Asbestos in pipe insulation: diatomite, testing, removal

Where is asbestos found in pipe insulation?

Asbestos was used to insulate heating and steam systems because the fibres withstand heat. Asbestos for insulation was banned in Denmark in 1972, but with exemptions. Buildings from before 1972 are therefore the main concern, but later buildings from before 1990 can have it too: blocks of flats with central heating, older houses with oil boilers, schools, institutions and industrial buildings.

The insulation sits on pipes in basements and plant rooms, on valves, bends, boilers and hot-water tanks, and in shafts and roof spaces. Sealing ropes and gaskets in boilers and flanges can also contain asbestos.

What does asbestos look like in pipe insulation?

Typically like diatomite insulation: a white or greyish-white, chalky mass, applied in layers and wrapped in gauze, canvas or a hard shell of plaster, often painted. At bends and valves it was shaped by hand. Cardboard and wrapped insulation from the same period can also contain asbestos.

But diatomite without asbestos also exists, and the difference cannot be seen. Only an asbestos sample analysed at a laboratory can show it. What an analysis covers is explained on the asbestos survey page.

What to do if you suspect asbestos in the pipe insulation

1. Leave the insulation in place. Pipe insulation is among the materials that release the most fibres when disturbed, because the asbestos is loosely bound in a soft mass. Do not cut into it, and do not let the plumber replace pipes until you know what is on them.
2. Is it already damaged? Then close off the room, and do not sweep or use an ordinary vacuum cleaner.
3. Have a sample taken. We arrange a sample from a spot that is already damaged, or from an edge, and a laboratory analysis. You get the answer in writing.
4. Decide based on the answer and the condition. If there is asbestos, we recommend removal or encapsulation based on the insulation’s condition, and you get a fixed written quote.

Can you remove asbestos pipe insulation yourself?

As a rule, no. Since 1 January 2025, demolition of asbestos-containing material requires an authorisation. Brief demolition work of a minor nature is exempt, and the Danish Working Environment Authority’s example is 1–2 pipe bends taken down whole. If the insulation has to be cut to get it off the pipe, the work requires authorisation, however small the piece. If you take down a pipe bend yourself, you must wet it, pack it tightly in labelled packaging and hand it in as your municipality directs.

A whole pipe run in the basement is not a small job, and a job may not be split into small ones to avoid the requirement. What you may do yourself is in the guide to the asbestos rules.

Encapsulation or removal of pipe insulation?

We recommend removal when the pipes are being replaced anyway, when it is damaged, or when people move about close to the pipes. Encapsulation is an option when the insulation is intact, the pipes are staying and the spot is out of everyday traffic. We seal the insulation so it cannot shed, and label it so the next tradesperson knows what is underneath.

Encapsulation does not remove the asbestos. Note it in the property’s records, and the day the pipes are replaced, the insulation has to be removed anyway.

How we remove asbestos pipe insulation

We notify the Danish Working Environment Authority and seal off the basement or plant room with an airlock and negative pressure, so air only flows into the zone and out through a filter. The insulation is wetted, taken off in pieces and packed straight into sealed, labelled packaging. Afterwards we clean the pipes and the room with an asbestos vacuum, and by agreement we carry out a clearance measurement of the air before the room is used again.

Pipe insulation sheds dust easily, and dusty asbestos waste is hazardous waste. It is taken to the approved waste site your municipality directs, and you get the receipt with the rest of the documentation. If the work covers more than 10 m² or produces more than 1 tonne of waste, you as the client must also notify the municipality of the waste. We help with the details.

What does it cost to remove asbestos pipe insulation?

The price depends on the number of metres of pipe, how much space there is around them, and whether the insulation is removed or encapsulated. A short basement run with good access is the smallest job. Risers through several floors, a boiler room with many valves and bends, or insulation in shafts and roof spaces are a bigger one.

You get a fixed written quote based on your details, and if anything is unclear, we come out and look at it free of charge. If we find more along the way than the quote is based on, you get a new quote before we continue. More on prices for indoor removal is on the pricing page.