The following sections contain provisions pertaining to performance standards.

(Ord. No. 17-O-13, 8-8-2017)

(a)

Applicability. The performance standards in this section apply town wide.

(b)

Nonconformities. The fact that the operations of a lawful use violate the performance standards of this article shall not of itself make such use subject to the requirements of this chapter relating to nonconformities.

(Ord. No. 17-O-13, 8-8-2017)

(a)

Required performance level. No machinery, mechanical apparatus or other stationary feature affixed to the property or structure, or operating within a structure operation or activity shall cause or create noise in excess of the sound levels prescribed in the table titled "Maximum Sound Levels" when measured from the property line of the sound source or any point within any other property affected by the sound.

(b)

Method of measurement. The following provisions shall apply to measurement of sound:

(1)

Intensity and frequency. For the purpose of measuring the intensity and frequency of sound, a sound level meter using the A-weighted network shall be employed. Specific to impulsive sound levels, the fast setting of the sound pressure meter using unweighted peak dB levels shall be employed.

(2)

Equipment. Sound pressure meters shall meet or exceed the American National Standards Institute (ANSI) Standard S1.4 for a "Type Two" meter and shall be calibrated by the manufacturer of a company that can certify the calibration as least one time each year.

(c)

Exemptions. The following uses and activities shall be exempt from the noise level regulations of this section:

(1)

Not under direct control. Noises not directly under the control of the property users shall be exempt.

(2)

Construction and maintenance noise. Noises emanating from construction and maintenance activities pursuant to section 26-222 of the Town Code shall be exempt.

(3)

Safety related noises. The noises of safety signals, warning devices and emergency pressure relief valves or related to the emission of sound for the purpose of alerting persons to the existence of an emergency, or the emission of sound during emergency circumstances that require immediate action and involving actual or imminent injury, illness, death, threat to public health or to public welfare or property damage shall be exempt.

(4)

Transient noises. Transient noises of moving sources such as automobiles, trucks, airplanes and railroads shall be exempt; provided, however, that noises of motor vehicles are pursuant to section 26-226 of the Town Code.

(Ord. No. 17-O-13, 8-8-2017)

(a)

Required performance level. No activity or operation shall cause or create earthborn vibrations in excess of the displacement values given in this section.

(b)

Method of measurement. The following provisions shall apply to measurement of vibrations:

(1)

Location. Measurements shall be made at or beyond the adjacent lot line or the nearest residential district boundary line, as described in this chapter division.

(2)

Equipment. Vibration displacements shall be measured with an instrument capable of simultaneously measuring in three mutually perpendicular directions.

(3)

Computation formula. The maximum permitted displacements shall be determined in each zoning district by the following formula: D = K/f. In which:

D = displacement in inches

K = a constant to be determined by reference to Table 78-130.3(c) in this section

f = the frequency of vibration transmitted through the ground in cycles per second.

(c)

Standards for all nonresidential uses. The maximum earth displacement permitted at the points described in this section shall be determined by use of the formula in this section and the appropriate K constant shown in Table 78-130.3(c) in this section.

(Ord. No. 17-O-13, 8-8-2017)

(a)

Required performance level. No operation or activity shall cause or create the emission of smoke from any vent, stack, chimney, flue or other opening that exceeds the density or equivalent opacity prescribed in this division. The total emission of particular matter from all vents, stacks, chimneys, flues or other openings of any process, operation or activity shall not exceed the particulate matter limitations prescribed in this division.

(b)

General limitations. The following limitations shall apply to emissions:

(1)

Particulate matter. Particulate matter emissions caused by the wind from open storage areas, yards, roads, etc., shall be kept to a minimum by appropriate landscaping, paving, oiling, wetting or other means.

(2)

Limit on open air emissions. No operation shall cause or allow to be emitted into the open air from any process or control equipment or to pass any convenient measuring point in a breaching or stack particulate matter in the gases that exceeds 0.60 pounds per 1,000 pounds of gases during any one hour.

(c)

Method of measurement. The following provisions shall apply to measurement of emissions:

(1)

Smoke. For the purpose of determining the density or equivalent opacity of smoke, the Ringelmann Smoke Chart as adopted and published by the United States Bureau of Mines in Information Circular No. 8333 shall be employed.

(2)

Particulate matter. Particulate matter loadings in pounds per acre described in this section shall be determined by selecting a continuous four-hour period which will result in the highest average emission rate. In computing pounds per acre, the gross area of the zoning lot on which the use is located shall be employed.

(d)

Standards for all nonresidential uses. The following standards shall be used to evaluate emissions:

(1)

Smoke standards. The continuous emission of smoke from any vent, stack, chimney or combustion process shall not exceed a density or equivalent opacity of Ringelmann No. 1. Smoke exceeding Ringelmann No. 1, but not exceeding Ringelmann No. 3, shall be permitted up to six minutes during any four-hour period. Smoke in excess of Ringelmann No. 3 is prohibited.

(2)

Particulate matter standards. The emission of particulate matter from all vents, stacks, chimneys and openings of any operation shall not exceed 0.2 pounds per hour, per acre.

(Ord. No. 17-O-13, 8-8-2017)

(a)

Required performance level. No operation or activity shall cause or create the emission of toxic matter in amounts or quantities that exceed the levels prescribed in this section.

(b)

Method of measurement. In determining the maximum permissible concentration allowed an industrial worker, the most recent listing of threshold limit values published by the American Conference of Governmental Industrial Hygienists shall be used. If a toxic substance is not contained in the most recent listing of threshold limit values published by the American Conference of Governmental Industrial Hygienists, then the applicant shall produce sufficient and satisfactory evidence showing that the proposed levels are safe to the general population. Concentrations shall be measured and calculated as the highest average that could occur over a continuous eight-hour period.

(c)

Standards for all nonresidential uses. The release of airborne toxic matter (including radioactive matter) shall not exceed five percent of the maximum permissible concentration allowed an industrial worker when measured at any point beyond the lot line, either at ground level or habitable elevation, whichever is more restrictive.

(Ord. No. 17-O-13, 8-8-2017)

(a)

Compliance. All operations, activities and uses shall be conducted so as to comply with the performance standards governing fire and explosion hazards prescribed in this section.

(b)

Materials that decompose by detonation. The following general requirements shall pertain to the storage, handling and use of materials that decompose by detonation:

(1)

Activities and materials subject to regulation. Activities involving the storage, utilization or manufacture of materials or products which decompose by detonation are permitted only in accordance with the use standards in Article VII and this section. Such materials shall include, but are not limited to: All primary explosives such as lead azide, lead styphnate, fulminates and tetracene; all high explosives such as TNT, RDK, HMX, PETN and picric acid; propellants and components thereof such as nitrocellulose, black powder, boron hydrides, hydrazine and its derivatives; pyrotechnics and fireworks such as magnesium powder, potassium chlorate and potassium nitrate; blasting explosives such as dynamite and nitroglycerine; unstable organic compounds such as acetyl ides, tetrazoles and ozonides; strong oxidizing agents such as 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.

(2)

National Fire Code. Where materials or products which decompose by detonation are permitted, these materials shall be handled, stored, utilized or manufactured in accordance with the National Fire Codes published by the National Fire Protection Association.

(c)

Standards for various materials. Uses involving fire and explosive matter shall be subject to the following:

(1)

Materials that decompose by detonation. Uses involving the manufacture, storage and utilization of materials and products that decompose by detonation may be allowed only as a special exception use.

(2)

Incompatible to moderate burning materials. The storage, utilization or manufacture of solid materials or products ranging from incombustible to moderate burning is permitted.

(3)

Free or active burning to intense burning materials. The storage, utilization or manufacture of solid materials or products ranging from free or active burning to intense burning is permitted, provided that such materials or products are stored, manufactured or utilized in fire-resistant and fire-protected buildings or spaces. Such materials or products may be stored outdoors, provided that such storage areas are setback at least 70 feet from all lot lines.

(4)

Flammable liquid, vapors and gases. The storage, utilization or manufacture of flammable liquids or materials which produce flammable or explosive vapors or gases shall be permitted in accordance with the following table, except that the storage of finished products in original sealed containers of 55 gallons or less shall be unrestricted.

(Ord. No. 17-O-13, 8-8-2017)

No operation or activity associated with any land use in any zoning district shall be conducted so as to cause any electrical disturbance or electromagnetic interference that is not in conformance with the regulations of the Federal Communications Commission that adversely affects, at any point, the operation of any equipment other than that belonging to the creator of such disturbance or interference.

(Ord. No. 17-O-13, 8-8-2017)

No operation or activity associated with any land use in any industrial district shall be conducted so as to discharge any liquid or solid waste products or materials into any ditch, stream, river, other body of water or drainage facilities; and there shall be no discharge of toxic or nonbiodegradable products or materials into any sewer or sewerage facility, except as otherwise specifically authorized by the governmental authorities having jurisdiction over the discharge of liquid or solid waste products or materials.

(Ord. No. 17-O-13, 8-8-2017)

(a)

Applicability. Various sections of this chapter address the need for site lighting to maintain adequate lighting levels on site and provide security for people and property. The installation of site lighting for these purposes may be required with development of townhouse, two-family, and multiple-family dwellings, public and institutional, commercial, and service and industrial uses. Whether required under this chapter, or provided at the applicant's option, the following standards shall be applied to exterior lighting.

(b)

Compliance. In addition to the standards contained in this section, exterior lighting shall also comply with the Herndon Guidelines for Planning and Design of Town Streetscape Projects (dated November 25, 2008, as may be amended, located in the Herndon Department of Community Development) as described in section 1-16, Herndon Town Code (2000) as amended.

(c)

Inconsistencies. Where there is conflict of inconsistency between this article and the Herndon Guidelines for Planning and Design of Town Streetscape Projects (dated November 25, 2008, as may be amended, located in the Herndon Department of Community Development) as described in section 1-16, Herndon Town Code (2000) as amended, the more restrictive standard shall apply.

(d)

Site lighting plan. Any development proposed within the town shall conform to the town's exterior lighting standards. As part of the site plan review process, information about site lighting shall be provided as required in section 78-155.6.

(e)

Exterior lighting standards. Exterior lighting shall meet the following standards:

(1)

Hours of illumination. Properties on which public and institutional uses, commercial uses, and service and industrial uses are located that are adjacent to existing residential development or vacant land in a residential zoning district have lighting that is turned off during non-operating hours, except lighting that is necessary for security or emergency purposes. Such lighting may be activated on-site by motion sensor devices.

(2)

Fixtures. Lighting is provided through the use of fixtures that are durable, yet avoid the use of tall light fixtures that unnecessarily disperse light and glare to surrounding properties.

(3)

Illumination direction. In all residential districts, lighting of nonresidential properties is directed downward except for low-voltage architectural lighting.

(4)

Maximum lighting height. Maximum lighting height shall conform to the following:

a.

Residential property light fixtures are no more than 14 feet above grade.

b.

On nonresidential properties, outdoor lighting is no greater than 15 feet in height, whether mounted on poles or walls or by other means, except:

1.

Light fixtures in parking lots containing between 100 and 250 spaces are no more than 25 feet high; and;

2.

Light fixtures in parking lots containing more than 250 spaces are no higher than 35 feet in height;

3.

In any event, where visible from residential properties, fixtures do not exceed 20 feet above grade;

4.

Wherever possible, illumination of outdoor seating areas, building entrances, and walkways is accomplished by use of ground mounted fixtures not more than four feet in height.

(5)

Shielding. Lighting shall be shielded as follows:

a.

Light fixtures in excess of 60 watts or 100 lumens use full cut-off lenses, hoods other shielding as warranted to prevent glare or spillover from the project site onto adjacent properties and roadways.

b.

No light source emits light directly onto adjacent residential property.

c.

No light source in a canopy structure extends downward further than the lowest edge of the canopy ceiling.

d.

Awnings or canopies used for building accents over doors, windows, etc., are not internally illuminated (i.e., from underneath or behind the awning).

(6)

Maximum light levels. Outdoor lighting and indoor lighting visible from outside are designed and located so that the maximum illumination measured in foot candles at a vertical distance of three feet above grade at the property line do not exceed the standards in Table 78-130.9(e)(6), maximum illumination values. Cut-off lighting shall be designed to direct light downward (e.g., shoe box style). In any case, spillage of indirect light onto adjacent residential properties is 0.1 foot candles or less, or 1.0 foot candles or less for other uses, measured at the boundary line of the site.

(7)

Uniformity ratios. The ratio of maximum to minimum lighting on a given property measured at ground level, does not exceed 15:1 in the residential districts; 10:1 in the business districts; and 3:1 in parking lots.

(8)

Direction of lighting. No light source is directed outward toward property boundaries or adjacent rights-of-way. No light source directly illuminates facades of buildings visible from residential properties.

(9)

Distance from property line. All exterior lighting fixtures are located a minimum of ten feet from a property line or five feet from a right-of-way line and are not located within a required perimeter buffer or streetscape unless they are located at the interior edge of the buffer or streetscape.

(10)

Hue. Lighting sources are color-neutral types such as LED (light emitting diode) or metal halide. Light types of limited spectral emission such as low-pressure sodium or mercury vapor lights, are prohibited.

(11)

Wall-mounted lights. Wall-mounted lights (other than entry lights of 100 watts or less) are fully shielded luminaries (such as shoebox or can style fixtures) to direct all light downward, and to prevent the light source from being visible from any adjacent residential property or public street right-of-way.

(12)

Floodlights and spotlights. Floodlights or other type of lighting attached to light poles that illuminate the site and/or building(s) are prohibited. Permitted floodlights and spotlights are selected, located, aimed, and shielded so that direct illumination is focused exclusively on a portion of the building facade or other intended site feature and away from adjoining properties or the right-of-way. On-site lighting may be used to accent architectural elements but is not used to illuminate entire portions of building(s). Such lighting is installed in a fixture that is shielded so that no portion of the light bulb extends below the bottom edge of the shield, and the main beam from the light source is not visible from adjacent properties of the adjacent right-of-way.

(13)

Wall pack lights. Wall packs on buildings may be used at entrances to a building to light unsafe areas. Such lights are not used to draw attention to the building or provide general building or site lighting. "Wall Packs" on the exterior of the building are fully shielded (true cut-off type bulb or light source not visible from off-site) to direct the light vertically downward at an angle that will limit output to prevent glare on adjacent property and be of low wattage (preferably 100 watts or lower). Wall pack lights visible from any location off the site are prohibited.

(14)

Illumination of outdoor sports fields and performance areas. Lighting of outdoor sports fields and performance areas shall comply with the following standards:

a.

All lighting fixtures shall be equipped with a glare control package (e.g., louvers, shields, or similar devices), and the fixtures shall be aimed so that their beams are directed and fall within the primary playing or performance area; and

b.

The hours of operation for the lighting system for any game or event shall not exceed one hour after the end of the game or event.

(Ord. No. 17-O-13, 8-8-2017)