All uses in any district of the City shall conform in operation, location and construction to the performance standards specified in this division for noise, odorous matter, toxic and noxious matter, glare, smoke, particulate matter and other air contaminants, fire and explosive or hazardous matter, vibration and open storage.
(Ordinance 6051-12 adopted 5/17/12)
(a) 
Generally.
At no point on the bounding property line of any use in any district shall the sound pressure level of any use, operation or plant exceed the standards specified in this division. For the purposes of this division, the bounding property line shall be interpreted as being at the far side of any street, alley, stream or other permanently dedicated open space from the noise source when such open space exists between the property line of the noise source and adjacent property. When no such open space exists, the common line between two (2) parcels of property shall be interpreted as the bounding property line.
(b) 
Standards.
The maximum permissible octave band-decibel limits at the bounding property line in any district shall be as shown in the following tables. Sound level may be measured in frequency bands as shown by Table C or by Table D as follows:
Table C. Preferred Frequencies
Center Frequency
(cycles per second)
Maximum Permitted Sound Pressure Levels
(decibels)
31.5
76
63.0
74
125.0
68
250.0
63
500.0
57
1,000.0
52
2,000.0
45
4,000.0
38
8,000.0
32
Table D. Octave Band Frequencies
Octave Band
(cycles per second)
Maximum Permitted Sound Pressure Level
(decibels)
20 - 75
75
75 - 150
70
150 - 300
64
300 - 600
59
600 - 1,200
53
1,200 - 2,400
47
2,400 - 4,800
40
4,800 - 10,000
34
(c) 
Modifications to standards.
The following corrections shall be made to the table of preferred frequencies (Table C) or octave band-decibel limits (Table D) in determining compliance with the noise level standards in any district:
Table E. Noise Standard Modifications
Type of Operation or Character of Noise
Correction in Decibels
Noise source operates less than:
 
20 percent of any one-hour period
Plus 5 (+5)
5 percent of any one-hour period
Plus 10 (+10)
1 percent of any one-hour period
Plus 15 (+15)
Noise of impulsive character (hammering, etc.)
Minus 5 (-5)
Noise of periodic character (hum, screech, etc.)
Minus 5 (-5)
(d) 
Noise measurement.
For the purpose of measuring the intensity and frequency of sound, the sound level meter, the octave band analyzer and the impact noises analyzer shall be employed. The flat network and fast meter response of the sound level meter shall be used. Sounds of short duration that cannot be accurately measured with the sound level meter shall be measured with the impact analyzer.
(1) 
Octave band analyzer calibrated in the Preferred Frequencies (American Standards Association S1-6-1960, Preferred Frequencies for Acoustical Measurement) shall be used with Table A [Table C].
(2) 
Octave band analyzers calibrated with pre-1960 octave bands (American Standards Association Z-24-1953, Octave Filter Set) shall be used with Table B [Table D].
(e) 
Exemptions.
The following uses and activities shall be exempt from the noise level regulations specified in this section:
(1) 
Noises not directly under the control of the property user.
(2) 
Noises emanating from construction and maintenance activities between the hours of 7:00 a.m. and 7:00 p.m. (daylight hours).
(3) 
Noises of safety signals, warning devices and emergency pressure relief valves.
(4) 
Transient noise of moving sources such as automobiles, trucks, airplanes and railroads.
(Ordinance 6051-12 adopted 5/17/12)
(a) 
Opacity limit.
No operation or use in any district shall cause, create or allow the emission for more than three minutes in any one hour of air contaminants, which at the emission point or with the bounds of the property are:
(1) 
As dark or darker in shade as that designated as No. 2 on the Ringelmann Chart, as published by the United States Bureau of Mines Information Circular 7118, or in violation of the standards specified by the Texas Air Control Board Regulations for the Control of Air Pollution, as published by the State, or as such regulations may be amended.
(2) 
Of such opacity as to obscure an observer’s view to a degree equal to or greater than does smoke or contaminants in the standard prescribed in subsection (a)(1) of this section.
(b) 
Exception to opacity limit.
When the presence of uncombined water is the only reason for failure to comply with subsection (a) of this section, or when such contaminants are emitted inside a building that prevents their escape into the outside atmosphere, the standards in subsection (a) of this section shall not apply.
(c) 
Open storage and processing.
Open storage and open processing operations (including on-site transportation movements that are the source of wind- or air-borne dust or other particulate matter, and processes involving dust or other particulate air contaminant generating equipment such as used in paint spraying, grain handling, sand or gravel processing or storage or sand blasting) shall be so conducted that dust and other particulate matter so generated are not transported across the bounding property line of the tract on which the use is located in concentrations exceeding four grains per one thousand (1,000) cubic feet of air.
(Ordinance 6051-12 adopted 5/17/12)
(a) 
Odor threshold.
No use shall be located or operated in any district that involves the emission of odorous matter from a source of operation where the odorous matter exceeds the odor threshold at the bounding property line or any point beyond the tract on which such use or operation is located. The odor threshold shall be the concentration of odorous matter in the atmosphere necessary to be perceptible to the olfactory nerve of a normal person.
(b) 
Measurement.
The odor threshold as set forth in subsection (a) of this section shall be determined by observation by a person. In any case, where uncertainty may arise or where the operator or owner of an odor-emitting use may disagree with the enforcing officer or where specific measurement of odor concentration is required, the method and procedures as specified by American Society for Testing Materials, ASTMD 1391-57, entitled “Standard Method for Measurement of Odor in Atmospheres” shall be used, and a copy of ASTMD 1391-57 is hereby incorporated into this section by reference.
(Ordinance 6051-12 adopted 5/17/12)
(a) 
Explosives.
No use involving the manufacture or storage of compounds or products that decompose by detonation shall be permitted in any district except that chlorates, nitrates, perchlorates, phosphorus, and similar substances and compounds in small quantities for use by industry, school laboratories, druggists or wholesalers may be permitted when approved by the City Manager and the Fire Chief of the City as not presenting a fire or explosion hazard.
(b) 
Flammables.
No storage and use of all flammable liquids and materials such as pyroxylin plastics, nitrocellulose film, solvents and petroleum products shall be permitted only when such storage or use conforms to the fire code of the City.
(Ordinance 6051-12 adopted 5/17/12)
No operation or use in any district shall emit a concentration across the bounding property line of the tract on which such operation or use is located of toxic or noxious matter that will exceed ten percent of the concentration (exposure) considered as the threshold limit for an industrial worker as such standards are set forth by the State in Threshold Limit Values Occupational Health Regulations.
(Ordinance 6051-12 adopted 5/17/12)
No operation or use in any district shall at any time create earthborne vibration that, when measured at the bounding property line of the source of operation, exceed[s] the limit of displacement set forth in the following table in the frequency ranges specified:
Table F. Frequency
Cycles per second
Displacement
(in inches)
Less than 10
0.0010
10 to 20
0.0008
20 to 30
0.0005
30 to 40
0.0004
40 and over
0.0003
(Ordinance 6051-12 adopted 5/17/12)
No open storage of materials or commodities shall be permitted in any district except as an accessory use to a main use located in a building in an “M-1” or “M-2” Manufacturing district. No open storage operation shall be located in front of a main building. No wrecking, junk or salvage yard shall be permitted as a storage use in any district.
(Ordinance 6051-12 adopted 5/17/12)
No use or operation in any district shall be located or conducted so as to produce glare, or either direct or indirect illumination across the bounding property line from a source of illumination into a residentially zoned property, nor shall any such light be of such intensity as to create a nuisance or detract from the use and enjoyment of adjacent property.
(Ordinance 6051-12 adopted 5/17/12)
Any use constructed, established, altered, or enlarged in a Manufacturing District, after the effective date of this Ordinance shall be so operated as to comply with the following standards. No use already established on the effective date of this Ordinance shall be so altered or modified as to conflict with, or further conflict with, the applicable standards hereinafter for a Manufacturing District is [as] required.
(a) 
No building shall be used for residential purposes, except a watchman may reside on the premises.
(b) 
No retail sales or services shall be permitted except as incidental to or accessory to a permitted use.
(c) 
No storage, manufacture, or assembly of goods shall be conducted out of a building unless the nearest point of said activity is more than one hundred (100) feet from the boundary of any Zoning District.
(d) 
Exterior lighting fixtures shall be shaded wherever necessary to avoid casting direct light upon property located in any Residential District.
(e) 
All manufacturing, fabricating[,] assembly, disassembly, repairing, storing, cleaning, servicing, and testing of goods, water [wares] and merchandise shall be carried on in such a manner as not to be injurious or offensive by reason of the emission or creation of noise, vibration, smoke, dust, or other particle matter, toxic or noxious matter, odors, glare, beat [heat], fire, or explosive hazards.
(f) 
No activities involving storage, utilization, or manufacture of materials or products which decompose by detonation shall be permitted.
(g) 
No operation or activity shall cause or create noise in excess of the sound levels prescribed below. In the “M-1” and “M-2” Districts, at no point on or beyond the boundary of any lot shall the sound pressure level resulting from any use, operation, or activity exceed the maximum permitted decibel levels for the designated octave as set forth in Tables G and H below.
Table G. Preferred Frequencies
Center Frequency Cycles per Sound
[Second]
Maximum Permitted Sound Pressure Level, Decibels
31.5
79
63
74
125
68
250
63
500
57
1000
52
2000
45
4000
38
8000
32
Table H. Pre-1960 Octave Bands
Octave Band Cycles per second
Maximum Permitted Sound Pressure Level, Decibels
20 - 75
75
75 - 100
70
150 - 300
64
300 - 600
59
600 - 1200
53
1200 - 2400
47
2400 - 4800
40
4800 - 10KC
34
(1) 
For the purpose of measuring the intensity and frequency of sound, the sound level meter, the octave band analyzer, and the impact noise analyzer shall be employed as the method of measurement. The flat network and the fast duration as from forge hammers, punch presses, and metal shears which cannot be measure[d] accurately with the sound level meter shall be measured with the impact noise analyzer.
(2) 
Octave band analyzers calibrated in the Preferred Frequencies (American Standards Association S1.6-1960, Preferred Frequencies for Acoustical Measurements) shall be used with Table I [Table G]. Octave band analyzers calibrated with pre-1960 octave band (American Standards Association Z24.10-1954, Octave Band Filter Set) shall use Table II [Table H].
(3) 
For impact sounds measured with the impact noise analyzer, the sound pressure levels set forth in Tables I and II [Tables G and H] may be increased by six decibels in each octave band.
(4) 
The following uses and activities shall be exempt from the noise level regulations:
(A) 
Noises not directly under the control of the property user.
(B) 
Noises emanating from construction and maintenance activities between 7:00 a.m. and 9:00 p.m.
(C) 
The noises of safety signals, warning devices, and emergency pressure relief valves.
(D) 
Transient noises of moving sources, such as automobile[s], truck[s], airplanes, and railroads.
(h) 
No toxic matter, noxious matter, smoke[,] gas, or odorous or particle matter shall be emitted that is detectable beyond the lot lines of the [property] on which the use is located.
(i) 
Earth-carried vibration shall be limited so that detection by seismograph at any property line of an industrial establishment shall not exceed a value measured and computed as follows:
(1) 
Method of Measurement:
Measurement shall be made at the property line, vibration displacements shall be measure[d] with an instrument capable of measuring in three (3) mutually perpendicular directions.
(2) 
Maximum Permissible Displacements:
The following formula shall be used in computing the maximum displacements permitted in the “M-1” district: D = K/f. (Where D = displacements in inches, K = .01, f = the frequency of the vibration transmitted through the ground in cycles per second.)
(j) 
Exterior lighting fixtures, wherever necessary, shall be shaded to avoid casting direct light upon property located in any Residential District.
(k) 
The manufacture of flammable materials which produce explosive vapors or gases is prohibited.
(l) 
No outside storage of equipment and/or material, except equipment in daily use, shall be permitted in such a location where it can be viewed from any public street.
(m) 
Any operation that produces intense glare or heat shall be performed within a completely enclosed building, and exposed sources of light shall be screened so as not to be detectable beyond the lot lines.
(Ordinance 6051-12 adopted 5/17/12)