§ 178.362-3 - Closure.

(a) Closure for the wooden protective jacket is provided by the steel reinforcing rods. The end cap (lid) must fit tightly to the body of the jacket to prevent a heat path to the inside of the jacket. The lid joint for specifications 20WC-3, 20WC-4, 20WC-5, and 20WC-6, may not be coplanar with the end of the inner containment vessel.

(b) Specifications 20WC-2 and 20WC-6. Locking ring closure, if used, must conform to § 178.354-4. Flanged closure, if used, must have at least 8 steel bolts (at least 6 mm (0.25-inch) diameter for 20WC-2 or 1.2 cm (0.50-inch) diameter for 20WC-6) and lock nuts (or equivalent device), spaced not more than 13 cm (5 inches) between centers.