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HydroGienic^® is a new concept in piping distribution for high purity pharmaceutical Purified Water (PW) and Water for Injection (WFI) ...
'A Dream Come True'

Honeyman Group is established as a leading specialist in high purity water systems for the pharmaceutical industry and has developed and patented an entirely new and novel concept which is set to revolutionise pharmaceutical water system piping design. In time, this new design concept will become the industry standard, as more and more pharmaceutical companies employ this elegant and effective solution to realise and appreciate its many benefits, advantages and efficiencies over conventional hygienic plumbing methods.

The new concept, registered as HydroGienic^®, complies with all current regulatory expectations, standards and design guidelines for hygienic piping as would be expected. The HydroGienic^® design consists of a combination of new and novel hydraulic considerations, based on standard, tried and tested engineering principles, combined with a variety of carefully selected components and materials from conventional suppliers ranges to complete the novel application packages.

PTFE hose delivery

Instead of using conventional polished stainless steel pipework, manufactured in-situ by a complex and time consuming autogenous Tungsten Inert Gas (TIG) welding process, HydroGienic^® employs a combination of small bore (typically 6.5mm to 20mm), Polytetrafluroethylene (PTFE) braided hoses for delivery of service to then end users. PTFE hoses were chosen for this application as they are ideally suited and widely used and accepted in the pharmaceutical industry for a variety of process applications.

These of course, can be installed in long lengths very quickly and with minimal facility disruption in contrast to conventional stainless steel tubing, which has to be welded every six metres or so over its length, plus three further time consuming welds around every 'Tee' joint and two around each bend/elbow.

The majority of hoses for a typical pharmaceutical water system

will be in the 6.0mm to 20mm size range

In contrast, PTFE hoses can be easily installed on a suitable support system without the need for welded jointing by suitably qualified installation personnel, thus avoiding the need for highly trained 'coded welders'. This means that HydroGienic^® PTFE tubing can be installed even in operational facilities where solvents etc may be in use.  Installation of distribution mains traditionally taking several months to complete, may take only weeks or even days, with the advent of HydroGienic^® design. There are also huge benefits in terms of the low level of resources needed for installation qualification. The validation effort, i.e. certification and qualification of PTFE HydroGienic^® piping installation is of course minimal when compared to that of conventional hygienic stainless steel piping, which involves considerable and rigorous traceability of all materials pipe lengths, fittings, components certifications, visual inspections, welding registrars and logs for each and every weld on the system. PTFE is ideally suited to this application as it is already a preferred and commonly used material in high purity water system components being inert, resistant to biofilm formation, and can tolerate high temperatures and many of the conventional sanitisation chemicals such as ozone, oxonia etc, that may be employed for sanitisation purposes. PTFE hoses of the diameters envisaged, can tolerate in excess of 200 bar pressure and temperatures over 250^oC.

Novel design application (Patented)

The change from conventional stainless steel pipework to PTFE hose is not in itself revolutionary. However, the new HydroGienic^® design enables small bore PTFE hoses to be employed to considerable advantage, as further described and illustrated.

Instead of designing the piped distribution system around the user points in conventional series, with all of the associated hydraulic design problems, the use of small bore hoses allows cost effective installation of users in parallel. In other words, each individual offtake point has a flow and return hose connection back to the plant room vessel through which a minimum flow velocity is maintained.

Parallel arrangement illustration

Parallel arrangement offers a multitude of operational advantages such as 100% diversity capability, ease of adding/removing offtakes without shutting down the system, modular installation i.e. adding offtakes one at a time, enabling temporary and semi-permanent installation to be easily achieved.

The hoses, which are of small bore, individually sized on a user-by-user basis, supply each offtake valve with recirculating water right up to the points of use i.e. without a 'dead leg'. The hoses can be neatly tucked away inside an outer stainless steel sleeve in the user areas i.e. cleanrooms, leading to a vastly superior aesthetic appearance and providing an easy ability to be cleaned in these critically controlled environments.

Conventional offtake arrangement

Conventional installation requires the recirculating pipe loop to be taken to the offtake valve assembly as shown, giving rise to unsightly and messy pipework at the offtake, particularly when insulated. These are undesirable and difficult arrangements to keep clean, and are not consistent with hygienic manufacturing or processing operations.

HydroGienic^® offers a range if very elegant offtake user solutions, which will not only enhance the appearance and operation of any preparation or processing situation, but enables easy cleaning of exposed pipework, examples illustrated below -:

HydroGienic^® offtake arrangements

The HydroGienic^® PTFE hoses may be supplied through a stainless steel sleeve to the offtake user, giving a neater and professional aesthetic appearance, which is much easier to keep clean. The inner sleeve may be internally insulated with expanded foam to protect operators from heat without detracting from the high standard of finish.

Obviously, since the hoses are of small bore, the volume of water flowing to maintain the minimum velocity is also small. Under normal circumstances, higher pressures would be needed to provide sufficient flow under demand conditions (i.e. when the user valve is open), but HydroGienic^® solves this problem by utilising a new and novel hydraulic balancing system within the plant room, thus delivering demand flows at 'normal' pressures over considerable distances.

This change in design to a parallel delivery configuration opens up a plethora of different opportunities and advantages to the system users.

There are a multitude of benefits, some major considerations being listed below -:

• Offtakes can be individually added or removed without the other system users being affected

• Distribution system construction can be modular i.e. future offtakes can be added singly or in groups in accordance with facility development programmes

• HydroGienic^® enables easy hook up of a temporary distribution system to any separate purification system which  could be skid or lorry mounted and could be external to the building

• Individual offtake points and their associated dedicated pipework can be separately sanitised

• Flow/return hoses may be coupled directly to the offtake valves providing zero-deadleg configuration both for hygienicity and sanitisation efficiency

• Systems can be conventionally sanitised with all common sanitisation chemicals, intermittent thermal shocking, or be run permanently at elevated temperatures as per typical WFI installations

• 100% diversity - design can allow for all offtake points to be opened simultaneously within normal operational design conditions

• HydroGienic^TM distribution can be added to an existing system via the storage vessel to serve additional/new users

Validation and qualification

In addition to the many benefits and advantages illustrated above relating to the design, installation and operation of the HydroGienic^® system, there are also considerable advantages over conventional installations when validation and qualification are taken into account. Both the IQ (Installation Qualification) and OQ (Operational Qualification) phases of HydroGienic^® are simple and straightforward to perform. In terms of the plant room installation, which will be predominantly stainless steel as conventional, there will be few changes.

However, installers and clients would agree that the most time consuming part of the installation i.e. the distribution pipework, can be run quickly with minimum facility disruption in PTFE hoses as described, and involves minimal installation qualification effort.

Each PTFE hose can be supplied with a material certificate, plus inspection and pressure test certification and will be fitted with identifying collar(s) along its length for traceability purposes. System 'as-built' drawings will thus simply indicate the position of each installed hose, and will cross-reference the associated certification. There will be no need to examine each pipe length, elbows, bends, tees etc as for conventional stainless steel installations. It will also not be necessary to inspect welding operations or procedures, test pieces etc by visual, X-ray or other Non-destructive techniques (NDT) typically employed to qualify welded stainless steel installations. This represents a major saving in time and effort over conventional construction techniques.

As far as OQ is concerned, all relevant parameters such as pressure, flow and temperature can be easily measured at all appropriate locations. The OQ protocol itself may vary from system to system, and from company to company, but the fundamental data needed for even the most rigorous situation can be easily available from suitable data acquisition points in the HydroGienic® system. The system should of course be validated in accordance with current expectations which require a 'no use' and 'maximum use' operational envelope being defined.

Minimise degrease and passivation effort

Further benefits arise from the setting to work (commissioning) of the system. Unlike conventional stainless steel, there will be no need to go through the rigorous and messy procedure of degreasing and passivation of the distribution pipework to prepare the surfaces and weld zones for use. All that will be required with a HydroGienic^® installation will be an 'as-assembled' pressure test and a flushing before the system is sanitised ready for use. The only degrease  and passivation needed for the system will therefore be restricted to the vessel and associated pipework i.e. in the plantroom, which is much easier to achieve and control.

Minimise 'Rouge' formation

Furthermore, there are an increasing number of hot 'purified' or 'water for injection' systems within the pharmaceutical industry which are exhibiting the alarming phenomenon of 'rouging. This is essentially an oxidation (rusting) phenomenon associated with the use and/or welding of stainless steel under this harsh operating environment. Our experience is that the more people look for rouge , the more it is being found. It is not easy to effectively remove rouge from a system once it is established, nor is it fully understood how best to avoid it and prevent its occurrence. It is however a major and increasing cause for concern at the moment.

Whilst the HydroGienic^® design does not eliminate the use of stainless steel altogether i.e. the storage vessel and plantroom piepwork may still utilise this material, the employment of PTFE hoses for the piping distribution presents a significant reduction of exposed stainless surfaces for water attack, and hence significantly reduces the opportunity for rouge formation in heated, high purity water systems.

Summary

All in all, HydroGienic^® represents a quantum leap forward in the design of high purity water system pipework delivery, which is a significant improvement over existing design in that the system is easier and less disruptive to install, flexible and adaptable in use, neater and more aesthetically pleasing, energy efficient and cost effective. There are no apparent disadvantages over conventional stainless steel systems that are configured in series.

Once users have installed and operated a HydroGienic^® system, they will wonder why anyone would ever want to build a high purity water system in the conventional way involving the plumbing of offtakes in series.