AWS A2.4 §6.9 · D1.1:2025

Field Weld Symbol

How to read the field weld flag — placement at the arrow junction, shop vs field weld distinction, and D1.1:2025 field welding requirements.

Field Weld Symbol — Anatomy
5/16 flag at junction
Field weld + fillet
+ weld-all-around
Field + all-around
field V-groove CJP
Field + V-groove
Key rule: The field weld flag is a solid triangle at the arrow-reference line junction. It sits at a right angle to the reference line. It does NOT indicate weld type, size, or side — those come from the primary weld symbol it accompanies.

Shop Weld vs Field Weld

In structural steel construction, members are fabricated in the shop (factory) and then assembled at the erection site (field). The field weld flag on a drawing tells the welder and inspector that this particular joint is to be welded on-site, not during shop fabrication.

Why the Distinction Matters

Shop welds are made under controlled conditions — overhead cranes for positioning, consistent temperature, wind protection, and full equipment access. Quality control is typically more streamlined.

Field welds face additional challenges: weather exposure (wind disrupts shielding gas coverage), limited access (welding in difficult positions), ambient temperature concerns (cold weather affects preheat and interpass temperatures), and inspector access considerations.

Per D1.1:2025, the same quality standards apply to both shop and field welds. The field weld flag does not change acceptance criteria — it alerts the erection team and inspection personnel that this joint requires field attention.

Combined symbols: The field weld flag can appear with the weld-all-around circle at the same junction point. Both are supplementary symbols that modify the primary weld — the flag specifies location (field), the circle specifies extent (all around).

Field Welding Conditions

D1.1:2025 Clause 7 governs fabrication requirements including field welding conditions. Field welds must satisfy the same procedural requirements as shop welds, with additional environmental considerations.

Requirement Detail Source
Min temperature 0°F [−20°C] ambient — welding not permitted below this Clause 7.11.2
Wind protection GMAW, GTAW, EGW, FCAW-G require shelter reducing wind to max 5 mph [8 km/h] at the weld Clause 7.11.1
Preheat Same Table 5.11 requirements — ambient cold may require higher preheat to compensate Clause 5
Acceptance criteria Same as shop welds — visual and NDE acceptance criteria both in Clause 8 Clause 8

Field Weld Symbol FAQ

What is a field weld symbol?
A field weld symbol is a solid triangular flag placed at the junction of the arrow and the reference line of a welding symbol. Per AWS A2.4 §6.9, it indicates the weld is to be made at the erection site (in the field), not in the fabrication shop. The flag sits at a right angle to the reference line. It is a supplementary symbol — it modifies the primary weld symbol (fillet, groove, etc.) and carries no dimensions of its own.
What is the difference between a field weld and a shop weld?
A shop weld is made in the fabrication shop under controlled conditions — overhead cranes, positioning equipment, consistent temperature, and wind protection. A field weld is made at the erection site where conditions are less controlled. Per D1.1:2025, field welds must meet the same quality standards as shop welds, but face additional challenges: weather exposure, limited access, difficult positions, and ambient temperature requirements. If ambient temperature is below 0°F [−20°C], welding is not permitted without special approval.
Where is the field weld flag placed on the symbol?
The field weld flag is placed at the junction where the arrow meets the reference line, at a right angle to the reference line. It can be combined with the weld-all-around circle at the same junction point. The flag does not indicate which side the weld is on — that is determined by the primary weld symbol's position above or below the reference line. The flag only specifies location: field, not shop.
Does D1.1 have different requirements for field welds?
D1.1:2025 applies the same weld quality acceptance criteria regardless of whether the weld is made in the shop or field. However, field welding faces additional procedural requirements: wind protection (shielding gas processes are especially sensitive), minimum ambient temperature of 0°F [−20°C] per Clause 7.11.2, preheat requirements that may be affected by ambient conditions, and inspector access considerations. The field weld flag on the drawing alerts the inspector that field inspection is required for that joint.