Why flame-retardant fabric is the most important safety choice in a sauna tent

A sauna tent combines two things we love: a wood-fired stove and a soft, portable room to enjoy a sauna in. For that combination to feel safe every time, the material has to be right from the start.

It is easy to focus on the stove, chimney, and stones when talking about safety. But the detail that makes the biggest difference if something unexpected happens is the fabric.

Why the material matters

Ordinary tent material is designed for rain and wind, not for proximity to fire. If a spark lands on the fabric, the flame can continue spreading through it even after the spark has gone out. That is the part that is easy to underestimate: it is not about the hole, but about what happens in the seconds afterward.

Flame-retardant fabric is designed to break that chain.

What flame-retardant fabric does in practice

Flame-retardant fabric does not eliminate the fire. It prevents it from spreading.

When a spark or flame hits the fabric, the material melts locally and pulls away from the heat. A hole forms. But when the heat source disappears, it goes out instead of continuing to burn.

That is also why you should not settle for fabric that merely "withstands heat." Almost all materials can tolerate becoming hot. The question is how they behave when they encounter an open flame.

See for yourself

In the video below, we direct a blowtorch at the tent fabric. The flame is far more powerful than anything the fabric will be exposed to in normal use.

The fabric melts and a hole forms. But it does not catch fire and does not continue burning when the flame is removed.

PFAS-free, including the flame retardant

This is an area we have devoted extra time to.

Traditionally, both impregnation and surface treatments for tent fabrics have been based on fluorocarbons, or PFAS. They work technically, but they break down extremely slowly in nature and do not belong in a space where you sit at 90+ degrees and breathe deeply.

All HOTT SAUNA tents use a PU coating that is free from PFAS and fluorocarbons, and the impregnation is also PFAS-free. We have maintained this throughout the range, not just on the latest models.

So you get flame resistance and water repellency without a group of chemicals that is harmful to both you and nature.

We take safety seriously

At HOTT SAUNA, we choose materials and construction based on how the tents are actually used: in snow, in strong winds, on the beach, with children and friends around. Flame-retardant fabric and PFAS-free coatings are not an extra feature for us; they are a prerequisite for us to want to put our name on the product.

You should be able to light the stove and think about anything but the fabric.

How you can make the biggest difference yourself

The material is the foundation. These are the habits that take care of the rest:

• Always use a stove with a spark arrestor on the chimney, and check that it is intact and that soot has not built up inside.
• Keep the fireproof mat in place under and in front of the stove door.
• Burn wood with the door closed.
• If you are using the sauna on a deck, place paving stones under the stove. The stove radiates heat downward and dries out the wood. The floor fabric and mat protect against sparks but are too thin to shield against the heat.
• Anchor the tent securely in windy conditions so that the fabric does not move against a hot chimney.
• Re-impregnate the fabric when water stops beading. We sell UV protection for sauna tents that is made for this purpose.

In summary

A good sauna tent should have built-in margin, so that it handles a bad day just as well as a perfect evening. That is why we build our tents from flame-retardant Oxford fabric with a PFAS-free PU coating. It is the kind of thing you rarely think about, and that is exactly the point.