• ByRouging Solutions Editorial Team  ·  12 October 2026

How to Write a Passivation Scope of Work

Three contractors quote for the same passivation job, and the prices are miles apart. One priced a quick spray on the welds. Another priced a full circulation of the loop, with a test at the end and a signed report. The third left out the effluent altogether. Each of them guessed at a job that nobody had written down. A one-page scope of work stops that guessing.

What Is a Passivation Scope of Work?

A passivation scope of work is a short document that describes the job before anyone prices it. It lists the equipment and its condition, the treatment, and the test that proves it worked. It also says who does what on site and which records come back. Every contractor then quotes the same job, so the prices finally compare.

The standards make this your job. ASTM A967 covers "several different types of chemical passivation treatments for stainless steel parts". Yet it "makes no recommendations regarding the suitability of any grade, treatment, or acceptance criteria" for a given use (ASTM A967/A967M-25). In plain words, the standard hands you a menu, and you still have to order.

ASTM A380 says much the same about cleaning and passivation steps. Its choice of procedures "may be specified upon agreement between the supplier and the purchaser" (ASTM A380/A380M-25). That agreement is your scope of work. Write it before the quotes arrive, and the terms are yours from the start.

What Goes in a Passivation Scope of Work?

Eight sections cover almost every job. They follow the order a contractor thinks in. First comes what the equipment is and what state it is in. Then comes what to do and how to prove it. Last come who handles what on site and what lands on your desk. One page is usually enough for a single vessel or loop.

1. Equipment list: tag numbers, steel grade, size and drawing references.
2. Condition: new or in service, plus any staining, where it sits and its color.
3. Treatment: citric or nitric acid, and onsite or in a workshop.
4. Standard: the document and edition to follow, such as ASTM A967/A967M-25.
5. Acceptance test: which test, at which points, and who from QA watches it.
6. Site duties: permits, isolation, water, power, access and the drain route.
7. Records: what the report must show, who signs it and when it arrives.
8. Window: the start date, the working hours and the date the plant gets the kit back.

The exact order matters less than full coverage. A missing section is where the price gaps come from. Each contractor fills the gap with a different guess, and you only find out which guess they made on the day.

How Do You Describe the Equipment and Its Condition?

List every item with its tag number, steel grade, size and drawing reference. Then say plainly whether it is new or has been in service. That one fact changes the job more than anything else. It decides whether passivation alone is enough, or whether another job has to come first.

ASTM A380 covers "new stainless steel parts, assemblies, equipment, and installed systems". It also says it "does not cover decontamination or cleaning of equipment or systems that have been in service". So a WFI loop (water for injection) with three years of running and a reddish film is not a plain passivation job. It needs derouging first, and the scope should say so.

Describe what you can see in plain terms. Note any rouge and its color, from reddish brown to gray-blue, and where it sits. Mark weld repairs, dead legs and any electropolished sections with their Ra value. Add dated photos. They tell a contractor more than three lines of adjectives.

Here is a made-up example of the difference. A formulation plant in Baddi writes "Passivate vessel and loop" and gets three quotes that cannot be compared. It rewrites the line as "Vessel T-104, 316L, new, installed April 2026. Loop WL-2, 316L, in service since 2023, light reddish film at two drops." Now three contractors are pricing one job.

Which Standard, Treatment and Test Should the Scope Name?

Name the standard and its edition, the treatment, and one test with a clear pass mark. ASTM A967 offers "several alternative tests, with acceptance criteria, for confirmation of effectiveness". If your scope leaves that choice open, each contractor will pick the test that suits their own price, and the quotes drift apart again.

Start with the treatment. ASTM A967 lists three kinds: dipping in nitric acid, dipping in citric acid, and an electrochemical treatment. Write down which one you want. Note that A967 is written for stainless steel parts, while A380 also names installed systems, so a loop may sit better under A380. Then say how the treatment gets to the steel, whether it is pumped round the loop, sprayed on, or done in a bath. Our guide on onsite or offsite passivation covers that choice.

The test needs three details: which test, where on the equipment, and who watches it. A pass mark that nobody witnessed is hard to defend later. The tests themselves are explained in our guide to passivation testing methods.

The figures in the last column are illustrations. Set your own numbers, and keep each line short enough that two people read it the same way.

Who Does What on Site?

Write down who does each task. The plant usually looks after permits, shutting off the lines, water, power and the drain. The contractor usually brings the chemicals, the crew, the method and the test. Any task with no owner turns into a phone call on the day, often at the worst time in the shutdown.

Effluent is an easy duty to leave blank. Spent citric solution has to be neutralized and disposed of under your site's own rules and its pollution control consent. Say who does that, where the drums go, and who signs for them. Then nobody argues about it at the end of a long shift.

Water is the next gap. The final rinse needs clean water in volume, and the scope should name the grade and who supplies it. Our passivation shutdown planning guide lists the rest of what has to be ready before the crew arrives.

What Paperwork Should the Scope Ask For?

Ask for the records your auditor will ask you for, and list them in the scope so they are priced in. A report that arrives late or thin is hard to fix after the crew has left. Writing the list down at the start costs nothing, and it saves an awkward call when the inspection is close.

For a finished-dosage plant that supplies the US, FDA rules set the bar. Cleaning procedures must include "A description in sufficient detail of the methods, equipment, and materials used in cleaning and maintenance operations". The same section adds that "Records shall be kept of maintenance, cleaning, sanitizing, and inspection" (21 CFR 211.67).

API plants follow ICH Q7 instead. It says equipment records "should show the date, time (if appropriate), product, and batch number" of each batch processed. They should also name "the person who performed the cleaning and maintenance". Indian drug plants also have the revised Schedule M to meet, which CDSCO notified on 28 December 2023.

So the scope should ask for each item's tag, the chemical and its batch number, the strength, temperature and contact time. Add the rinse, the test result with photos, and the names and signatures. Our note on passivation documentation for audits shows how a full file is laid out.

Mistakes That Make Quotes Hard to Compare

Weak scopes tend to fail in the same few places. The standard has no edition, the test says "as required", and the condition of the steel is missing. Effluent has no owner, and there is no hand-back date. Each gap lets a contractor price a different job, which is exactly what the scope was meant to stop.

Calling an in-service system "new" is the costly one. A crew that arrives for a quick passivation and finds rouge either stops work or does a second job nobody priced. Both cost you a day you may not have in the window.

A missing hand-back date causes quieter trouble. The crew works to their plan, and production works to yours. Write the date and the hour the kit must be back in service.

Once the quotes are in, compare them line by line against your own scope. Our guide to choosing a passivation service provider lists the questions to ask before you sign.

Where to Start

A good scope of work lets every contractor price the same job. Start with the equipment list and the honest condition of each item. Everything else in the scope follows from those two lines, so get them right and the quotes start to line up.

On Monday, walk the line with your maintenance lead and fill in the first two sections. Take photos of any stained welds or drops while you are there.

If you want a second pair of eyes, our passivation team can read your draft and point out the gaps. We reply within 24 hours.

Frequently Asked Questions