17/02/2005

Braby builds vessels for Allergan

For the pharmaceutical industry, purchasing new process vessels can be a time consuming and onerous task. The industry must ensure that their new equipment meets with current legislation, operating procedures and approvals as well ensure that any ancillary equipment is fully integrated and validated for successful operation.

For process engineers wishing to purchase a new vessel, a number of procedures must be completed before a vessel and its ancillary equipment can be legally operated. Allergan pharmaceuticals based in County Mayo, Ireland recently commissioned Braby, manufacturers of silo’s tanks and vessels to update and expand vessels in their clean room facility.

Allergan required stainless steel vessels that could hold 250 litres to 1200 litres of compound liquid pharmaceutical chemicals. Prior to Braby winning the tender they met Allergan to discuss the basic design requirements of the vessels. These early meetings were vital to provide Braby with a detailed brief which would save time if the tender was successful. Details included budgets and operational requirements such as what the vessel would be used for and where. Connor Brennan, Project Engineer at Allergan said “Usually vessel suppliers request that we come up with our own basic design for them to work from. However, this can be difficult for us since although we know what we want in terms of operation – we do not often know what constraints there are. Having Braby in right from the start solved a lot of problems that later down the line would have been a lot more effort to resolve.”

After presenting the basic design to Allergan (which won them the tender) Braby’s first task was to ensure that the vessel would be both operationally functional as well as meet with the strict standards of the pharmaceutical industry. There were also a number of issues that needed to be solved in a hazop study specifically looking at the health and safety aspects of the vessel in terms of operation.

One of the main design requirements were that the vessels were mobile, easily cleaned and had the ability to operate under pressure. Three vessels were also designed with a control panel that would operate the mixer and load cells (to be added at a later date). To provide Alleragn with a clear idea of how they would meet these requirements, Braby used 3D solid modelling which would demonstrate the highest level of functional detail.

Manoeuvrability was solved by adding wheels to the four legs of the vessel. Bending one of the lower support bars inwards and fixing handles to its side, Braby designed a vessel that could be safely pushed without an engineer’s legs becoming entangled. To prevent the vessel from tipping, Braby kept the centre of gravity low and pushed the vessel legs outwards. For those vessels that required future load cell installation, Braby provided alternative designs which would allow the load cells to be inserted into the foot plate assembly.

Other considerations such as the operating pressure and the surface finish (to ensure high levels of sterilisation after use) were also considered at the design stages. The accessibility of the nozzles and man ways were also added to clearly indicate how the vessel would operate on a functional level.

Once the design was complete, the 3D modelling as well as a list of materials, time scales and budgets gave Allergan a clear idea of how the vessel would look, how long it would take to make and also how it would comply with the relevant regulations.

The final design also included the design codes and structural calculations. Design codes are standards of construction guidelines that set down the parameters that can be used for calculation. For example, they will determine the thickness of the metal required when considering the maximum temperature or pressure during operation. Connor commented “the final design’s were in great detail, and although it is usually the pharmaceutical industry’s responsibility to make sure that the design codes meet with the requirements of the vessel –Braby aided Allergan in ensuring the right choices were made.”

Manufacture of the vessels commenced as soon as Allergan approved the final design. It was Braby’s responsibility to source and purchase all the material for the vessel. On arrival it was inspected to ensure it was certified to the relevant standards. This was imperative as this information would form part of the detail in the Quality Assurance documentation for independent inspectors.

Building the vessels was also an intricate procedure as there are many factors such as hygiene that need to be taken into consideration. All welders were required to be qualified to the relevant standard. In addition, many of the welds had to be individually tested for accuracy with constant x-ray’s and inspection. Other inspection’s included Non Destructive Testing (NDT) which included examinations on pressure, vacuum and cleaning. As hygiene was a particularly important issue, Braby tested the cleaning efficiency of the spray heads by using a non harmful dye called Riboflavin. By ensuring that all the dye was removed during the cleaning test, the quality was assured. To complete the testing procedure and to give Allergan third party approval, Braby also used independent specialists to confirm the vessels were manufactured to the relevant standards.

Once manufacture was complete, Braby cleaned the vessel to operational standards before delivery to Allergan. This was achieved by pressure washing, solvent cleaning, passivation (chemically lifting the top surface of stainless steel) and performing constant swab tests for bacteria on the vessels. Braby also coated the vessels with light oil on the outside of the vessels for further protection. Not only did the vessels arrive at Allergan, totally sealed and sterile but they were also fully prepared for operation. All wiring was completed and the Control Panels on three of the vessels were linked to its ancillary equipment. This meant that installation time was significantly reduced.

Before operation can commence however, it is usually the pharmaceutical facility’s responsibility to verify that the quality assurance documentation put together by the manufacturer is correct. The QA certifies that all the components that make up the vessels are checked, certified and recorded to the required health and safety standards. This is often time consuming, especially if the ancillary equipment has been manufactured independently to the vessels since separate QA files are needed. In Allergan’s case however, Braby also sourced the ancillary equipment and consequently provided a complete QA, which could then be verified easily. All Allergan were required to do was verify that the validation of the equipment was correct, and that what was supplied was clearly indicated in the literature.

Connor Brennan said “Braby took this project on in its entirety and worked at all levels from sourcing small pieces ancillary equipment, to designing a bespoke vessel that does just the job. Without the consistent aid of Braby we would have found creating the designs, hazop studies, sourcing ancillary equipment and installation very time consuming. By bringing all these components together and