Asbestos pipe insulation: how to identify and handle it

Where it is found

Asbestos was widely used to insulate hot pipes and heating equipment until the 1970s, and it remains in many older houses and buildings. Look for it in basements, crawlspaces and service rooms, on:

• Hot water and steam heating pipes, especially in houses with radiators
• Boilers and old furnaces, as a jacket or coating
• Elbows, tees and valves, where it was applied as a hard plaster-like lump
• Heating ducts, as a wrap or as tape over the joints
• Pipes that run inside walls and ceilings to upper floors

Houses that have been converted from a boiler to a forced-air furnace often still have the old insulated pipes, or leftover pieces, in the basement.

What it looks like

• Corrugated wrap. Layers of grey-white paper that look like corrugated cardboard in cross-section, often called air-cell insulation, usually covered with a canvas or paper jacket.
• Block or pre-formed sections. White, chalky half-cylinders fitted round the pipe and wrapped in canvas.
• Plastered fittings. Hard, lumpy white or grey material trowelled over elbows and valves.
• Duct wrap and tape. White or grey paper on ducts, or white tape on duct joints.
• Boiler jackets. A thick white coating, sometimes under a metal skin.

Appearance is a reason to suspect asbestos, not proof. Similar-looking insulation was made without it. Laboratory analysis of a sample confirms it.

Why its condition matters

Pipe insulation is friable. When it is in good condition and sealed in its jacket, fibres stay put. When the jacket is torn, the insulation is crumbling or pieces have fallen, fibres can be released into the air, and a basement furnace fan can carry them through the house.

Signs of trouble:

• Torn, hanging or missing sections
• White dust or debris on the floor beneath pipes
• Water damage from a leak, which breaks the material down
• Damage where things have been stored against it or hung from the pipes
• Sections cut away by a previous owner or tradesperson

What not to do

• Do not cut it, pull it off or brush it
• Do not wrap it in duct tape. Disturbing loose material to tape it can release fibres, and ordinary tape fails.
• Do not sweep or vacuum debris with a household vacuum
• Do not hang laundry or store things on the pipes
• Do not let a plumber or heating contractor work on the pipes until it has been dealt with

If there is debris on the floor, keep people out of the area and switch off the furnace fan until it has been assessed.

The options

Leave it and monitor it

Intact insulation that will not be disturbed can stay. Check it now and then for damage, and tell tradespeople it is there.

Repair or encapsulate

Minor damage can be sealed with products made for the purpose, such as a coating or a wrap that hardens. This is asbestos work, and under Ontario’s rules a contractor has to follow the precautions for it.

Enclose

Pipes can be boxed in so that the insulation cannot be knocked. The asbestos remains and should be recorded.

Remove

Removal is usual before replacing a boiler, altering the heating pipes, finishing a basement or selling to a buyer who wants it gone. It is also the answer for insulation that is badly damaged.

How removal is done

Ontario Regulation 278/05 classifies asbestos work as Type 1, 2 or 3. Removing pipe insulation is friable work. The method and classification depend on the amount and the technique:

• Glove bags. A sealed plastic bag with built-in gloves is fixed round a section of pipe. The insulation is wetted and removed inside the bag, which is then sealed and taken away. This is a recognised Type 2 method for pipe insulation.
• Full enclosure. For larger amounts, boilers and badly damaged material, the area is enclosed in plastic and kept under negative pressure, with decontamination and clearance air testing. This is Type 3 work.

Either way, workers wear respirators and protective clothing, the material is kept wet, waste is sealed and labelled for disposal at a licensed site, and the area is HEPA vacuumed and wiped.

Bare pipes are then re-insulated with a modern material.

After a flood or burst pipe

Water wrecks old pipe insulation. If a basement with suspect lagging has flooded, or a pipe has burst inside it, tell the restoration contractor before work starts so that sampling and the right precautions are built into the drying and cleanup plan.

Buying an older house

Home inspectors commonly report suspected asbestos pipe insulation. It does not have to stop a purchase. Get it tested, get a written quote for removal or repair, and factor that into your decision.

More: asbestos removal and abatement.