The most recent edition of CBRNe WORLD Magazine includes a highly informative article on the rationale for the procurement and deployment of mobile laboratories. The article, authored by Monica Heyl, discusses the use of mobile labs by first responders, military, law enforcement and civil support teams.  Ms. Heyl describes a range of applications for these units:

“Mobile laboratories can be integrated to fill a wide variety of challenges: sample receipt, screening and evaluating suspect unknown materials, environmental health protection and remediation, narcotics analysis and confirmation of clandestine laboratories. They can respond to catastrophes, terrorism, and a myriad of other actions in theatres of conflict or on our own homelands.” 

The CBRNe World article also discusses the critical role of proper engineering controls in mobile laboratories, stating that:

“Engineering controls (primary and secondary) become vital to sample collection, reception, preparation, analysis and spent effluent that could contaminate the environment. Robust engineering controls to include redundant and hybrid filtration systems, breakthrough monitors and backup uninterrupted power are only as good as the quality assurances associated with the development, building, manufacturing and testing of such safeguards.”

The article, “Mobile Laboratories: Do They Know Their Rank,” by Monica Heyl is available in the Spring 2010 edition of CBRNe World Magazine.

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Monica Heyl is an internationally recognized mobile laboratory expert.  She Co-founded,  Monica Heyl and Associates after retiring from the United States Department of Defense, US Army. This firm specializes in field analytical solutions particularly in high hazard environments. Her 35 years of service included a range of leadership positions, including: US Army Senior Leader; Director of International Programs and Leader of the US Army’s Mobile Laboratory & Kits (ML&K) Team and the Advanced CBRNE Training Team.

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 CBRNe World  is a internationally distributed quarterly publication based in the UK. The magazine is geared for professionals in a range of fields where their work involves “planning for or responding to a chemical, biological, radiological, nuclear or explosives (CBRNe) threat or incident.”  According to the publishers, the CBRNe World content spans the “divide of operational and scientific, it brings together opinion formers from the world of civil response, military leaders, academia, government agencies, research labs and industry.”

What type of airflow should be used in a Class III BSC?  Is higher velocity better?

Class II BSC vs. Class III BSC Airflow

Unlike Class II BSC which employs laminar flow to protect personnel, the Class III Biological Safety Cabinet does not have an open sash in the front, hence does not require laminar airflow to provide personnel protection.  The main consideration for laminar air flow in a Class III BSC is for product protection.  Laminar flow could be important if an internal process generates copious amounts of aerosol, when work is conducted with fine powders, or if there is a risk of cross-contamination between different procedures being performed in the cabinet. Laminar air flow has a set mass airflow where clean HEPA filtered air comes from one direction at a given speed to entrain particles and carry them directly to the exhaust HEPA. The velocity can be very low, as low as 30 ft/min. However, note that 30 ft/min may cause extremely fine powders to become aerosolized. 

Generally, Class III Biosafety Cabinets use turbulent air flow designs. In a turbulent airflow design clean HEPA filtered air is continuously supplied to the cabinet where it dilutes the concentration of aerosolized particles by carrying them to the exhaust HEPA. This is a more passive mechanism of particle removal as compared to that of the air current generated when laminar airflow is established. The rate at which the particles are exhausted depends on the supply velocity (which is equal to the exhaust velocity). In reality, work in a Class III BSC is conducted methodically and carefully.  Most activities conducted in a Class III BSC produce minimal aerosols so turbulent airflow is the norm.  Turbulent airflows are easily adjustable and can have lower air velocity than those required to maintain laminar airflow, hence can pose less of a problem when working with fine powders.

Another question that comes up is whether the Biological Safety Cabinet should be operated at high airflow velocity to remove particles more rapidly.  Typically higher velocity airflows are used when working with volatile chemicals, but not with microbiological agents or toxins.  High velocity airflow can inadvertently, and very effectively, cause powders to be disseminated throughout the interior of the BSC.

A decision regarding whether laminar or turbulent airflow is needed, and the velocity of supply air required for operations should be made based on the anticipated work and user needs. Use of laminar air flow in a Class III Biosafety Cabinet will typically increase the volumetric supply and exhaust airflow  as compared to a BSC using turbulent airflow.  Higher velocity airflow will similarly increase volumetric supply and exhaust as compared to maintaining low velocity airflow.  Increased exhaust flow rate from the Class III BSC should be considered during facility and HVAC design if the cabinet is connected to facility supply air and is to be exhausted out of the building.

Three events have come together in the past few years that codified a need for rapidly deployable, mobile and cost effective containment equipment.  First, there was recognition that many regions and countries in the world did not have adequate infrastructure, reliable power, or primary containment to provide a safe environment when working with emerging, re-emerging and dangerous infectious agents. In the US and elsewhere following the 2001 anthrax letters Public Health Labs and First Responders began experiencing an increase in their mission scope to collect, transport and perform analysis on unknown samples that may contain biological or chemical hazards. That mission had increased significantly due to copycat, hoax and criminal activity.  In the same timeframe, advances in biomedical research created a need to move samples, animals and materials from room to room, or into and out of imaging suites and equipment while maintaining containment.  In response to these needs portable Class III Biosafety Cabinets, flexible film isolators and compact, easily deployable hybrids were developed and refined.

Portable Class III Biological Safety Cabinet

SEA benchtop (Portable)

Small, bench top units were developed that provide safe, effective and affordable primary containment (i.e. SEA) enabling flexibility for laboratory use or field deployment. It was originally developed for diagnostic screening of unknown and highly pathogenic samples in facilities, laboratories or field settings that lack reliable secondary containment controls.  The closed system decreases the chance of aerosol escape, resultant accidental exposure and potential laboratory acquired illnesses.   

In animal research, portable battery powered Class III BSCs are increasingly being used to move animals from holding rooms to procedure rooms.  The supply is single HEPA filtered, the exhaust is double HEPA filtered as required by the CDC (Download BMBL 5th Ed. pdf).  By use of large RTPs integrated into transporter carts of Class III design, the walls of animal holding rooms, and stationary Class III systems, scientists can safely transport exposed animals from holding rooms to procedure areas equipped with devices such as magnetic resonance imaging (MRI), positron emission tomography (PET), and other non-invasive scanning devices. The systems reduce personnel and environmental exposure and reduce the time the animal must be handled and anesthetized.

 

Class III animal transfer with RTP dock

SEA with passthrough and legs built in

        

 

 

 

 

 

 

 

Transportable Class III BSC

All hazard reciept Transportable Class III Biological Safety Cabinet

Transportable Class III Biological Safety Cabinets are used in Public Health Laboratories for the receipt of unknown hazardous samples associated with chemical or biological terrorism or criminal activities.  Workers use the transport BSCs to move the unknown hazardous sample from the loading dock area or other delivery site used by the First Responder, to the containment lab without risking contamination of non-contained and public areas, as well as the containment lab itself.

Taken together, the advent of the use of transport and mobile Class III BSCs provides a significantly safer way of moving and handling infected animals or unknown samples than any past capability.

 

 

Flexible Film Isolator

Transportable flexible film isolator

The negative-pressure flexible-film isolator is a self-contained primary containment device that provides maximum protection against hazardous biological materials. Isolators can be placed on a counter top or on a mobile cart. The workspace is enclosed in a transparent polyvinylchloride (PVC) film that suspended from a plastic or steel framework. Like Class III BSC, the supply air passes through one HEPA filter and exhaust air passes through two HEPA  filters.

WHO recognizes the double HEPA exhaust obviates the need to duct exhaust air outside the building.  Flexible-film isolators are used frequently and very successfully in animal containment, field work and other instances where it is not feasible to install or maintain conventional BSC.  Hybrids (semi-flexible film isolators) exist where some of the panels are made of a rigid material such as polycarbonate, and typically the front panel is soft PVC.

 

 Deployable Isolators 

Field deployable flexible isolator

The deployable isolator unit is a self-contained negative pressure filtration system that operates on two standard D cell batteries.  Supply air is HEPA filtered. Exhaust air is double HEPA or double HEPA and carbon filtered. All filters are readily available and easily replaceable by First Responders and those involved in field collection and preliminary screening and triage. It is a rapidly deployable, light-weight, disposable system that comes in a compact transport case and sets up much like a dome tent. The isolator is made of durable 15mil polyurethane to withstand field use, repeated assembly/disassembly, and can be assembled and operational within minutes for on-demand use requirements.  Large samples and equipment are introduced through a zipper system similar to those on a BSL-4 suit.  Sampling ports are provided for use with external detectors and analytical equipment.         

The diversity in containment equipment is almost limitless and depends on user requirements and design team innovation and advances in materials. 

 

I was at a meeting recently when someone asked, ‘What are mobile and modular BSL-3 labs and when should they be used?”  It is a good question that comes up often.   Deciding  which platform is the best choice depends on the institute mission, size requirements and in the case of mobile labs, the local road conditions.   For example, if the roads are narrow and turns are very tight, a 12.5 meter long truck lab may not be able to navigate the roads, while a Sprinter van would have no problem.

Mobile Labs: Trucks, Sprinter Vans, Trailers

Mobile labs are those labs which can be moved from place to place easily and often by their own power.  They include platforms built into 12 meter long trucks, 4 meter Sprinter vans, and trailers of various sizes (i.e. 6, 7,12 meters).

Rapid Sample Triage and Screening

They are rapidly deployable and often used in incident investigation (i.e. suspicious materials), military and civil preparedness applications (NBC sampling and analysis at high level events), surge capacity at different locations, and in support of testing during natural disease outbreaks.  They are designed to provide on-the-spot rapid sample triage and screening, and presumptive diagnostic capability to assist in prioritizing samples being sent to national reference labs.  
Mobile labs were initially developed in 1986. It wasn’t until the late 1990’s with the advent of decreased size and ease of portability of analytical equipment and prepackaged reagents, and the availability of igh speed communications technology that these labs became increasingly popular.

Hazmat trailer lab interior

They are rapidly available from time of order to time of delivery, and can be cost effective.  Mobile labs are not however meant to be a substitute for fixed labs, rather they augment the mission and provide a capability not possible with a fixed asset.  The advantages and disadvantages various platforms such as trucks, vans, trailers and containers on flatbeds will be discussed in a later blog.

Truck lab with slide out

Modular labs are constructed using containers that are retrofit and finished at the factory then shipped to a location where they are permanently installed.  The containers are fabricated to be strong and durable enough to withstand handling and stacking during shipping while acting as a protective enclosure to the valuable cargo they contain.  Containers come in a variety of sizes and while one container can be turned into a lab, it is not uncommon in the US and overseas to use multiple containers to build a versatile suite of labs with support and change areas, animal housing and a separate mechanical space.  Connecting 3 containers provides a space that is approximately 7.3 meters wide and 12.2 meters long. 

 

Truck lab interior

Once they are installed onsite they become fixed labs and do not move.  These labs are used for teaching, research, public health and as diagnostic reference labs.  

Modular containment labs have become increasing popular over the past 10-15 years.  They do not require the same process for construction approval as ‘stick-built’ labs and are an increasingly attractive solution to providing additional facility space and new technology capability to existing buildings.

  

 

 

 

Truck lab interior 2

Modular labs are designed and assembled by organizations with expertise in biocontainment, making them a sensible solution to providing turn-key containment capability in countries where resident expertise is not yet available or is nascent and would benefit from partnering with experienced entities. 

  

  

  

 

   

 

Modular Laboratories: Rapidly Available | Easily Shipped

They also are rapidly available from time of order to time of delivery (compared to ‘stick built labs’, the container itself is of low relative cost and can house a lab that is custom designed with ample space, and is easily shipped nationally and internationally.

Modular Container - just delivered

Modular container lab interior rm 1

Modular lab interior- rm 2

Sprinter van lab

Sprinter lab interior