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The Differences Between Biosafety Cabinet Class I and Class II

When it comes to purchasing biosafety cabinets for laboratories, you need to undertake the appropriate level of research and make sure that you purchase a product that’s fit-for-purpose. The safety of your laboratory and lab staff could very well depend on it.

There are three different classes of biosafety cabinet, but even these are broken down into further sub-categories. It pays to know what work certain cabinet classes are designed for, and what they’re not designed for.

Here we’ll explain a few of the major differences between Class I and Class II cabinets, including why ISG’s Class II biological cabinets offer unbeatable value.

What Are Biosafety Cabinets?

For new readers and readers unfamiliar with traditional lab equipment, you’re probably asking “what are biosafety cabinets anyway”?

Often referred to as biological, biohazard, microbiological (the list is endless) safety cabinets, are ventilated workspaces that protect users from any potentially harmful specimen and the specimen from being contaminated by unclean air.

The purpose-built cabinets include a fully enclosed workspace that allows the user to carry out experimental tasks without exposing themselves or their surrounding environment to hazardous pathogens.

These units are standard in clinical and research labs all over the world.

Ok, So What Are Biohazard Cabinet Classes?

We’ve made them sound like one coverall piece of laboratory equipment. However, the truth is that there are several different types of units, a range of categories, and various levels of protection on offer from each of them.

As with many other pieces of classic laboratory equipment, different cabinets are suited to different purposes and experiments.

For instance, some biological safety cabinets are designed so that the transparent shield doesn’t cover the whole wall and allows the user to access the enclosed space freely. The ventilation and design still protect the user, but in a less restrictive way than other classes of cabinet.

For those other classes, the transparent shield completely encloses the operational space and internal gloves (attached to the surface) must be used to carry out experiments. There are also class-dependent stipulations for flow velocity, airflow pressure, exhaust configuration, and more.

Typically, there are three different types of cabinet class, as explained below.

Class I

This is the most basic, fundamental class of safety cabinet. It’s defined as “a ventilated unit for personnel and environmental protection”, and it focuses on nothing more than making that protection possible in an efficient and budget-friendly way.

With Class I cabinets, there is no protection from contamination or from the sample being manipulated. This means that they’re perfectly suited to basic procedures and nothing more.

Airflow is not recirculated, flows away from the operator under negative airflow pressure, and has a HEPA filter at the exhaust outlet.

Class II

Class II biosafety cabinets take that level of protection up a notch, and in some cases, the design can become quite complex. This class of cabinet is subcategorised into 5 more types: A1; A2; B1; B2; C1.

In the simplest terms, this class of cabinet offers the same as Class I, but they also protect users carrying out microbiological work or sterile pharmacy compounding. They provide security for the sample as well as the user and the surrounding environment.

In a similar design to Class I, there is still an inward airflow through the open front screen. A HEPA filter still cleans the air, but a key difference is that the HEPA-filtered air instead has a downward flow to protect the sample.

For each type of Class II biological cabinet, every contaminated duct and plenum must be under negative pressure. There are minimum average airflow velocity requirements (depending on the type) and a range of exhaust arrangements that can recirculate clean air both within the exhaust and the working chamber.

The key difference between Class I and Class II cabinets is that latter provide additional protection for the sample. The former doesn’t have any minimum airflow requirements, and they can’t offer the advanced exhaust system designs available with most types of Class II cabinets.

This class of cabinet in both A2 and B2 formats are a primary focus of ISG, as these are by far the most popular specifications in the industry.

Class III

This version is are completely enclosed, ventilated, and leak-tight. For obvious reasons, they are often known as ‘glove boxes.’

Biosafety Cabinets with ISG Fume Extraction

Our biosafety units have been designed for optimum operator protection and laboratory safety. With stainless steel worksurfaces making maintenance straightforward and portable cabinets being height-adjustable too. A corrosion-proof carcass, programmable sterilisation lights, and the user-friendly interface make our cabinets the safest in the industry.

There’s a reason why many of the leading pharmaceutical and technological brands trust our fume extraction systems. Get in touch to find out how we can help equip your lab with the safest biohazard cabinets.

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