What your WPQR covers: EN ISO 15614-1 range calculator
Enter the test piece data and the calculator shows what the WPQR covers: thickness, diameter, positions, heat input, preheat and interpass temperature. Level 2 is calculated — the familiar ISO 15614-1 ranges.
Short answer
One test piece does not qualify one thickness; it qualifies a range around it. A multi-run weld on a 12 mm test piece covers 3–24 mm, and a 114.3 mm pipe covers everything from 57 mm upwards. That is why the test piece is chosen not for ease but for the range it buys. The calculator below gives that range for level 2 of EN ISO 15614-1.
Level 1 and level 2
The 2017 edition introduced two levels of qualification. Level 2 carries the earlier ISO 15614-1 ranges — they did not change, and existing records stayed valid. Level 1 is built on ASME IX and asks for less: it appeared for shops working to EN 1090 execution class EXC2 and on lightly loaded structures, where the full test programme cost more than the work justified.
There is a direction between the levels: a level 2 record also serves level 1 work, but not the other way round. The calculator works out level 2; level 1 has its own table taken from a different code, and one cannot stand in for the other.
The material group coverage to ISO/TR 15608. That table was reworked in 2017 more than the others, and its “parent material 1 — parent material 2” matrix reads ambiguously in secondary sources; putting a plausible-looking figure here would mean deciding on the inspector’s behalf. The principle is set out below in words, and a particular pair belongs in the standard itself.
Level 1 is left out too: it has its own ranges, and mixing them with level 2 in one document is not allowed.
Rules worth remembering
Positions. As long as there are no impact or hardness requirements, one position covers them all — the position simply is not an essential variable, except vertical-down PG and J-L045, which only a test in that same position covers. The moment impact testing is required, the positions covered are those with the same or lower heat input; for hardness it is the reverse, the same or higher. If both a high and a low heat input position were tested, everything between them is covered.
Heat input. With an impact requirement it is capped from above: no more than +25 % of the tested value. With a hardness requirement it is held from below: no less than −25 %. The logic is simple — overheating ruins toughness, and cooling too fast raises hardness.
Material groups. In groups 1 to 3 the sub-groups are not counted: the steels covered are those of the same main group with equal or lower specified yield strength. In the other groups it is the same sub-group, sometimes together with the lower ones. A test on 304, for example, covers 316, 347 and 321, but neither 309 nor 310.
Where the values come from
The thickness table, the position rules and the heat input tolerance come from the open review of EN ISO 15614-1 on gowelding.com; the 2017 changes (the “test piece up to 3 mm” row, preheat and interpass) from the review on weldnote.com; the position rule is confirmed by TWI material, and the “plate qualifies pipe” rule by the Polish wikiweld. The links are collected at the end of the page.
I do not have the full text of the standard, and I say so plainly: the values are for guidance, and its text together with your own record settles any dispute.
Sources
- gowelding.com — European Welding Standards (PDF)
- weldnote.com — ISO 15614-1 (2017): Changes and Updates
- TWI — Weld Procedure and Welder Qualifications (PDF)
- wikiweld.pl — Zakres kwalifikowania technologii EN ISO 15614-1
How to use the calculator, step by step
- Weld type and runs. Pick butt or fillet, and whether the test piece was single-run or multi-run. For a fillet, also enter the throat a — without it the throat range shows only as a formula.
- Test piece thickness and diameter. Thickness t is the parent metal thickness of the test piece, not the weld. Leave diameter at 0 for plate.
- Position and test requirements. This is the key field: with no impact or hardness requirement the position range is full (except vertical-down PG and J-L045); with them it narrows through heat input.
- Material, preheat and interpass. Enter the temperatures actually measured on the test piece, not those in the pWPS. For stainless, duplex and nickel alloys choose the second option — there interpass gets no allowance.
The result appears straight away above the form; the full range sheet downloads with the CSV button. Run the calculator twice: before welding the test piece (to choose it) and after the tests (to check against the report).
Worked examples
12 mm plate, multi-run butt, PF, with impact testing
Input: butt, multi-run, t = 12 mm, plate, PF, impact required, steel, preheat 100 °C, interpass 250 °C. The calculator gives:
| Variable | Range | Why |
|---|---|---|
| Parent metal and deposit thickness | 3–24 mm | row 3–12 mm, multi-run: 3 mm to 2t |
| Diameter | pipes over Ø 150 mm in PA and PC rotated; Ø 500 mm and above in the other positions | plate test piece |
| Positions | same or lower heat input | impact required |
| Heat input | ≤ +25 % | impact required |
| Preheat | not below 50 °C | 100 − 50 (2017 edition) |
| Interpass | not above 300 °C | 250 + 50 |
The calculator also adds a separate line: the upper thickness limit drops to 12 mm when impact is required but no impact test was carried out. So 24 mm holds only if impact specimens from this plate were actually tested. PF is a high heat input position, so it also covers PA as long as its heat input does not exceed the test piece’s; PG needs a test of its own.
Stainless pipe Ø 273 × 8 mm, H-L045, no requirements
Input: butt, multi-run, t = 8 mm, diameter 273 mm, H-L045, no impact or hardness requirement, stainless, preheat 0, interpass 150 °C. Result: thickness 3–16 mm, pipes from Ø 136.5 mm upwards (half the test diameter, no upper limit), all positions except PG and J-L045, heat input not limited, preheat not applicable, interpass 150 °C “as used”, because the +50 °C allowance does not apply to austenitic steel.
Single-run fillet a = 4 mm on 10 mm plate
Plate 5–12 mm (fillet table: from max(0.5t; 3 mm) to 1.2t), throat 3–6 mm (0.75a–1.5a). Had the test piece been multi-run, the throat would have no restriction. That is a good reason to weld the fillet test piece the way production does, not as a quick single run.
How to choose a test piece that covers production
Start from the list of thicknesses and positions on the drawings, not from whatever plate is lying around. A multi-run butt test piece in the 3–12 mm band covers 3 mm to 2t — so 12 mm gives 3–24 mm and 6 mm only 3–12 mm. Above 12 mm the range is 0.5t–2t: a 20 mm test piece covers 10–40 mm but not 8 mm. If production runs from 4 to 30 mm, one test piece will not do, and it is better to plan two than to find the gap at acceptance.
Positions work the same way: without impact requirements any one will do, so weld the easiest. With impact — the highest heat input position you expect in production (usually PF), because it covers positions with lower heat input. Work out the test piece heat input with the heat input calculator — it sets the upper limit in the WPS.
Common mistakes when reading the range
- The butt table used for a fillet. Fillet welds have their own plate thickness table; a 10 mm fillet test piece covers 5–12 mm, not 3–20 mm.
- “One position covers all” with impact required. That rule only works with no impact or hardness requirement.
- The +50 °C allowance on stainless. For austenitic, duplex and nickel alloys interpass stays as used on the test piece.
- pWPS temperatures instead of measured ones. The range is based on what happened on the test piece, not on what was planned.
- Mixing up levels. A level 1 report does not do for work that calls for level 2.
The range of a qualified procedure goes into the WPS; the test piece itself is described by a pWPS from the generator, and the test result by the WPQR. The welder’s range has its own ISO 9606-1 calculator.
Frequently asked questions
Which level should I go for, one or two?
Level two is stricter and covers both kinds of work; level one is cheaper and enough where the structure is lightly loaded and the client asks for no more. Convenience does not decide it — the order specification does: if that names level 2, level 1 will not do under any circumstances.
Why are the material groups not calculated?
Because their table was rewritten in 2017, and the matrix cannot be reconstructed from summaries without risking a mistake on some pair of steels. The general rule is given on this page, but a particular pair needs the text of the standard: this is exactly the case where a guess costs more than fetching the document.
Why does one position cover all of them?
Because without impact or hardness requirements the position does not affect what the test proves. The exception is vertical-down PG and J-L045: only a test in that same position covers them. As soon as those requirements appear the position starts to matter a great deal — through the heat input — and the range narrows to the positions with a suitable one.
What did the 2017 edition change about preheat?
The preheat used on the test piece used to become the lower limit literally: nothing below it. A 50 °C reduction on the WPS is now permitted. The interpass temperature got a symmetrical +50 °C, but not for austenitic and duplex steels or nickel alloys — there it stays as it was on the test piece.
Does a WPQR expire?
EN ISO 15614-1 sets no validity period for the report — unlike welder qualification to ISO 9606-1, which has to be confirmed. A WPQR stops covering the work when an essential variable changes: process, material group, thickness range or impact requirements. Then you need a new test piece, not an extension.
Who sets the range of qualification, if not the calculator?
The examiner or examining body that witnessed the test piece: the range is written into the WPQR itself. The calculator lets you predict it before you order the tests — and choose the test piece so that it covers production. If the calculator and the report disagree, the report applies.
Is the procedure range the same as the welder’s range of qualification?
No. A WPQR to ISO 15614-1 qualifies the manufacturer’s procedure, a test to ISO 9606-1 qualifies the welder’s hand, and their range tables differ. The welder’s range has its own calculator; in practice one test piece often serves both, but each document is read against its own standard.
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