This paper describes some of the technical aspects of street lighting column design and manufacture, and the protection of their surfaces against corrosion. The main types of column used are: (1) concrete; (2) aluminium; (3) stainless steel; (4) tubular steel; and (5) polygonal steel, usually six-sided or eight-sided. Important types of corrosion, affecting columns, include: (1) atmospheric corrosion; (2) bi-metallic corrosion; (3) corrosion of concrete; (4) water corrosion; (5) fretting corrosion; (6) microbial corrosion; (7) pitting corrosion; (8) stray current corrosion; (9) stress corrosion; and (10) corrosion from soils. Protection methods include: (1) hot dip galvanising of steel columns; (2) metal spraying of metal columns; (3) paint coatings; and (4) plastic coatings. About 5 million lighting columns are in service in the UK, of which perhaps about a half need replacement, but public spending cuts have aggravated the problem of column replacement. There are several ways of slightly prolonging column life by appropriate repairs. Typical replacement costs vary from £600 to £800 per column. Recent changes in design have made some columns vulnerable to corrosion. Six recommendations are presented for future lighting column policy.
Abstract