Oxygen Barrier Films Explained: Why a Single Sheet Outperforms Double-Plastic Systems – Technical comparison of oxygen transmission rates and performance metrics
Executive Summary
· Silage preservation performance is driven by oxygen transmission rate (OTR), not plastic thickness alone.
· Double-plastic polyethylene (PE) systems reduce oxygen ingress compared with a single PE sheet, but both layers remain oxygen-permeable and allow oxygen transfer at levels that cause surface spoilage and dry matter loss.
· High oxygen barrier (HOB) silage films use engineered barrier polymers to restrict oxygen diffusion at a molecular level, achieving OTR values one to two orders of magnitude lower than standard PE, even at lower thickness.
· Single-sheet HOB systems consistently deliver lower dry matter losses, improved aerobic stability, reduced mould and spoilage, and cooler silage compared with double-plastic PE covers.
· ARK Agriculture’s and Silostop system applies this approach by combining a true oxygen barrier film with a separate protective cover, providing effective oxygen control alongside practical durability for modern silage clamps.
Effective silage preservation depends on one primary factor: limiting oxygen ingress. The ability of a clamp cover to restrict oxygen directly influences dry matter losses, surface spoilage, aerobic stability, and overall feed quality.
While double-plastic systems using conventional polyethylene (PE) sheets have long been used to improve sealing, modern high oxygen barrier (HOB) films now offer significantly better technical performance with less total plastic. Silostop Max and Orange are built around this principle, using a true oxygen barrier film combined with appropriate surface protection to create a more stable silage environment.
Oxygen transmission: why material choice matters more than thickness
Conventional polyethylene (PE) films
PE silage films are durable and widely used, but they are inherently permeable to oxygen. Increasing thickness reduces oxygen transfer, but only proportionally.
Typical oxygen transmission rates (OTR) for PE films are:
· 90 µm PE: ~459 cm³/m²/24 h
· 125–150 µm PE: ~250–400 cm³/m²/24 h
· 200 µm PE: ~188 cm³/m²/24 h
Using two PE sheets lowers oxygen ingress compared with a single thin sheet, but both layers remain oxygen-permeable. Even double-PE systems typically maintain OTR values well above 100 cm³/m²/24 h, allowing sufficient oxygen to support aerobic deterioration in the upper silage layers.
High oxygen barrier (HOB) films
HOB films use specialised barrier polymers designed to restrict oxygen diffusion at a molecular level. This delivers a step change in performance:
· Typical HOB films: <25 cm³/m²/24 h
· Advanced barrier structures: as low as 0–0.5 cm³/m²/24 h
This means a single barrier film at just 45–50 µm thickness can match or outperform the oxygen protection provided by double-PE systems totalling 125–250 µm.
Silostop Max and Orange are designed to deliver this level of oxygen protection, forming the primary seal directly against the silage surface.
Measured effects on silage quality
Lower oxygen transmission produces clear, measurable improvements in silage preservation, particularly in the top layers of the clamp.
· Dry matter losses in the top layer typically reduce from around 14% under PE covers to approximately 3–4% under barrier films.
· Organic matter losses are around 6 percentage points lower than with PE-only systems.
· Spoiled or mould-affected silage in the upper 50 cm is reduced by around 70%.
· Dry matter loss in this zone is reduced by approximately 40%.
Barrier films also improve aerobic stability. Lower oxygen ingress results in cooler silage and delayed heating, with time to visible spoilage increasing from around 3.1 days under standard PE to approximately 5.6 days under oxygen barrier films.
Why a single-sheet barrier system works best in practice
Adding PE layers increases thickness but does not change the material’s oxygen permeability. Barrier films are engineered specifically to block oxygen diffusion, achieving far lower OTR with less material.
Single-sheet barrier systems also offer practical advantages at the clamp surface:
· Lower effective oxygen transmission per square metre.
· Fewer layers and seams, reducing the risk of trapped air.
· More consistent contact with the silage surface.
· Reduced potential for oxygen pockets between layers.
In our oxygen barrier system, the film provides oxygen control, while a separate protective cover supplies mechanical strength and handling durability without compromising barrier performance.
Technical summary
Silage cover performance is governed by oxygen transmission rate rather than plastic thickness alone. While double-plastic PE systems reduce oxygen ingress, they cannot match the performance of modern high oxygen barrier materials.
A single engineered barrier film, such as the Silostop Max, delivers substantially lower oxygen transmission, improved dry matter preservation, better aerobic stability, and reduced surface spoilage. Combined with a dedicated protective layer, it provides an efficient and practical solution for modern silage preparation.