In decoration or tooling projects, PVC pipes are "frequent customers" - they can be seen from tap water transportation to sewage discharge. But many people do not know that although PVC water supply pipes and PVC drainage pipes look alike, their uses are very different. The core difference lies in the three key points of pressure requirements, temperature resistance and connection method.

First talk about the core pressure level. PVC water supply pipes are "pressure pipes". To send tap water from the community pipe network to the faucet at home, you have to withstand the pressure in the pipe network (for example, the water pressure of high-rise residential buildings can reach more than 10 kilograms). Therefore, the pressure level of the water supply pipe is higher, and there are two common types: PN1.0 (carrying 10 kilograms per square centimeter) and PN1.6 (carrying 16 kilograms per square centimeter). The pipe wall is also thicker - for example, for pipes with the same DN50, the wall thickness of the water supply pipe of PN1.6 can reach 3.7mm, while the drain pipe may only be 2.0mm. In contrast, the PVC drain pipe is a "gravity pipe", which flows down by the weight of the water and hardly bears internal pressure. Therefore, the pressure level is usually below PN0.6, and the pipe wall is thin, light in weight, and the cost is much lower. If the drain pipe is used as a water supply pipe, the water pressure will explode as soon as it rises; if the water supply pipe is used as a drain pipe, it is equivalent to spending "luxury car money" to buy a "bicycle", which is completely unnecessary.

Let's talk about temperature resistance. The PVC material itself is not very heat-resistant, but the temperature resistance requirements of the two are different. The PVC water supply pipe needs to transport drinking water for a long time, and the temperature change will affect its "pressure life" - if the water temperature exceeds 45 ° C, the pipe will gradually become soft and deformed, and the interface will leak over time. So the temperature of the water supply pipe is strictly limited to 0-45 ° C, and hot water must not be connected. And what about the PVC drain pipe? Although it occasionally encounters warm water (such as the dishwashing water in the kitchen, the bath water in the bathroom), because it does not have to bear pressure, the short-term temperature resistance can reach 60 ° C. As long as it does not pour boiling water for a long time, it is not a big problem. However, it should be noted that whether it is the water supply pipe or the drain pipe, do not soak in hot water for a long time. After all, PVC is plastic and has limited heat resistance. 1172779 The connection of the water supply pipe should be "seamless", because water leakage not only wastes water, but also may soak the wall. There are two commonly used connection methods: one is PVC glue bonding - wipe the socket of the pipe and pipe fittings clean, apply a layer of glue, plug it tightly, and wait for the glue to dry to become a "seamless whole"; the other is sealing ring connection - large-diameter water supply pipes (such as DN100 or more) are often used in this way. One end of the pipe is flared, stuffed into the elastic sealing ring, and then inserted into the pipe fittings. It is sealed by the elastic force of the sealing ring, and the installation is faster. The connection of the drain pipe is much more "arbitrary", because there is no need to carry pressure, as long as there is no leakage. Commonly used is socket bonding (similar to the water supply pipe, but do not need to wipe it very clean, just apply the glue evenly), or clamp connection - use plastic or metal clamp to clamp the pipe and pipe fittings, and it is also convenient when you want to remove it. However, I would like to remind you that the water supply pipe must not be connected with a clamp, the clamp will loosen when the pressure comes up; the drain pipe should not be connected with a sealing ring, which is a waste of money and trouble.

In fact, the difference between PVC water supply pipe and drain pipe is "use determines the design" - the water supply pipe should be "pressure, sealing, stable temperature", and the drain pipe should be "light, easy to install, and cost-saving". When choosing, think clearly: is it water supply or drainage? Pressure or no pressure? If you understand these two questions, you will not choose the wrong one.