These districts are designed for a wide range of manufacturing and related uses which can conform to a high level of performance standards. Manufacturing establishments of this type, within completely enclosed buildings, provide a buffer between Residence (or Commercial) Districts and other industrial uses which involve more objectionable influences. New residences are excluded from these districts, except for:

(a)        joint living-work quarters for artists in M1-5B Districts;

(b)        dwelling units in M1-5M and M1-6M Districts;

(c)        dwelling units in M1-1D, M1-2D, M1-3D, M1-4D and M1-5D Districts, where authorized by the City Planning Commission, both to protect residences from an undesirable environment and to ensure the reservation of adequate areas for industrial development; and

(d)        dwelling units in M1-6D Districts.