description

All countries