angles building building construction building site building work cables chains construction construction site construction work crane danger height heights high hoist hoisting hooks lifting metal work pipes railing rails raising safety safety mesh scaffolding security skip steel scaffolding tall work workers working workmen attention germany isolated pictogram sign traffic uneven road warning circuit clamps copper current electrical electricity ground power stake wires arm basket cherry-picker cleaning dangerous elevated elevation equipment extension external Harness insulators machinery on-high perspectives power-lines power-pole raised raised-platform risks risky safety-harness surface surfaces up-high washing workman demining explosive minehunters minesweeper navy sea ship war barricade flash flasher lens light safe sicherheit sicurezza sikkerhed texture veiligheid warn yellow cool float floater fun lifesaver lifesavers pink sparkling summer water computerised computerized hardhats helmet laser level levels measurement measuring men skilled skills surveying surveyors technology theodolite triangulation tripod