(a) Class I: Asbestos removal from piping, ductwork and surfaces;

(b) On the outside of sealed air supply, return and exhaust ductwork;

• The necessity of fitting new systems into existing situations, for example, new ductwork cutting through an existing wall — in a new building, the piping would be installed first

These could be intrusive technologies, such as sampling within ductwork, taking smears for subsequent radio-chemical analysis or taking direct radiometric and other measurements from facility effluents.

The United Nations Headquarters buildings were built when the use of asbestos-containing materials was common for thermal insulation of piping and ductwork, for fireproofing/acoustic treatment of walls and ceilings, for strengthening vinyl floor tiles and for electrical insulation.

It was common practice, until the early 1970s, to use asbestos-containing materials in homes and buildings as thermal insulation on piping and ductwork, as electrical insulation on cables and panels, as a vapour barrier on exterior walls, as sprayed-on water-proofing or acoustic treatment on walls, ceilings and structural elements, and as a strengthening compound for certain vinyl floor tiles.

(d) Refurbishment/replacement/restoration of ageing mechanical, electrical and building infrastructure elements, including incoming electric, steam, water, gas and river-water services; central plant heating and cooling equipment; heating, ventilating and air-conditioning equipment; piping and ductwork; electrical distribution systems, backup power systems; lighting and ceilings; facility-wide building management and environment control systems; elevators and escalators; damaged finishes; deteriorated paving, railing, walkways, site amenities and drainage; and diseased and decayed plantings;