Noise Barrier Specifications & Selection Guide

Panel construction, acoustic ratings and post systems for metal noise barriers used along highways, railways and industrial boundaries. Compiled from our standard supply envelope, in-house quality controls and typical traffic-noise design practice.

Last updated: September 5, 2026

How a noise barrier actually works

A noise barrier reduces sound by blocking the direct line of sight between a source (traffic, rail, plant equipment) and a receiver (residences, schools, offices). The two physical levers are mass — a heavier panel transmits less sound (the mass law) — and absorption — a perforated, absorptive face stops sound reflecting back across the road and reduces reverberation at the barrier itself.

Most of our barriers are built from galvanized steel sheet or aluminium alloy, formed into louvered or micro-perforated panels with a sound-absorbing core (mineral wool or fibre composite). For corrosive, coastal or wash-down environments, stainless steel or an upgraded coating system is specified. Where sightlines and daylight matter — urban roads, bridge decks, residential frontages — transparent polycarbonate (PC) or PMMA modules share the same post system and stack into one continuous wall.

Once you have fixed the acoustic target and panel type, see the noise barrier product page for our standard supply envelope, MOQ and lead times.

Four panel constructions

Pick the face and core that match your site — absorptive panels for traffic, transparent for sightlines, reflective for budget industrial screening.

Louvered absorptive panel

A perforated metal face over a sound-absorbing core. The most common choice for highways and railways — it cuts reflected noise and meets typical traffic attenuation targets.

Micro-perforated panel

Finer perforations deliver a higher NRC with a cleaner architectural look. Preferred for urban roads, bridges and prestige frontages where appearance matters.

Transparent panel (PC / PMMA)

Polycarbonate or acrylic modules preserve sightlines and daylight. Stacked with metal panels on the same post system for continuous walls along sensitive frontages.

Full-metal reflective panel

No absorptive core — sound is reflected back to the source side. A cost-effective option for industrial plant boundaries where reflected noise is acceptable.

Technical specifications

Parameter ranges for standard noise barrier configurations. Custom specifications available on request.

Parameter Standard range
Panel type Louvered / Micro-perforated / Transparent / Full-metal reflective
Material Galvanized steel sheet, Aluminium alloy (Stainless optional)
Sheet thickness 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm (customizable)
Panel height 1.0 m – 6.0 m (modular sections)
Panel length 1.96 m, 2.46 m, 3.0 m (customizable)
Surface treatment Hot-dip galvanized, Electrostatic powder coated
Color RAL system (grey, green, blue, white, etc.), customizable
Acoustic performance NRC 0.80 – 0.95; Sound Reduction Index STC 25 – 35 dB (by design & installation)
Absorptive core Mineral wool / fibre composite (non-combustible grade)
Post system H-section steel post, 2.0 – 4.0 m spacing
Wind load Rated per project wind zone; foundation sized accordingly
Quality control In-house per-order inspection; third-party on request

Acoustic values are typical for the stated constructions; final attenuation depends on barrier height, position relative to source and receiver, and installation quality. A project acoustic report should confirm the required STC / insert-loss target.

How to specify your noise barrier

Five steps from acoustic target to a quotable bill of materials.

1

Define the attenuation target

Start from the project's required insert loss (dB). This sets the STC the panel must deliver and frames how much height and mass you need.

2

Pick the panel type by location

Highway / railway → louvered or micro-perforated absorptive. Urban sightline → transparent (PC/PMMA). Industrial boundary where reflection is acceptable → full-metal reflective.

3

Set height and length

Modular from 1.0 m to 6.0 m. Remember the line-of-sight principle: the barrier must break the direct source–receiver path. Standard module lengths are 1.96 / 2.46 / 3.0 m.

4

Choose material and surface

Galvanized steel for general service, aluminium for lighter weight / corrosion resistance, stainless for aggressive environments. Finish in any RAL colour via powder coating.

5

Fix the post system and foundation

H-steel posts at 2.0 – 4.0 m spacing, set into concrete foundations sized from the local wind zone. We supply panels, posts and drawings; the contractor handles foundations and erection.

Referenced Standards & Specifications

Zhaobang Metal manufactures and inspects to the following internationally recognized standards. Links open the issuing organization's official page.

  • JT/T 646.1-2025 & JT/T 646.2-2025 & JT/T 646.4-2025 — 《公路声屏障》 (Highway Noise Barriers), Ministry of Transport of China. Specifies acoustic requirements (weighted sound reduction index Rw ≥ 26 dB for non-transparent panels; noise reduction coefficient NRC ≥ 0.60 for absorptive panels), plus structural, safety and durability requirements. Zhaobang panels are specified to meet or exceed these thresholds. 交通运输标准化信息系统 ↗
  • GB/T 51335-2018 — 《声屏障结构技术标准》 (Technical Standard for Noise Barrier Structures). 全国标准信息公共服务平台 ↗
  • HJ/T 90-2004 — 《声屏障声学设计和测量规范》 (Acoustic Design and Measurement Specification for Noise Barriers), Ministry of Ecology and Environment. 生态环境部标准 ↗
  • ASTM E90 / ISO 10140 — Laboratory measurement of airborne sound insulation (basis for reported STC / Rw values). ASTM E90 ↗ · ISO 10140 ↗
From the blog: for a step-by-step tender-focused walkthrough — insert-loss targets, absorptive vs reflective choice, height and post spacing — read How to Select a Highway Noise Barrier: Acoustic Targets, Standards and Panel Specification. More guides in our Technical Blog.

Frequently asked questions

Technical questions about specifying metal noise barriers.

What is the difference between STC and NRC for a noise barrier?

STC (Sound Transmission Class) measures how much sound a panel blocks from passing through it — important when noise must not reach the receiver side. NRC (Noise Reduction Coefficient) measures how much sound a perforated, absorptive face soaks up on the source side, reducing reflection and reverberation. A good traffic barrier combines a high-NRC absorptive face with enough mass to deliver a useful STC. Our standard panels reach NRC 0.80–0.95 and STC 25–35 dB depending on construction.

How tall should a highway noise barrier be?

Height drives attenuation through the line-of-sight principle: the barrier must break the direct path between the noise source and the receiver. Our panels are modular from 1.0 m up to 6.0 m. As a rule of thumb, each additional metre of height close to the source or receiver adds roughly 1.5 dB, but returns diminish above about 4–5 m, so extending height alone is rarely the most cost-effective fix — panel mass and absorptive treatment matter as much. Final height should follow the project's acoustic design report.

Can transparent panels be combined with metal noise barriers?

Yes. Transparent sections use polycarbonate (PC) or PMMA acrylic and are commonly combined with metal panels where sightlines, lighting or aesthetics matter — for example along urban roads, bridge decks and residential frontages. The transparent and metal modules share the same post system so they stack into one continuous wall. PC is impact-rated (shatter-resistant) and UV-stabilised for outdoor service.

What post spacing and foundation are typical for noise barrier installation?

Panels are fixed between H-section steel posts. Standard post spacing is 2.0 m to 4.0 m depending on panel length (1.96 m / 2.46 m / 3.0 m) and local wind-load requirements. Posts are set into cast-in-place concrete foundations sized from the site's wind load and soil conditions. We supply the panels and posts with detailing drawings; foundation and on-site construction are handled by the local contractor.

Do you provide on-site installation for noise barrier projects?

No. Zhaobang Metal is a direct manufacturer supplying barrier panels, posts and fixing accessories for global export. We provide material supply, export packaging, shop drawings and installation guidance documents, but we do not dispatch on-site construction teams. Installation is performed by the project's local contractor or EPC.

Need a noise barrier quotation?

Send us your required height, length, material, surface treatment or drawings. We will provide a clear quotation based on your project specifications.