When decorating and choosing a drain pipe, many people will be stunned by "PVC-U" and "ordinary PVC" - obviously only one "-U" is missing, how can the price and use be so different? In fact, these two "PVC" seem like brothers, but in essence they are completely different "track players". Today we will disassemble it in plain language, and you will know how to choose in seconds after reading it.

First of all, we must clarify a foundation: PVC itself is an abbreviation of "polyvinyl chloride", which is a common plastic raw material. But whether to add "-U" or not directly determines its "character" -

1. The key hidden in the raw material: Is there a plasticizer?

In order to make the plastic more flexible and easy to process, ordinary PVC drainage pipes will add "plasticizers" (such as phthalates). These additives are like "softeners", making the originally hard PVC flexible and easy to shape. But PVC-U is different - its full name is "hard polyvinyl chloride", and it does not add plasticizers at all during production, and adjusts the molecular structure to make the material itself hard. Simply put: ordinary PVC is "chocolate with fudge", PVC-U is "pure black clever", the former is soft, the latter is hard.

2. What is the performance difference? Compression resistance and hardness are the key

Because of the lack of plasticizers, the hardness and pressure resistance of PVC-U drainage pipes far exceed that of ordinary PVC: break the PVC-U pipe by hand, almost motionless; smash it, at most leave a small mark, will not break. But ordinary PVC pipes are bent as soon as they are broken, and will deform or even crack if they are too hard.

In addition, PVC-U has better high temperature resistance - kitchen drainage occasionally has hot water, PVC-U can withstand temperatures of 40-60 ° C; ordinary PVC pipes are easy to become soft when exposed to hot water, and may "collapse" after long-term use.

3. Where to use? The scene decides to choose

PVC-U's "hard" just to meet the needs of building drainage: the main drain pipe of the bathroom, kitchen, buried in the wall or underground pipes, need to withstand the pressure of the upper layer, the impact of water flow, choose PVC-U is right.

Ordinary PVC is more suitable for non-pressure and flexible scenarios because it is "soft": such as the inlet pipe of the washing machine (bending back and forth), the temporary drain pipe of the balcony, or the temporary threading pipe during decoration - but it must not be used as the main drain pipe, otherwise it will leak in three or five years.

4. Environmental protection and lifespan: Plasticizers are "invisible lightning"

Plasticizers in ordinary PVC have a big problem: long-term contact with water or high temperature, will slowly "precipitate" - that is, dissolve into water, although the amount is not large, but long-term drinking of such water (such as water pipe leakage into groundwater) is a health hazard. Moreover, plasticizers will make plastics age faster. The lifespan of ordinary PVC pipes is generally only 5-8 years; PVC-U has no plasticizer, the molecular structure is more stable, and it can be used for 20-30 years, or even the same lifespan as buildings.

Seeing this, you should understand how to choose, right? To sum up, choose PVC-U for the main drainage pipe, and ordinary PVC for small pipes that need flexibility. Don't be confused by "-U" again, choose the right one to avoid the trouble of leaking and smelling later!

In fact, the "small details" in the decoration hide the big truth, choose the drain pipe is not the more expensive the better, but to "take a seat" - suitable for the scene, is the best.