When asbestos fibres are bonded to another material, such as portland cement or various resins, and can't be crushed by hand when dry it is referred to as bonded asbestos.
Asbestos cement (AC) products and electrical metering boards in good condition are examples of bonded asbestos material. A large number of products made from asbestos cement are still found in Australian buildings including flat, corrugated or compressed asbestos cement sheeting (Fibro). Asbestos cement pipes such as electrical, water, drainage and flue pipes are also common.
Friable asbestos material is any material that contains asbestos and is in the form of a powder, or can be crumbled, pulverized or reduced to powder by hand pressure when dry. This may also include previously non-friable material which becomes broken or damaged by mechanical force.
Sprayed limpet, millboard, pipe and boiler lagging, are all examples of friable asbestos. Also, any asbestos cement product that has been subjected to weathering, severely damaged by hail, damaged by heat/fire or other mechanical action or illegal water blasting may also result the asbestos becoming friable and hence the fibres becoming airborne.