Performance requirements for PVC pressure drains: Pressure grades and usage restrictions

Many people may be a little vague about the concept of "pressure" of PVC pressure drainage pipes - it is not an ordinary drainage pipe, but a special PVC pipe that can withstand a certain internal pressure. It is often used to deal with drainage risers in high-rise residential buildings, pressure drainage systems in underground garages, or wastewater discharge with pressure requirements in industrial sites. To choose and use this pipe well, you must first understand its core performance requirements: pressure grade and use restrictions.

First talk about the pressure grade. The pressure grade of PVC pressure drainage pipes is divided according to "nominal pressure (PN) ", which is the maximum working pressure that the pipe can withstand for a long time at room temperature (20 ° C). According to the national standard GB/T 5836.2-2018, the common grades are PN0.63, PN1.0, PN1.6 (unit MPa). For example, PN1.0 grade is suitable for drainage systems of multi-storey residences (6 floors and below); PN1.0 grade is suitable for drainage risers of 18-30-storey high-rise residences - the dynamic pressure of high-rise drainage may reach 0.8MPa, and PN1.0 can just handle it; PN1.6 grade is used for industrial pressure wastewater discharge or fire pressure drainage systems to cope with higher pressure demands.

The higher the pressure level, the better: PN1.6 for multi-storey use will waste costs, and PN0.63 for high-rise use will break due to excessive pressure. The key is to match the needs of the scene.

Let's talk about the easily overlooked use restrictions, which directly affect the life of the pipeline:

The first is the temperature limit. The long-term use temperature of PVC cannot exceed 40 ° C - draining hot water or industrial wastewater exceeding 40 ° C will soften and deform the pipeline; even if the occasional high temperature water (such as kitchen dishwashing water), it should be controlled within 60 ° C and not continuous.

The second is the medium limit. Do not come into contact with strong corrosive media: Sulfuric acid, caustic soda, or organic solvents such as gasoline and alcohol with a concentration exceeding 10% will corrode the molecular structure of PVC, resulting in leakage and rupture.

The third is the installation environment limit. Fear of sun exposure - choose UV-resistant PVC pipes or do protection outdoors; lay a sandstone cushion to prevent sharp objects in the buried ground; the adhesive connection needs to be ground at the end of the pipe, evenly glued, and fixed for 24 hours before water.

The fourth is the pressure fluctuation limit. The water hammer effect started by the pump will produce instantaneous high pressure, and a water hammer eliminator needs to be installed to avoid cracking the pipeline.

In fact, the "performance requirements" of PVC pressure drainage pipes are essentially "matching requirements": the pressure level is suitable for the scene, and the use restrictions can keep the conditions, so that it can be used for 50 years; otherwise, there may be problems in 3-5 years.

Finally, remind: buy a pipe to see the test report, confirm that it meets the national standard, and the pressure level is clearly marked (the pipe body is printed with "PN1.0", etc.). Don't be greedy to buy "three no" pipes cheaply - save small money and pay big money.