§ 56-445. Property development standards.

The following property development standards shall apply to all land and structures in the I2 General Industrial District.

(1)

Lot area. No requirement.

(2)

Lot dimensions. No requirement.

(3)

Ground floor area. No requirement.

(4)

Building height. No requirement.

(5)

Yards.

a.

General yard requirements. The following are minimum yard sizes except as otherwise provided by this chapter.

1.

Front. No requirements.

2.

Side. Except where an industrial district adjoins a residential district, there is no minimum side yard for an industrial use. Where an industrial district is separated from an adjoining residential district by a street, the minimum side yard is five feet. Where the two districts adjoin within the same block, the minimum side yard is 30 feet.

3.

Rear. Except where an industrial district adjoins a residential district, there is no minimum rear yard for an industrial use. Where an industrial district is separated from an adjoining residential district by a street, the minimum rear yard is five feet. Where the two districts adjoin within the same block, the minimum rear yard is 30 feet.

e.

Exceptions. The provisions of article IX of this chapter, pertaining to property development standards, shall apply.

(6)

Lot coverage. No requirements.

(7)

Off-street parking. The provisions of article IX of this chapter shall apply.

(8)

Outdoor advertising. The provisions of the I1 district shall apply.

(9)

Loading. The provisions of article IX of this chapter shall apply.

(10)

Other requirements for industrial uses. The following restrictions shall apply to all industrial uses, in addition to the previous requirements.

a.

Smoke.

1.

No general industrial use may emit more than 30 smoke units per hour per stack or smoke in excess of Ringelmann No. 2. However, once during any six-hour period, for soot blowing, process purging, and fire cleaning, each stack shall be permitted an additional ten smoke units, and during that time it may emit smoke up to and including Ringelmann No. 3.

2.

Definition. As used in this subsection:

Ringelmann number —the number of the area on the Ringelmann chart that most nearly matches the light-obscuring capacity of smoke. The Ringelmann chart is described in the U.S. Bureau of Mines Information Circular 6888, on which are illustrated graduated shades of gray for use in estimating smoke density. Smoke below the density of Ringelmann No. 1 shall be considered as no smoke or Ringelmann No. 0.

Smoke unit —the number obtained when the smoke density in Ringelmann number is multiplied by the time of emission in minutes. For the purpose of this calculation, a Ringelmann density reading shall be made at least once a minute during the period of observation. Each reading shall then be multiplied by the time in minutes during which it is observed. The products so computed shall then be added to give the total number of smoke units observed during the entire observation period.

b.

Odor. No general industrial use may release an odor that is detectable at the lot line.

c.

Toxic materials. For a general industrial use, the emission of toxic and noxious materials may not produce any concentration at a residence or business district boundary line exceeding the following percentage of the threshold limit values for toxic materials in industry as set forth in threshold limit values for the current year, as adopted at the annual meeting of the American Conference of Governmental Industrial Hygienists:

General industrial use

10 percent

 

d.

Glare and heat.

1.

No general industrial use may cause heat at the lot line so intense as to be a public nuisance or hazard. No such use may cause illumination at or beyond any residence district boundary in excess of 0.1 foot candle in any plain.

2.

Definition. As used in this subsection:

Foot candle —a unit of illumination equal to the illuminating at all points that are 1 foot from a uniform point source of one candle power.

e.

Vibration.

1.

No general industrial use may cause at any R, or C district boundary continuous earth borne vibrations higher than the limits set forth in column I of the following table. Nor may it cause at any residence district boundary continuous earth borne vibrations higher than the limits set forth in column II.

Frequency (cycles per second)		I Displacement (inches)	II Displacement (inches)
More than	But not more than
0	10	.0020	.0004
10	20	.0010	.0002
20	30	.0006	.0001
30	40	.0004	.0001
40	50	.0003	.0001
50		.0002	.0001
Discrete pulses that do not exceed 100 impulses per minute may not produce higher than twice the displacement specified in the table.

 

2.

Definition. As used in this subsection:

Displacement —the maximum amount of motion in any direction determined by any three component (simultaneous) measuring system approved by the board.

Three-component measuring system —instrumentation that can measure earth borne vibrations in a horizontal as well as a vertical plane.

f.

Noise.

1.

At no boundary of a residence or business district may the sound pressure level of any general industrial use, except for background noises produced by sources not under control of this chapter, such as the operation of motor vehicles or other transportation facilities, exceed the following decibel limits:

Octave band frequency (cycles per second)		I Maximum permitted sound level (decibels) along residence district boundaries	II Maximum permitted sound level (decibels) along business district boundaries
20	75	72	79
75	150	67	74
150	300	59	66
300	600	52	59
600	1200	46	53
1200	2400	40	47
2400	4800	34	41
4800	——	32	39
The prescribed limits of column I apply between 8:00 a.m. and 6:00 p.m. At other times, the allowable levels in each octave band are each reduced by six decibels.

 

2.

Sound levels shall be measured with a sound-level meter and associated octave band filter, manufactured and calibrated according to standards prescribed by the American Standards Association. Measurements shall be made using the flat C network of the sound level meter and the fast meter movement of the octave band analyzer. Impulsive noises are subject to the performance standards prescribed by this section if they cause rapid fluctuations of the needle of the sound level meter with a variation of no more than plus or minus two decibels. Noises incapable of being so measured, such as irregular and intermittent noises, shall be controlled so as not to be a nuisance to adjacent uses.

3.

Definition. As used in this subsection:

Octave band —all the frequencies from one frequency to a second. In sound octave bands, the second frequency is usually twice the first one.

Octave band filter —an electrical device that separates the sounds in each octave band and presents them to the sound level meter.

g.

Fire hazards.

1.

Solid substances ranging from free or active burning to intense burning may be stored, used, or manufactured only within completely enclosed buildings having incombustible exterior walls and protected throughout by an automatic fire extinguishing system.

2.

The storage, utilization, or manufacture of flammable liquids or materials which produce flammable vapors or gases shall be permitted in accordance with the rules and regulations of the state fire marshal. A certificate of compliance, issued by the state fire marshal's office, stating that the plans and specifications for a general industrial use comply with the rules and regulations of the state fire marshal shall accompany the application for an improvement location permit.

3.

As used in this section:

Free burning —a rate of combustion described by a substance that burns actively and easily supports combustion; and

Intense burning —a rate of combustion described by a substance that burns with a high degree of activity and is consumed rapidly.

h.

Detonation materials. No activity involving the storage, use, or manufacture of materials that decompose by detonation may be carried on except in accordance with the rules issued by the state fire marshal. These materials include primary explosives such as lead azide, lead styphnate, fulminates, and tetracene; high explosives such as TNT, RDX, HMX, PETN, and picric acid; propellants and their components, such as nitrocellulose, black powder, boron hydrides, hydrazine and its derivatives; pyrotechnics and fireworks such as magnesium power, potassium chlorate, and potassium nitrate; blasting explosives such as dynamite and nitroglycerine; unstable organic compounds such as acetylides, tetrazoles, and ozonides; strong oxidizing agents such as liquid oxygen, perchloric acid, perchlorates chlorates, and hydrogen peroxide in concentrations greater than 35 percent; and nuclear fuels, fissionable materials and products, and reactor elements such as Uranium 235 and Plutonium 239.

i.

Particulate matter.

1.

The rate of emission of particulate matter from all sources within the boundaries of any lot may not exceed a net figure of three pounds per hour per acre for a general industrial use of which no more than ten percent by weight may be particles larger than 44 microns (325 mesh). The net rate of emission shall be computed by:

(i)

Determining the maximum emission in pounds per hour from each source of emission within the boundaries of the lot and dividing this figure by the number of acres of lot area, thus obtaining the gross hourly emission rate per acre for each source;

(ii)

Deducting from that gross rate the appropriate correction factors for height of emission and stack velocity as respectively specified in subsections (10)i.2. and 3. of this section, thus obtaining the net hourly emission rate per acre for each source; and

(iii)

Adding the individual rates of emission so computed to obtain the total net hourly emission rate per hour from all sources within the boundaries of the lot.

2.

The allowance for height of emission is as follows (interpolate for intermediate values):

Height of emission above grade (feet)	Correction for general industrial use (pounds per hour per acre)
50	0.02
100	0.12
150	0.20
200	0.32
300	0.60
400	1.00
500 and above	1.50

 

3.

The allowance for velocity of emission is as follows (interpolate for intermediate values):

Exit velocity up (feet per second)	Correction for general industrial use (pounds per hour per acre)
0	0
20	0.06
40	0.18
60	0.32
80	0.48
100 and above	1.00

 

4.

Dust and other kinds of air pollution that are borne by the wind from such sources within lot boundaries as storage areas, yards, and roads shall be kept to a minimum by appropriate landscaping, paving, oiling, fencing, or other means.

5.

As used in this section:

Particulate matter —divided liquid or solid material that is discharged and carried along in the air.

j.

Exceptions. Subsections (10)a. through i. of this section do not apply to:

1.

Site preparation or construction, maintenance, repair, alteration, or improvement of buildings, structures, equipment, or other improvements on or within the lot line;

2.

The operation of motor vehicles or other facilities for the transportation of personnel, materials, or products;

3.

Conditions beyond the control of the user such as fire, explosion, accident, failure, or breakdown;

4.

Safety or emergency warning signals or alarms necessary for the protection of life, limb, or property; or

5.

Processes for which there is no known means of control. Research shall be promptly conducted to discover methods of control leading to the installation of protective equipment.

k.

General industrial uses near residence districts. The performance standards prescribed by subsections (10)a. through i. of this section for light industrial uses apply also to general industrial uses that are located within 500 feet of a residence district boundary.

(Ord. of 12-4-1973, § 17.3)