All warm air and cold air registers in floors in places open to the public shall be screened with a fireproof material having a mesh of one-eighth of an inch or less. Any person who owns, controls or occupies premises open to the public shall screen all such floor registers within thirty days after the effective date of this section (Ordinance 493, passed April 2, 1953) and shall maintain such screens at all times thereafter.
(Ord. 493. Passed 4-16-53.)