The integrity of a piping system depends on the considerations and principles used in design, construction and maintenance of the system. Piping systems are made of components as pipes, flanges, supports, gaskets, bolts, valves, strainers, flexible and expansion joints. The components can be made in a variety of materials, in different types and sizes and may be manufactured to common national standards or according a manufacturers proprietary item. Some companies even publish their own internal piping standards based upon national and industry sector standards. Piping codes and standards from standardization organizations as ANSI ASME ISO DIN and others, are the most common used. The difference between piping codes and piping standards can be summarized: Piping Codes Piping codes defines the requirements of design, fabrication, use of materials, tests and inspection of pipes and piping systems. A code has a limited jurisdiction defined by the code. Piping Standards Piping standards define application design and construction rules and requirements for piping components as flanges, elbows, tees, valves etc. A standard has a limited scope defined by the standard.