NDT in Pharmaceutical Manufacturing

What can fail, and why it matters

Pharmaceutical failures rarely look like a dramatic structural collapse. They look like a crevice in a weld that harbors bacteria and defeats cleaning, a pinhole in a heat exchanger that lets a utility fluid touch product, a corroded vessel wall, or a vial whose seal lets in air and microorganisms. Any of these can mean a lost batch, a deviation investigation, a regulatory observation or a recall. When the product is a sterile injectable, patient safety is directly at stake.

Because so much depends on equipment being exactly what it was validated to be, pharmaceutical companies care about inspection twice: once when equipment is built and installed, and again throughout its service life.

Where NDT is used

Hygienic process piping and tubing. Product-contact systems are typically built from austenitic stainless steel tubing joined by automatic orbital welding. The inside of those welds is what the product sees, so it is inspected:

• Visual and borescope inspection (VT) of the weld's internal surface checks for full penetration, discoloration, concavity, misalignment and other features that could trap product or resist cleaning. Sample welds (coupons) are commonly made and examined to confirm the welding setup before and during production.
• Radiographic testing (RT) is used where specifications call for it, to examine weld soundness through the wall.
• Positive material identification (PMI), often by portable X-ray fluorescence, confirms that the right alloy was installed, since a mix-up can lead to corrosion later.

Pressure equipment. Reactors, fermenters, autoclaves, sterilizers and clean-steam generators are usually pressure vessels. Their welds are examined during fabrication with RT or UT, and surface methods such as liquid penetrant testing (PT) are used on stainless welds. In service, ultrasonic thickness measurement tracks wall loss, and inspections look for stress-corrosion cracking and pitting in chloride-bearing environments.

Heat exchangers. Plate and shell-and-tube exchangers separate product from utilities. Leak tests — pressure, dye or tracer-gas methods — check that the barrier is intact, and eddy current testing (ET) can assess the condition of tubes.

Isolators, lyophilizers and cleanroom systems. Enclosures that maintain sterility or containment are leak tested, and freeze dryers are tested to confirm their vacuum integrity.

The final container. Container closure integrity testing (CCIT) checks that vials, syringes, cartridges and bags stay sealed. Deterministic, nondestructive methods — such as vacuum decay, high-voltage leak detection and laser-based headspace analysis — are widely used because they give a measured result and leave the unit intact.

How inspection fits into the equipment lifecycle

Design and fabrication. Specifications set the materials, surface finish, weld inspection and documentation. The fabricator performs and records the examinations.

Installation and commissioning. Field welds are inspected and documented in weld logs and isometric drawings, so every weld can be traced to the welder, the procedure and the inspection. This turnover package becomes evidence during qualification (IQ/OQ/PQ).

Operation and maintenance. Periodic inspection of vessels, rouge and corrosion monitoring, heat exchanger leak testing and CCIT on stability samples or production lots keep the validated state intact. Any repair weld is a change, and it needs the same inspection and documentation as the original.

Standards and regulations

• ASME BPE (Bioprocessing Equipment) is the reference many owners specify for hygienic design, materials, surface finish, orbital welding and weld examination in product-contact systems.
• The ASME Boiler and Pressure Vessel Code, including Section VIII for pressure vessels and Section V for nondestructive examination methods, governs much of the pressure equipment, with jurisdictional requirements varying by location.
• FDA current good manufacturing practice (cGMP) regulations for drugs, in 21 CFR Parts 210 and 211, expect equipment to be of appropriate design, construction and maintenance. They do not prescribe NDT methods, but inspection records are part of how a firm demonstrates it.
• USP general chapters on package integrity, and ASTM test methods for container and package leak testing, describe how CCIT methods are selected and applied.
• Industry guidance, including from ISPE, is widely used for commissioning, qualification and good engineering practice.

NDT personnel on pharmaceutical projects are commonly qualified under ASNT SNT-TC-1A (Level I, II and III) or to the requirements of the applicable ASME code section. Borescope and visual weld inspectors should be trained on the specific acceptance criteria the owner has adopted, which are often stricter than general industrial practice.

What this means for owners and buyers

If you are buying process equipment or a skid, specify the inspection in the purchase order rather than assuming it. Say which welds get borescope or radiography, what percentage, to what acceptance criteria, and what documentation you expect at turnover. Ask how the fabricator qualifies its inspectors and calibrates its equipment. Review the weld documentation before the system is installed, when problems are still cheap to fix.

If you operate a facility, treat inspection data as part of your asset history. Trending wall thickness, leak-test results and CCIT outcomes over time is far more useful than a pile of pass/fail certificates, and it gives you a defensible story when an auditor asks how you know your equipment is still fit for use.

How NDT LLC can help

NDT LLC helps pharmaceutical and biotech owners, engineering firms and fabricators specify inspection, review weld documentation, develop procedures, and audit inspection vendors. If you have a project in design, a turnover package to review, or a leak or corrosion question in an existing plant, contact us.