Synonyms for Noncombustible:

adj.

fireproof (adjective)
incombustible, nonflammable, fire-resistant.

n.

noncombustible (noun)
fire-resisting, incombustible, flameproof, fireproof, nonflammable, fire-resistive, flame-retardant, fire-retardant, fire-resistant.

Other synonyms:

adj.
fireproof.
n.
incombustible.