JP2787221B

PURPOSE:To obtain a preventing function against a leakage spreading as sure as or surer than a conventional one by placing a portable dam of which height can be freely selected, in a ditch formed at a place surrounding a leak prevention area. CONSTITUTION:A ditch 2 into which a portable dam 5 can be inserted, is provided on a floor 1 of a facility. Besides, a drain funnel 3 having a drain pipe 4, is placed at a bottom of the ditch 2, according to a requirement. With this constitution, a leak spreading during a normal operation, can be prevented by the portable dam 5. Otherwise, during a periodical inspection or the like, the portable dam 5 can be removed to prepare an almost flat floor and therefore a transportation of equipments and workers' walking around are not disturbed. Moreover, in case that a liquid flows into the ditch 2, the liquid can be quickly drained to a drain pipe 4 from the drain funnel 3 placed at the bottom of the ditch 2, regardlessly to during a normal operation or during a periodical inspection.