... gutters, wall, underground piping, sashes, beams, fences, scaffolding, indoor decorations, ducts, ventilating pipes, steel frames and ... noise screens, highway signs, air cleaners, conveyor systems and guard rails(4) AGRICULTURAL EQUIPMENTBarns, drying machines ... , animal houses, hoppers, irrigation systems, greenhouses, water tanks, sheds, silos, agricultural implements ...