HomeMy WebLinkAbout20250907 75 Clinton St Area Variance Ashland Fence - DOT Highway Noise Wall Stndards ComparisonNOISE BARRIER COMPLIANCE REFERENCE SUMMARY
SimTek Ashland Fence — 12-Foot Sound Wall
Submitted in Support of Fence Variance Hearing
PURPOSE
This document demonstrates that the 12-foot SimTek Ashland fence installed at the subject property is consistent
with the height, materials, and noise-reduction standards used in Department of Transportation (DOT) highway
sound wall projects nationwide and in New York State specifically. The fence meets or exceeds the material
specifications required by NYSDOT for approved noise barrier systems.
SPECIFICATION COMPARISON: THIS FENCE VS. DOT STANDARDS
Metric DOT / NYSDOT Standard Industry Typical Range My SimTek Ashland
Fence
Height
Determined by acoustical
model; design goal: 7
dB(A) reduction
12 – 15 ft (national avg:
14 ft) 12 ft ✓
Min. STC Rating
(NYSDOT)
STC 25 minimum
(NYSDOT Item 643) STC 25 – 35+ STC 26 ✓
Sound Blockage Minimum 5 dB(A)
reduction required 5 – 10 dB(A) typical Blocks 98% of direct
sound ✓
Wind Rating Structural integrity per
AASHTO Varies by material 130 MPH certified ✓
Approved DOT Use State DOT approval
required
Concrete, masonry,
SimTek
IDOT-approved
(SimTek EcoStone
family) ✓
HEIGHT STANDARDS: WHY 12 FEET IS THE INDUSTRY NORM
Multiple federal and state DOT agencies confirm that 12 feet is a standard — not exceptional — height for highway
noise barriers:
• FHWA National Inventory: 93% of all U.S. highway noise barriers range from 6 to 20 feet tall. The national
average barrier height is 14 feet.
• Washington State DOT: Noise walls "normally are 12 to 15 feet tall" (WSDOT Noise Walls & Barriers
guidance).
• California DOT (Caltrans): Minimum barrier height of 6 feet; standard working heights up to 14–16 feet.
• Florida DOT: Maximum ground-mounted noise wall height of 22 feet; typical project heights 12–16 feet.
• South Carolina DOT: Maximum permissible wall height of 25 feet.
WHY HEIGHT MUST INTERCEPT THE NOISE SOURCE
Sound travels in a straight line of sight from the noise source to the receiver. A barrier only works if it
physically breaks that line of sight. Once line-of-sight is broken:
• A 5 dB(A) noise reduction is achieved at the moment line-of-sight is broken (FHWA)
• Each additional 2 feet of height beyond that point delivers approximately 1 additional dB(A) of
reduction
• FHWA guidance specifies the barrier must intercept the line of sight from a truck exhaust stack
(11.5 ft above pavement) to the receptor
• A fence that is too short — even by a few feet — can render the wall largely ineffective
Conclusion: At 12 feet, this fence is sized within the industry's standard working range (12–15 ft)
and meets or exceeds the height needed to intercept typical highway noise sources at grade.
Reducing the height would materially impair the fence's noise attenuation function.
PRODUCT: SIMTEK ASHLAND — DOT-GRADE NOISE BARRIER
SimTek Ashland — Product Overview
Manufacturer: SimTek by CertainTeed (now marketed as Catalyst Fence Solutions)
Product Line: Ashland — deep-grain wood-texture, rotationally-molded polyethylene with galvanized
steel reinforcement
STC Rating: 26 — blocks up to 98% of direct sound (source: vinylfenceanddeck.com)
Wind Rating: Certified to 130 MPH; certified to Florida Building Code
DOT Applications: SimTek EcoStone (same product family) is IDOT-approved for DOT highway
sound wall projects at 9 ft, 12 ft, and 16 ft heights (source: vinylfenceanddeck.com)
NYSDOT Minimum STC: STC 25 required (NYSDOT Item 643.0100NN11) — Ashland STC 26
meets this threshold
Heights Available: Panels stack to 8 ft, 12 ft, and 16 ft — used in commercial, DOT, and residential
applications
Note on product photography: SimTek EcoStone (same structural system as Ashland) is in active use as highway
sound walls in DOT projects. Documentation and IDOT approval images are available at:
vinylfenceanddeck.com/products/simulated-stone-fence/
CONCLUSION
The 12-foot SimTek Ashland fence at the subject property:
• Is sized within the industry-standard range of 12–15 feet used in DOT highway sound wall projects
nationwide
• Exceeds the NYSDOT minimum STC 25 material requirement (Ashland STC 26)
• Is manufactured by a company whose product line (SimTek EcoStone) is IDOT-approved for DOT highway
sound wall applications
• Must be 12 feet to physically intercept the line of sight from highway noise sources to the property —
reducing the height would directly reduce the fence's noise attenuation effectiveness
• Is wind-certified to 130 MPH and meets the Florida Building Code — demonstrating structural rigor consistent
with DOT-level engineering requirements
Based on the above, this fence is not an oversized residential structure — it is a properly engineered noise
barrier consistent with the specifications routinely approved by state DOTs across the country and
specifically consistent with NYSDOT noise barrier standards.
Sources & References
1. FHWA Highway Traffic Noise Barrier Design Handbook — fhwa.dot.gov
2. NYSDOT Item 643.0100NN11 — Sound Absorptive Noise Barrier System Spec (STC 25 minimum)
3. FHWA National Noise Barrier Inventory — average barrier height 14 ft; 93% of all barriers range 6–20 ft
4. WSDOT Noise Walls & Barriers — walls "normally 12 to 15 feet tall" (wsdot.wa.gov)
5. SimTek Ashland Product Specs — STC 26, 130 MPH wind rating (vinylfenceanddeck.com)
6. SimTek IDOT Approval — EcoStone 12-ft sound wall approved for DOT projects (vinylfenceanddeck.com)
7. California HDM 1102.3; FDOT Design Manual 264; SCDOT Noise Barrier Design Criteria — state DOT height
standards