Cleanroom Protocols
Industrial differences in the control of 'Unwanted Matter'
Cleanrooms are a method of controlling the transfer of 'unwanted matter'. 'Unwanted matter' varies as to the application and process. Generally the cleanest cleanrooms are used for high specification mechanical assembly, i.e. items such as disc drive units.
Mechanical process, such as disc drive assembly, which have very low reader head 'flying heights' and rotating or mechanical seals, can be susceptible to sub micron particle inclusions and subsequent damage. Within the pharmaceutical industry it is also necessary to minimise levels of unwanted matter for their manufacturing requirements in producing 'sterile products'. They do so in a different way, which embodies possibly a more pragmatic method (not available to the operation dependent process of mechanical assembly) by removing at every possible opportunity the major source of contamination – the number of operatives present in the cleanroom.
The pharmaceutical industry further remove the process behind additional mechanical defences such as random access barrier systems, glove boxes and isolators as they are very aware that operators provide not only more than 80% of the contamination in cleanrooms but also the human error and product failure situations. It is also necessary to ensure clean and sterile containers in which to package their products - another process required prior to entering into the cleanroom environment.
Between the mechanical and pharmaceutical processes there are many other disciplines and products that require a level of cleanliness and care. This is needed for either meeting industry standards or for avoiding the possibility of inclusions that would fail the final assembly, or process, producing effectively rejected products – generally an expensive experience.
By virtue of the high levels of regulation, which requires proof of product sterility, the pharmaceutical industry carries high levels of testing and validation of testing. This has, over the development of these systems, made them focus more closely than other manufacturing areas on examining their manufacturing procedures.
BS EN ISO 14644-2 introduces a very visual method for examining requirements of a cleanroom or cleanroom process. This has been referred to as the ‘onion skin’ method of assessment. The centre of the onion is the clean zone, the area that is most important to keep clean. This is protected by a cleanroom, which is further protected by a change area thus adding two more 'skins' of protection. Good practise would dictate, where possible, the employment of additional 'skins'.
In-depth pharmaceutical processes at the highest level would have a clean zone referred to as the 'Grade A' area. This exists in a cleanroom designated 'Grade B'. A 'Grade B' area can only be accessed from a 'Grade B' change area that connects to a 'Grade C' cleanroom. The 'Grade C' cleanroom can only be accessed from a 'Grade C' change area which is accessed from a 'Grade D' clean zone! No less than 6 levels of cascading protection all of which will also have a pressure regime between each physical barrier.
To take it a step further, generally, staff and visitors will, when entering a pharmaceutical manufacturing company also go through an early change area and, where designated, put on overshoes and garments prior to entering the 'Grade D' area.
With the physical barriers established, we need to examine the items, processes and procedures that cross these barriers. A typical list is included on the accompanying diagram.
PROTOCOLS: Items that cross zones or barriers
Such as:
- Personnel
- Product
- Tools
- Servicing
- Cleaning Equipment (Product)
- Cleaning Equipment (Room)
- Testing Equipment
- Occasional Supervisors / Inspectors / Visitors
- Waste Disposal
This list is merely an example. As a rule; by reducing the number of actions / protocols, the chance of transferring 'Unwanted Matter' will be reduced.
This list only illustrates some of the common cross barrier processes that can only be controlled by 'protocols'.
Minimising or removing the protocols is the aim but unless these are carefully researched and identified they are liable to 'bite back' in possibly a very vicious manner.