In the building drainage system, the PVC drain pipe is a well-deserved "protagonist" - the characteristics of high cost performance, corrosion resistance and easy installation make it cover almost all drainage scenarios from home decoration to municipal engineering. But many people may not care, the thickness of the PVC pipe is not randomly selected, it must strictly follow the caliber, and different sizes of pipes correspond to different wall thickness requirements. If you choose the right one, the drainage system can last for decades; if you choose the wrong one, it will leak and rework, and if you choose the wrong one, it will cause the big problem of pipe rupture and drainage paralysis.

First, you must make it clear: Why is the thickness of the PVC pipe important? In fact, the wall thickness directly determines the "resistance" of the pipe - buried pipes have to carry soil pressure and ground loads, high-rise residential risers have to withstand top-down water pressure, and even surface-mounted branch pipes have to withstand daily collisions. If the wall thickness is not enough, the pipe may slowly deform and crack after three or five years, and then the water will flood the bathroom and leak downstairs, which will be a big problem.

Next is the key point: how thick should PVC drainage pipes of different diameters be? According to the national recommended standard GB/T 5836.1-2018 "rigid polyvinyl chloride (PVC-U) drainage pipes and pipe fittings for construction", PVC pipes are divided into two categories: "light (L) " and "heavy (M) ", corresponding to different use scenarios. Let's make it clear one by one:

1 .50mm caliber (commonly known as "2 inch pipe")

This is the most common "small water pipe", such as the drainage branch pipe of the bathroom sink and the balcony washing machine, most of them use it. Standard requirements: light wall thickness 2.0mm, heavy weight 2.5mm. Light is enough for home use, but if it is buried under the balcony floor or needs to withstand a slight load (such as putting a cabinet under pressure), you have to choose heavy - after all, buried pipes, one more layer of thickness is one more layer of protection.

2 caliber ("3 inch pipe")

kitchen sink, small bathroom main drainage, or multi-storey residential branch pipe commonly used this size. The standard is: light wall thickness 2.3mm, heavy 2.9mm. For example, kitchen drainage to go oil, although the pressure is not big, but occasionally there may be heavy collisions (such as moving cabinets), choose heavy more stable.

3 110mm caliber ("4 inch pipe")

This is the "main pipe" of residential drainage! The drainage of toilet, the main riser of the whole building, all rely on it. Standard requirements: light wall thickness 3.2mm, heavy 3.8mm. Focus: high-rise residential main riser must choose heavy! Because of the high-rise water flow and pressure, light pipes may crack due to excessive circumferential stress after three or five years - at that time, the drainage of the whole building has to stop, and the maintenance cost can be ten times more expensive than buying heavy pipes.

4 160mm caliber ("6 inch pipe")

Main drainage of commercial buildings (such as supermarkets, office buildings), or outdoor drainage pipe networks in residential areas. Standard: light wall thickness 4.0mm, heavy weight 4.8mm. Most of these pipes are buried in the ground, and they have to carry soil pressure and the load of ground vehicles, so almost all have to choose heavy-duty pipes - don't be greedy for that cheap, buried pipes are broken and dug for repair, which is much more expensive than buying pipes.

5. 200mm caliber ("8 inch pipe")

is mainly used for large municipal projects, such as the rain water pipe network of urban roads, the centralized drainage of shopping malls and hotels. Standard: light wall thickness 5.0mm, heavy 6.0mm. If the wall thickness of this large pipe is not enough, even if it is buried on the side of the road, the pressure of passing vehicles can deform it, so it must be strictly according to the heavy standard.

Some people may ask: Why is the wall thickness thicker with a larger diameter? In fact, the principle is very simple - the thicker the pipe, the greater the "circumferential stress". For example, a thin straw and a thick plastic pipe, the same pinch, the wall of the thick pipe will be more easily deformed, because its circumference is longer and it needs to withstand more tension. Therefore, in order to ensure the strength, the larger the diameter, the wall thickness must follow the "increase", which is determined by the laws of mechanics.

Finally, a few small reminders for selection:

First, clarify the demand - is it a household branch pipe or an engineering riser? Is it surface-mounted or buried? Buried, high-rise, and commercial scenarios, heavy-duty is preferred; household surface-mounted branches, light-duty is enough.

Second, don't buy "non-standard pipes"! Some merchants make 110mm light pipes 2.8mm thick (the standard is 3.2mm) in order to save costs. It looks cheap, but it will definitely crack in a few years when used on high-rise risers. Be sure to choose a regular product printed with the "GB/T 5836.1-2018" logo.

Third, you can measure it when you buy it - use a vernier caliper to measure the thickness of the pipe wall, such as 110mm heavy-duty pipe, the wall thickness must be more than 3.8mm, no less.

In the end, the thickness standard of PVC drain pipes is not a "dogma", but a "safety line" piled up by countless engineering experiences. Understanding the wall thickness requirements corresponding to different diameters is not to "remember numbers", but to help us "have a bottom line" when choosing pipes - after all, the drainage system is the "blood vessel" of the house, and choosing the right pipe can make this "blood vessel" safe and stable for decades.