Styrofoam is toxic to humans

Polystyrene: what is it? And is it dangerous?

Many insulated houses have polystyrene on the outside walls. Where does the substance come from? And how often do facades burn? What's up with the substance?

What is polystyrene

The plastic is made from the toxic liquid styrene. In a chemical reaction, individual molecules combine to form long chains - solid polystyrene is formed. If this is foamed using blowing agent and hot water or steam, it is called expanded polystyrene (EPS) - also known under the brand name Styrofoam. In general, a substance is more flammable as a foam than in a solid state. Styrofoam, with its white globules sticking together, consists of 98 percent air.

Where is it used?

In its pure form, the material is transparent, brittle and not very resilient - it is used to make packaging such as CD cases. Modified versions of yogurt pots, Lego bricks or drill machine housings, for example, are much more unbreakable. Polystyrene is usually used as an insulating material in the form of rigid foam. It is pressure-resistant and water-repellent, easy to work with and is well suited for sound and heat insulation. The fabric was probably attached to London's Grenfell Tower, among other places.

How long have the fabrics been around?

Styrene was discovered in 1831 when Styrax, a tree resin, was heated, but it is also formed when coal and lignite are coked. In today's production, the liquid is obtained from petroleum. Polystyrene was first described in 1839, but it was not until 1930 that I.G. Farben started production in Ludwigshafen.

Foam polystyrene was developed at BASF and came onto the market in the 1950s under the brand name Styropor. Today it is one of the most important insulation materials. Experts from the Karlsruhe Institute of Technology underline its very good insulation properties, other materials are often less energy efficient - also in production.

How much polystyrene is used in houses in Germany?

In a response to a small request from the Greens in the Bundestag, the Federal Environment Ministry wrote in 2015 that "Styrofoam insulation materials have a market share of 50 percent". The Association of Private Builders announces that, in its experience, four out of five new buildings are provided with polystyrene insulation.

What are the fire protection rules in this country?

Fire protection is the responsibility of the federal states, but the regulations for high-rise buildings are fairly uniform in Germany. Polystyrene may only be used in buildings up to a maximum height of 22 meters. In the case of higher buildings, the use of non-combustible materials without exception is mandatory. This is what the building ministers of the federal states laid down in the model guideline for high-rise buildings from 2008.

So is everything safe in Germany's skyscrapers?

Yes, say experts - if all the rules are followed. There are older houses and buildings that are less than 22 meters - apartment buildings with several floors. The regulations do not apply here, and rigid polystyrene foam is often used. The material is more expensive and therefore not so popular.

Is polystyrene dangerous as an insulating material on houses?

There are different opinions. If polystyrene catches fire, it burns with a bright and sooty flame. In Germany, however, rigid foam is used, the flammability of which is greatly reduced by the addition of protective agents. It is classified as flame retardant. In addition, there are often fireproof lintels or fire bars made of non-combustible material on the facades. The interest group of rigid foam manufacturers sees no increased risk of fire. The owners' association Haus und Grund has been warning for years that polystyrene can be life-threatening.

How often do fires occur in connection with the insulation?

The Frankfurt am Main fire brigade has listed almost three dozen fires in connection with insulation systems across Germany since the beginning of 2015. In comparison: The General Association of German Insurers estimates the number of apartment fires at around 230,000 in 2015. A facade fire in Duisburg in May 2016 was particularly devastating, in which a fire from the ground floor of a four-story house hit the outer wall upwards - three people died in the attic. However, according to media reports at the time, the building regulations for the insulation had been complied with.

German fire protection organizations have counted more than 90 cases in connection with polystyrene facades since 2012 - with a total of 11 dead and 124 injured. dpa / nd

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