Passivation Services

Ask which standard they work to and whether it will be named in the report, ASTM A967 for passivation and ASTM A380 for cleaning and descaling. Require the verification method to be stated before the work begins. Ask how they prove coverage of the whole flow path rather than that chemistry merely circulated. Confirm they pre-clean, since passivating over grease, heat tint or weld scale achieves nothing. Ask whether they can remove heat tint, confirm they neutralize spent chemistry, and require the documented package indexed to your IQ checklist.

The written procedure actually followed on that system, the chemistry with concentration and batch, measured temperature and contact time rather than specified values, evidence of pre-cleaning to ASTM A380, confirmation of flow path coverage, final rinse quality and neutralization endpoint, the verification method and its measured result, operator and date for traceability, and how spent chemistry was handled. A generic procedure not tied to the specific system is weak evidence at audit.

It depends on what is being passivated, because there are two different industries. Metal-finishing job shops immerse loose parts in a bath at their own facility, which is correct for components and fabricated parts. Installed systems such as WFI loops, vessels and sanitary piping runs cannot be shipped anywhere and must be passivated in place by a contractor circulating chemistry through the system. Paul Industries performs in-place passivation to ASTM A967 with ASTM A380 pre-cleaning, nationwide, on our own installations and on systems built by others.

Job-shop passivation immerses loose parts in a bath, so chemistry coverage is inherent. In-place passivation circulates or fills chemistry through an installed system, so coverage has to be engineered and proven. That is the key risk difference: an in-place job can run the full contact time and still leave branches, high points or dead legs untreated because flow took the path of least resistance. Immersion cannot fail that way, which is why coverage evidence rather than contact time alone is what to require.

Almost always. Welding destroys the passive layer in the heat-affected zone and leaves heat tint and weld scale, which become the corrosion and rouge initiation point. Any weld into an installed stainless system, including an emergency repair, requires re-passivation of the affected section to ASTM A967 with pre-cleaning to ASTM A380, verified and documented. A repair that stops a leak without re-passivation can create a contamination source months later.

There is no universal interval. Passivation is always required after installation, after any weld or repair, and after mechanical work that embeds free iron. Beyond that, frequency is set by service duty: hot WFI and clean steam systems degrade fastest and need the most attention, ambient purified water less so, and food process lines are usually tied to the shutdown cycle. The right approach is to monitor for rouge and let the monitoring set the interval rather than guessing a calendar figure.

Set it from monitoring rather than a fixed schedule. Re-passivate immediately when rouge appears, since rouge is direct evidence the passive layer is failing, and after any chemical excursion that could have stripped it. For routine intervals, use rouge inspection and service history: a system showing no rouge does not need re-passivating on a calendar, and a system that rouges at nine months does not care that the procedure says annually.

Commissioning is the engineering activity of making the system work: checking installation, running it, tuning loops, resolving punch list items. Qualification is the documented, regulated evidence that it was installed correctly (IQ), operates across its range (OQ) and performs consistently for the intended process (PQ). Commissioning proves it functions; qualification proves it, in a form an inspector accepts. Well-run projects align the two so commissioning evidence feeds qualification rather than duplicating it.

For in-place work proximity matters far less than buyers expect, because the crew, heated circulation equipment, chemistry, containment and test kit all travel regardless of where the contractor is based, and mobilization is a fixed cost spread across a job measured in days. What genuinely turns on distance is emergency work. For planned passivation the questions that matter are which ASTM A967 treatment class will be used and why it suits your alloy, how cleanliness is verified before acid is introduced, what the rinse endpoint is expressed as a water quality, and who neutralizes and disposes of spent solution under whose permit. A local shop that immerses parts may hold none of that in-place capability.

In-place passivation of a distribution loop typically runs $6 to $18 per linear foot, vessel interiors $3 to $9 per square foot, and shop immersion of loose parts $2 to $9 per pound in volume. Acceptance testing to ASTM A967 adds $500 to $3,500 per system and the documentation package $800 to $4,000. Nitric chemistry generally carries higher neutralization and disposal cost than citric, which is a large part of why citric has displaced it across much of the pharmaceutical sector. The variable that moves a quote most is the surface condition beforehand: a system needing derouging first, at $12 to $35 per linear foot, can cost several times one that does not.

Industrial passivation differs from hygienic work and the screening changes accordingly. The concern is corrosion resistance rather than bioburden, so acceptance testing tends toward salt spray, high humidity or copper sulfate rather than the full ASTM A967 documentation package a pharmaceutical system needs. Alloy range matters more, since industrial work spans free-machining grades, martensitic grades and duplex, each needing different chemistry and concentration to avoid flash attack. Ask which treatment class they propose for your specific grade and why, whether they have treated that alloy before, and how they handle mixed-grade assemblies, because a single recipe applied across grades is how a passivation job damages the surface it was meant to protect.

Medical device passivation is a distinct specialism and the reference standard is different. ASTM F86 covers surface preparation and marking of surgical implants and applies alongside ASTM A967, and the work is governed by the Quality System Regulation rather than drug cGMP. Most device work is on discrete components rather than installed systems, which means shop immersion is appropriate and produces more uniform results than any in-place method. The concerns shift toward particulate, residual manufacturing materials and biocompatibility rather than the rouge and bioburden that dominate a pharmaceutical water loop. Ask any provider whether they work to ASTM F86, what cleaning precedes treatment, and what documentation they supply for a device history file.

ASTM F86 is the practice for surface preparation and marking of surgical implants and is the device-specific reference, applied together with ASTM A967 for the chemical treatment itself and ASTM A380 for the cleaning and descaling that must precede it. ISO 13485 governs the quality system under which the work is performed, and the results feed the device history record. What differs from pharmaceutical work is emphasis rather than chemistry: cleanliness verification focuses on residual manufacturing materials and particulate, biocompatibility considerations apply where the device contacts tissue or blood, and traceability is expected at batch or even individual component level. A provider who treats device work as ordinary industrial passivation will not produce documentation a device auditor accepts.