Special Regulations Applicable to Certain Districts and Uses
Mature Livestock | Acres Required Per Animal |
|---|---|
Horses and cows | 1.0 |
Sheep and goats | 0.5 |
Minimum lot area | 0.5 gross acre |
Minimum lot width at lot frontage on Market Street, Gay Street, Strasburg Road, Downingtown Pike, or Hannum Avenue | 50 feet |
Minimum front yard setback | 5 feet |
Minimum rear yard setback | 10 feet |
Minimum side yard setback | 10 feet |
Maximum building coverage | 65% |
Maximum impervious lot coverage | 85% |
Building height | 45 feet by right (provided, however, that a building may exceed 45 feet in height if otherwise in the HO-75 Overlay District and when in compliance with the standards in § 112-402 as to height) |
Data Center Noise Standards Tables |
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The following tables establish objective noise limits, modeling requirements, and enforcement procedures applicable to data center use. These standards shall supersede noise standards set forth in Chapter 73 of the Borough Code. |
Table 1: Data Center Noise Limits, Measurement, and Compliance Requirements | |
|---|---|
Category | Requirement |
Applicable uses | Data centers, including all accessory mechanical equipment, generators, cooling systems, and substations |
Measurement basis | A-weighted sound levels (dBA), unless noted otherwise for low-frequency noise |
Receptor locations | Measurements and modeling shall be conducted at or beyond the nearest property line and at sensitive receptors, when present |
Operating condition assumption | All compliance evaluations shall assume simultaneous operation of all generators, cooling equipment, and other noise-producing devices at maximum rated capacity |
Table 2: Numeric Noise Limits by Zoning Use | ||
|---|---|---|
Receiving Land Use | Daytime (7:00 A.M. – 10:00 P.M.) | Nighttime (10:00 P.M. – 7:00 A.M.) |
Residential or sensitive receptor | 55 dBA Leq (1 hour) | 45 dBA Leq (1 hour) |
Mixed-use/commercial | 60 dBA Leq (1 hour) | 50 dBA Leq (1 hour) |
Industrial | 65 dBA Leq (1 hour) | 55 dBA Leq (1 hour) |
Short-term tonal or impulsive noise exceeding the above limits by five dBA or more shall constitute a violation. | ||
Table 3: Low-Frequency Noise Criteria | |
|---|---|
Parameter | Requirement |
Frequency sensitivity | C-weighted sound levels (dBC), capturing enhanced sensitivity to low-frequency noise |
Measurement metric | Equivalent continuous sound level (Leq, 1 hour) in dBC |
Measurement locations | At the nearest property line and at sensitive receptors, when present |
Daytime limit (7:00 A.M. - 10:00 P.M.) | 70 dBC Leq (1 hour) |
Nighttime limit (10:00 P.M. - 7:00 A.M.) | 60 dBC Leq (1 hour) |
Tonal/narrowband noise | Clearly perceptible low-frequency tonal noise shall require mitigation regardless of overall dBC compliance, as determined by the qualified professional or the Borough based on clearly perceptible tonal characteristics |
Applicability | Limits apply under simultaneous operation of all generators, cooling systems, and mechanical equipment |
Table 4: Modeling and Study Requirements | |
|---|---|
Requirement | Standard |
Pre-construction study | Required with conditional use application |
Post-construction verification | Required within 180 days of commencement of operations |
Prepared by | Qualified professional with demonstrated noise expertise |
Modeling methodology | ISO 9613-2, CadnaA, SoundPLAN, or equivalent accepted industry model |
Meteorological assumptions | Downwind propagation, ISO-conservative conditions |
Equipment data | Manufacturer sound power levels and octave-band spectra |
Low-frequency evaluation | Required where large generators or cooling systems are used |
Table 5: Measurement Procedures | |
|---|---|
Element | Requirement |
Instrumentation | Type 1 or Type 2 ANSI-certified sound level meter |
Calibration | Pre- and post-measurement field calibration required |
Measurement duration | Minimum 15 minutes per location unless otherwise specified. Sound level limits expressed as hourly equivalent levels (Leq, 1 hour) may be evaluated using shorter-duration measurements, including the minimum durations identified in this table, where such measurements are conducted under steady-state operating conditions and are representative of normal operations. |
Operating conditions | Measurements shall include peak cooling load and generator operation under load |
Background noise | Baseline ambient levels documented prior to construction |
Table 6: Compliance | |
|---|---|
Item | Requirement |
Material increase definition | An increase of ≥ 3 dBA above baseline ambient sound level |
Violation determination | Exceedance of numeric limits or material increase |
Retesting authority | Borough may require additional testing following substantiated complaints or equipment changes |