Dimensioning requirement: In piping drawings (plan, elevation, isometric, or developed), is it acceptable to omit pipe sizes, or should the size of each pipe/run be clearly indicated to avoid ambiguity in fabrication and procurement?

Introduction / Context:
Pipe size determines hydraulic capacity, pressure drop, insulation size, hanger selection, and fittings. Drawings that omit sizes create confusion, rework, and potential installation errors. This item clarifies that clear size indication is a basic requirement in detailed piping drawings used for fabrication or construction.

Given Data / Assumptions:

• Drawings are intended for takeoff, prefabrication, or installation.
• Line lists, P&IDs, or schedules may complement the drawings.
• Units (e.g., NPS/DN) are standardized across the project.

Concept / Approach:
Each pipe or line class should have an identifiable size on the drawing or via an unambiguous reference to a schedule/line list. Even when a general note exists, explicit labeling near runs, at changes, and on isometric callouts prevents misinterpretation. Sizes drive material takeoffs and are essential for ordering pipe, fittings, and valves of the correct bore and end connections.

Step-by-Step Solution:

Verification / Alternative check:
Material takeoff accuracy and field RFIs decrease when sizes are clearly shown; procurement can match bills of materials without guesswork.

Why Other Options Are Wrong:
“Correct” implies omission is fine; it is not. Limiting clarity to schematics, relying on vague general notes, or exempting small lines ignores the need for precise communication.

Common Pitfalls:
Missing size updates after design changes; inconsistent units; unlabeled branches; ambiguous reducer orientation.

Final Answer:
Incorrect