What is the meaning of double doors, double locks and double ledgers?

Does the questioner want to ask "what is the meaning of double doors, double locks and double accounts"? The five double management system of highly toxic chemicals. Explosive hazardous chemicals in the management of the "five double" system refers to two people to keep, two locks (key) two books, two people to ship, two people to receive. Whether any explosive hazardous chemicals warehouse, must adhere to the "five double" system. Double custody is the custodian shall not be less than two people, one rest, there must be a third person to replace. Two locks of the key must be held by two people each, not by a person in charge. Shipments must be two people present at the same time. Collaterals should be two people to go, and is responsible for delivery. Double book is the custodian of a book, the head of the inspection section to execute a book.