81-251 - Purpose of height and setback regulations

LAST AMENDED
2/2/2011

The common purpose of these two sets of regulations is to offer maximum design flexibility while setting reasonable but firm standards to
protect access of light and air to public #streets# and adjacent #buildings#.

This purpose is implemented by the two alternate sets of regulations, which are based on two distinct approaches. Both sets are concerned
with daylight at #street# level.

The daylight compensation regulations require any #building# generally to be built within a sky exposure curve which relates required
setbacks to #building# heights. Within limits, the #buildings# may encroach outside the curve but only if extra setbacks or recesses
provided elsewhere on the same #street# frontage of the #zoning lot# compensate for the #encroachment#. In the regulations, the sky
exposure curve for three #street# width categories is represented in each case by a table of required setbacks related to #building# heights.

The daylight evaluation regulations measure and evaluate portions of sky blocked by a #building# as viewed from specified #vantage
points# in the #street#. The #building# is plotted on #daylight evaluation charts# representing the #zoning lot's# available daylight from
specified #vantage points#, measured in daylight squares as defined in paragraph (b) of Section 81-272. Daylight blockage by the #building#
is then measured to determine the #building's# score on each frontage and the average score for the #building# as a whole. The regulations
specify the minimum passing scores for compliance.