Finnish Sauna Society

Vaskiniementie 10, 00200 Helsinki
Cafeteria 050 372 4167
(during opening hours)

Fires at summer houses and in saunas tend to become more common during the holiday season, in particular. At a summer house, a fire can start from a fireplace or a stove, an electric device or a gas appliance. The risk of fire is made worse by aging equipment and lack of maintenance, but accidents can be avoided by using appliances appropriately and keeping them in good working order. That is why a safety checkup of a summer house should be carried out after the winter. Approximately 80% of fires that take place in June and July happen in the sauna, which points to carelessness and lack of maintenance at leisure homes when it comes to heaters and chimneys.

In addition to that, many fires are caused by installation errors. The most common cause of a fire is an insufficient distance to flammable material or an incompatibility between a stove and the flue. Furthermore, improper storage of hot ashes can cause a fire.    

Ovens and flues

Many fires are cause by cracks in the flue or oven. Cracks in the flue are relatively difficult to detect without an expert’s help, and therefore a chimney sweep should regularly be used. During their visit, they will check the condition of a fireplace, oven, flue and chimney. The flues and any heaters or fireplaces at a leisure home and its sauna must be swept clean every three years.

Furthermore, when heating them up for the first time after the winter, you should take your time and start with a small fire. Heating them up too quickly with a large fire may cause damage to a heater, the flue and the joint that connects them.   

Firefighting equipment and first aid

A fire blanket and a fire extinguisher are effective ways to combat a fire, even at a more rural setting. A traditional bucket pump kept full of water is another good option, but it must never be used to put out a grease fire or an electrical fire. Keep your firefighting equipment at hand whenever you are handling fire. A first aid kit is also a useful thing to have.

It is important to consider in advance what to do if a dangerous situation occurs. Explain to all your family members and guests how they can exit the building and where you should meet up in case there is a fire. You should also practise how to put out a fire.   

Summer house location straight from the internet

Do you know the exact address and location of your summer house? You should also make sure that the road signs and house numbers are clearly visible. This will help the rescue crew find you in case of an emergency. You can find the precise coordinates at MapSite ( Print them out and place them in a visible spot at your leisure home.   

Most fires could be prevented

The Finnish Safety and Chemicals Agency (Tukes) reviewed the number of, damage from and reasons behind fires caused by heaters and fireplaces in three consecutive years (2002–2004). Each year, the conclusion was that the condition of heaters, fireplaces and flues in Finland tends to be questionable or downright appalling. Most fires could be prevented, as the majority of them are caused by the poor condition, technical faults, clear installation mistakes, human error and careless handling of these pieces of equipment.

Regular maintenance and checkups of heaters and fireplaces can prevent most fires resulting from a technical fault or damage to the equipment. A chimney sweep can detect faults and damage caused by wear and tear during their annual check, and any instructions or recommendations that they give to make repairs must be carried out immediately.

Owners should monitor their heaters and fireplaces and ensure proper use to prevent accidents. 

  • Never leave a heater or a fireplace unattended during heating.
  • Keep an eye on the condition of a heater or fireplace and the flue (adequate draught, cracks, soot, etc.).
  • Only use fuels that comply with the manufacturer’s instructions. Burning rubbish is prohibited.
  • The owner must ensure that all the users know how to use the equipment and are aware of the risks involved.

 Ashes can remain hot for a long time. Therefore, they must be stored in a non-combustible container. Moreover, ashes must be allowed to cool down for up to 24 hours before disposal.

Metal chimneys should undergo more testing, particularly when it comes to their durability against sustained heat. Some metal chimneys have caused fires due to their insulation becoming vitrified, i.e. destroyed because of the effects of long-term thermal stress.

Tukes is aware of cases of incompatible stoves and flue pipes being used together. The flue pipes were either too flimsy to match the stoves’ output, or the stoves were not used according to the instructions.

The fire gases that enter the flue must not exceed the flue pipe’s temperature rating. Excessive heat for a sustained period of time may damage a metal chimney’s structures and, in the worst case, the insulation around the chimney. Furthermore, significant and rapid temperature changes may cause damage to a masonry flue, for example if a fireplace in a building that has been cold for a while is heated up too quickly. 

Electric sauna heaters pose a fire risk when maximum heating time is exceeded

Tukes has also studied the fire safety of saunas with electric heaters. A number of fires and close calls have taken place in recent years in the saunas of hotels, care facilities and other public places. Based on the study, the maximum continued use of heaters is commonly exceeded. Problems are also caused by ventilation points and heater thermostats that have been incorrectly positioned in relation to one another.   The standard on saunas with electric heaters states that the maximum continuous time that an electric heater should be used is 12 hours, after which it must be allowed to cool down for at least six hours.

The locations of the ventilation points may also involve some safety risks. When designing a sauna, the air intake and the heater’s thermostat must be placed in a way that prevents cold air from cooling down the thermostat.

More detailed guidelines are required on electric heater installation, heater usage instructions and ventilation in order to avoid the fire risks.

A common cause of fires involving electric heaters in residential saunas is that clothes left to dry over the heater fall off the clothesline loosened by the heat. When turning on a heater, you should always make sure that there is nothing on top or above the heater and that the heater can be safely switched on. As a rule of thumb, laundry should never be dried in the hot room, and, even in a residential sauna, the heater should never be left on for too long, the thermostat and timer should be periodically checked and the heater and ventilation should be correctly installed.

The information on the page was compiled by Raili Vihavainen.