(A) Those outdoor light fixtures requiring a filter in § 151.017 shall be equipped with a filter whose transmission is less than 5% total emergent flux at wavelengths less than 3,900 angstroms. Total emergent flux is defined as that between 3,000 and 7,000 angstrom units.
(B) It is recommended that existing mercury vapor fixtures shall be equipped with a filter whose transmission is less that 10% total emergent flux at wavelengths less than 4,400 angstroms. Total emergent flux is defined as that between 3,000 and 7,000 angstrom units, or replaced.
(C) Low pressure sodium lamps are the preferred lamp for minimizing adverse effects on astronomical observations.
(Prior Code, § 19-3-2)