AWS A2.4 §6.9 · D1.1:2025

Field Weld Symbol

How to read the 現場溶接フラグ — placement at the arrow junction, shop vs 現場溶接 distinction, and D1.1:2025 field 溶接要求事項.

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Field 溶接記号 — Anatomy

Field weld + fillet

Field + all-around

Field + V-groove

Key rule: The field weld flag is a solid triangle at the arrow-基線 junction. It sits at a right angle to the reference line. It does NOT indicate 溶接の種類, サイズ, or side — those come from the primary weld symbol it accompanies.

How to Read

Shop Weld vs Field Weld

In 構造用鋼 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 溶接士 and 検査員 that this particular joint is to be welded on-site, not during shop 製作.

Why the Distinction Matters

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

Field welds face additional challenges: weather exposure (wind disrupts シールドガス coverage), limited access (welding in difficult positions), ambient temperature concerns (寒冷環境 affects 予熱 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 受入基準 — it alerts the erection team and 検査 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).

D1.1:2025 Field Requirements

Field Welding Conditions

D1.1:2025 条項 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 表 5.11 requirements — ambient cold may require higher preheat to compensate	Clause 5
Acceptance criteria	Same as shop welds — 目視 and NDE 合否基準 criteria both in Clause 8	Clause 8

Field welds face more variables than shop welds — wind, temperature, fit-up tolerances, and limited access. That is why field welding typically requires the inspector who verifies 基準 compliance to be present during critical operations, not just for final acceptance.

Common Questions

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.

Related Reference

Field Weld Symbol

Shop Weld vs Field Weld

Why the Distinction Matters

Field Welding Conditions

Field Weld Symbol FAQ

More Weld Symbol Pages