A facility to make you green

Published: 30-Nov--0001

A £1m cleanroom complex for the manufacture of investigational medical products up to Phase III clinical trials has recently been completed by Cleanroom Solutions. Jan Pyrgies reviews the pharmaceutical protocols and concepts involved

A £1m cleanroom complex for the manufacture of investigational medical products up to Phase III clinical trials has recently been completed by Cleanroom Solutions. Jan Pyrgies reviews the pharmaceutical protocols and concepts involved.

The client, a pharmaceutical product development company focused on a range of therapies, wanted a state-of-the-art development complex that included six process rooms with associated storage, washroom and assembly facilities.

The complex was designed by Cleanroom Solutions to meet grade ‘C’ GMP conditions with varying pressure regimes for pharmaceutical production, storage and cleaning. Process rooms are kept at a negative pressure compared with the main corridor to help prevent cross-contamination. A range of stainless steel grade ‘A’ powder control booths are incorporated into the design for handling powder-generating processes, and stainless steel electrically interlocked pass-through hatches are used to enable items to be moved in and out of the cleanrooms without extra personnel entering the facility, thus saving on consumables.

Frequently pharmaceutical cleanrooms use 100% fresh air to prevent cross contamination of the product as well as provide operator safety. With current ‘green’ issues coming to the fore, this cleanroom was designed to be environmentally friendly by re-circulating the expensive, treated air and using fresh air only for pressurisation. The return air, therefore, had to have extra treatment to make it re-usable.

The return air is passed through a bank of safe-change return air HEPA filters before it is passed back to the air handling unit for re-use. The air is then further filtered before it is passed back to the rooms through terminal HEPA filter units. On average, this design should easily achieve a saving of 30% of the running costs associated with a 100% fresh air facility, owing to the reduction in fresh air volume from 100% to 20%. The savings would be greatest during peak summer time and mid-winter.

The cleanroom air conditioning was designed with optimum running in mind. Both supply and extract fan motors have inverter drive control to optimise airflow at design conditions; additionally the client benefits from reduced running costs.

At the heart of the cooling system is a step-less screw compressor, giving very precise control of the chilled water temperature circulating around the system. This unit was selected partly because the refrigeration system uses refrigerant R134A, which has an ozone depletion factor of zero and also a very low global warming factor. The chiller is matched to a remote air-cooled condenser and both units are linked to the site Facility Management System (FMS), enabling easy access for the end user to monitor operation. A resistive type humidifier was selected to give greater accuracy of control and optimised energy usage. The unit also benefits from a cleanable and re-usable scale collector tank, which ensures longer periods between maintenance.

One of the process rooms required occasional low relative humidity (RH) usage. This was achieved using a totally separate air handling system operating in conjunction with a dehumidifier that when in operation maintains the room humidity at 20%RH. The dehumidifier utilises a speed controlled desiccant rotor, which is optimised by the control system to maximise energy efficiency.

Motorised constant volume boxes are used to maintain and monitor the correct airflows at design conditions.

Control of the cleanroom is achieved using Honeywell’s latest AX facilities management system. The AX range was chosen for its ease of engineering, fast response times and the ability to integrate with other open protocol systems without using expensive conversion hardware. The main plant is controlled from an AX Hawk Controller located within the HVAC control panel. This system is linked via Lonworks Open Protocol to the air handling unit (AHU) inverters and the all-new Spyder constant air volume controllers. The controllers were specially supplied from the US for this project, and are the only ones of this type in the UK at the moment.

These controllers are linked with the room pressure transducers and provide the data for the pressure displays and monitoring equipment. The system also links into the chiller and remote air-cooled condenser, allowing the FMS to view all the operating parameters using a BACnet gateway.

The entire system can be interrogated by password controlled authorised users via the touch screen mounted on the HVAC panel local to the system or alternatively via the computer screen in the facilities offices. The screen displays full graphics of the system together with set points, pressures and other critical data.

Each room is linked to a digital monitoring system, which enables room pressures to be displayed on an LCD readout panel at the entrance to the cleanroom and allows operators to check conditions are in specification before entry. The site FMS also records and monitors the pressures and any alarms that may be generated. In critical rooms additional LCD displays indicate room pressure and lights give a healthy/warning to the operators.

To meet industry standard 21 CFR part 11, an Arena AX Graphical Interface has been installed, which provides and stores all data required for the manufacturing process. The complex was designed to be compact and self-supporting. A steel mezzanine supports the air conditioning services above the cleanroom ceiling as well as supporting the electrical services, piped services and purified water system. All services are easily accessed and maintained from the mezzanine.

Room fabric was chosen to be clean and hardwearing and suitable for a modern pharmaceutical cleanroom. Wall/ceiling and wall/floor joints were coved to enable efficient cleaning. Floor drains in cleaning rooms are stainless steel, double trapped. Walls and ceiling are flush, with all joints silicone mastic-sealed. The nitrogen and compressed air systems all include point-of-use regulators. Air leakage between rooms is minimised by the use of door perimeter seals as well as drop down seals on the floor edge.

From the customer’s various user requirement documents a detailed validation procedure was produced and agreed, including DQ, IQ, OQ. The room has been inspected and approved by the MHRA.

Contact Jan Pyrgies Cleanroom Solutions Ltd PO Box 5156 Hove East Sussex BN52 9GJ UK T +44 1273 760060 F +44 1273 760061

www.cleanroom-solutions.co.uk

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