Why Polystyrene?

Is polystyrene a suitable material for beehives?

Geert Staemmler, master beekeeper, Wahlstedt

Organic beekeeping rejects polystyrene as a material for hives. Organic beekeepers compare the energy and environmental balance of different hive materials. They take a holistic view that includes environmentally friendly sourcing of raw materials, closed material cycles and a long-lasting end product that can go back into the raw-material cycle after decades of use.

Natural insulating and building materials have been used in beekeeping forever: straw, moss, clay and the like. Straw is the best material for hives (inner climate, low material cost), but straw hives take a long time to build (expensive) and are just as exposed to mechanical damage, for example from mice and woodpeckers, as polystyrene. They only last long enough if they are well protected from the weather (bee houses and so on). Moss and other fibrous fillers have not proved themselves, because they usually absorb moisture and then lose their insulation. Clay is too heavy and too sensitive to the weather in our region.

Like straw, wood has been used in European beekeeping for centuries, with all its advantages and disadvantages: it is easy to work and a renewable resource, but relatively heavy compared with polystyrene and straw, and it must be protected from the weather with wood preservatives or considerable effort (cow dung on skeps, bee houses, hive stands, and so on). In my experience wooden hives are too damp inside in cold, wet weather unless the colonies are very strong.

I bought my first Segeberg hives in 1971 and they are still in use. If one is ever destroyed or becomes unusable through carelessness, I can send it for recycling, so the arguments above also apply to polystyrene.

What is polystyrene?

It is expanded polystyrene rigid foam. The raw materials are styrene and pentane, from which expandable polystyrene is made by polymerisation in closed plants. The foam itself is made in a simple process: the polystyrene granulate, which contains a blowing agent, is heated with steam and expands into closed-cell particles (the air-filled polystyrene beads).

Polystyrene is a biologically neutral product with no expected negative effects on living organisms. Decades of use in agriculture, medicine and food packaging, and more than 40 years of use in hive building, prove this. Polystyrene is chemically neutral, not water-soluble and releases no water-soluble substances. A test I commissioned for styrene in honey found no residues. Pentane, the blowing agent, is not a greenhouse gas, because its half-life is only 10–15 hours and it makes up only 0.000009% of the atmosphere.

Polystyrene is easy to recycle because it is chemically and physically stable. Used polystyrene is ground to specific particle sizes and reused in construction (plaster, lightweight concrete, clay bricks and so on), used as a soil improver in agriculture and horticulture, or turned back into polystyrene granulate. Finally, it can be burnt very well in suitable plants to recover energy without producing dioxins. With a calorific value of 11 kWh/kg it is well suited as a support fuel in waste incineration plants, which saves oil.

The requirements of organic beekeeping described above could be met with polystyrene. According to Regulation (EC) 1804/99 and Regulation (EEC) No 2092/91 on organic farming, “… hives must be made mainly of natural materials that cannot contaminate the environment or the bee products.” Even this regulation could be met with polystyrene, if this plastic were permitted in organic beekeeping.

Hives made of polystyrene last long with little care, are light and “homely” for the bees. Because it is inexpensive to produce and can be moulded into any shape, polystyrene is widely accepted in hive building. These hives keep warmth well and are warmer than wooden hives in spring and autumn.

(References available from the author.)

Our recommendation

When you buy Segeberg hive parts, check these quality features:

• The surface must be hard and smooth (thumb-press test).
• Check the weight of each part. The density of the Segeberg plastic hive is set at 100 g per litre.

All our Segeberg products meet these quality standards.