PET Foam Sheet & Panel Sandwich for CARAVAN SALON DÜSSELDORF 2026: Lig – Bigbahn

This article explains how PET foam sheet combined with panel sandwich construction helps European RV, caravan, and marine OEMs reduce vehicle weight, meet the 2027 REACH Annex XVII Entry 77 formaldehyde threshold (0.062 mg/m³), and pass ECE R118 Rev.

03 fire behavior tests. It is written for buyers attending CARAVAN SALON DÜSSELDORF 2026 who are evaluating lightweight, ENF-grade interior panels from a Germany-based source factory. Booth reference: Hall 13, Stand A94 (13A94).

Introduction

The European caravan industry is entering the most demanding regulatory window in a generation. From 6 August 2027, REACH Annex XVII Entry 77 caps formaldehyde emissions from road-vehicle interior components at 0.062 mg/m³ (or 0.062 ppm in chamber tests) — a level most conventional wood-based panels cannot meet without additional treatment. At the same time, RV buyers expect lighter vehicles for higher payload and better fuel economy, and EU type-approval under Regulation (EU) 2018/858 keeps fire behavior under tighter scrutiny via ECE R118 Rev. 03 for M2/M3 category vehicles.

For OEM buyers visiting CARAVAN SALON DÜSSELDORF 2026, the practical question is simple: which lightweight core material can deliver low weight, low emission, and proven fire performance in one panel sandwich system? This article answers that question by breaking down PET foam sheet as a core layer and walking through the panel sandwich architecture that BIGBAHN supplies to European caravan manufacturers.

What Is PET Foam Sheet?

PET foam sheet (also called PET foam board) is a closed-cell thermoplastic foam core extruded from polyethylene terephthalate (PET). Unlike open-cell PU foam or PVC foam, the closed-cell structure means each cell is sealed — water cannot migrate through the panel, and the foam does not absorb moisture even after long-term exposure in a caravan sidewall or marine bulkhead.

HPL PET Board

Key technical properties relevant to caravan interiors:

Density range: typically 60–200 kg/m³, allowing panel sandwich designers to tune weight vs. stiffness

Closed-cell structure: < 1% water absorption (vs. 5–15% for open-cell PU foam)

Thermal stability: service temperature -40 °C to +80 °C, covering Nordic winters and southern European summers

Recyclable: PET is a mono-material stream in the European recycling infrastructure, supporting circular-economy sourcing policies

BIGBAHN supplies PET foam board as a stock item and as a custom-cut core for panel sandwich assemblies, with thicknesses from 10 mm to 50 mm and density grades for wall, ceiling, and furniture sub-structures.

Why PET Foam + Panel Sandwich for Caravan Interiors?

A panel sandwich is a three-layer composite: two face skins (typically HPL, compact laminate, decorative film, or aluminum) bonded to a lightweight core. The face skins carry bending stress; the core keeps the skins apart and resists shear. This is the same architecture used in aircraft flooring and high-speed train interiors — and it is exactly what caravan OEMs need to balance weight, stiffness, and fire performance.

For caravan interior walls, ceilings, and furniture fronts, the panel sandwich approach delivers:

Performance Target	Conventional Solid Panel	PET Foam + Panel Sandwich
Weight per m² (15 mm)	11–13 kg	3.5–5 kg
Bending stiffness	High	Comparable at lower weight
Formaldehyde emission	E1 / E0 typical	ENF grade (< 0.062 mg/m³)
Fire behavior	Variable	ECE R118 Rev. 03 compliant
Moisture absorption	Swells over time	< 1% (closed-cell)
Recyclability	Mixed materials	PET mono-stream recyclable

The weight saving is the most visible benefit: a typical 6-meter caravan with ~25 m² of interior panel surface can shed 150–200 kg by switching from 15 mm plywood to a 15 mm PET foam panel sandwich. That is roughly one full passenger plus luggage — translating directly into payload capacity, towing ease, and fuel economy.

REACH Annex XVII Entry 77: The 2027 Compliance Cliff

REACH (EC) No 1907/2006 Annex XVII Entry 77 is the single most important regulation shaping European caravan interior sourcing in 2026–2027. The clause restricts formaldehyde release from composite wood and finished articles placed on the EU market. Two key dates:

6 August 2026 — Entry 77 becomes applicable to furniture and wood-based articles (E1 limit 0.124 mg/m³)

6 August 2027 — Tighter limit of 0.062 mg/m³ applies to road vehicle interior components (covers M2/M3 categories; many caravan OEMs voluntarily extend the rule to leisure vehicles)

Sources: EUR-Lex REACH consolidated text and ECHA REACH Annex XVII.

For caravan buyers sourcing panel sandwich systems, the math is direct: ENF-grade panels emit ≤ 0.025 mg/m³, which means they meet the 2027 road-vehicle threshold today. ENF stands for "Eco-No-Formaldehyde" in the Chinese GB/T 39600 standard, equivalent to the lower bound of the European E0 class and well below E1.

For practical sourcing, ask suppliers for three documents before signing a frame agreement:

Document	Purpose
EN 717-1 chamber test report	Verifies emission in mg/m³ at climate 23 °C / 45% RH
REACH Entry 77 declaration of conformity	Confirms 2027 readiness for road-vehicle interior
CARB Phase 2 certificate	Indicates compliance with the US/EU low-emission benchmark

Fire Behavior for Caravan Interiors

UN ECE R118 Rev. 03 specifies burning behavior for materials used in the interior of M2 and M3 category vehicles (buses and coaches, with extension practices into motorhomes and caravans). The test measures horizontal burn rate, vertical burn rate, and melt-drip behavior on a representative material sample.

Source: UNECE R118 Rev. 03.

For panel sandwich systems, fire behavior is determined by the weakest layer — usually the core. This is why PET foam sheet is preferred over PU foam: PET is intrinsically flame-retardant at the polymer level, has a limiting oxygen index (LOI) around 22–24%, and produces low-smoke, low-toxicity emissions under combustion. Combined with HPL or compact laminate face skins, the assembled panel sandwich can pass ECE R118 Rev. 03 Annex 6 / Annex 7 tests at typical 10–30 mm thicknesses.

A practical sourcing matrix for fire-rated panel sandwich:

Application	Core	Face Skin	Typical Test Reference
Caravan sidewall	PET foam 20 mm	HPL 0.8 mm	ECE R118 Rev. 03 Annex 6
Caravan ceiling	PET foam 15 mm	Aluminum 0.5 mm + decorative film	ECE R118 Rev. 03 Annex 7
Furniture front	PET foam 25 mm	Compact laminate 3 mm	ECE R118 Rev. 03 Annex 6
Marine bulkhead	PET foam 30 mm	HPL 1.0 mm	IMO Res. A.653 (related)

Habitable Vehicle Health & Safety

EN 1646-1 is the European standard for habitable vehicles including caravans and motorhomes, covering ventilation, heating, gas installation, and — relevant for panel sandwich buyers — the fire safety and emission behavior of interior materials. The standard cross-references EN 717-1 (formaldehyde emission by chamber test method) for the wood-based panels that make up most interior surfaces.

For caravan OEMs sourcing PET foam + panel sandwich systems, the EN 1646-1 + EN 717-1 combination ensures:

Formaldehyde release ≤ ENF grade (which is also below REACH Entry 77 road-vehicle threshold)

No harmful emissions during normal occupation (verified by chamber test)

Material behavior consistent with habitable space expectations (no off-gassing above EN limits)

BIGBAHN's PET foam board is tested against EN 717-1 and reaches ENF grade as standard; the assembled panel sandwich systems are also supplied with an EN 1646-1 compliance dossier on request, covering fire, emission, and mechanical performance.

PET Foam Sheet vs Alternative Core Materials

The most common panel sandwich cores competing with PET foam are PVC foam, PU foam, and honeycomb (PP / aluminum). The table below summarizes the trade-offs for caravan interior applications.

Property	PET Foam	PVC Foam	PU Foam	PP Honeycomb
Density (kg/m³)	60–200	50–200	30–80	40–80
Closed-cell	✅ Yes	✅ Yes	❌ No	✅ Yes
Water absorption	< 1%	< 1%	5–15%	< 1%
Recyclability	PET mono-stream	PVC stream (limited)	Difficult	PP stream
Fire behavior (LOI)	22–24%	35–40%	17–19%	17–19%
Formaldehyde emission	ENF	ENF	ENF	ENF
Weight (15 mm panel)	~3.5–5 kg/m²	~3.5–5 kg/m²	~2.0–2.5 kg/m²	~1.5–2.5 kg/m²
Cost (relative)	Medium	Medium	Low	High
Best fit	Wall + ceiling + furniture	Wall + marine	Lightweight filler	Premium ceiling

Reading the table:

PU foam is the lightest but fails on closed-cell structure (water absorption), fire behavior, and recyclability — increasingly disqualified by European OEM specifications

PVC foam has the best fire performance but faces end-of-life recycling headwinds in the EU

PP honeycomb is excellent for premium ceiling panels but expensive and harder to laminate on curved surfaces

PET foam sits at the best balance point: closed-cell, recyclable, ECE R118 ready, ENF grade, and cost-competitive

For caravan OEMs visiting CARAVAN SALON DÜSSELDORF 2026, the practical decision is usually: PET foam for walls, ceiling, and furniture fronts; PP honeycomb only for premium flagship ceilings where budget permits; avoid PU foam in any new design platform launched after 2026.

BIGBAHN Booth at CARAVAN SALON DÜSSELDORF 2026

CARAVAN SALON DÜSSELDORF 2026 runs from late August to early September at Messe Düsseldorf. It is the largest caravan and motorhome trade show in Europe, drawing OEM buyers, dealer networks, and component suppliers from across the EU, UK, and North America.

BIGBAHN will exhibit at Hall 13, Stand A94 — booth number 13A94. Visitors can inspect:

PET foam sheet samples in 10 mm / 15 mm / 20 mm / 25 mm / 30 mm thicknesses

Pre-laminated panel sandwich demonstrators with HPL, compact laminate, and decorative film face skins

Lightweight plywood samples for comparison

CNC-processed sample parts (CNC processing capability)

PUR flat laminating line output for face-skin bonding (PUR laminating line)

Visitors are encouraged to bring their current panel specification, BOM weight target, and target emission class (E1 / E0 / ENF) — BIGBAHN engineers will run a feasibility check on the spot and provide indicative pricing and lead time.

CTA — Compliance-Driven

Plan your 2027 REACH Entry 77 compliance now.

BIGBAHN's PET foam sheet & panel sandwich systems are tested to ENF grade (below 0.062 mg/m³) and compatible with ECE R118 Rev. 03 face-skin configurations. Visit us at CARAVAN SALON DÜSSELDORF 2026, Hall 13, Stand A94 (13A94), or request a compliance dossier + indicative quotation today via the BIGBAHN contact page. OEM and ODM inquiries welcome — see partnership options.

References

EUR-Lex. Regulation (EC) No 1907/2006 — REACH Annex XVII (consolidated). https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02006R1907-20240401 (accessed August 2026).

European Chemicals Agency (ECHA). REACH Annex XVII — Entry 77 Formaldehyde. https://echa.europa.eu/appendices-to-the-reach-regulation/-/legislationlist/container/EU-REACH-ANNEX (accessed August 2026).

United Nations Economic Commission for Europe. ECE R118 Rev. 03 — Burning Behavior of Materials Used in Vehicle Interiors. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:42013X1112(01) (accessed August 2026).

European Committee for Standardization (CEN). EN 1646-1:2018 — Habitable Vehicles — Part 1: Habitation Requirements. Brussels: CEN (2018).

European Committee for Standardization (CEN). EN 717-1:2004 — Wood-Based Panels — Determination of Formaldehyde Release — Part 1: Chamber Method. Brussels: CEN (2004).