Specifying the Right Hose Product for Transferring Non-Conductive Solvents in Pharmaceutical Applications

Specification considerations

• Continuously Conductive vs. Static Dissipating
• Materials of Construction Traceability – Class VI Certification / 316L Stainless Steel Connections
• Superior Flexibility across a complete range of sizes, ¼” to 4”
• Easy to clean – Smooth Bore PTFE internal and Silicone external surfaces
• Stainless steel braid for superior hoop strength
• Natural PTFE and Static Dissipating tubing liner
• Trace Ability and Inventory Control – Laser engraving and Molded Silicone Labels

One of the newest technologies in the Pharmaceutical Industry is the manufacturing of Oligonucleotides. The term Oligonucleotide or “Oligo” usually refers to a synthetic laboratory-made DNA or RNA strand.

The “Oligo” process is very different as compared to traditional cell culture therapies posing several challenges for the traditional Life Science professionals. Traditional cell culture is usually an aqueous based batch process followed by Cleaning and Sterilization protocols to reduce potential Bio Burden (organic Compounds) largely responsible for contamination. In contrast, The Oligo process also has some aqueous steps but is generally a solvent based process with little need for sterilization, due to the lack of an organic compound’s ability to live in these solvents.

In addition, the use of solvents like Toluene result in the need to Classify areas within the plant as Class I Division 1 and Division 2 explosion proof.

Continuously conductive protection in a flexible hose

Electricity is the flow of energy in the form of mobile electrons moving in one direction across a conductor. (i.e. a copper wire) Hoses need to be continuously conductive to ground, to be used safely in many applications. However, grounding of continuously conductive hose does not fully protect the hose tube from failures due to static electrical charges.

Static Electricity is a condition when electrons are not moving and are Static because they rest on a nonconductive surface. For example, a natural PTFE Liner in a flexible hose is a nonconductive surface.

When 2 dissimilar solids or fluid insulators are brought together then separated, a static condition can be created. The result of 2 nonconductive solids rubbing together or a nonconductive liquid running over a nonconductive solid (Like in a flexible hose) is called Contact Charging or triboelectrification. Electrons are transferred on contact and remain, generating a static charge. The more contact and separation that occurs (the faster the fluid flows through the hose) the greater the static charge.

How applying a conductor can relax a static charge

Applying a conductor to a static charge allows the charge, over time, to dissipate. This is also known as “relaxation”. In a flexible fluoropolymer hose, a static dissipating liner allows the charge to be reduced and trickle away to earth.

When specifying a hose with a PTFE liner and a fluid with an electrical conductance of less than 10~8 Siemens per Meter, a static dissipating inner tubing is recommended. For example, the solvent Toluene and a natural PTFE tube liner both have very low conductivities. Therefore, as the fluid passes through the hose tubing, a net static charge will build up on the PTFE liner. The faster the flow, the greater the charge.

How Static Discharges can compromise safety and sterility

If the static charge is not dissipated to earth and continues to grow, the charge can become high enough to generate an electrical discharge, penetrating the PTFE liner in search of a path to earth. The result is a dangerous leak to atmosphere. In some cases, where the pressure is low enough, the outer jacket of the hose can trap and contain the fluid between layers. Trapping of fluid or media in a hose due to pin holes caused by a static discharge could be the root cause of product contamination. These events can be avoided by adding a homogenous mixture of carbon black into the PTFE liner before extrusion to reach the desired level of static dissipation.

Natural PTFE vs Static Dissipating PTFE Liners

Ace Sanitary offers both a natural PTFE and Carbon filled Static Dissipating liners in their TSC and TSC-C series hose. In addition, all the TSC and TSC-C hose series materials of construction meet ASME – BPE requirements for material compatibility, and trace ability. MTRs and Certificates of Compliance are available. The TSC and TSC-C hoses are also continuously conductive through the stainless-steel braid connection across both end connection.

What is the best Hose for BioTech and Pharmaceutical Manufacturing Facilities?

In summary, the TSC and TSC-C series of hose is user friendly, offering superior flexibility. Both TSC and TSC-C meet or exceed ASME BPE standards for acceptable materials of construction including all the benefits of a smooth bore PTFE liner. The TSC-C is static dissipating and is recommended for Explosion Proof environments. Both Series are available in ¼” through 3” diameters. Therefore, the TSC and TSC-C series of hose is an excellent choice to meet nearly all applications (Aqueous and Solvent based) in Sanitary or Aseptic Biotech and Pharmaceutical manufacturing facilities.

How to specify sanitary hoses

While the TSC and TSC-C series hose in an excellent choice for many sanitary applications, trying to meet all the applications within a plant with one hose type is often not recommended or cost effective. The experts at Acuity Process Solutions will help you specify the right hose for your application. It is important that you understand the service, temperature ranges, pressure and vacuum ranges, pumping media, and environment for each specification. Orientation and bend radius as well as proper length are critical to the life of your hose. Safe storage and handling can also extend hose life.

How to implement a sanitary hose program

Acuity Process Solutions delivers the expertise to deliver a comprehensive hose management program. Implementing the proper hose identification can enhance trace ability to determine root cause of a failure. Proper PM’s and visual inspection can improve operator safety. Proper storage deployment carts can improve ergonomic safety. Please contact an Acuity Process Solutions expert to learn more about your choices.