Biosafety Cabinet Airflow Testing, Servicing & Validation

What is Biological Safety Cabinet Testing?

Biosafety cabinets, also known as BSC’s or MSC’s, are primary barriers of containment used in cleanroom environments or research centres and hospitals, for work with potentially infectious agents. They offer localised environmental protection for the user using hepa filtration and an exhaust system. These units must therefore be reliable as it is a key safety measure. A BSC is an enclosed ventilated work area and the different types that exist are distinguished by the level of necessary biocontainment or operator protection. Biosafety cabinets are predominantly for operator protection, but a class II cabinet also offers product protection. Qualified personnel who are specialised in maintenance and certification of such equipment must certify the equipment at least annually depending on your requirements. A BSC that contains a Grade A or ISO 5 environment should be tested bi-annually. The process leading to the certification is known as biological safety cabinet validation testing, or BCS testing. This is a legal requirement for regular maintenance and examination under COSHH regulations. It’s important to have a validation process to control the routine validation testing of all biosafety cabinet devices and a risk assessment may be necessary.

Once the biosafety cabinet field testing is done and all the approved parameters are met, the relevant certification is issued.

To protect workers and the environment, precautions such as a biological safety cabinet may be used to prevent exposure to microbiological contamination. If this equipment is not working properly, the risk increases, especially if the user is unaware of the failure.

Poor placement, poor inflow velocity or downflow velocity, failed hepa filters, elevated sashes, crowded work area and poor user techniques can compromise the BCS’s containment capacity and these problems will not be noticed unless a BSC test is conducted or if they become seriously contaminated and consequently ill. Because of this, biological safety cabinet validation is extremely important.

Total Clean Air specialises in the biological safety cabinet testing, certification, maintenance and field testing of biological safety cabinets to confirm best practises. All tests are conducted with calibrated equipment in accordance with the relevant industry test standard and/or guidelines. Get in touch by calling 01737924700 or email sales@tca.group to book a biological safety cabinet test for your equipment. As part of the validation and certification various tests include:

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Air Velocities

Air velocity testing is a vital process involved in biosafety cabinet testing and validation. This test is divided into two:

Downflow Velocity Test

The downflow velocity test is used only for a class II biosafety cabinet to determine the average air descent speed and to verify the laminar flow within the work area.

The downflow velocity test is specific to class II safety cabinets as it is created from direct hepa filtration to keep the air uniform. Downflow velocity plays a critical role in product protection and maintaining an ultra low particulate environment. It can also have an effect on the noise level if set up incorrectly. A risk assessment for product entry and exit of the cabinet should always be carried out.

Inflow Velocity Test

The inflow velocity test calculates the average inflow air speed entering the cabinet. The inflow velocity test has different requirements for class I, class II and class III cabinets as they all have slightly different functions. It’s imperative that the inflow velocity is accurate for each type of cabinet as it jeopardises operator protection for the user if it’s incorrect. Inflow velocity plays an important role as it is uniquely linked to the exhaust system of the cabinet. If the cabinet is ducted, it may be linked to the building exhaust system. If it is set up incorrectly, it can also affect the noise level of the cabinet and has other impacts for environmental protection.

A class 1 biosafety cabinet is measured at the aperture, whereas a class II biosafety cabinet is more accurately measured using the exhaust air and calculating the inflow velocity using surface area calculations. For detailed information on biosafety cabinets and velocity testing, contact a Total Clean Air specialist to get specific answers to your project. Call 01737924700 to speak to someone today, or contact sales@tca.group

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HEPA Filter Integrity Leak Testing

HEPA filters are the critical components of any biological safety cabinet, and as such should be regularly tested for performance, safety and filter leak .

HEPA filter integrity testing is extremely important and ISO 14644-3 states the correct method to determine the integrity of the HEPA filters, housings and mounting frames for air supply and exhaust, when the cabinet is operated at nominal speeds. Each cabinet has a specific filter housing or clamping arrangement that’s suitable for exact dimensions and ratings.

The standard HEPA filter media is a single sheet of borosilicate fibres treated with a water-repellent, water-resistant binding agent.

In order to increase the overall surface area inside the filter frames, the filter media is pleated, and the pleats can be separated by layers of aluminium. The separators prevent the pleats in the air stream from collapsing and provide a pathway for air. Careless filter handling may damage the glue medium and cause tears or filter shifts that result in a filter leak to the media. This is the main reason for checking the integrity of the hepa filters when a biological safety cabinet is first mounted, and each time it is transferred or relocated. It’s important to routinely perform a filter integrity leak test to ensure the cabinet is still operating safely.

Hepa filtration is a fundamental part of biological safety testing and looking for a filter leak using best practises for the field certifiers, cannot be underestimated. Airflow smoke at specific micron sized particles should be dispersed within the biological safety cabinet to provide a suitable upstream concentration. This is usually done by injecting the airflow smoke in the work area of the biosafety cabinet.

HEPA filter integrity testing requires an aerosol in the form of generated dioctyl phthalate (DOP) particles or another accepted alternative such as di(2-ethylhexyl) sebecate, polyalpha olefin, polyethylene glycol or medical grade mineral oil.

The aerosol is produced on the intake side of the filter and particles that move through the filter or around the seal are measured on the release side with a photometer. This test is designed to determine the integrity of all HEPA filters.

A cabinet qualifies for certification when the penetration of aerosols does not exceed 0.01% at any given time.

At Total Clean Air, we provide a range of specialised on-site test solutions, including HEPA filter integrity leak testing for your class I or class II biosafety cabinets, as part of your cleanroom certification. For more details or to book a test, call 01737924700 at your earliest convenience.

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Particle Counts (this is also known as ‘Airborne Particle Counts’ or ‘Non Viable Particle Counts’).

Environmental monitoring of non-viable microorganisms and particulate matter is an important control function since both are important if standard requirements are to be met. While airborne microorganisms are not single cells or float free, they often associate with 10-20 μm particles. In a cleanroom, particles and microbial counts vary with the sampling site and activities conducted during sampling.

Particle counting is only associated with a class II biosafety cabinet, as it has a work area suitably designed for both operator protection and product protection. A class II biosafety cabinet work area, is considered to be a Grade A environment due to the air cleanliness it offers, however this classification may not be necessary for some situations. The air quality is created by hepa filtration from the laminar flow filter above, which is then exhausted below the work area and partially recirculates. The remaining air enters the exhaust system and is then ducted away or recirculated into the room.

A test is carried out to determine whether the cabinet complies with the requirements for non-viable particle counts in accordance with ISO-14644-1 (2015).

This non-viable test is done with the use of particle counters and serves as an early warning system for possible problems with pollution.

Particles are noteworthy because they can become a foreign contaminant in a product and can also biologically contaminate it by acting as a vehicle for microorganisms.

A biosafety cabinet can be certified when looking for the overall particulate levels at requested particle sizes. These are usually 0.5 & 5.0 micron but there changes to remove the 5.0 micron particle size. The next considered particle size would be 1.0 micron.

It is vital that you understand the importance of creating a strong BSC monitoring programme for routine monitoring and certification of biosafety cabinets. Total Clean Air can point you in the right direction. Please contact us at sales@tca.group for more details.

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Airflow Visualisation (Smoke Visualisation)

On a class II biosafety cabinet, airflow smoke patterns tests are done to verify that the air flows down smoothly in the work area without any dead spots and does not escape from the cabinet. It is necessary to verify that no smoke escapes from the cabinet after being drawn in and that no smoke blows or penetrates the work surface.

A class I cabinet will look to see that the airflow smoke is captured at all areas around it’s aperture and that no airflow smoke escapes.

Ultimately, this test verifies that the cabinet window is well sealed. An airflow visualisation test must be conducted using the authorised chemical or smoke generator that is especially developed for the purpose. The current trend is to conduct the test with ultrasound nebulised, distilled or ultra-pure water.

Total Clean Air offers custom-tailored, airflow visualisation studies. To maintain environmental control in a cleanroom, it is necessary to be aware of airflow smoke patterns. It is best to visualise and document the airflow patterns.

Our experts offer airflow visualisation tests that record current airflow patterns with our unique techniques and the process can be recorded for evidence as requested.

BS EN 12469 (2000)

In compliance with British Standard, microbiological precautions must be designed, installed, operated, and maintained in an appropriate working order, and implemented by an appropriately trained person who adheres to approved routine containment and filter checks. It is a legal requirement under COSHH that Biological Safety Cabinets be subject to continuous testing to ensure that they do not lose their effectiveness. This involves the analysis of HEPA filters and the fulfilment of efficiency and containment requirements.

Information on the type, specification, and performance of the various types of biological safety cabinets is provided by BS EN 12469. This European standard outlines the fundamentals of health and sanitation for biological safety cabinets. It sets minimum biosafety cabinet efficiency requirements. It also describes microbiological health-cabinet monitoring protocols with regard to product protection, worker and environmental protection and cross-contamination. At Total Clean Air, our solutions, designs, and applications all adhere to the BS 12469 standard, so you can be sure that the job we do is of high quality and meets the relevant certification needs. Get in touch at sales@tca.group to find out more.

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Ducted Biosafety Cabinet

The need to protect workers, products, and the environment from exposure to cross-contamination and biohazards during routine procedures has never been more critical.

Thankfully, users often have a wide range of choices when choosing a cabinet and may prefer to go for the ducted biosafety cabinet for its benefits.

Despite the efficiency and effectiveness of ducted biosafety cabinets, it is important that these devices are subjected to routine testing for performance and safety purposes in the same way. These are also subject to the same legal requirements and must be serviced and validated at least annually under COSHH.

Total Clean Air has developed a wide variety of biological safety cabinets solutions and tests designed to help you meet your certification requirements

We invite questions and comments by telephone, on our website, or during personal visits to our manufacturing facility and research laboratories. Contact sales@tca.group for further information

Ductless Biosafety Cabinet

Ductless biological safety cabinets are also known as recirculating. The exhaust air is expelled through a HEPA filter and back in to the atmosphere of the room. Users should be aware of the need for regular testing to ensure that the cabinet is up to the approved standard and to prevent contamination problems.

Total Clean Air Biological Safety Cabinet solutions and tests are designed to meet the specific specifications of the environment and run within a power envelope that ensures the broadest safety margin and product protection for the most challenging laboratory conditions.

Get in touch to discuss with one of our experts on the features of each biosafety cabinet and talk more about your cabinet needs. Call 01737924700 to speak to someone today.

Double HEPA Safety Cabinet

Absolute barrier protection is provided to operators with certain types of biosafety cabinets such as class 3 Microbiological Safety Cabinets, a device that is ideal for highly bio-hazardous operations. A double HEPA filter on the exhaust is not limited to a class III cabinet though, as they can also be used for a class I or class II cabinet.

In a class III cabinet, the inflow of air is HEPA filtered through a side-mounted inlet filter chamber before entering the biological safety cabinet.

Released air is usually HEPA filtered and burnt. Double HEPA filtration, however, with two series filters can be used to improve efficiency.

The heart of the biological protection cabinet is the HEPA filter. The HEPA Filter is a flexible, dry filter, consisting of microfibers set in a thin layer of borosilicate similar to a piece of parchment.

The filters are intended to shield persons from a wide variety of toxins but do not last indefinitely and can wear and tear, which pose a significant danger to the workplace and workers.

It is therefore critical that experts continuously test the efficiency of the double HEPA biosafety cabinet, both for performance and safety purposes.

At Total Clean Air, we have experienced technicians who are experts in HEPA and ULPA filters and who can carry out the necessary checks to your double HEPA cabinet to ensure it meets the required standard.

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01737 924 700

Class 1 Safety Cabinet Testing

Class I cabinets offer protection for workers and the environment but do not offer protection for products manufactured in the cleanroom. In fact, the internal air flow may lead to sample contamination. The class I BSC operates at a negative pressure, and draws in external air.

These BSCs are widely used to enclose specific equipment such as centrifuges or processes such as aerating cultures that have the potential to generate aerosols.

This type of BSC can be either ducted and connected with the exhaust system of the building or ductless, with the filtered exhaust being recycled back to the laboratory. Class 1 safety cabinets are suitable for all types of biological agents, with the exception of hazard group 4. Modern Class 1 Biological safety cabinets conform with British Standard BS EN 12469 and provide the consumer with a high level of protection. A class I cabinet should always be in the ‘cabinet running’ mode, unless sealed for formaldehyde gas or VHP fumigation.

However, due to its critical nature of use, it is important to regularly test this type of safety cabinet to ensure that it meets – and can be recertified to – the approved BS 12469 standard. Total Clean Air are experts when it comes to Class 1 safety cabinet testing. We make use of the most modern and up-to-date equipment for testing and hire only highly qualified personnel for this purpose. Give is a call on 01737924700 to book a test and ensure that your class 1 biosafety cabinet is up to standard.

Class 2 Safety Cabinet Testing

A Class 2 Safety Cabinet is a type of microbiological safety cabinet that provides user and product protection in cleanroom environments.

Class II biosafety cabinets offer protection against potential biohazard infections to both operators and working materials. The Microbiological Safety Cabinet Class 2 provides protection against contamination by combining inflow and downflow air. The overall negative pressure contains contaminants within the cabinet.

Class 2 systems are currently the most popular biosafety cabinets used by most cleanroom applications.

They are ideal for any research institution that seeks sterile and secure contamination-free environments for microbiological agents and organisms, workers, facilities, and materials.

It is also vital that the class II safety cabinet is regularly checked for performance and certification up to the BS 12469 standard and it is vital that this is done by trained personnel with sophisticated, current and calibrated test equipment.

Total Clean Air are experts when it comes to Class II biological safety cabinet testing.

Give is a call on 01737924700 to book a test and ensure that your class 2 biosafety cabinet is up to standard. We look forward to hearing from you.

Total Clean Air - Testing & Validation Services

01737 924 700

Why is safety cabinet testing required?

A biological safety cabinet (BSC) may also be known as a Microbiological Safety Cabinet (MSC), a Class I, Class II or Class III, depending on application.

Biological safety cabinets are specialist pieces of laboratory equipment that house contaminants and are primarily designed to protect the operator and environment from potentially hazardous airborne material. There are several types of BSC’s or MSC’s depending on the level of containment and protection required.

Due to their hazardous nature, and the content they will likely hold, it is very important that routine validation is carried out on all safety cabinets. Validation, inspection and maintenance provide confidence that the user is not exposed to potentially harmful material.

What validation is required?

Biological or microbiological safety cabinets (BSC’s or MSC’s) have to comply with BS EN ISO 12469 (2000). Within the routine validation testing procedure, there are mandatory tests and requirements that the cabinet must adhere to. As there are 3 different classes of safety cabinet (Class I, class II, class III), there are varying levels of acceptance criteria, specific to each type. In the first instance, the functions of the cabinet should be thoroughly examined and reviewed. Things such as correctly functioning lights and switches should be reported and documented as it helps to build a historical back ground, and addresses issues that are necessary for basic functionality to the user.

For all types of cabinet, the air velocities need to be measured as there are strict levels of compliance for each class of cabinet. The air velocities will need to be measured with a calibrated vane anemometer, or similar. Due to the specific velocity requirement, it’s very important that the speed controllers are not accessible to the user. These should only be adjusted by a trained, certified engineer and testing company. At TCA, we can look after your safety cabinets and create a schedule that works for you. Contact sales@tca.group to speak with one of our friendly team. Now, let’s look at other testing requirements.

Do the HEPA filters need testing?

Yes, absolutely. The HEPA filters are installed in safety cabinets to primarily capture contaminants from escaping to the atmosphere or back into the room. A class II cabinet also has a downflow HEPA filter that provides protection for the product in a Grade A particulate environment (if required). The filter provides purified air supply that is then partially recirculated around the cabinet. The HEPA filter should be routinely tested at 6 monthly intervals, as well as the extract HEPA filters.

The test procedure utilises a controlled aerosol contaminant of either hot or cold generated smoke. The smoke is introduced into the upstream, or dirty, side of the filter and, if fitted, an upstream sample will need to be taken. This sample calculates the level of aerosol, or challenge, that the HEPA filter is receiving. Checks are then made on seals and joints of the safety cabinet as well as scanning in over-lapping strokes of the HEPA filter media. If the safety cabinet is ducted, checks should be made on duct work from the cabinet to confirm the integrity. All HEPA filter tests need to record a <0.01% penetration in order to achieve a pass. Contact sales@tca.group for further information or to set up a testing schedule.

Do I need to perform particle counts?

Not necessarily. If you own a class I or class III cabinet, there is no need to test for particulate cleanliness. A class I safety cabinet only offers user protection. It draws in regular air from the laboratory or other environment that you’re working in. Because the air is drawn in from another environment, a particulate test wouldn’t test the validity or the quality of air inside the cabinet. In this sense, it operates in much the same way as a fume cabinet, but at a higher velocity (0.70 – 1.0 m/s). A class III cabinet is usually considered to house such harmful material, that sampling the air quality inside the unit is considered dangerous to the user , equipment and environment. A class II cabinet however, should be routinely particle count tested, along with the other validation testing requirements. Usually, the working zone is considered to be of GMP Grade A standard but users and requirements make the overall decision to classification levels. Some users may monitor the particulate cleanliness at frequent intervals, or in some cases, permanent monitoring, however, it’s always important to have independent validation testing. Please contact sales@tca.group to chat about all aspects of test procedures for safety cabinets and what we can do for you.

How do I know my safety cabinet is safe?

A class I and a class II safety cabinet may be required to have an operator protection test. This test was originally designed to simulate a catastrophic event occurring inside the cabinet and is designed to see whether or not the safety cabinet will still offer protection to the user in an emergency. Nowadays, it offers an insight to the level of protection that the safety cabinet provides. The test procedure is known as a KI, as it uses potassium iodide as a contaminant inside the working zone of the cabinet. The potassium iodide is dropped on to a spinning disk at a known RPM and, essentially, thrown towards the aperture of the safety cabinet. Sampling heads are placed at known distances outside the cabinet and at the end of each test, the filter membrane can be washed in palladium chloride to display any dots of potassium that have escaped from the cabinet. The test has been around since the early 1980’s and it’s complicated and expensive to perform but at the moment, there are no other alternatives. According to the BS EN ISO 12469 (2000) standard, the test only needs to be performed at commissioning. If the surroundings are significantly altered or the safety cabinet is moved, the test should be repeated.
Please contact sales@tca.group for further information.

Phillip Godden

Phillip Godden is the Founder & Chief/Executive Officer at Total Clean Air.

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