Author: Marketing Ekopres

Almost 9 in 10 infrastructure projects exceed their planned budget, by an average of 28%. The most common single cause is design errors and the resulting need for rework. For noise barriers, this statistic has a specific mechanism: the designer, the panel manufacturer and the installation contractor are three separate parties who do not share responsibility for the final result. Each is responsible for their own piece — and none for the whole.

Why building through several subcontractors burdens the investor

On large infrastructure projects — motorways, expressways, railway lines — noise barriers are usually just one of many elements in a contract. A general contractor responsible for the whole build often subcontracts individual elements to specialist firms. That is normal and efficient for most works. For noise barriers, though, it creates a specific problem.

A barrier’s acoustic performance depends on a chain: analysis → design → panel → installation. Every link in that chain has to be consistent with the others. The acoustic design has to account for the real parameters of a specific panel. The panel has to match the design assumptions. Installation has to execute the design without deviation. When each link comes from a different party — a design office, a panel manufacturer, an installation firm — consistency becomes a coordination task rather than a technical one. And coordination tasks tend to generate errors precisely at the interfaces between parties, not within them.

How the traditional delivery model works — and where it breaks

Under the traditional model (design-bid-build, or DBB), the client or general contractor signs separate contracts with a designer, a panel manufacturer and an installation firm. The phases are sequential: the design comes first, then a manufacturer is selected by tender, then an installation firm.

Three potential breaking points:

The design-to-panel interface

The designer produces acoustic calculations based on catalogue parameters for typical panels available on the market. When the tender selects a specific manufacturer with a specific batch of panels, it often turns out that the batch’s actual DLα and DLr values deviate slightly from what was assumed in the design. A minimal discrepancy — especially for barriers operating at the edge of the environmental decision’s requirements — can mean the finished barrier fails post-installation measurements.

The panel-to-installation interface.

The panel manufacturer has no visibility into how the panels will be installed. The installer has no visibility into how the panel is built at its joints. Sealing the base zone — the gap between the barrier’s lower edge and the ground — is the most common reason acoustic requirements are not met after handover. The manufacturer and the installer can each be individually blameless, and the barrier still doesn’t perform as it should.

After handover.

When post-installation measurements show the standard hasn’t been met, the search for who’s responsible begins. The designer points to the manufacturer: “the panel had different parameters than assumed in the design.” The manufacturer points to the installer: “the unsealed base ruined the acoustic result.” The installer points to the design: “the installation details weren’t specified in enough detail.” The investor is caught between three parties, none of whom holds overall responsibility, while a settlement or a court judgment drags on.

Three concrete risk areas for the investor with noise barriers

Design-Build vs. Design-Bid-Build: what the numbers show

The single point of accountability model — known in the literature as Single Point of Accountability or the Design-Build (D+B) approach — has been the subject of quantitative research in the construction industry for decades. The results are consistent across several key areas.

Delivery speed. The Design-Build Institute of America (DBIA), analysing data from thousands of projects in the United States, found that D+B projects are delivered 102% faster from design through completion than comparable traditional-model projects.

Cost growth. D+B projects show 3.8% lower cost growth than DBB and 1.7% lower schedule growth — meaning they finish closer to the originally planned completion date. Federal Highway Administration (FHWA) research confirmed that D+B infrastructure projects had an average final cost nearly 3% lower than DBB.

Design changes. The number of change orders (design changes that generate additional costs) is 6% lower in D+B projects than in DBB. For noise barriers, this is exactly the category that generates the largest costs: rework after discovering a mismatch between the design and the panel, additional as-built documentation, repeat acoustic measurements.

How linking design and production closes the acoustic gap

The most important consequence of the single point of accountability model in the context of noise barriers is technical, not organisational. When the designer and the panel manufacturer are the same entity, the acoustic design isn’t built on generic catalogue data — it’s built with exact knowledge of which panel will be manufactured, from which materials, with which real DLα and DLr parameters.

At Ekopres Group, this is how it works: the acoustic calculations and the test data for the panels produced at the MATI plant sit within the same structure. The design does not refer to catalogue values from an unknown manufacturer — it refers to the actual parameters of our panel. Everything is backed by ITB, TZUS and CE testing and compliance. The panels are manufactured for that specific project. The Declaration of Performance (DoP) that Ekopres provides at handover matches exactly what was assumed in the design. There is no gap to paper over.

For the investor, this means one thing: post-installation measurement results aren’t a surprise. If the design specifies a particular level of noise attenuation, and the panel produced at MATI matches that design, the acoustic result can be predicted before installation is even finished. Surprises in post-installation measurements almost always come from a mismatch between the design and the actual product, or from installation errors. Under the single point of accountability model, both of those discrepancies stay internal.

The MATI plant as part of the process, not an external supplier

Most noise barrier contractors outsource panel production. That means they have limited influence over the quality of a specific batch, delivery dates, and the documentation that comes with the panels. The MATI plant is part of Ekopres Group — not an independent supplier.

Two parameters this changes in practice:

Delivery schedule. A 1,000 m² production hall, with automated machinery and a capacity of up to 20,000 m² of panels a month, is managed together with the schedule of a specific construction project. When a general contractor reports that installation on a given section is slipping by two weeks, that information goes straight into production planning — not into a complaint sent to an external supplier while waiting for a reply.

Quality of every batch. Quality control at the MATI plant is part of the production process for every batch of panels. The control results become part of the documentation handed to the client at handover, as part of the documentation package. Every batch of panels is covered by a Declaration of Performance compliant with PN-EN 14388:2005.

Workshop drawings: where the single point of accountability pays for itself

Workshop drawings are the construction drawings for every post, every foundation and every non-standard element for a specific location on site. Under the traditional model, they’re either produced by the installer based on the executive design (with a risk of discrepancies), or skipped and replaced with improvisation on site.

Improvisation on site is costly. For noise barriers it also has concrete acoustic consequences: the size and position of a post, the depth of a foundation, and how precisely the barrier’s lower edge is set all directly affect the acoustic result. A barrier designed for an effective height of 4.0 m and installed with a 5–10 cm levelling error attenuates less noise than the design calls for. Under the single point of accountability model, that kind of discrepancy is caught internally at the workshop drawing stage — before money is spent on a foundation in the wrong place.

Installation under one point of control: why the base zone is critical

The stage that most often determines whether a noise barrier passes or fails its post-installation measurements is, paradoxically, the one least discussed in technical specifications: sealing the base zone. The gap between the barrier’s lower edge and the pavement or ground may be only a few millimetres, but a low-frequency sound wave passes through a gap like that with little resistance. Post-construction measurements then show that a barrier rated A4/B3 actually achieves A2 or worse in practice, because part of the acoustic energy simply slips under the panel.

Under the single point of accountability model, sealing the base zone is a standard part of the scope of works and a standard part of handover. The works acceptance protocol includes verifying seal integrity at every point along the barrier’s lower edge.

The warranty as financial confirmation of assumed risk

Ekopres’ manufacturer’s warranty on its aluminium panels is 10 years. That’s a financial commitment, and an enforceable one. A company that guarantees a product for 10 years has to be confident in its quality, because any manufacturing defect that surfaces in that period falls on the manufacturer directly.

Under the single point of accountability model, the warranty carries an extra dimension. It covers not just the panel itself, but — as part of the obligations under the D+B agreement — the acoustic outcome as a whole. If post-installation measurements show the requirements haven’t been met, Ekopres can’t shift responsibility onto a designer, a manufacturer or an installer. We are all three of those parties.

That’s a concentration of risk — and it’s exactly what forces our internal processes, from acoustic analysis through production to installation, to be managed with a precision that’s never demanded of a subcontractor responsible for only their own slice.

For the investor, the difference is simple: one contract, one guarantor, one entity to hold accountable. If something goes wrong, there’s no need to work out who’s at fault between three parties to a contract.

When the single point of accountability model delivers the most value for the investor

Not every noise barrier project needs the full D+B model. There are a few scenarios where its value is clearly higher than in others.

A tight schedule with liquidated damages. When a project has strict deadlines and penalties for every day of delay, the risk of an external panel supplier disrupting the schedule is unacceptable. In-house production with queue management inside the group removes that risk entirely.

Acoustically complex projects. Tunnels, deep cuttings, development on both sides of the barrier, projects that need a non-standard combination of DLα and DLr parameters — these are the scenarios where a mismatch between design and panel has the biggest consequences. An acoustic design built with knowledge of the actual panel is essential here.

Publicly or EU-funded investments. Grant-funded projects require complete documentation at every stage, from the acoustic analysis, through the DoP for every batch of panels, to post-installation measurement results. When one entity is accountable for the whole, that documentation is consistent and complete as a single package.

An investor without an in-house acoustic inspector. A client without an experienced acoustics specialist can’t effectively check for mismatches between the design, the panel and the installation across three separate parties. Assigning the full scope to one company brings that verification in-house, where a mismatch is a quality control issue rather than a contractual dispute.

When the single point of accountability model is not optimal

The D+B model is less price-competitive when a project is straightforward, the route’s geometry doesn’t create acoustic risks, the barrier is single-sided in open terrain, and the investor or general contractor already has in-house experience managing acoustic subcontractors. In that scenario, the traditional tender model — selecting the cheapest party that meets the specification — can be a rational choice.

The single point of accountability model usually costs more at the outset than the sum of the cheapest bids from separate subcontractors. It costs less once you factor in the costs that show up along the way: design changes, delivery delays, post-handover disputes, and any rework after a standard isn’t met. DBIA research shows that this calculation favours D+B by 3.8% in terms of cost growth — but on projects where everything goes smoothly, the difference may be smaller or non-existent.

How Ekopres delivers the single point of accountability model step by step

Under the D+B format, Ekopres takes on the full scope of work that, under the traditional model, would span three separate contracts:

Analysis and environment. Acoustic analyses carried out using ISO 9613 or ray-tracing methods, an Environmental Impact Report (EIR) or a Project Information Card. The analysis results directly determine the required panel class and are developed with knowledge of the panel systems available from the MATI plant.

Design. Structural and executive documentation in the required format (GDDKiA, PKP PLK or another client), workshop drawings for every structural element, delivered to the client or general contractor before works begin.

Production. Single-sided absorptive aluminium panels (A4/B3: DLα 20 dB, DLr 26 dB), double-sided panels (A4/B3 both sides: DLα 12 dB, DLr 25 dB, fire class B-s1 d0), reflective panels (B3: DLr 30 dB), or timber anti-glare systems — manufactured at the MATI plant with ITB, TZUS and CE testing and compliance, and a 10-year manufacturer’s warranty. A Declaration of Performance (DoP) for every batch.

Installation. Support post foundations, panel installation, sealing the base zone, fitting end sections. As-built documentation including as-built drawings and — wherever the environmental decision requires it — post-installation measurement results confirming the acoustic outcome.

How Ekopres’ D+B model works as a subcontract to a general contractor

Most Ekopres Group projects are delivered as a subcontract within a general contractor’s contract — Strabag, Warbud, Eurovia, Mostostal Warszawa and others. In that setup, the single point of accountability model works on two levels: internally within Ekopres (designer, manufacturer and installer are one entity) and externally, toward the general contractor (one subcontractor instead of three to coordinate).

For a general contractor delivering a GDDKiA road contract, that has concrete value. Instead of separately coordinating a design office, a panel manufacturer and an installation firm — and managing the interfaces between them — they manage one subcontractor who takes responsibility for the entire barrier scope. A mismatch between design and panel, a delayed panel delivery, a base-zone problem — these become Ekopres’ internal matters, not the general contractor’s coordination headaches.

On projects where the general contractor holds a D+B contract from the client, Ekopres delivers a full documentation package: structural and executive design, workshop drawings, DoP for every batch of panels, and as-built documentation. The result is consistent documentation under a single name, not a patchwork of documents from three different parties.

Frequently asked questions about the single point of accountability model

What is the single point of accountability model in noise barrier construction?

The single point of accountability model (D+B, Single Point of Accountability) means one entity takes on the entire scope of an acoustic project: from the acoustic analysis and design, through panel production, to installation and as-built documentation. Under the traditional model, these three scopes are handled by three separate parties, each with its own contract and its own accountability.

What data supports the case for the D+B model?

Research from the Design-Build Institute of America (DBIA) found that D+B projects are completed (after the design stage) 102% faster, have 3.8% lower cost growth, and 6% fewer design changes than traditional projects. Federal Highway Administration research confirmed these findings for infrastructure projects.

What are the three main risk areas under the traditional delivery model?

1) The acoustic gap between the design and the actual parameters of the panel supplied by an external manufacturer; 2) The risk of delayed panel deliveries from an external manufacturer managing its own order queue; 3) Dispersed accountability after handover — when a barrier fails to meet standards, the designer, manufacturer and installer can each shift responsibility onto the others.

How does Ekopres deliver the single point of accountability model?

Ekopres Group combines Ekopres S.A. (engineering, design, delivery) with the MATI production facility (aluminium panels, capacity up to 20,000 m²/month, ITB/TZUS/CE testing and compliance, 10-year warranty). Under D+B, Ekopres delivers: the acoustic analysis and EIR, structural and executive documentation, workshop drawings, panel production with DoP, and installation. One entity is accountable for every stage.

When is the D+B model most valuable?

On projects with tight schedules and liquidated damages, acoustically complex projects (tunnels, development on both sides, non-standard parameters), publicly or EU-funded investments requiring complete documentation, and for investors without an experienced in-house acoustic inspector.

When might the traditional model be the better choice?

On straightforward projects (a single-sided barrier in open terrain, standard acoustic requirements) and when the investor or general contractor already has experience managing acoustic subcontractors. In those cases, a traditional tender for the cheapest panel that meets the specification can be a rational choice on price.

Before any conversation about a specific tender or project, a client should know exactly who they are dealing with. Not in marketing terms, but operational ones: what Ekopres makes, to what performance specifications, who certifies it, which general contractors we work with, and what single-point accountability actually means on a construction site. That is what this article covers.

At a glance: EKOPRES Group combines the engineering expertise of EKOPRES S.A. with its own MATI manufacturing facility, providing a single point of accountability for acoustic analysis, design, panel manufacturing and installation. With over 15 years of specialization, ITB / TZUS / CE certifications and a 10-year manufacturer’s warranty, the Group has delivered projects with Strabag, Warbud and Eurovia, as well as directly for GDDKiA.

Over 15 Years in a Single Specialism

Ekopres S.A. has been building acoustic protection systems for over 15 years. Acoustic infrastructure was our focus from the start, covering road, rail and industrial applications.

Over that period the industry has changed several times. Standards tightened: since January 2024, panels require CE marking with a Declaration of Performance. Client expectations shifted: GDDKiA and major general contractors increasingly want a single entity responsible for analysis, design, manufacture and installation — because splitting those functions across three separate subcontractors creates too many liability gaps. Project volumes grew: the Polish motorway programme and the National Railway Programme have generated larger acoustic screen orders than at any point in the past two decades.

Ekopres adapted to each of those shifts. The integration of Ekopres S.A. with the MATI production facility was s a deliberate response to observing that firms controlling the full chain – from acoustic analysis through to panel manufacturing and on-site installation – consistently produced better acoustic outcomes and fewer problems at technical handover.

Two Entities, One Contractual Accountability

Ekopres Group is built from two entities that function within a single accountability structure. Ekopres S.A. is the engineering and contracting firm: it carries out acoustic analyses, produces structural and executive design documentation, and manages on-site construction. MATI is the production facility: it manufactures aluminium noise barrier panels and timber anti-glare barrier systems.

This distinction has practical implications for how a contract works. In a typical market arrangement, a client or general contractor coordinates three separate parties: a design office, a panel manufacturer and an installation firm. If a panel arrives on site and does not match the acoustic design, each of those parties can point responsibility at the others. Disputes run on, construction stops.

In the Ekopres model that problem does not exist structurally. One entity is accountable for the analysis, the design, the panel and the installation. If something does not match, we know before it becomes a site problem, because the engineers who calculated the acoustic performance also know what panel will be produced and how it will be installed.

The MATI Facility: What It Means for Delivery and Consistency

A 1,000 m² production hall, automated CNC machinery and a nominal output of up to 20,000 m² of panels per month. These figures have a direct bearing on two parameters that matter most to a general contractor managing a construction programme: delivery schedule and performance consistency.

On scheduling: a disruption to panel supply can stop acoustic screen installation for weeks, and at a road contract with liquidated damages clauses, that carries serious cost consequences. In-house production, with order scheduling managed within the group, provides predictability that an external supplier serving several dozen clients simultaneously cannot guarantee.

On consistency: a panel’s acoustic performance – its DLα and DLr values – depends not only on design but on manufacturing precision: uniformity of mineral wool infill, joint integrity between sheets, dimensional accuracy. Automated CNC production minimises batch-to-batch variation. Every batch is subject to quality control, and the results form part of the technical documentation handed to the client at project close.

Automated CNC machinery · full RAL colour range · anti-graffiti coatings on request · manufactured in Poland to European standards

Acoustic Analysis and EIA: Where Every Project Starts

Clients sometimes treat an acoustic analysis as a regulatory formality, a document required by the environmental authority that sits in a file once produced. That approach tends to generate problems at technical handover.

For Ekopres, acoustic analysis is a design tool. Baseline noise measurement results, computer modelling output (calculated to ISO 9613 or ray-tracing methodology) and post-construction noise level forecasts, these three inputs determine which panel class is required (A2, A3 or A4), what screen height is optimal, and whether the site geometry demands single-sided absorptive, double-sided, or whether a reflective configuration is acoustically sufficient. Running this analysis after the panel type has been selected – rather than before – is a design error that typically surfaces at post-installation measurement.

The Environmental Impact Assessment (EIA) for new road or rail infrastructure contains the minimum acoustic performance requirements for the project. These flow into the Environmental Decision issued by the Regional Directorate for Environmental Protection (RDOŚ), and from there into the technical specification in the tender documents. Ekopres participates in this process from the analysis stage, which avoids situations where a tender specification demands performance levels that are geometrically unachievable at the available screen height.

Design Documentation and the Design-and-Build Model

Structural design and executive design for an acoustic screen must satisfy the requirements of three different audiences: the administrative authority issuing the building permit or approving the works notification; the client verifying compliance with the environmental decision; and the installation crew that executes the documentation on site.

In a design-and-build framework, Ekopres produces the full documentation chain:

• structural design (including static and structural calculations for support posts and foundations),
• executive design (with material specifications and installation requirements)
• workshop drawings – detailed construction drawings for each post, each foundation and each non-standard element specific to the site geometry.

Workshop drawings are frequently omitted by firms that manage a project without executing it. Their absence means improvisation on site, and improvisation on site means deviations from the design that can compromise acoustic performance.

For projects delivered as subcontracts to a general contractor, Ekopres aligns documentation formats and schedules to the standards required under the main contract. GDDKiA, PKP PLK and individual general contractors operate under different format and reporting requirements – building those constraints into the design process from the outset eliminates expensive revisions at a late stage.

On-Site Installation: Posts, Panels and the Base Seal

Acoustic screen installation has several stages, each with its own bearing on final acoustic performance.

Installation sequence:

• post foundations (depth determined by geotechnical investigation results and ground category)
• panel installation from bottom to top,
• base zone sealing,
• fitting of end closures and any diffraction elements on the upper edge

After installation, as-built documentation is produced, including revised installation drawings and – where required by the environmental decision – post-installation noise measurements confirming that the required attenuation level has been achieved.

ITB, TZUS and CE: What Each Certificate Confirms and Why It Matters in a Tender

Three certifications, three distinct functions.

ITB. The Polish Institute of Building Technology is the national technical assessment body whose approval is required for construction products used in Polish infrastructure projects. An ITB technical assessment confirms that the product is approved for use in Polish construction and meets national requirements – providing clients with an independent national-body evaluation, not only a manufacturer’s declaration.

TZUS. Technický a zkušební ústav stavební Praha is a Czech notified body recognised within the European system. TZUS certification is widely accepted across Central European markets and confirms compliance with European construction product standards. For contracts involving European general contractors or for panel export outside Poland, this certificate is an important qualification document.

CE. CE marking has been a legal requirement since January 2024. Every acoustic panel sold into the EU market must carry a Declaration of Performance (DoP) declaring DLα and DLr values in accordance with EN 14388:2015. A DoP is issued per batch and must correspond to the actual performance achieved by that specific batch. A panel without a DoP, or with a DoP whose values do not match the environmental decision requirements, will not pass a formal technical handover inspection.

10-Year Warranty and Expected Service Life

Ekopres offers a 10-year manufacturer’s warranty on aluminium noise barrier panels. This commitment appears rarely in industry marketing materials, most manufacturers choose not to take it on formally. For a client, it represents concrete protection across a meaningful portion of the asset’s operational life: any material or manufacturing defect that becomes apparent within ten years of delivery is covered by the manufacturer’s liability.

The principal maintenance requirements are base seal condition checks and periodic inspection of coating integrity. Aluminium does not corrode in the conventional sense, is resistant to road salt, vehicle exhaust and atmospheric weathering, and requires no repainting, compared to timber or concrete panels.

Colour Range, Anti-Graffiti Coatings and Long-Term Appearance

Acoustic screens stand for decades. Over that time, they become part of a local landscape, often adjacent to residential neighbourhoods or designated nature areas where appearance carries weight alongside acoustic function. Clients increasingly specify colour explicitly, and some local planning authorities or design review bodies have a formal role in approving barrier aesthetics for significant projects.

Ekopres panels are available across the full RAL colour range. Colour specification is agreed project by project and does not affect the declared DLα and DLr acoustic performance values. Anti-graffiti coatings are available on request, substantially reducing cleaning costs and maintenance interventions over the full operational life of the barrier, a particular consideration for installations in urban or peri-urban environments.

Our Partners and What That List Represents

The Ekopres partner list is specific. These are companies with whom we have delivered projects: Warbud, Colas, Strabag, Eurovia, Aldesa, Mostostal Warszawa, PORR, NDI, Mirbud and also GDDKiA.

Strabag, Warbud and Eurovia are among the largest construction companies operating in Polish infrastructure. Working with each requires meeting the quality, scheduling and documentation standards imposed by their contract management systems, standards calibrated to the most demanding public procurement frameworks in Europe. GDDKiA’s presence on the list indicates that Ekopres has worked directly for the Polish national road administration, not only as a subcontractor. Every collaboration on this list is a completed project that can be verified.

Poland and European Projects

Panels manufactured at MATI carry CE marking and meet European standards, which allows their use on EU infrastructure projects without additional product certification. Ekopres is available for projects outside Poland and serves European clients looking for a noise barrier manufacturer with in-house production capacity and general contracting capabilities.

Technical documentation is available in English. Ekopres’ office in Poland coordinates with English-speaking clients and is set up to work with design offices or general contractors regardless of where the principal client is located.

How Collaboration Starts: Three Entry Points

Every acoustic screen project begins with the same set of questions: what is the site, what is the noise source, what does the environmental decision or tender specification require. The earlier Ekopres enters that conversation, the better the outcome, both acoustically and in terms of budget management.

• Pre-tender stage – an investor or road authority wants to understand what panel classes are needed for a planned investment and what the order-of-magnitude costs look like. Ekopres can conduct a preliminary acoustic analysis and define minimum performance parameters before the tender specification is drafted.
• Tender stage – a general contractor or consortium is looking for a noise barrier subcontractor to include in their bid. Ekopres prepares a costing against the technical specification; in a D+B framework, we develop the technical concept as part of the bid submission.
  
  
• Post-award stage – the contract is placed and the project moves into design, manufacturing and installation. Ekopres takes on the full delivery scope and coordinates all stages within the group.

An initial technical review – answering whether and how a project can be delivered – is part of standard pre-contract dialogue and carries no cost.

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Ekopres Group: Frequently Asked Questions

What is Ekopres Group and how is it structured?

Ekopres Group combines engineering firm Ekopres S.A. with the MATI production facility. Ekopres S.A. handles acoustic analyses, design, technical documentation and on-site construction management. MATI manufactures aluminium noise barrier panels and timber anti-glare systems. Together they operate under single-point contractual accountability covering every stage of an acoustic infrastructure project.

What noise barrier panel systems does Ekopres Group manufacture?

Four systems: single-sided absorptive (A4/B3: DLα 20 dB, DLr 26 dB), double-sided absorptive (A4/B3 double-sided: DLα 12 dB, DLr 25 dB, fire B-s1 d0), reflective (B3: DLr 30 dB) and a timber anti-glare system in C24 softwood with S235 steel access doors.

What is the output capacity of the MATI production facility?

1,000 m² production hall, automated CNC machinery, output up to 20,000 m² of acoustic panels per month. Certifications: ITB, TZUS, CE. 10-year manufacturer’s warranty on all panels.

What certifications do Ekopres panels hold?

ITB (Polish Institute of Building Technology), TZUS (Czech EU notified body) and CE. CE marking has been mandatory since January 2024 and must be accompanied by a Declaration of Performance (DoP) declaring DLα and DLr values per EN 14388:2015.

Which general contractors and clients has Ekopres worked with?

Projects delivered in collaboration with: Warbud, Colas, Strabag, Eurovia, Aldesa, Mostostal Warszawa, PORR, NDI, Mirbud and directly for GDDKiA (Polish National Road Administration).

What does single-point accountability mean in practice?

Ekopres takes on the full scope of an acoustic infrastructure project: acoustic analysis and EIA, structural and executive design within a D+B framework, workshop drawings, panel manufacturing at MATI with stage-by-stage quality control, structural and barrier installation. One entity is accountable from the initial analysis to the technical handover protocol.

Are panels available in custom colours and with anti-graffiti coatings?

Yes. Aluminium panels are available across the full RAL colour range. Anti-graffiti coatings are available on request. Colour specification is agreed project by project and does not affect the declared DLα and DLr acoustic performance values.

Choosing between an absorptive and a reflective acoustic panel is a design decision that defines the acoustic performance of a noise barrier across its entire service life. The wrong choice does not simply reduce effectiveness, it can reverse it, actually increasing noise levels in protected areas. This guide explains how both panel types work physically, which standard parameters quantify their performance, and how to match the choice to specific project geometry.

In a nutshell: a sound-reflective acoustic panel redirects noise rather than eliminating it. A sound-absorbing panel absorbs acoustic energy, effectively reducing it. Where noise barriers are installed on both sides of a road, the use of reflective panels may increase noise levels at the receiver by as much as 3–6 dB (the so-called “canyon effect”).
The choice of panel type should be based on acoustic analysis, route geometry and the requirements of the environmental decision, not on catalogue price.

Road Traffic Noise: Scale of the Problem and Why Panel Selection Matters

Road traffic noise is one of the most serious environmental health threats in Europe. WHO night noise guidelines recommend values below 40 dB, and the threshold at which measurable health effects begin is estimated at 55 dB. Epidemiological studies published in PMC confirmed that chronic exposure to traffic noise increases the risk of cardiovascular disease and depression.

In Poland alone, over 6 million square metres of acoustic screens line the national road network managed by GDDKiA. The Regulation of the Minister of the Environment of 14 June 2007 establishes permissible noise levels: for residential areas adjacent to roads, these are 61–65 dB during the daytime and 56 dB at night. The choice between absorptive and reflective panel type determines whether the investment meets noise thresholds and whether it inadvertently worsens conditions on the far side of the road.

Reflection and Absorption. What Physically Happens to the Sound Wave?

When a sound wave encounters an obstacle, three phenomena may occur simultaneously: reflection, absorption, and diffraction at the edge of the screen. Which mechanism dominates depends directly on the surface material and panel structure. That is the essential distinction between the two types

Reflection – the acoustic wave energy bounces off a hard, smooth surface and propagates in a new direction. The panel does not destroy noise; it relocates it. Like light bouncing off a mirror: wave intensity remains similar, only direction changes.

Absorption – the acoustic wave energy penetrates into the porous or fibrous structure of the material (e.g. mineral wool), where it is dissipated through friction between air molecules in the pores. The result is a genuine reduction in wave intensity. Acoustic energy is converted into negligible heat and does not return to the environment.

Reflective Panels: Definition, Properties, Materials

A reflective barrier is built from hard, acoustically impermeable surface materials: concrete, metal, glass, plastic, or solid wood. As SoundFighter and Jacksons Security both state: “by default, a noise barrier without any added absorptive treatment is reflective”, meaning every screen without an absorptive layer is effectively a reflective barrier.

Reflective panels are effective when the goal is simply to block the line of sight between the traffic source and the protected area. The key parameter is sound insulation DLR – the barrier’s ability to block sound transmission through the panel – measured under EN 1793-2 in diffuse field conditions and classified in categories B0–B3. Aluminium reflective panels typically achieve category B3, meaning DLR exceeding 24 dB.(Hammerglass, EN 14388).

Absorptive Panels: Definition, Properties, Materials

An absorptive panel combines two functions: sound insulation (blocking transmission, parameter DLR) and absorption (absorbing acoustic energy from the traffic face, parameter DLα). A typical single-sided aluminium absorptive panel construction consists of: a perforated aluminium face sheet on the traffic side, mineral wool infill (density approx. 100 kg/m³, thickness 50 mm), and a solid aluminium back plate. The perforation allows the sound wave to enter the interior, where the wool absorbs it; the back plate blocks transmission to the protected area.

The DLα parameter is measured under EN 1793-1 and classified in categories A0–A4. For aluminium panels with mineral wool, the standard performance is category A3 (DLα> = 8–11 dB) or A4 (DLα > 11 dB). As the Hammerglass description of EN 14388 notes: class A2 is normally sufficient for most applications, with A3 and A4 indicated for more demanding conditions — dense urban environments, viaducts, or tunnels

Acoustic Performance Categories under EN 1793 and EN 14388

Double-Sided Absorptive Panels: When a Third Option Appears

Beyond single-sided absorptive panels (perforated traffic-side face, solid rear plate), there is a double-sided variant in which absorption functions on both faces of the barrier. This is applied in situations where the noise source or sensitive receivers may be on both sides of the screen – in tunnels, deep cuttings, on viaducts above residential areas, or at compact road junctions where noise arrives from multiple directions simultaneously (Air Acoustics, EN 1793).

A double-sided absorptive panel carries a higher unit cost than a single-sided one, but in the right conditions it eliminates the need for separate mitigation on both sides of a complex intersection. The decision to use it should always stem from an acoustic analysis covering both faces of the barrier, not only the emission side.

The Canyon Effect: When Reflective Barriers Cause More Harm Than Good

The canyon effect is one of the most important phenomena that determines the choice between absorptive and reflective panels. When two parallel reflective screens stand on both sides of a road, sound waves reverberate between them rather than losing energy. In the confined space between the screens and the vehicles, sound behaves like a tennis ball bouncing between two walls.

Maryland DOT research on solid road barriers found that continuous reflection can increase noise levels at the receiver by 3–6 dB compared with an absorptive barrier, particularly in dense urban settings.

When to Specify Absorptive Panels: Five Scenarios

Synthesising technical reports and GDDKiA guidance, five clear scenarios emerge in which absorptive panels are required or strongly recommended:

1. Dual-sided barriers (both sides of the road). The most critical scenario. When barriers stand on both sides of the carriageway, applying absorptive panels on at least the traffic face is essential to prevent the canyon effect. Contemporary standards (cited by CEDR and ScienceDirect) indicate that modern barriers prefer an absorptive face on the traffic side even when the panel is primarily insulating.
2. Dense urban environments, narrow streets and courtyards. Reverberant conditions, where sound waves repeatedly reflect off building façades. mean that energy reflected from a reflective screen does not escape into open space; it remains trapped between elevations. In such geometry, absorption is the only effective damping mechanism. Minimum specification: class A3.
3. Tunnels, deep cuttings, covered roads. EN 1793-1 in its current version explicitly states that under reverberant conditions (tunnels, covers), high absorptivity is required. In enclosed structures the canyon effect is extreme, and reflective panels can be actively counterproductive.
4. Viaducts and elevated structures above residential areas. When a road runs above inhabited terrain, noise propagates downward and sideways. Side screens effectively act as two parallel panels, and absorptive panels reduce noise leaking from below the bridge structure.
5. High-speed railway lines. Railway noise has different spectral characteristics from road traffic — with pronounced low-frequency components. Absorption in these ranges requires deeper infill and appropriately specified mineral wool density.

When Reflective Panels Are Sufficient?

Reflective panels are technically adequate and economically rational in specific geometric and environmental conditions:

1. Single-sided barrier with open terrain on the source side. When a road runs through open countryside and the screen stands only on one side, the reflected wave has space to dissipate without creating secondary effects. In such geometry, a reflective panel meeting B3 is sufficient to satisfy noise regulations.
2. Transparent screens requiring maintained visibility. Toughened glass or acrylic screens by definition have no absorptive properties yet are used on viaducts and in city centres where sight lines must be preserved. In these cases, the specifier must compensate for the lack of absorption through other means, barrier height and geometry, rather than panel type.
3. Industrial noise isolation screens. At manufacturing facilities, the goal is often to isolate external areas from noise emitted by an internal source. The DLR insulation parameter is critical; absorption on the outer face is less important. Reflective or hybrid panels with absorption only on the emission side may be optimal.

Absorptive vs Reflective Noise Barrier Panels: Decision Matrix

Panel type selection follows four input factors: road geometry, character of development on both sides, requirements of the Environmental Decision, and project budget. The matrix below synthesises EN 1793 standard GDDKiA guidance and road authority technical requirements for the most common road infrastructure configurations:

Źródła: CEDR TR2017-02 · GDDKiA — kompendium wiedzy

Norms and Certification: What Must Be in the Declaration of Performance

From January 2024, EN 14388:2015 requires that every acoustic panel intended for EU road infrastructure carry CE marking with a Declaration of Performance (DoP) declaring, among other properties, the DLα absorption value (with category A per EN 1793-1) and the DLR insulation value (with category B per EN 1793-2) as described in Materiały Budowlane.

Detailed performance requirements for a specific road infrastructure project are defined in the Decision on Environmental Conditions (DUŚ) issued by the Regional Directorate for Environmental Protection (RDOŚ) or, in the case of existing roads, by a decision of the Marshal of the Voivodeship or the relevant District Governor (Starosta). These documents specify the minimum acoustic performance classes that the selected panel system must meet.
Selecting panels solely on the basis of a manufacturer’s catalogue, without taking into account the requirements set out in the relevant environmental decision, constitutes a design error that may prevent the project from obtaining technical acceptance.

Why Aluminium Panels Dominate Polish Road Infrastructure

In Poland, as in Western Europe, aluminium acoustic panels – both sound-absorbing and sound-reflective – are widely used along expressways and motorways. The reasons are practical and well established:

1. Corrosion Resistance Roadside environments create highly aggressive conditions: de-icing salts, exhaust emissions and fluctuating temperatures. Aluminium does not rust and does not require repainting every few years, unlike non-alloy steel.
2. Precise Control of Acoustic Performance Factory-manufactured sound-absorbing aluminium panels have precisely defined DLα and DLR performance parameters, which remain consistent across production batches. This is particularly important in the context of GDDKiA tender requirements, where a Declaration of Performance (DoP) is required for each batch delivered to the construction site.
3. Low Weight and Fast Installation Compared with concrete elements, aluminium is several times lighter, which reduces installation time, limits the need for heavy lifting equipment and decreases loads on foundations and supporting posts.

Beyond Acoustics: Durability, Aesthetics and Environmental Resistance

In addition to acoustic performance, PN-EN 1794 (Parts 1 and 2) specifies the mechanical and environmental requirements that noise barriers must meet. These include resistance to wind loads (for Polish wind zones: 0.7–1.3 kN/m²), resistance to impact loads (e.g. snow thrown against the barrier during snow clearing, in accordance with PN-EN 1794-1), fire classification (D-s1,d0 or higher for certain applications) and long-term durability.

Mineral wool used in sound-absorbing panels requires proper sealing and protection against moisture. Failure to ensure adequate protection is one of the main causes of deterioration in acoustic performance over time. Sound-reflective panels, which do not contain such infill, are more resistant to water ingress, although they may be more susceptible to vibration transmission in railway applications, where vibration levels are higher than in road infrastructure.

How Ekopres Selects the Right Panels: From Acoustic Analysis to System Selection

The Ekopres Group delivers acoustic infrastructure projects under a design-and-build model, meaning that a single entity is responsible for every stage, from acoustic analysis and design, through manufacturing at the Polish MATI production facility, to installation and as-built documentation. This enables the panel system to be optimised at a very early stage, before the structural geometry is finalised.

In practice, the choice between sound-absorbing and sound-reflective panels is based on four key inputs:

• the results of the acoustic analysis or Environmental Impact Assessment (EIA) Report,
• the requirements of the environmental decision issued by the Regional Directorate for Environmental Protection (RDOŚ) or another competent environmental authority,
• the geometry of the route and the surrounding development on both sides of the barrier,
• the investor’s budget, taking into account the total life-cycle cost (purchase, installation and maintenance).

Projects delivered by Ekopres, including the A1 Stryków–Piątek, S8 Radzymin–Wyszków, S2 Konotopa–Puławska and GPEC Tczew, involved different panel configurations tailored to the specific requirements of each location.

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Pytania zadawane przez projektantów i inwestorów

Jaka jest podstawowa różnica między panelem pochłaniającym a odbijającym?

Panel odbijający przekierowuje energię akustyczną, nie eliminuje jej, lecz zmienia kierunek propagacji. Panel pochłaniający absorbuje energię fali dźwiękowej wewnątrz struktury (wypełnienie z wełny mineralnej) i zamienia ją na minimalne ciepło. Parametr pochłaniania to DLα (PN-EN 1793-1), a izolacyjności — DLR (PN-EN 1793-2). Oba parametry muszą być zadeklarowane w DoP zgodnie z PN-EN 14388.

Kiedy należy stosować panele pochłaniające?

Panele pochłaniające są wymagane lub zalecane przy ekranach obustronnych (ryzyko efektu kanionu), w gęstej zabudowie miejskiej i warunkach powstawania pogłosu (tunele, głębokie przekopy), na liniach kolejowych i przy wiaduktach nad obszarami mieszkalnymi. Wymagana klasa: minimum A3 przy obustronnych ekranach.

Kiedy panel odbijający jest wystarczający?

Panel odbijający jest technicznie wystarczający przy ekranie jednostronnym, gdy droga przebiega przez otwarty teren bez zabudowy po stronie odbicia. W takich warunkach spełnia wymogi normy PN-EN 14388 w zakresie izolacyjności (DLR ≥ B3) i jest prostszym oraz tańszym rozwiązaniem.

Czym jest efekt kanionu i jak mu zapobiec?

Efekt kanionu to zjawisko zwiększenia poziomu hałasu (o 3–6 dB wg Maryland DOT) przy odbiorniku, spowodowane wielokrotnym odbijaniem fal dźwiękowych między dwoma równoległymi ekranami odbijającymi. Zapobieganie: zastosowanie paneli pochłaniających przynajmniej po jednej stronie drogi, a najlepiej po obu.

Co oznaczają kategorie DLα i DLR w normie EN 1793?

DLα (EN 1793-1): pochłanianie dźwięku, kategorie A0–A4. A3 = 8–11 dB, A4 > 11 dB. DLR (EN 1793-2): izolacyjność od dźwięków powietrznych, kategorie B0–B3. B3 > 24 dB. Oba parametry muszą być zadeklarowane w DoP zgodnie z PN-EN 14388:2015-10 (obowiązkowe oznakowanie CE od 01.2024).

Jakie normy regulują panele akustyczne w Polsce?

Główne normy: PN-EN 14388:2015-10 (wymagania produktu, oznakowanie CE), PN-EN 1793-1 (pochłanianie DLα), PN-EN 1793-2 (izolacyjność DLR), PN-EN 1794-1 i -2 (właściwości mechaniczne i środowiskowe), PN-EN 14389:2024-02 (procedury długoterminowe). Uzupełnia je Rozporządzenie Ministra Środowiska z 14 czerwca 2007 r. w sprawie dopuszczalnych poziomów hałasu.

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Sources

• Jacksons Security — Absorptive vs Reflective Noise Barriers
• PMC / NCBI — Health Effects of Traffic Noise
• GDDKiA — Ekrany akustyczne przy drogach: kompendium wiedzy
• ISAP Sejm — Rozporządzenie Ministra Środowiska z 14.06.2007 r. (Dz.U. Nr 120, poz. 826)
• SoundFighter — Absorptive vs Reflective Sound Barrier Walls
• Hammerglass — CE Marking of Noise Barriers, EN 14388
• Air Acoustics — Understanding BS EN 1793
• Maryland DOT — Effectiveness of Short Solid Barriers
• ScienceDirect — Noise Barrier Overview
• CEDR Technical Report 2017-02 — Road Traffic Noise
• Materiały Budowlane — Ekrany akustyczne w świetle PN-EN 14388
• ICM / BazTech — Drogowe ekrany akustyczne i bezpieczeństwo (PN-EN 1794)