Clean Build Protocols Design and Implementation Conor Murray

Cleanrooms have got cleaner: people want them built better, faster and smarter. A modular approach to construction helps to ensure they are built on time, within the budget and have a faster production ramp up.

Establishing design and construction protocols starts with the aim that the project will succeed.

Nobody plans for a project not to succeed! This means that it is necessary to think about unrealistic expectations, changes that might occur and resources, or lack of, available for the job.

The process of construction is divided into whether it is to be done on site or not and whether it takes place in parallel to the existing process or is sequential to it.

Protocols relate to the informative part of standards. Industry is plagued by inappropriate use of protocols. ISO 14644-5 has a clean-built protocol. The bottom line is: either use clean-built protocols, or suffer the consequences of not using them.

Design protocols can vary. Protocol design for Class 1/10 wafer fab has the emphasis on ongoing filtration/clean up whereas all other classes have the emphasis on construction control and viability.

Conor is Chairman of The Irish Cleanroom Society and Group Technical Director of Armac Group Ltd (Eire)

Aches, Pains and Isolators Linda Abbott

At Sheffield Children's Hospital they have run a CIVA service using isolators since 1992. As demand for this service has increased (and consequent increase in workload) so has the incidence of work related aches and pains amongst the staff increased. A common complaint is Repetitive Strain Injury of either neck, shoulders, forearm back, wrists or thumb.

It would appear that this problem is being experienced in other areas where people use isolators. To this end Linda has produced a questionnaire for isolator users and hopes to identify possible causes of strain injuries, how many staff are affected and how much working time is lost through sick leave.

Linda Abbott, Senior Pharmacy Technician, Aseptic Services, Sheffield Children's Hospital [October 2000]

If you would like to get in touch about any problems, or, indeed, solutions, please contact Linda through the Pharmacy Department, Sheffield Children's Hospital, Western Bank, Sheffield, Sl0 2TH. Tel. 0114 2717 488. Email: L.A.Abbott@talk2l.com

Approach to Cleanliness

Neil Bell

From time to time, and no doubt with increasing frequency, those who labour in the field of contamination control come up with a new concept, not just a new improvement. Just-in-time adhesive-contamination-trap machines may have been such a development.

The Just-in-time concept suggests a scenario of car assembly factories that do not wish to be lumbered with large storage costs and solve the problem by making demands on component suppliers to make very precisely timed deliveries. However, on this occasion, it means the logical thought that a very efficient cleaning process should be applied as close as possible to the time and place that cleanliness is required, so that the material has very little time to become soiled again, whatever the environmental air quality.

The principle is applied by bringing an elastomer, with an affinity for particles, into contact with the surface to be cleaned. The properties of the "spent" elastomer can then be restored by contact with a matched adhesive surface that has a still greater affinity for the particles. A machine can then be constructed using a roller coated with the elastomer and a roll supplying up to twenty metres of adhesive-coated film. The elastomer performs its cleansing cycle once per revolution and the used adhesive film accumulates in a suitable location for discard. The machine can therefore perform its task at a significant speed or, at its simplest, can take the form of a hand-held roller and an adhesive pad. In fact, on an individual basis, it seems that the apparatus can readily be integrated with, or even replace, existing equipment.

For those with a quality assurance interest in the process, the discarded adhesive film represents a qualitative and quantitative record of the soil removed and also a "map" record of its spatial occurrence.

The versatility of the system opens up a large number of applications in or outside conventional cleanrooms and indeed may often reduce the need for sophisticated control of the environment. Neutralization of static is easily built into the process and the applications appear to be immense. Examples include successive stages of Bare Printed Circuit Board manufacture, all kinds of printing, laminating and assembly, and hologram printing on such things as credit cards where details are becoming finer at the same time as higher quality products are in demand. The manufacture of copper foil for the laminate industry has already made extensive use of it. Exports in this connection go already to Germany, Luxembourg, USA, Japan, Taiwan and Korea

Readers of The Cleanroom Monitor will be already familiar, through the Nordic News articles, that contamination control has become an important feature in industries far outside of the confines of traditional cleanroom users. This technique promises to expand the concept of contamination control much further still.

Many aspects of the printing industry lend themselves to the "Just-in-time" idea. Among these are the cleaning of high quality gloss materials before printing, the cleaning of images before they are scanned into computer programmes, and the demands of customers for durable printing on glass oven doors, on backlit signs for service stations and telephone booths, and on polycarbonates and other plastics. While the process is essentially one for cleaning flat surfaces, it appears that automotive windscreens, which get more and more curved, also benefit from the treatment. This is particularly beneficial between the laminating stages necessary for the production of safety glass, where reject rates due to dust have been quoted to be as high as ten percent. In addition to this, the implantation of the elements in heated rear windows is a screenprint process which is also dust-sensitive. By contrast, television screens are becoming flatter or, as the jargon has it, flatter, squarer and thinner. They are also becoming larger and more sophisticated, so rejects become ever more costly. Automotive fascia panels that are much brighter and sharper than in years gone past, have benefited from just-in-time, preprint cleaning for a considerable time. Just-in-time cleaning seems set to convince more and more industries that particles that are hardly visible can produce costs that are only too easy to see, if one knows where to look.