Everyday Plumbers Bristol
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Heating and cooling piping are used in residences to carry water, gas, or air from a home's heating unit to the rooms within the residence. This heat transfer process (conduction) means that pipes must remain insulated as well as buried underground, under concrete slabs for example for maximum efficiency and safety-being hot enough to burn flesh. The pipes that carry hot water, cold water, or coolant are generally made of copper, aluminum, vinyl and should be properly insulated. Hot-water heating lines can usually vary in thickness from inch to more than two inches depending on the manufacturer's instructions for the system. Bending hot water supply lines is generally not recommended as this can cause a slight increase in pressure drop across the line, but there may be exceptions where it may be acceptable to bend them slightly. Pipes carrying drinking water (cold water) need to withstand higher pressure than pipes used for heating. The maximum allowable working pressure of copper pipe is 4 bar (70 psi). The minimum thickness of pipe walls and therefore the pressure-carrying capacity is slightly increased when cross-country lines are run for long distances in northern countries (e.g. Canada, Sweden). Pressurized hot water pipes made of copper should not be installed underground if there will be freezing temperatures below around 5 °C as some materials expand and contract by more than 3–4%. While plastic piping has no such limitations it deteriorates over time, especially in direct sunlight, thus requiring replacement every 10 years or so. The piping used to carry natural gas must have a very low-pressure drop. Only smaller pipes (diameter no more than about 12 inches) can be connected to the gas supply pipe as larger diameter pipes will result in unacceptable pressure drops. Chillers, heat pumps, and air conditioners are cooled with refrigerant (Freon).