What standard must sheets for fixed and floating roofs conform to according to API 650?

• A. ASTM A123
• B. ASTM A1011M
• C. ASTM A500
• D. ASTM A36

Answer: (B)

The correct answer pertains to the material standards that are required for sheets used in fixed and floating roofs of welded tanks for oil storage as specified in API 650. ASTM A1011M is the standard that covers hot-rolled, low-carbon steel sheets, which are commonly utilized in the construction of tank roofs due to their necessary mechanical properties, weldability, and corrosion resistance.

This standard specifically addresses the various grades and specifications of steel sheets that are suitable for tank construction, ensuring that the materials can withstand the operational conditions they will be exposed to, such as impact, stress, and environmental factors. Compliance with this standard ensures that the materials meet both safety and performance criteria essential for the integrity of the tank systems.

The other choices represent different standards that may not specifically meet the requirements for tank roof sheets. For instance, ASTM A123 covers zinc coatings, ASTM A500 pertains to structural tubing, and ASTM A36 applies to carbon structural steel plates, none of which are suitable for the specific applications outlined in API 650 regarding tank roofs.