I.7Multi-Walled Piping

Multi-walled piping incorporating a leak detection port, in which all surfaces that come in direct contact with the chemical(s) are made from the following materials:
(a) nickel or alloys with more than 40% nickel by weight;
(b) alloys with more than 25% nickel and 20% chromium by weight;
(c) fluoropolymers (polymeric or elastomeric materials with more than 35% fluorine by weight);
(d) glass or glass-lined (including vitrified or enamelled coating);
(e) graphite or carbon-graphite;
(f) tantalum or tantalum alloys;
(g) titanium or titanium alloys;
(h) zirconium or zirconium alloys; or
(i) niobium (columbium) or niobium alloys.
Technical note: carbon-graphite is a composition consisting of amorphous carbon and graphite, in which the graphite-content is eight percent or more by weight.