Written by Mr. Xiao — Acoustic Materials Specialist, Feltcombo

10+ years in PET acoustic panel production & global project supply  |  Updated: 2026

Fire-Rated PET Acoustic Panels: Understanding Class A Compliance for US & International Projects in 2026

I am going to be straightforward with you. If you are sourcing acoustic panels for a commercial project in the United States — a hotel, an office building, a hospital, a retail centre, a school — fire rating is not a value-add feature you consider after pricing. It is the first filter. It determines whether the product can legally be installed in the space at all. Everything else — colour, NRC value, aesthetics, lead time — comes after that question is resolved.

The reason I am writing this article is that I talk to buyers every month who have been burned — sometimes literally in terms of project delay and financial exposure — by suppliers who presented certificates that did not hold up under scrutiny. A PDF certificate is not the same as a verifiable test report from an accredited laboratory. A self-declaration is not the same as a third-party certification. And a certificate issued for one product specification does not automatically cover a different thickness, density, or surface treatment of the same base material.

Feltcombo holds ASTM E84 Class A certification, EN13501-1 Class B, BS476-1 Class 1, and AS ISO 9705 Group 1. We can provide original laboratory test reports. Our certifications are issued against specific product formulations, and we re-test when formulations change. This article will explain what those certifications mean, how to verify any supplier's claims — including ours — and how to make sure the product you specify is actually the product that gets tested and delivered.

Why Fire Rating Is Non-Negotiable for Commercial Acoustic Panels

In residential construction, fire rating requirements for interior finish materials are relatively lenient in most jurisdictions. That changes dramatically when you enter commercial occupancy categories. The International Building Code (IBC), which is adopted in some form across all 50 US states, sets interior finish flame spread requirements based on occupancy type and sprinkler status. For assembly spaces (A-1 through A-5), educational facilities (E), and business occupancies (B) — the very categories where acoustic treatment is most commonly specified — the requirements for wall and ceiling finish materials range from Class A to Class B under ASTM E84.

In practice, for any commercial project involving a licensed architect, a code-compliant specification review, and a building inspection process, acoustic panels that cannot demonstrate ASTM E84 Class A or Class B compliance will not pass inspection. Full stop. And increasingly, owners and general contractors are requiring Class A — not just Class B — as the default specification to reduce liability and simplify the approval process.

This is not unique to the US. The UK's Building Regulations Part B, the EU's Construction Products Regulation (CPR), and Australia's National Construction Code all have analogous requirements. The specific standards differ — EN13501, BS476, AS ISO 9705 — but the principle is identical: interior finish materials in commercial spaces must meet documented, third-party verified fire performance thresholds.

Where this creates a supply chain problem is straightforward: the global market for PET acoustic panels has expanded rapidly over the past decade, and a large proportion of suppliers — particularly those entering the market recently — have not invested in genuine third-party certification. They may have a certificate of some kind. But whether that certificate covers the specific product being sold, whether the issuing laboratory is accredited, and whether the test was conducted on the same formulation as the delivered product, are three separate questions with separate answers.

I have seen projects delayed by weeks because a contractor arrived on site with panels whose certificates did not survive a fire marshal review. I have seen projects where substitution with a compliant product had to happen at short notice, at significant cost. These are avoidable outcomes — but only if the compliance verification happens at the sourcing stage, not at the installation stage.

ASTM E84 Explained: Flame Spread & Smoke Development Index

ASTM E84 is the standard test method for surface burning characteristics of building materials, published by ASTM International. It is sometimes referred to as the "tunnel test" because the test apparatus — the Steiner Tunnel — is a 25-foot horizontal tunnel in which a sample is exposed to a controlled flame at one end, and the spread of the flame along the surface and the smoke density generated are both measured over a 10-minute period.

The test produces two index values:

• Flame Spread Index (FSI) — A numerical score representing how quickly flame travels along the surface relative to a reference material (red oak = 100). A lower FSI indicates less surface flame propagation.

• Smoke Developed Index (SDI) — A numerical score representing the quantity of smoke generated during the test. A lower SDI indicates less smoke production.

The three ASTM E84 classification levels relevant to commercial specification are:

Feltcombo's PET acoustic panels at 9mm / 1800gsm achieve ASTM E84 Class A — FSI ≤ 25 and SDI ≤ 450. This is the highest fire classification under ASTM E84 and is accepted for all commercial interior finish applications in IBC-governed jurisdictions without further restriction.

One technical point that is worth understanding: the SDI threshold of 450 is the same across Class A, B, and C. This means that smoke production — not just flame spread — is independently constrained. A material that achieves low FSI but generates dense smoke would still fail to reach Class A. PET fibre, when formulated with appropriate flame retardant chemistry, performs well on both indices. The flame retardant treatment suppresses both surface flame propagation and the combustion reactions that generate smoke.

A second point: ASTM E84 test results are tied to the specific sample tested. If a manufacturer changes the resin binder, the fibre density, the surface coating, or the thickness of the panel, the previously issued ASTM E84 certificate no longer applies. This is not a technicality — it is a fundamental aspect of how the standard works. Any supplier who cannot tell you which specific formulation their ASTM certificate applies to is either uninformed about their own product or being imprecise in a way that should concern you.

EN13501-1 Class B vs. Class A: What's the Difference?

The European fire classification system operates under EN13501-1, which classifies construction products using a letter-based reaction-to-fire system: A1, A2, B, C, D, E, F — running from non-combustible (A1) to no performance determined (F). Unlike ASTM E84's tunnel test, EN13501-1 draws on results from multiple tests, primarily the Single Burning Item (SBI) test (EN13823) for Classes A2 through D, and the ignitability test (EN ISO 11925-2) as a secondary criterion.

For PET acoustic panels, the practically relevant classifications are:

• EN13501-1 Class A2 — Limited combustibility. Typically requires materials with low organic content. PET fibre, being a polymer-based material, does not naturally achieve A2 classification without exceptional flame retardant formulations. In practice, very few PET panel manufacturers hold Class A2.

• EN13501-1 Class B — Very limited contribution to fire. This is the standard that high-quality flame-retardant PET panels can achieve with a well-engineered formulation and is accepted for commercial interior applications across EU member states and many other markets that reference Euroclass ratings. Feltcombo's PET panels at 9mm / 1800gsm hold Class B.

• EN13501-1 Class C — Limited contribution to fire. This is acceptable for some commercial applications in some jurisdictions but does not meet the specification requirements for high-occupancy or high-risk spaces in the EU regulatory framework.

A common source of confusion in North American procurement is the mapping between ASTM E84 Class A and EN13501 Class A. These are not the same classification system, and the letter designations do not correspond directly. ASTM E84 Class A is broadly comparable to EN13501 Class B in terms of the risk level addressed — both represent the threshold for high-occupancy commercial interior applications. EN13501 Class A1/A2 represents a higher bar (non- or limited-combustibility) that most organic materials, including high-performance PET, do not meet.

For projects that need to satisfy both US and European fire requirements — international hotel chains, multinational corporate campuses, globally tendered projects — Feltcombo's dual ASTM E84 Class A and EN13501 Class B certification covers both jurisdictions from a single product supply. This avoids the operational complexity of sourcing different certified products for different markets.

BS476-1 Class 1: Requirements for UK Specifications

British Standard BS476 is the UK's legacy fire test framework for building materials, developed and published by the British Standards Institution. Part 7 of BS476 — "Method of test to determine the classification of the surface spread of flame of products" — classifies materials into four classes based on how far flame spreads across the surface under defined test conditions.

BS476 Part 7 classifications run from Class 1 (best performance — least surface flame spread) to Class 4 (highest flame spread, no commercial application). For UK commercial interior specifications, Class 1 is the standard required for wall and ceiling linings in offices, hotels, retail spaces, and all other non-domestic buildings under Approved Document B of the Building Regulations.

Feltcombo's PET panels at 12mm achieve BS476-1 Class 1. This is significant for any buyer sourcing for UK projects, or for markets that reference BS standards — including Hong Kong, Singapore, parts of the Middle East, and several Commonwealth countries whose building regulations historically followed the British framework.

A note on the relationship between BS476 and EN13501: following the UK's departure from the EU, the Approved Document B guidance was updated to accept both BS476 classifications and Euroclass EN13501 ratings for compliance purposes. In practice, for new projects, specifiers increasingly use EN13501 because it provides finer discrimination between performance levels and aligns with European product documentation. However, for renovation projects in existing buildings where the original specification references BS476, or for procurement programmes that span both UK and Commonwealth markets, BS476 Class 1 certification remains the required document.

Feltcombo's Complete Certification Portfolio (ASTM E84 Class A / EN13501 Class B / BS476 / AS ISO 9705)

The table below is a definitive summary of Feltcombo's current fire certification holdings for PET acoustic panels. I want to be clear about what this table shows and, just as importantly, what it does not show.

What it shows: the certifications we currently hold, the specific product parameters those certifications apply to, and the markets they are relevant for.

What it does not show: certifications that apply to all products across all thicknesses and densities. No manufacturer's single certificate covers every product variant. If you need certification for a product configuration not listed here — a different thickness, a different density, a custom colour — the right answer is to ask us directly about the applicable certification pathway, not to assume coverage extends automatically.

On the GRS certification: I include this in a fire certification article because for many commercial projects in 2026 — particularly hotel and corporate real estate development with ESG reporting requirements — GRS certification is evaluated alongside fire certification in the supplier qualification process. Our PET panels contain a minimum of 50% recycled PET, and the GRS certificate provides the chain-of-custody documentation needed for LEED v4.1 Material and Resources credits and BREEAM Mat category submissions.

How to Verify a Manufacturer's Fire Certification (Red Flags to Avoid)

This is the section of the article I wish more procurement teams read before issuing purchase orders rather than after. The following is based on situations I have encountered in real sourcing conversations, not hypothetical scenarios.

Green Flags: What Good Certification Documentation Looks Like

• Original laboratory test report, not just a certificate summary. A valid test report runs multiple pages. It includes the laboratory's letterhead, the test date, the exact sample description (material, thickness, density, dimensions), the test method applied, the raw test measurements, and the final classification result. A one-page certificate summary with no underlying report is not independently verifiable.

• Named, accredited testing laboratory. For ASTM E84, the testing must be conducted by a laboratory accredited by a body recognised by the International Laboratory Accreditation Cooperation (ILAC). In the US, common accrediting bodies include IAS (International Accreditation Service) and A2LA (American Association for Laboratory Accreditation). The laboratory's accreditation should be verifiable on the accrediting body's public database.

• Product description that matches what you are buying. The test report should describe a product that is consistent with what is being quoted: same base material (PET), same thickness (e.g. 9mm), same density (e.g. 1800gsm), and ideally same surface treatment. If you are buying 9mm plain panel and the certificate is for a 12mm carved panel, those are not the same product and the certificate does not apply.

• Test date within a reasonable window and formulation confirmation. Ask the supplier whether the product formulation has changed since the test date. A certificate that is 7 years old is not automatically invalid — PET formulations are often stable over long periods — but it warrants a direct question about whether any changes to the flame retardant chemistry, fibre supplier, or processing conditions have occurred in the interim.

Red Flags: Patterns That Should Give You Pause

• "We have certifications" with no documents provided. This is the most common evasion. Any supplier with genuine certifications can send them within 24 hours. Delay is not a workflow issue — it is either an organisation problem or a document problem. Neither is reassuring.

• Certificate issued in Chinese with no accredited translation, or from an unrecognised Chinese testing body. China has excellent CNAS-accredited testing laboratories (CNAS is a member body of ILAC). However, there are also many domestic Chinese quality certificates that are not recognised under ASTM, Euroclass, or BS frameworks. A certificate that references only a Chinese national standard (GB) does not constitute ASTM E84 compliance. These are separate tests.

• Certificates that describe a different thickness or product than what is in the quotation. This is surprisingly common. A supplier holds a Class A certificate for their 9mm panel and presents it as coverage for their 12mm or 24mm product. Ask directly: "Is this certificate for the exact product in your quotation?"

• Inability to name the testing laboratory. If a supplier cannot immediately tell you which laboratory conducted their fire tests, that is worth investigating further. Legitimate certifications have a named laboratory on the document.

• Certificates for composite products where the facing material is the variable. If a supplier tests a plain PET panel and then sells carved, printed, or wood-veneer-faced versions using the same certificate, ask whether those surface treatments were included in the test sample or tested separately. Surface treatments — particularly printed coatings — can affect both FSI and SDI. A responsible manufacturer tests representative samples of each product configuration sold under a fire classification.

Which Feltcombo Products Carry Which Certifications?

The following matrix maps Feltcombo's product lines to applicable fire and sustainability certifications. Use this as a reference when reviewing a specification and deciding which product line to enquire about.

I want to draw specific attention to the "Confirm at enquiry" entries. These are not evasions — they reflect the genuine complexity of fire certification applied to product ranges with multiple configurations. A plain 9mm panel with 1800gsm density that has been ASTM-tested is not the same product as a printed 9mm panel with a UV coating layer. The base substrate may be identical, but the surface treatment adds a variable that the test did not evaluate. For most standard commercial projects, the plain panel certification is sufficient for submittal purposes. For projects where the fire marshal or specification authority requires certification of the exact installed product configuration, we discuss testing options at the project level.

Requesting Certification Documents & Test Reports

This is the practical end of the article. You know what certifications exist, what they mean, and how to evaluate a supplier's claims. Now, how do you actually get the documents from Feltcombo for your specific project?

Standard Certification Pack

For any enquiry involving a commercial project, Feltcombo provides a standard certification pack at no charge upon request. This includes:

• ASTM E84 test report (original, from accredited US laboratory) — for 9mm / 1800gsm PET panels

• EN13501-1 Class B declaration of performance and supporting test data

• BS476 Part 7 Class 1 test report — for 12mm panels

• AS ISO 9705 Group 1 test report — for 9mm / 1500gsm panels (Australia enquiries)

• GRS certificate (current valid certificate with chain-of-custody scope)

Project-Specific Certification Submissions

For projects that require documentation in a specific format — such as formatted submittal packages for US general contractors, DoP (Declaration of Performance) format for EU CPR compliance, or CE marking documentation — we can prepare project-specific packages. These take 3–5 business days to compile properly. Please provide the project name, destination jurisdiction, specifying architect or acoustic consultant name, and the specific certification standards required when making this request.

For Specifications That Reference a Non-Standard Format

Occasionally, projects — particularly in the Middle East, Southeast Asia, or custom-requirement markets — reference fire testing standards that do not map directly to our current certification portfolio. Where this happens, we advise on the closest equivalent we hold and flag any gap clearly. We do not present a certificate as covering a standard it was not tested against. If additional testing is required and the project volume justifies it, we discuss options including arranging supplementary testing through our laboratory partners.

How to Request

Email info@feltcombo.com with the subject line "Certification Request — [Project Name / Market]". Include the product specification you are evaluating (thickness, density, surface finish if relevant) and the standard(s) required. Our standard response time for certification documentation requests is 48 hours on business days. For urgent project deadlines, state the date by which you need the documents and we will prioritise accordingly.

Phone: +86 512 6728 5061  |  Address: No. 108 Yunhui Road, Industrial Park, Suzhou 215000, China

Frequently Asked Questions: Fire-Rated PET Acoustic Panels