Low-emission valve packing on a Korean order — API 622, 624 or ISO 15848-1
You are closing out a valve datasheet for a package being built in Korea, and the emissions line reads something like "Packing shall be low-emission type, certified to API 622 / ISO 15848." It looks finished. It is also one of the few lines on the sheet that cannot be priced, because it does not say what gets tested, on what object, against which number.
What comes back is a certificate that is genuine and covers something adjacent to what you meant — a packing product rather than an assembled valve, or a valve one size band away from yours, or a tightness class measured in a gas your plant will never sniff for. The gap does not show up at quotation. It shows up at document review, after the bodies are cast and the trim is machined, when a retest means booking a test bay already committed elsewhere.
What each of these standards actually tests
These standards are not a ladder from loose to strict. They test different objects, and that is the whole problem.
API 622 is a packing test, not a valve test. A packing set runs in a test fixture for 1,510 mechanical cycles and five thermal cycles, and the material is separately checked for corrosion behaviour and oxidation loss. What passes is a packing product with a part number. Nothing has been demonstrated about the stuffing box on your valve.
API 624 is an assembly test on rising-stem valves — gate and globe — built with packing that already holds API 622. It runs on methane, sniffed on the EPA Method 21 basis, for 310 mechanical and three thermal cycles, and no gland adjustment is permitted during the test.
API 641 applies the same construction rule to quarter-turn valves — ball, butterfly, plug — at a higher cycle count, 610.
ISO 15848-1 type-tests a complete valve — stem seal and body joints together — and covers isolating and control valves alike. The test medium is helium or methane, and the result is reported as three classes rather than a pass mark.
ISO 15848-2 is the production acceptance test. Valves are taken off the line and sniffed with helium at room temperature, on a design that already carries a Part 1 type approval. It is the only one that touches the valve you are actually buying.
TA-Luft sits slightly apart. The 2021 revision of the German air-quality instruction took ISO 15848-1 as its test basis, and VDI 2440 was revised to reference tightness class B. A "TA-Luft packing" statement from a packing maker is still a statement about packing.
Reading the clause you already have
| What the clause says | What it actually asks for | How to confirm it | If you read it wrong |
|---|---|---|---|
| "Packing shall be API 622 qualified" | A packing product test on a fixture | Packing maker's report, matched to the packing part number on the valve bill of material | You hold no evidence about the assembled valve; the stem and stuffing box were never tested |
| "Valve shall be API 624 tested" | A rising-stem assembly test, plus API 622 behind the packing | Type test report for the tested valve, and the API 622 report for the packing fitted to yours | A ball or butterfly valve cannot hold it; the shop quotes API 641 instead or asks for a deviation |
| "ISO 15848 certified" | Nothing enforceable yet — no classes named | Name tightness, endurance and temperature class, plus the test medium and the edition | Each maker prices against whatever it already holds; two quotes stop being comparable |
| "Class B" | Tightness only, medium unstated | Write BH or BM — helium or methane — and say which | Helium and methane results do not convert into each other; you cannot compare the two reports |
| "TA-Luft packing" | A packing supplier statement | Ask which ISO 15848-1 class and edition it is written against | Packing qualification is treated as valve qualification during document review |
| "ISO 15848-2 at FAT" | A sniff test on production valves | Lot size and sample count fixed in the purchase order, then carried into the inspection plan | With no Part 1 type approval behind it, there is no class to accept the result against |
An ISO clause needs three classes, not one letter
ISO 15848-1 classifies on three axes, and a requirement that names only one of them is not a requirement.
- Tightness class — A, B or C, carrying a letter for the medium — H for helium, M for methane. On methane in the 2015 edition the limits run AM ≤ 50 ppm, BM ≤ 100 ppm, CM ≤ 500 ppm. Helium is reported instead as a mass leak rate normalised to stem diameter — milligrams per second per metre of stem diameter — and the standard states no correlation between the two media. Pick one medium and stay in it.
- Endurance class — how many mechanical cycles the seal held for. Isolating valves run CO1, CO2 or CO3 at 205, 1,500 and 2,500 cycles. Control valves run CC1, CC2 or CC3 at 20,000, 60,000 and 100,000 cycles, with thermal cycles increasing alongside. This is where most of the cost sits, and most of the misapplied specification: a clause drafted for isolation valves, pasted onto a control valve datasheet, asks a throttling valve to prove itself against a shut-off duty cycle.
- Temperature class — the classes span cryogenic service up to 400 °C. The class tested has to cover your design temperature, not sit near it.
Name the edition as well. The classification changed between the 2006 and 2015 editions and Part 2 has been under revision; confirm the current edition before the specification is issued, not after a certificate arrives written against another one.
Which valve was actually tested
A type test qualifies a design, and the standard allows that qualification to extend to valves that were never physically tested — which is normal engineering practice, not a shortcut. Section 8 of ISO 15848-1 sets the envelope. Broadly, the untested valve has to share the tested valve's materials and sealing design, sit at an equal or lower pressure class, run at or below the tested temperature and pressure, carry a stem diameter between half and twice the tested stem, keep stem seal height within roughly 75 to 125 percent of the tested arrangement, and meet a tightness class no more severe than the one achieved.
So the useful question at bid stage is not whether a certificate exists, but which valve was on the test rig and whether yours falls inside that envelope. That is answered from the cover page of the test report: tested size, pressure class, stem diameter, packing part number, and the three classes achieved. Any shop holding the certificate can send those five items in a short reply, and the answer either closes the point or puts a new type test in scope — a price and a schedule, not a dispute.
Ask for it in the request for quotation. Asking after the purchase order converts a paperwork question into a delivery problem, and it is the same conversation you want to have about the seat leakage class on the same quotation, where an equivalent mismatch of standards is waiting.
Nothing on your valve is tested unless the inspection plan says so
A type test is a design event. It happened once, in a laboratory, possibly years before your enquiry, on a valve later cut up or shelved. Everything downstream of it is paper linking that valve to yours.
If you want a measurement on the hardware you are paying for, ISO 15848-2 is the instrument. It runs on helium of stated purity, sniffed at room temperature at a default test pressure unless another is agreed, on a lot sample drawn at random. The sampling percentage is agreed between maker and purchaser, with one valve per lot as the floor. Both numbers belong in the purchase order and then the inspection and test plan. A sample rate that first appears at the works is a sample rate somebody has to concede. The rest of the inspection sequence is covered in what a first-time buyer meets on a Korean valve order.
One thing worth checking early: whether the packing part number that appears on the type test report is the one written on the bill of material for your order. Packing products get superseded, and a maker's current standard packing may be a later item than the one tested. It is a two-line comparison, much cheaper while the datasheet is still open. Severe-service and throttling valves bite hardest here, since gland arrangements on those bodies — the KOSO 501T, or the severe-service designs from Kent Introl — are specified per order rather than pulled from a standard build.
If the valve stays in Korea, a second number waits for it. Valves, flanges and connectors in refining and petrochemical service fall under the fugitive-emission facility management scheme of Korea's Clean Air Conservation Act, and the operating company runs an LDAR programme against it — tagged components, periodic monitoring, repair within a set period. The scope and the thresholds have been revised more than once, so confirm the current requirement with the end user rather than carrying it over from a previous project. Which of those certificates has to travel with the valve rather than stay in a supplier file is set by the owner's specification, not by the test standard, so it belongs on the vendor document list at order stage — the same list that carries the rest of the documentation the site expects with the goods.
When the stricter standard is the wrong certificate
The usual advice is that ISO 15848-1 is the more demanding document — whole valve, higher temperatures, far more cycles — so specify ISO and you are covered. Most of the time that holds. Here is where it does not.
Take rising-stem gate and globe valves going into a Korean refining unit whose operating side runs its LDAR rounds on a sniffed ppm reading from the installed valve. Specify ISO 15848-1 class BH and you receive a helium mass-rate figure. It is the stricter test by almost any measure, and it converts into no ppm screening value, because the standard declines to correlate the media. The plant then monitors against a threshold with no relationship to the certificate in the file, and at the first round nobody can say whether the valve meets its specification. The fix is not to drop ISO but to name the methane class — BM, reported in ppmv — so the certificate and the monitoring round share a unit. Where the maker only holds a helium type test for that body, the API 624 report is the weaker test and the more useful evidence, because it is measured the way the valve will be measured for the rest of its life.
The driver is not which standard is stricter, but which number the plant will be measured against, and whether your valve type sits inside the scope of the standard you named.
If you want the wording checked before it goes out, send us the emissions clause as it stands in your specification, with the valve type and size range. What comes back is which of these tests the makers here already hold for that combination, and which one needs a new type test.