6.9. Nonresidential district standards.

   A.   Nonresidential development standards. The following table illustrates the dimensional standards that apply in the Town's commercial, industrial and special purpose districts.

Standard	NO	NC	CBD	OI	CR	SB	I-1	I-2
Lot Dimensions:
Lot area , minimum	6,000 sq. ft.	6,000 sq. ft.	6,000 sq. ft.	6,000 sq. ft.	6,000 sq. ft.	6,000 sq. ft.	None	None
Lot width, Minimum	60 ft.	60 ft.	60 ft.	60 ft.	60 ft.	60 ft.	100 ft.	100 ft.
Lot depth, minimum	None	None	None	None	None	None	None	None
Minimum Yards:*
Front yard	35 ft.	35 ft.	None	35 ft.	35 ft.	35 ft.	50 ft.	50 ft.
Rear yard	25 ft.	0/25 ft.	0/15 ft.	25 ft.	0/25 ft.	0/25 ft.	0/50 ft.	0/50 ft.
Side yard	0/15 ft.	10/15 ft.	0/15 ft.	10/15 ft.	10/15 ft.	0/25 ft.	0/25 ft.	0/25 ft.
Corner lotside yard	35 ft.	35 ft.	20 ft.	35 ft.	35 ft.	35 ft.	35 ft.	35 ft.
Maximum Height	35 ft.	35 ft.	None	None	None	None	None	None
Maximum Net DU/Acre	6,000 sq. ft. per single family detached dwelling unit	6,000 sq. ft. per unit	3,000 sq. ft. per unit	6,000 sq. ft. per unit	None	None	None	None

* Note:

      1.   The minimum setback distance from a building to a street right-of-way is 35 feet; except front yard setbacks in the I-1 and I-2 districts required to be a minimum of 50 feet.

      2.   Where two-yard standards are shown in the tables above (0/15 feet, for example), the first standard shall apply if the lot is not adjacent to a residential, NC, NO or OI district. Additional fire-rated wall construction may be required on side and rear facades.

   B.   Industrial performance standards.

      1.   In general.

         a.   Zoning regulations typically attempt to classify and segregate uses according to their differing impacts. For example, residences are usually allowed in certain zones and manufacturing plants in others because it is perceived that the impact of the latter would be detrimental to the former. Because the impacts associated with certain types of uses are well recognized, it is possible to regulate impacts indirectly by controlling the types of uses permissible in various zoning districts. Given the wide variety of impacts possible within the industrial use classification, it is not feasible to use an indirect method of controlling impacts. Therefore this part attempts to control impacts of industrial classification uses directly by establishing the performance standards set forth in this part.

         b.   For the reasons set forth in paragraph above, it is necessary to use performance standards to determine what types of industrial and manufacturing uses (see Article 5) should be permissible in various zoning districts. However, the use of performance standards involves advance prediction of the extent to which a proposed development will generate negative impacts, and subsequent monitoring to determine the actual extent of such impacts. Because this advance prediction and subsequent verification may be cumbersome, time-consuming, and expensive, performance standards (other than noise standards) are applied only to uses within the industrial use classification.

      2.   Smoke.

         a.   To determine the density of equivalent opacity of smoke, the Ringlemann Chart, as adopted and published by the United States Department of Interior, Bureau of Mines Info. Circular 8333, May 1967, shall be used. The Ringlemann numbers cited refer to the area of the Ringlemann Chart that coincides most nearly with the visual equivalent opacity of the smoke emission observed.

         b.   All measurements shall be taken at the point of emission of the smoke.

         c.   In the OI, NC, CR, CBD, SB, MXD-l and all PUD districts, no industrial use classification use may emit from a vent, stack, chimney, or combustion process any smoke that is visible to the naked eye.

         d.   In the I-1 district, no industrial use classification use may emit from a vent, stack, chimney, or combustion process any smoke that exceeds a density or equivalent opacity of Ringlemann No. 1, except one emission not exceeding an equivalent of Ringlemann No. 2 is permissible for a duration of not more than four minutes during any eight hour period if the emission source is not within 250 feet of a residential district.

         e.   In the I-2 district, no industrial use classification use may emit from a vent, stack, chimney, or combustion process any smoke that exceeds a density or equivalent opacity of Ringlemann No. 2, except that an emission not exceeding an equivalent of Ringlemann No. 3 is permissible for a duration not more than four minutes during any eight hour period if the source of emission is not located within 500 feet of a residential district.

      3.   Noise.

         a.   The following definitions shall apply in this section. All definitions shall be in conformance with those contained in ANSI 5.1.1-1960, R 1971, Acoustical Terminology.

         b.   With respect to the standards established in the table of maximum permitted sound level (paragraph c., below), dB(A) are expressed in terms of the tenth percentile sound level (L10), which must be calculated by taking 100 instantaneous A-weighted sound levels at ten second intervals and computing the (L10) in accordance with the community noise measurement data sheet set forth in Appendix C.

         c.   No person may operate or cause or permit the operation of any stationary source of sound that exceeds the limits set forth herein for the following receiving land use districts when measured at the boundary or at any point within the property affected by the noise.

 

Table of Maximum Permitted Sound Level [dB(A) ]
Receiving  Use Districts	Day  (7:00 a.m.—10:00 p.m.)	Night  (10:00 p.m.—7:00 a.m.)
Residential	60	55
Commercial	65	60
Industrial	75	75

 

         d.   When a noise source can be identified and its noise measured in more than one land use category, the limits of the most restrictive use shall apply at the boundaries between different land use categories.

         e.   For any stationary source of sound which emits a pure tone , cyclically varyingsound or repetitive impulsive sound , the standards defined herein shall be reduced by five dB(A) .

         f.   The standards set forth in this section shall not apply to the following sources:

            (1)   Emergency warning devices and emergency equipment including medical transport helicopters;

            (2)   Lawn care equipment used during daytime hours;

            (3)   Equipment being used for construction .

         g.   Notwithstanding any other provision of Article VIII (Nonconforming situations ), any person who operates or permits to be operated any new stationary noise source after the effective date of this section shall comply with the standards defined herein.

         h.   Measurement techniques to determine compliance with this section are set forth in Appendix C.

      4.   Vibration.

         a.   No industrial use classification in any commercial district may generate any ground-transmitted vibration perceptible to the human sense of touch measured at (i) the outside boundary of the space leased, rented or occupied by the enterprise generating the vibration if the enterprise is one of several located on a lot , or (ii) the lot line if the enterprise generating the vibration is the only enterprise located on a lot .

         b.   No industrial use classification use in the MXD-1, I-1 or I-2 district may generate any ground transmitted vibration in excess of the limits set forth in paragraph e below. Vibration shall be measured at any adjacent lot line or residential district line as indicated in the table set forth below in paragraph d.

         c.   The instrument used to measure vibrations shall be a three component measuring system capable of simultaneous measurement of vibration in three mutually perpendicular directions.

         d.   The vibration maximum set forth in paragraph e below are stated in terms of particle velocity, which may be measured directly with suitable instrumentation or computed on the basis of displacement and frequency. When computed, the following formula shall be used:

   P.V. = 6.28 F × D

   P.V. = Particle velocity, inches per second

   F = Vibration frequency, cycles per second

   D = Single amplitude displacement of the vibration, inches

   The maximum velocity shall be the vector sum of the three components recorded.

 

Table of Maximum Ground Transmitted Vibration
Zoning District	Adjacent Lot Lines	Residential  District
MXD	0.10	0.02
I-1	0.10	0.02
I-2	0.20	0.02

 

         e.   The values stated in paragraph d above may be multiplied by two for impact vibrations, i.e., discrete vibration pulsations not exceeding one second between pulses.

         f.   Vibrations resulting from temporary construction activity that occurs between 7:00 a.m. and 7:00 p.m. shall be exempt from the requirements of this section

      5.   Odors.

         a.   For purposes of this section, the odor threshold is defined as the minimum concentration in air of a gas, vapor, or particulate matter than can be detected by the olfactory systems of a panel of healthy observers.

         b.   No Industrial use classification in any district may generate any odor that reaches the odor threshold, measured at:

            (1)   The outside boundary of the space leased, rented or occupied by the enterprise generating the odor; or

            (2)   The lot line if the enterprise generating the odor is the only enterprise located on a lot .

      6.   Air pollution.

         a.   Any industrial use classification that emits any air contaminant (as defined in G.S. 143-213) shall comply with applicable state standards concerning air pollution, as set forth in Article 21B of Chapter 143 of the North Carolina General Statutes.

         b.   No site or special use permit may be issued with respect to any development covered by paragraph a above until the state Division of Environmental Management has certified that the appropriate state permits have been received by the developer (as provided in G.S. 143-215.108) or that the developer will be eligible to receive such permits, and that the development is otherwise in compliance with applicable air pollution laws.

      7.   Disposal of liquid wastes.

         a.   No industrial use classification in any district may discharge any waste contrary to the provisions of G.S. 143-214.2.

         b.   No industrial use classification in any district may discharge into the City of Raleigh's sewage treatment facilities any waste that cannot be adequately treated by biological means or otherwise violates applicable City of Raleigh requirements or standards.

      8.   Water consumption. No industrial use classification that requires for its operations a one and one-half-inch or larger meter is permissible in any district unless specifically approved to do so by the Town Council.

      9.   Electrical disturbance or interference. No industrial use classification may:

         a.   Create any electrical disturbance that adversely affects any operations or equipment other than those of the creator of such disturbance; or

         b.   Otherwise cause, create, or contribute to the interference with electronic signals (including television, and radio broadcasting transmissions) to the extent that the operation of any equipment not owned by the creator of such disturbance is adversely affected.

(Ord. No. 3502, § 4, 3-3-08; Ord. No. 3558, § 2, 7-7-09; Ord. No. 3656, § 5, 2-21-12; Ord. No. 3813, § 2, 4-19-16; Ord. 5006, § 3, 1-4-21; Ord., 3-16-21)