Fibreglass in mattresses: the UK position, and how to check yours
Search any marketplace for one-star mattress reviews and the same story comes up: someone unzipped the cover to wash it, found a layer of what looked like fine white fabric underneath, and spent the next month vacuuming glass fibres out of the carpet, the bedding and the children. This is fibreglass, it is used as a fire barrier in a lot of cheap mattresses, and it is worth understanding before you buy.
Why it is there
Every mattress sold in the UK has to pass a fire test. The Furniture and Furnishings (Fire) (Safety) Regulations 1988 apply, and for mattresses the relevant standard is BS 7177, which sets ignition-resistance levels. Domestic mattresses must meet the "low hazard" level: resist a smouldering cigarette and a small flame.
Polyurethane and memory foam burn readily on their own, so a foam mattress needs something to stop a flame reaching the foam. There are three ways to do that:
- A fire-retardant treatment in the foam or the fabric.
- A woven barrier under the cover, usually a knitted fabric made from inherently flame-resistant fibres (modacrylic, aramid, treated viscose or a blend), sometimes with wool.
- A fibreglass sock: a thin knitted sleeve of glass fibre around the foam core. Glass does not burn. It is also very cheap.
Option three is what a lot of low-cost rolled foam mattresses use, particularly imported ones sold through marketplaces, because it passes the test for pennies.
Why it is a problem
Fibreglass is harmless while it is sealed inside the mattress. The trouble starts when the cover comes off. Many of these mattresses have a zip on the cover, and nothing on the label saying not to use it. Unzip it, and the sock is exposed. Glass fibres break off, become airborne, and get into everything. They irritate skin, eyes and airways, and they are close to impossible to remove from soft furnishings and carpet. There have been group legal actions in the United States over exactly this, and a steady stream of the same complaint in UK reviews.
Even without removing the cover, a fibreglass sock can shed through a worn or damaged cover over the years.
How to tell if a mattress has it
- Read the label. Look for "glass fibre", "fiberglass", "glass wool" or "GF" in the materials list. Some say "silica" instead. If the label lists the materials and does not mention a barrier at all, ask.
- Look for a warning against removing the cover. "Do not remove cover" on a mattress with a zip is a strong sign there is a fibreglass sock under it.
- Check the country of manufacture and the price. A rolled foam mattress under £150 for a double, made outside the UK and EU, more likely than not uses fibreglass. This is not universal, but it is the pattern.
- Ask the seller directly, in writing: "What is the fire barrier made of?" A maker who uses a woven barrier will tell you what it is. Vagueness is an answer.
What UK-made mattresses use instead
The UK trade has met BS 7177 for decades without fibreglass, because the traditional builds have wool and natural fibres in them (wool is inherently flame resistant) and because woven barrier fabrics are a mature product. A UK-made pocket-sprung mattress will almost always use a knitted FR barrier or FR-treated ticking. It costs more than a glass sock. It is the kind of cost that is worth paying.
If you already own one
Do not unzip the cover. If the cover is damaged, put a fully enclosed mattress encasement over the whole mattress, the sort sold for dust mites, and plan to replace it. If fibres have already escaped, wet-wipe hard surfaces rather than dry dusting, vacuum with a HEPA filter, and wash bedding separately.
Our rule
No fibreglass, anywhere, in any build. Every Chapter mattress uses a woven fire barrier and is tested to BS 7177 low hazard as a complete build, not as a foam sample. It is on the label and on every product page. It is one of the reasons we make in Yorkshire rather than import.
The short version
- UK law requires a fire barrier; it does not require fibreglass.
- Fibreglass socks are cheap, common in low-cost imported foam mattresses, and dangerous if the cover comes off.
- Check the label for glass fibre, look for "do not remove cover", and ask what the barrier is.
- UK-made mattresses use woven barriers and wool. Pay for it.
What BS 7177 on a mattress label means, and what "low hazard" is
The fire-safety standard every UK mattress has to meet, in plain words: the four hazard levels, which one your bedroom needs, what the tests involve, and how makers pass it with and without fibreglass.
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