Asbestos Corrugated Cardboard

Asbestos corrugated cardboard is a ridged, layered insulation material manufactured from asbestos fibres compressed into a corrugated form. The corrugations create air pockets that enhance thermal insulation performance, similar in principle to conventional corrugated cardboard but engineered for high-temperature environments. Asbestos content typically ranges from 80 % to 95 %, with chrysotile and amosite being the most common fibre types.

This product was widely used from the 1930s through the late 1970s in industrial insulation applications. It was wrapped around steam pipes, heating ducts, and process piping, often as an inner layer beneath an outer jacket of asbestos cement, metal cladding, or canvas. It was also used inside industrial ovens, furnaces, and kilns as thermal lining, and in shipbuilding as insulation within bulkheads and around steam systems.

Asbestos corrugated cardboard is classified as friable. The corrugated structure, while providing thermal benefits, also means the material is inherently fragile. The ridged layers crush, crack, and crumble under pressure, and the thin walls of each corrugation break down easily when aged or exposed to moisture. When deteriorated, even gentle handling releases significant fibre clouds.

The material is frequently concealed beneath outer cladding or within multi-layer insulation systems, making it a common unexpected discovery during refurbishment, decommissioning, or demolition works. Workers removing what they believe to be metal pipe cladding may encounter deteriorated asbestos corrugated cardboard underneath.

A refurbishment and demolition survey is essential before any work on insulated piping systems in pre-1980 buildings. Laboratory analysis using polarised light microscopy (PLM) or transmission electron microscopy (TEM) is needed to confirm asbestos content. Removal must be carried out under controlled conditions by a licensed contractor with appropriate containment and personal protective equipment.