8. Steels for simple pressure vessels (plates, strips and bars)

Within the meaning of Directive 87/404 EEC, Articles XX1, 2 and 3, a simple pressure vessel is any welded container subject to a relative internal pressure greater than 0.5 bar, intended to contain air or nitrogen and not intended to be subjected to flame.

In addition :

• the parts and assemblies contributing to the container's resistance to pressure are made either of unalloyed quality steel, or of unalloyed aluminum or untempered aluminum alloys;

• the container consists of :

  • or a cylindrical part of circular cross-section closed by curved bottoms with their concavity turned inwards and/or flat bottoms; these bottoms have the same axis of revolution as the cylindrical part;

  • or two convex bottoms with the same axis of...