Title 18 - Unified Development Ordinance

 

18.150 Zoning Districts

18.150.050 Performance Standards; Measurement

In some districts, performance standards capable of quantitative measurement are established. Except to the extent modified in the specific zoning district regulations, the following general provisions shall apply to measure compliance with such performance standards.

  1. A.
    Smoke

    For the purpose of determining the density of equivalent opacity of smoke, the Ringlemann Chart, as adopted and published by the United States Department of Interior, Bureau of Mines, shall be used. The Ringlemann number indicated as the performance standard in certain zoning districts refers to the number of the area of the Ringlemann Chart that coincides most nearly with the visual density of equivalent opacity of the emission of smoke observed.

  2. B.
    Vibration

    Vibrations are measured in particle velocity and are to be measured at the property line or other designated location. The instrument used to measure vibrations shall be a three- component measuring system capable of simultaneous measurement of vibration in three mutually perpendicular directions. The vibration maximums indicated as the performance standard in certain zoning districts may be measured directly with suitable instrumentation or computed on the basis of displacement and frequency. When computed, the following formula shall be used:

PV = 6.28 F x D

Where:

PV = particle velocity, inches-per-second

F = vibration frequency, cycles-per-second

D = single amplitude displacement of the vibration, inches

  1.   
    The maximum velocity shall be the vector sum of the three components recorded. Unless specifically indicated to the contrary in the zoning district regulations, vibration resulting from temporary construction activity that occurs between 7:00 a.m. and 7:00 p.m. shall be exempt from the indicated performance standard.
  1. C.
    Glare
    Illumination levels shall be measured with a photoelectric photometer having a spectral response similar to that of the human eye, following the standard spectral luminous efficiency curve adopted by the International Commission on Illumination.

(History: Ord. ZRR-2285 §1, 2001; ZRR-1725; ZRR-1637; ZRR-1314)

Effective on: 1/1/1901