Enclosure supplied to Jaguar Land Rover for enclosure of a Mettler Toledo robotic filter comparator

Demands for greater precision in new standards leads to
innovative controlled environment cleanroom solutions

BIGNEAT CONTAINMENT TECHNOLOGY is a manufacturer of modular cleanrooms, enclosures and cabinets for laboratory robotics systems.  The company is a world leader in the pharmaceutical industry where enclosed processes and experimentation require clean air, protection for the operator, or both.  For more demanding processes, Bigneat specialises in the design and construction of controlled temperature and humidity environments.

Demands on the performance of their technology has reached new levels within a system supplied to Jaguar Land Rover and installed at its Emission Test Laboratory at their Product Compliance Centre in Solihull, UK.

The Product Compliance Centre is one of the most modern purpose-built end-of-line facilities in Europe.  The facility is an important element in Jaguar Land Rover's commitment to reducing emissions and working toward greater environmental efficiency.

Background
Until recently, European and Federal legislation has only focused attention on the emission of particulate from diesel engines, also referred to as compression ignition or ‘CI’ sources.  However, in the last few years, legislative amendments on both sides of the Atlantic have seen the introduction of more rigorous standards governing the measurement of particulate emission from both diesel and petrol engines employing direct injection (or ‘DI’) technology.

To date, the quantity, composition and size of particulates from CI sources have proven reliably measured with existing measurement technologies; however, the new requirements for petrol-engined DI sources and the mandatory introduction of diesel after-treatments have resulted in specifications calling for sample masses of considerably lower magnitude.

In order not only to meet these new regulatory standards, but to exceed them, Jaguar Land Rover decided that it would need to upgrade its particulate emission testing capability knowing that it would need to obtain higher precision and more consistent test sample results than has previously been possible.

The Complication
The measurement of particulates in exhaust emissions requires the assessment of filters through which exhaust fumes have passed.  However, the problem encountered here is that sample mass collection and filter paper media can be influenced by secondary factors – such as moisture, dust, electrostatic effects, temperature fluctuations and air buoyancy.

JLR knew that by precise control of air cleanliness, temperature and humidity, it would be assured of consistency in testing conditions and therefore the accuracy of test results.

It was decided that an automatic weighing system, the F-A747 Filter Robot, manufactured by  Mettler-Toledo would be required.  This system allows for up to sixty filters an hour to be weighed to within an accuracy of ±0.1μg – well within present and upcoming US and EU emission standards.

Options for installation of the weighing system included locating it within a cleanroom which JLR would have to build or installation within a bespoke enclosure which would offer greater flexibility in the location of the system.

A specific requirement for JLR was to have good access to the testing equipment for loading and maintenance without a period of temperature and humidity stabilization.  Essentially, this was to be an ‘open’ system.

Bigneat was consulted on the basis of their knowledge and expertise in building and designing enclosures for robotics systems.  Following extensive discussion with Jaguar Land Rover, Bigneat was selected to move forward with design of the new system.

System Development
The challenge in front of Bigneat was twofold.  Firstly, the requirements set forth by JLR specified the development of a high-quality controlled environment system which would allow for constant monitoring and adjustment of the air temperature/humidity balance.  And secondly, the system needed to provide the operator with a high level of protection from potentially harmful exhaust particulates.  With these two broad specifications in mind, Bigneat set about design of the enclosure.

Controlling air temperature and humidity within a clean air system is a technology that is already available within Bigneat’s enclosures; however, in this particular case the very fine control of the air quality required would make the system innovative in many respects.

Bigneat, working from Jaguar Land Rover’s initial design proposal, was able to design an enclosure which fulfilled the ‘open system’ requirement.  Their suggestions lead to the concept of converting an existing room into a cleanroom using the make-up air from the same plant that was running the enclosure.  This ensured that very fine control of the various compartments would be possible within the cabinet with minimum plant running costs.

Operational Features
The clean, particulate free, air supply for the enclosure and the test room is provided by the filtration and conditioning plant housed below the preparation area work bench; air is first passed through high-capacity HEPA Class H-14 filters capable of handling three times the design-flow requirement of 1000m3/hour, filtering with an efficiency of >99.995%.  It is then conditioned by passing it through a chilled water-cooling coil plant to reduce its initial temperature and dehumidify.  A heating element raises the air temperature when it falls below 23°C ±0.5°C.  Steam is then injected into the airflow from a separate humidifier unit to develop the correct humidity.  The entire system is controlled and monitored by a precision electronic control system.

The control system is where precise management of the recirculating and room ‘make-up’ air fan velocities is constantly calibrated.  All operator and service engineer functions, settings and calibration during operation are applied via the menus selected by a ‘soft-key’ control panel.  An audible alarm warns of low airflow conditions.

A significant and innovative feature of the project is the provision of clean air (‘make-up’ air) into the especially dedicated room.  This is achieved by mixing filtered air (unconditioned air) from an external plant mixed with the filtered, conditioned recirculating air, developed within the conditioning plant underneath the enclosure.  Airflow throughout the system, for both the external and internal airflows, is via the HEPA Class H-14 filters.  Contamination risks are minimised (and  consequently, operator safety much enhanced) by virtue of the fact that the preparation enclosure receives both downflow air from the main fan, as well as recirculated inflow of air from the room, creating downdrafts at both the front and rear of the sample storage area.

An absolute requirement specified by Jaguar Land Rover was that the balance table for the F-A747 Filter Robot was to be vibration-free.  Bigneat achieved this by ensuring that the support frame and ancillary environmental conditioning equipment was isolated from (i.e., not secured to) the enclosure.  The main fan blower, which generates all of the enclosure’s internal airstreams is roof-mounted at the rear and right-hand side; the air conditioning unit with its internal fan was similarly located to the far right, but below the preparation enclosure.  Thus in order to ensure a vibration-free weighing enclosure, all moving parts equipment was situated as far away as possible from the weighing compartment.

Status indication of the installed Mettler-Toledo F-A747 robot is provided by a tri-colour beacon system, with a repeater beacon system installed in the outer test room.

The new controlled environment cabinet was subsequently named by JLR as the Tesla Automated Cleanroom 1000.

Air Specifications

Robot Compartment – Clean Air Classification ISO Class 5
HEPA filtration provides ‘downflow air’ to ISO Class 5 classification, with temperature and humidity controlled at positive pressure within the enclosure.  Temperature is maintained between 23°C ± 0.5°C and humidity controlled to 45% RH ± 3% (±1°C dew point).

Preparation and Storage Compartment – Clean Air Classification >ISO Class 6
Filtered and conditioned downflow air is utilised within the preparation area zone, supplementing the test room make-up air and providing a particle free environment at positive pressure.

Operator Protection – Clean Air Classification >ISO Class 6
Room ‘make-up’ air mixes with conditioned, filtered air and is drawn into the preparation compartment zone frontal intake grille via the open aperture and frontal intake grille as ‘inflow air’ to provide a level of operator protection throughout the process of handling filter samples.

Other Custom Applications
Although the application for the Tesla cleanroom has been automotive, the technology is available for many other uses.  Bigneat designs and builds a wide range of customized controlled environment cabinets and enclosures, all tailored precisely to the clients’ needs.  Variations in operational atmospheres can be specified for clients’ particular applications, within the following parameters:  Humidity (<1% to 85% RH); Temperature (4°C to 40°C); Clean Air (ISO Class 5 to EN 14644 Standard); and Modified Atmospheres for aerobic, hypoxic or anaerobic conditions.

Bigneat’s Managing Director, Robert Monks, sees a wide range of possibilities.  He explained that: “The requirements we fulfilled for Jaguar Land Rover are not merely the requirements of the automotive industry but of many areas of the pharmaceutical industry as well, which is a large part of our business.”  Monks says that his company will be taking the expertise developed with the JLR project and applying it to a wide range of applications in such varied areas as blood and cell culture incubation, micro-economic plant and seed propagation, as well as numerous potential areas across the pharmaceutical industry.

Bigneat manufactures clean air and hazard containment equipment for hospitals, laboratories, schools and industry.  Products include fume cabinets (ductless), fume cupboards, fume and dust arm extraction systems, biological safety cabinets, chemical storage systems, controlled atmosphere glove boxes, PCR workstations, powder weighing cabinets, robotics and laboratory automation enclosures.