Drawing symbol conflict on a field-welded stiffener
Fabrication drawing F-204 shows a 10 mm stiffener plate welded to the web of a 16 mm built-up column. The weld symbol on the arrow side of the reference line is a fillet with '8' to the left and '150–300' to the right; a circle sits at the arrow-to-reference-line junction, a black flag is shown at the same junction, and the tail reads 'FCAW'. Note 4 states: 'All fillet welds continuous unless shown intermittent.' Note 7 states: 'FCAW root pass only; fill and cap with SMAW.' The only approved WPS covers FCAW continuous fillets, 6 mm maximum leg, 8–20 mm base metal, flat and horizontal positions. Project specification requires a field WPS for field welds, 100% visual inspection, and 10% MT. The stiffener contact length around three sides is 700 mm. The field crew has FCAW equipment and an E71T-1 wire, but no SMAW electrodes on site. The schedule allows a 4-hour RFI turnaround.
1. Interpret the symbol and state the required weld, position, and inspection implications.
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Reading the symbol: 8 mm fillet leg, arrow side, length 150 mm, pitch 300 mm, all around, field weld, FCAW in the tail. Pitch is centre-to-centre, so the pattern is 150 mm weld and 150 mm gap, 50% coverage. All-around means the weld continues around the joint, but an intermittent length/pitch with all-around is internally ambiguous because the start point and closure segment are not defined. The field flag means the weld is made at site and requires a field WPS and field inspection. Note 4 does not make it continuous because the intermittent symbol is shown. Note 7 changes the process for fill and cap to SMAW, so the tail 'FCAW' conflicts with that note unless the note is a project-wide override.
2. List the conflicts the crew faces and calculate the weld length if the intermittent symbol is followed.
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Conflicts: (1) drawing 8 mm leg vs the only WPS maximum 6 mm; (2) tail FCAW vs Note 7 requiring SMAW fill/cap, with no SMAW electrodes or SMAW WPS on site; (3) field weld with no field WPS; (4) all-around plus intermittent is not a complete instruction. For length: 700 mm contact at 50% coverage is nominally 350 mm of weld. If full 150 mm segments are laid from one corner on 300 mm centres, 700 mm fits two full segments plus a 100 mm end segment (300 mm), or three segments if the last is shortened; the all-around closure makes the end condition unclear. Do not choose a number arbitrarily - the engineer must define the start point and end segment. Also, an 8 mm fillet cannot be welded to the 6 mm WPS without a new PQR/WPS.
3. What should the supervisor do before any welding, and what interim response is defensible?
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Stop the fit-up and welding, raise an RFI with the symbol sketch and the exact conflicts, and request either a revised symbol, a field WPS for 8 mm FCAW, or written approval for a 6 mm fillet if design allows. Do not substitute 6 mm on the shop floor, do not weld the field joint without a field WPS, and do not mix SMAW without a qualified procedure and electrodes. In the meantime, verify joint fit-up, cleanliness and tack welds, and document the drawing revision, RFI number and responses. The defensible interim position is 'no weld until clarified'; production pressure is not a technical basis. If the engineer authorises 6 mm, record the concession and inspect to the revised requirement.