(A) Use, Lot and Bulk Regulations (Performance Standards, Glare and Heat): Any use established in the Light Industrial District after April 1, 1963 shall be so operated as to comply with the performance standards governing glare and heat set forth hereinafter. No use lawfully established on April 1, 1963 shall be so altered or modified as to conflict with, or further conflict with, the performance standards governing glare and heat established hereinafter.
(B) Light Industrial District (Performance Standards, Glare and Heat): Any operation producing intense glare or heat shall be performed within a completely enclosed building in such manner as not to create a public nuisance or hazard along lot lines. Exposed sources of light shall be shielded so as not to create a nuisance across lot lines.