因故宫中的主要建筑材质以木质为主，很易引起火灾，而在通常在门口的铜雕大缸中注满水，以备不时之需。但是这些铜雕缸实际存在的意义不仅局限于消防，同时还是宫内大殿等的陈列品，这些吉祥大铜缸雕塑在材质上多选用优质青铜而铸，以鎏金铜缸等级最高，也最显豪华高贵，而一些后宫及长街，则摆设一些小铜缸或铁缸。铜大缸有祈福祛灾的吉祥作用，又称“门海”、“福海”、“吉祥缸”。同时，大 缸也是一个循环的“小五行”：金生水、水克火！紫禁城中最豪华的鎏 金铜缸摆置在象征皇权的太和殿东西两侧，据说每次鎏这种规格的大铜 缸要用去3公斤黄金。故宫里的一些大殿前、庭院中都摆放着一个个这样腹宽口收、容量极大，而且装饰精美，两耳处还加挂着兽面铜环的金属缸。这些大缸除了有装饰作用外，其主要功能为储水防火，因而又被称作“吉祥缸”，“太平缸”。

Because the main building material in the Palace Museum is mainly wood, it is easy to cause fire, but usually in the doorway of the copper cylinder filled with water, in case of occasional need. However, the actual significance of these copper cylinders is not only limited to fire protection, but also exhibits in palace halls. These auspicious large copper cylinders are mostly made of high-quality bronze, with the highest grade of gold cylinders and the most luxurious and noble. Some rear palaces and long streets are equipped with small copper cylinders or iron cylinders. Copper cylinder has the auspicious function of praying for good fortune and dispelling disaster, also known as "Menhai", "Fuhai", "auspicious cylinder". At the same time, the cylinder is also a cycle of "small five elements": Jinshengshui, Shuike fire! The most luxurious bronze VATS in the Forbidden City are located on both sides of the Taihe Temple, which symbolizes the imperial power. It is said that every time a large copper vat of this size is used up to 3 kilograms of gold. In front of some palaces and courtyards in the Palace Museum, there are metal cylinders with wide abdomen, large capacity and exquisite decoration, with copper rings on both ears. In addition to decorative functions, the main functions of these large cylinders are water storage and fire prevention, so they are also called "auspicious cylinders" and "taiping cylinders".