Water ingress in new construction requires several joints.
A water joint is any device or procedure used to facilitate the joining of water pipes or the addition of ancillary equipment, preserving the integrity and continuity of the piping circuit. Water pipe joints can be permanent or removable, depending on the application and the type of pipe involved. These joints can be rigid or flexible or even include bellows-type expansion elements to provide increases in water pressure. Water joints may not include external parts and be based on welded, brazed or welded pipe or fittings alone or consist of separate joining elements. The water joints must be able to withstand the same pressure as the rest of the piping circuit without leaks or mechanical failure.
Water-brazed joints are typically used on small copper pipe.
Water piping systems are typically made up of many separate sections of piping and various pieces of ancillary equipment, such as valves, pressure compensating bellows, flow meters, backflow protectors, and access port fittings. The average water pipe installation will also change direction or elevation frequently and have many branches, splits, or extensions along its route. All these deviations and additions require a watertight union between different sections of pipe, accessories and external equipment. The type of gasket used depends on several factors. This includes pipe size, pipe material, system pressure, and whether or not the joint or fitting will require periodic removal or maintenance.
There are several different types of water seals, each with its own benefits and specific area of application. The two main classifications of water pipe joints are permanent and removable. Permanent water joints include brazed, soldered and brazed joints and are typically used on smaller copper water pipes and very large steel distribution lines. The welded water joint on large feeder pipes is often part of a pipe section prefabrication system and is usually done off-site prior to installation. However, steel water pipes can be welded on site for repairs or additions to the system.
Smaller on-site copper piping systems are often joined by brazing or welding pipe and fittings. If done correctly, a brazed, welded, or soldered water joint is often the strongest and toughest of all joints. Removable joints generally consist of flanges, casing, and two-part compression fittings. A water flange joint consists of two similar discs that are placed at the ends of the pipes to be joined. A packing element is inserted between the two and they are screwed together. This joins the two flanges together tightly, thus forming a tight joint.
Compression and casing joints are typically two-part connections with internal compression seals. One half is located at each end of the tube and is screwed on, thus compressing the sealing element and forming a watertight joint. This type of gasket is quickly replaced if the seals become worn or damaged and allows easy extension of the piping circuit or the inclusion of other accessories. Single element single sleeve joints are also often used on steel pipes and consist of a single threaded sleeve sealed with hemp wire or PTFE tape. The most important defining characteristic of all water seals is their ability to withstand system pressure without leaking or allowing in contaminants and air.