We carry out all types of industrial piping assemblies and construction, as well as preventive maintenance of mechanical equipment and scheduled shutdown services.
Types of piping materials
In order to guarantee a long durability and performance of the piping systems we make sure that the material used is completely safe in the expected operating conditions of pressure, temperature, corrosion and erosion. Some of the most commonly used materials are
- Steel: this material is the most commonly used for piping. Forged steel is widely used for fittings, while cast steel is mainly used for special applications. Pipe is manufactured in two main categories: seamless and welded.
- Cast iron: Cast iron has a high resistance to corrosion and abrasion and is used for ash handling systems, sewer lines and subway water lines. However, it is very brittle and is not suitable for most power plant services. It is manufactured in different grades, such as gray cast iron, malleable cast iron and ductile cast iron.
- Brass and copper: used in power plants in instrumentation and water services where temperature is not a major factor.
Fittings used in piping
- Elbows: used to make angular turns in pipes.
- Nipples: used to make tight connections. They are threaded at both ends with the closed nipple threaded along its entire length.
- Couplings: allow two pieces of pipe of the same size to be connected in a straight line.
- Unions: to provide a simple method for disassembling pipes.
- Tees and crosses: to make 90° branch connections.
- Y-bends: to make branch connections at 45º.
- Return bends: to reverse the direction of a pipe run.
- Plugs and caps: to close open ends of pipes or fittings.
- Bushings: these allow pipes of different sizes to be connected.
- Reducers: to reduce pipe size.
Pipe joining methods
Various types of connections are used to join pipes together, the most common being:
- Bolted connections: with these, threads are cut at each end of the pipe and bolted fittings such as unions, couplings and elbows are used to join the lengths together. This method is generally used for pipe less than 101.6 mm (4 inches) for low and moderate pressures. It has the advantage that the pipe can be easily disassembled or assembled. However, threaded connections are subject to leakage and pipe strength is reduced when threads are cut into the pipe wall.
- Flanged Connections: This method uses flanges on the pipe ends that are bolted face to face, usually with a gasket between the two faces. Flanged connections have the advantage over welded connections of allowing disassembly and are more convenient to assemble and disassemble than bolted connections. To avoid leakage in flanged connections, the flange faces, which are joined together, should be absolutely flat and smooth. While it is theoretically possible to grind the faces in this condition, it is a costly and time-consuming proposition. Therefore, gaskets are generally used between the flange faces. The gaskets are made of a comparatively soft material which, when the flanged connection is tightened, will fill any small depressions in the flange faces and thus prevent leakage.
- Welded joints: In this method, pipe sections are welded directly to each other and directly to any valves or fittings that may be required. The use of these welded pipe joints has several advantages over the use of bolted connections or flanged connections:
- The possibility of leakage is eliminated with the elimination of bolted or flanged joints.
- The weight of the piping system is reduced due to the elimination of flanges or fittings.
- Material cost and maintenance requirements are reduced with the elimination of flanges and fittings.
- The pipeline looks neater and is easier to insulate with the elimination of bulky flanges and fittings.
- Welded joints give more flexibility to the piping design, as pipes can be joined at virtually any angle to each other.