The following noncombustible materials may be used in merchant vessel construction though not specifically approved under this subpart:
- (a) Sheet glass, block glass, clay, ceramics, and uncoated fibers.
- (b) All metals, except magnesium and magnesium alloys.
- (c) Portland cement, gypsum, and magnesite concretes having aggregates of only sand, gravel, expanded vermiculite, expanded or vesicular slags, diatomaceous silica, perlite, or pumice.
- (d) Woven, knitted or needle punched glass fabric containing no additives other than lubricants not exceeding 2.5 percent.
[CGD 86-035, 54 FR 36316, Sept. 1, 1989]