In the oil and chemical process industries, a spade is a round piece of metal with a small tab that is placed in between two pipe flanges to give positive isolation from the centre; usually to prevent cross contamination between fluids or to allow work on the line.
 

 Flange Type   Spade Flange

 Material   ASTM A516 Gr.60, A516 Gr.65, A516 Gr. 70 (Carbon Steel, CS)

 Standards  ANSI B16.48, API590 or according to the client drawing

 Pressure  ANSI class 150 to 1500

 Size range  1/2 to 24 inches (DN 15 to DN 600)

 Coating   Anti-Rust Black Coating