Mix System Unit in Design and Material System Unit

[nashki]

Dear Members,

I am designing a pressure vessel in accordance to ASME Section VIII Division 1. The unit system used in design is Metric system.
Shall we mention the metric system unit also for material in General Arrangement Drawing (Bill of Material).
For example, the material SA-516-70 shall be mentioned as SA-516M-485 in drawing since the general system unit is Metric system.

 

[goutam_freelance]

Metric system of units need to be mentioned in documents.

 

[IdanPV]

Read ASME VIII-1, U-4. Especially U-4(g), that shall answer all of your questions.

 

[goutam_freelance]

From ASME VIII-1, U-4
"In general, it is expected that a single system of units shall be used for all aspects of design except where unfeasible or impractical"

 

[nashki]

U-4(b) : A single system of units shall be used for all aspects of design except where otherwise permitted by this Division.
U-4(g) : Material that has been manufactured and certified to either the U.S. Customary or SI material specification (e.g., SA-516M) may be used regardless of the unit system used in design.

In my interpretation, according to U-4(g) that we can specify in drawing either the U.S. Customary or SI material specification regardless of the unit system used in design.

This interpretation is also based on the U-4(b), "where otherwise permitted by this Division".