White Papers

Antimicrobial Effectiveness of Isocide™ Powder Coating on Esco Biological Safety Cabinets Author: Dian Susanti, Fajar Mustika and Alexander Atmadi


Many undesired bioburden cause the contaminations on equipment and facilities used by lab professionals, whereas it is critical for them to keep everything clean and free from any health hazard. The bioburden commonly presence on many surfaces and it is hard to control their numbers effectively. Esco is presenting laboratory and cleanroom products equipped with organisms’ growth control, by coating all of these products with Isocide™ powder coating.

Two types of testing were performed by adopting JIS and ASTM standards to evaluate antimicrobial effectiveness of Isocide™ powder coating. The tests showed that bacteria, yeast and mold, that came into contact with Isocide™ coated surfaces were inhibited or effectively eliminated.




Personnel Protection Test on Biosafety Cabinet With Width Less Than 3 ftAuthor: Dian Susanti and Alexander Atmadi

Operator protection test is done by using a nebulizer to spray the challenge spores from inside the cabinet work zone, and sampling the air outside the cabinet sash opening to check for potential spore escape. Air sampling is at the center of sash opening is taken by 6x impingers, and at the right & left side of sash opening is taken by slit air samplers.

The existing ANSI/NSF 49 standard specifies that the slit air samplers should be placed at 203 mm (8") from the cabinet interior side walls. However, given the size limitations of smaller than 3 ft, such 8" distance is not possible. Therefore, the Joint Committee is seeking to establish a new measurement distance or method to test cabinets smaller than 3ft.



Personnel Protection Test on Standard Width (4ft) Biosafety CabinetAuthor: Dian Susanti and Alexander Atmadi

The existing ANSI/NSF 49 standard specifies that the slit air samplers should be placed at 203 mm (8") from the cabinet interior side walls. However, given the size limitations of cabinets smaller than 3 ft, such 8" distance is not possible. Therefore, the Joint Committee is seeking to establish a new measurement distance or method to test cabinets smaller than 3ft, and as a member of the Joint Committe, Esco is seeking to contribute on this study.

The authors recently conducted a study on operator protection test on Esco Airstream Class II BSC with 2 ft width by varying the distance of slit air sampler to the side walls, and found out that the most challenging test condition occurs when the slit air samplers are placed at 5" (127 mm) from the side walls. Any further distance than that would make the slit air samplers collide with the impingers.

The purpose of this study is to compare the findings on the 2ft width cabinet to standard 4ft cabinet of identical model and airflow setting, specifically to see which slit air sampler distance from the walls that would pose the greatest challenge for the cabinet, and to compare the test result if similar 5" (127 mm) distance is used on this cabinet.



Nebulizer Placement for Cross contamination Test on BSCAuthor: Dian Susanti and Alexander Atmadi

The existing ANSI/NSF 49 standard specifies that the nebulizershould be placed at the midpoint(front to back)of the interior side wall, pointing towards the opposite wall. As comparison, the European Biosafety Standard EN 12469 specifies that the nebulizer should be placed at the air split point, to create the most challenging condition to pass the test.The air split point should be determined by a smoke generator, and the nebulizer should be placed accordingly. This European approach is being considered by the NSF Joint Committee.

The purpose of this study is to compare the cross contamination test result, between placing the nebulizer at the midpoint of the work surface per existing NSF/ANSI 49, versus at the actual air split point as determined by a smoke generator per EN 12469.



Understanding Airflow Stability Behavior with Incoming Power Voltage FluctuationsAuthor: Franky Tanuwijaya and Fikri Muhammad

Adjustable stable airflow is the fundamental for biosafety cabinet operation. Biosafety cabinets must maintain airflows at designed parameters. To do this a speed controller is used to vary the voltage to the blower motor. Increasing or decreasing the voltage to the motor directly increases or decreases the motor speed or rpm. In turn the fan attached to the motor increases or decreases the speed of the air moving within the cabinet. The most common speed controller used in biosafety cabinets is a phase cutting electronic speed controller. These types of controllers are commercially available at reasonable prices and due to their robustness are practical to implement in various cabinet designs.



True RMS vs AC Average Rectified Multimeter Readings when a Phase Cutting Speed Control is UsedAuthor: Franky Tanuwijaya and Fikri Muhammad

There are two methods commonly used in Digital Volt Meter (DVM) AC measurements, one is AC average rectified measurement and the other is True RMS measurement. True RMS is a consistent and standard way to measure and compare dynamic signals of all shapes and sizes. In other words, RMS measurement is equivalent to the heating potential of a dynamic waveform.



Class II Type A1 and Class II Type A2 Biosafety CabinetsAuthor: Alexander Atmadi

Class II Type A cabinets are the most common biosafety cabinets, which accounts for about 90% of all biosafety cabinets in the world. According to the 2002 version of NSF/ANSI 49 standard for biosafety cabinets, Class II Type A cabinets are divided into two variants: Type A1 and Type A2



Energy Efficient Biosafety CabinetsAuthor: Alexander Atmadi

When selecting potentially power-consuming equipment, such as a biosafety cabinet, the key to face those problems is energy saving. Esco’s solution to the abovementioned problems is to provide energy efficient product lines, such as the Airstream Class II and Labculture Plus Class II biological safety cabinets.



Sound Level Measurement On Biosafety CabinetsAuthor: Alexander Atmadi

Sound is vibration transmitted through a solid, liquid, or gas. Particularly, sound means those vibrations composed of frequencies capable of being detected by ears, and the intensity is commonly measured in decibel (dB). Prolonged exposure to loud sound intensity can lead to fatigue and distraction, which can be fatal during a contamination-sensitive work performed in biosafety cabinets, so it’s important to measure the sound exposure.


TÜV Test Report


UV Lamps in Laminar Flow and Biological Safety CabinetsAuthor: Lin Xiang Qian

Ultraviolet light is part of the electromagnetic (EM) spectrum, and is divided into 3 wavelength ranges: UV-C, from 100 nanometers (nm) to 280 nm; UV-B, from 280 nm to 315 nm; and UV-A from 315 nm to 400 nm. The germicidal ultraviolet lamp emits high intensity ultraviolet radiation concentrated around the wavelength of 253.7 nm (i.e. "UV-C radiation") 95% of the radiation emitted by germicidal lamps is at this wavelength which also happens to be region of maximum germicidal effectiveness.



The Role of The Pressure Gauge In HEPA-FIltered Clean Air DevicesAuthor: Lin Xiang Qian

HEPA-filtered clean air devices - systems conatining both a fan and a HEPA filter are prevalent today in many modern applications. They include laminar flow / biological safety cabinets (hoods) for laboratory applications, in addition to cleanroom equipment such as fan filter units. This technical paper outlines the theory of operation of the pressure gauge, which is commonly used in the industry as an indicator on HEPA-filtered clean air devices. Most significantly, common misconceptions as regards the functionality of pressure gauges with regards to HEPA-filtered clean air devices are discussed in detail. Proper usage practices are also recommended.



What Makes A Biological Safety Cabinet SafeAuthor: Lin Xiang Qian

Some people may not appreciate it, but a biological safety cabinet is a more complicated device than simply a large metal box with a fan and some HEPA filters. Similarly, keeping a safety cabinet performing safely is also a more complicated process than simply "changing the filters regularly".
This technical paper was written to address some of these myths and fallacies, and to educate laboratory scientists, cabinet users, facility safety officers, and other people - in the hope that the knowledge shared here will improve the safety of our environment for the common good.



Operator Protection Test for Open - Fronted Biological Safety Cabinets: The Unique Potassium Iodide TestAuthor: Lin Xiang Qian, Alexander Atmadi, Amit Kumar Singh

Laboratory-acquired infections (LAIs) are a matter of concern for the microbiological community of the world. There are reports of individuals, particularly laboratory investigators, succumbing to infection transmitted by an aerosol or splash from the material being handled (Kruse et al. 1991; Collins 1993). The strategies to eliminate such LAIs include the use of biological safety cabinets. There have been several attempts made by the manufacturers, legislative bodies, and national and international standards bodies to standardize containment testing strategies for open fronted containment systems. Operator protection tests should be an integral part of the routine servicing regime to ensure that the biological safety cabinets meet the required performance levels, and additionally to allow detection and rectification of poor containment, particularly those induced by the environmental factors.

For many parts of Europe and North America, Operator Protection Tests (OPTs) may only be required for initial certification but not following installation, or routinely thereafter, e.g. post servicing. Moreover, the levels of containment required, unfortunately, are not fully comparable between countries, as the recommended testing methodologies and/or protocols vary (Anon. 1992; Richmond and McKinney 1995; Anon 1998). Manufacturers of contamination control equipment have the expense of testing by varying methods in different countries where standards apply. The most common type of open fronted containment system found in laboratories are the biological safety cabinets (BSCs). This paper describes the unique potassium iodide test conducted on biological safety cabinets in a tertiary hospital of Singapore.



The KI-Discus TestAuthor: Lin Xiang Qian

The KI discus test is defined in The European Standard for microbiological safety cabinets, EN12469:2000 as a test method for validating the operator protection capabilities of the cabinet.



Filter Selection For Safety CabinetsAuthor: Lin Xiang Qian

Modern safety cabinets can reliably achieve an aperture retention efficiency of >99.999% (tested according to the KI Discus method - see Esco technical article on the topic). This refers to the percentage of particles (released at the weakest point inside the cabinet) that are retained in the air barrier and do not escape to the laboratory.



Comparison Between EN12469:2000 and ANSI/NSF49:2002 StandardsAuthor: Lin Xiang Qian

The EN12469:2000 is the harmonized European standard for microbiological safety cabinets. It specifies requirements for both safety cabinet construction and performance criteria. In 2000, the year of its introduction, it replaced the former German, British and French standards in the same field.

The ANSI/NSF49 is the American National Standard which also specifies requirements for both cabinet construction and performance criteria. It gained official ANSI (American National Standards Institute) recognition in 2002, the date of the most current revision. The NSF49 has been in existence since the 1970s and is arguably the most established standard in this field in the world.



Motor-Blower Performance Test for Labculture Class II Type A2 CabinetsAuthor: Kevin Yong

Purpose of experiment: To demonstrate that the motor/blower will operate at a static pressure sufficient to compensate an increase in pressure drop across the new filter. NSF 49:2002 requires that for a motor/blower performance test, when operating at the nominal set point velocities and without readjusting the fan speed control, a 50% increase in pressure drop across the new filter shall not decrease total air delivery more than 10%.



Increased Microbiological Challenge Test with Bunsen Burner Inside the Cabinet

Bunsen Burner is the most frequently used apparatus in the laboratory as a source of heat. Typically used inside the biological safety cabinets and laminar flow hoods for sterilizing inoculating loops, test tube lips and Petri dishes lids. This barrier is designed so that gaseous fuel may be mixed with the correct amount of air to yield the maximum amount of heat. However, placing a lighted burner into a cabinet, produces a dramatic effect. In a Class II type cabinet, the hot upflow from the burner mixed the downflowing airstreams to produce turbulence and recirculation within the working area. The notion of laminar flow may be completely destroyed and any aerosols generated beneath the burner may be carried upwards to contaminate the whole of the air within the cabinet. This is why a Bunsen burner should not be used inside the cabinet; and an alternative technique should be found.

In this experiment Esco will try to find out where the Bunsen burner can be placed safe inside the cabinet. Experiment will be composed of three different tests: Cross contamination, Product protection and Operator protection test (KI Discus test). Each test will be done twice with different location of the Bunsen burner inside the cabinet.



Sound Spectrum at 1/3 octave frequency band on the Labculture® Class II Type A2 Biohazard Safety Cabinets

Purpose of experiment: This test ensures that the alarm of the cabinet is loud enough so that when activated, it can be heard by the operator whenever the blower is on or off. This safety feature is enforced by the TUV, from Germany, which states that the alarm noise must exceed the cabinet base noise level (that is the noise level recorded when the blower is operating) by a minimum of 13 dB for at least one 1/3 octave frequency band.



NSF & UL Stability Testing for 4 feet Labculture® Class II Type A2 Cabinets

Purpose of experiment: The stability tests that are described below are performed according to and with compliance with 2 standards, namely NSF49:2002 (19 March) and UL 61010A-1 2002 (April 30). These tests have been designed to mainly ensure that the biosafety cabinet is safe for the operator to be used in terms of rigidity, structural integrity and stability. These tests ensure that the cabinet does not overbalance/overturn/tip/deflect/distort in case of an accident which may result in endangering the operator or damaging the cabinet. NSF49 states that the tests (*)1 demonstrate the structural integrity and stability of a biosafety cabinet through a series of tests and standards. The cabinet (**) shall be designed and constructed to resist overturning and distortion under applied forces, resist deflection of the work surfaces under load, and resist tipping under workload. UL 61010A-1 on the other hand exhibits the same safety features and requirements except that the tests and the standards/acceptance are different.



Increased Microbiological Challenge Test with Objects Inside the Work Zone To Simulate Loaded Cabinet

Purpose of Experiment: Loading the cabinet with objects will completely disturb the airflow. The notion of linearity or laminar flow may be completely destroyed and any aerosols generated may be carried upwards to contaminate the whole of the air within the cabinet. In this experiment different glass wares and equipments were used to generate air disturbance to simulate loaded cabinet. The dimensions and distance of each objects was measured to make sure that this test can be repeatable for all Esco cabinet.



Increased Microbiological Challenge Cabinet side-by-side

The air curtain of the front of the cabinet is fragile and can easily be disrupted by people walking parallel to it, by open windows, air supply registers or laboratory equipment that creates air movement, and even another cabinet placed beside it. This is why biosafety cabinets should be located away from high traffic areas, doors and air supply/exhaust grilles that may interrupt airflow patterns. Whenever possible, a 30 cm clearance should be provided on each side and behind the cabinet to allow for maintenance access and for undisrupted air supply.

In this experiment Esco will check the cabinet performance whether it can still aid protection to the operator as well as to the products and processes being handle inside the cabinet. Biosafety cabinet model LA2-4A2 will be used instead of the AC2 because it has stronger inflow thus allowing greater challenge to the cabinet.



Increased Microbiological Challenge Test with Fan Filter Unit (FFU) Simulating Person Walking Past the Cabinet

This test demonstrates that the cabinet will maintain operator protection even with an external air disturbance such as people walking past the cabinet. In this experiment, Fan Filter Unit (FFU) was used to generate air disturbance to simulate the person walking in front of the cabinet, FFU is used in contamination control environments such as cleanrooms. It consist of a small fan, controller, and a ULPA filter enclosed in a box. It maintains specific and uniform airflow.



Cleanability test on the 4 feet Labculture® Class II Type A2 Biohazard Safety Cabinets

Purpose of Experiment: Biological Safety Cabinets have been designed to give many years' trouble-free efficient service and to keep maintenance to a minimum. However, to ensure this, it must be regularly cleaned and checked. Through this experiment, it will demonstrate that Esco's BSC was easily cleanable even with its other parts.



Factors to Consider When Selecting a Biosafety Cabinet

Users often have a large choice when selecting a safety cabinet and may be confused by the multitude of features and design styles which are offered. This article adopts the point of view that no safety cabinet design is perfect and seeks to independently and objectively explain the pros and cons of each design style, so that the user may make his or her own assessment in deciding which cabinet is more suitable for his or her own application and ergonomics.