What is a floor heating pipe?
Floor heating pipe refers to a kind of pipe used as a carrier of low-temperature hot water circulation in the low-temperature hot water floor radiant heating system (referred to as floor heating).
From the birth of floor heating to the present, the following types of pipes have been used as floor heating pipes. XPAPR: Cross-linked aluminum pipe PE-X: Cross-linked polyethylene 1 PAP: Aluminum-plastic composite pipe 2 PP-B: Impact-resistant copolymer polypropylene (Korea used to call it PP-C) PP-R: Random copolymer Propylene PB: Polybutene (super high temperature resistant pipe) PE-RT:: High temperature resistant polyethylene Note 1: Cross-linked polyethylene is divided into peroxide cross-linking (PE-Xa) and silane cross-linking (PE- Xb), electron beam crosslinking (PE-XC) and azo crosslinking (PE-Xd). Among them, peroxide crosslinking and silane crosslinking are two commonly used crosslinked polyethylene pipe products in China. However, peroxide crosslinking is not widely used due to excessive oxygen permeation. Silane crosslinking is banned in Europe in 2004 due to the toxic crosslinking agent silane. Electron beam crosslinking (PE-XC) is a healthy and environmentally friendly pipe material that uses physical methods to change the molecular structure. , Azo crosslinking (PE-Xd) is in experimental state. Note 2: There are three types of aluminum-plastic composite pipes on the market, PE/AL/PE; PE/AL/XPE; XPE/AL/XPE. The first is that the inner and outer layers are polyethylene, the second is that the inner layer is cross-linked polyethylene and the outer layer is polyethylene, and the third is that the inner and outer layers are both cross-linked polyethylene, and the middle layer is both aluminum layers. The first type is generally used for cold water piping systems, and the latter two are generally used for hot water pipes, which can be used as floor heating pipes.
According to the requirements of national and international product standards, the raw materials for the production of plastic pipes and plastic pipe fittings for cold and hot water must be in accordance with GB/T18252-2000 "Determination of the Long-term Hydrostatic Strength of Thermoplastic Pipes by Extrapolation of Plastic Piping Systems" Specified pipe special materials that passed the test and passed the qualification test. In other words, each raw material manufacturer must make a creep failure curve that meets the predicted strength reference curve according to the floor heating pipe product standard to prove that the raw materials sold are qualified. Only one point test of thermal stability under the hydrostatic state at 110°C for 8760 hours cannot prove whether the pipe material is qualified. If you do not know whether the raw material product is qualified, it is the same as the cement has not been identified, and the strength of use cannot be determined. Regardless of which type of pipe is used to lay the floor heating, only qualified pipes produced by using raw materials that meet the requirements of product standards and reasonable production equipment and technology can be reliably guaranteed for the use of plastic pipes for floor radiant heating through correct design, installation and use. Life span is fifty years.
PE-X domestic production generally adopts medium-density polyethylene or high-density polyethylene and silane cross-linking or peroxide cross-linking method. It is the chemical bond connection between the linear long molecular chains of polyethylene to form a three-dimensional network molecular chain structure. Compared with general polyethylene, it has improved tensile strength, heat resistance, aging resistance, stress crack resistance and dimensional stability. The entire production process is a chemical reaction process. This kind of floor heating has difficulties such as the cross-linking agent is not easy to disperse uniformly, the degree of cross-linking is difficult to control and the screw needs to be cleaned regularly to prevent the generation of gel particles. The quality control of the product is difficult, and it is difficult for ordinary small manufacturers to do well. Qualified PE-X pipe has the advantages of good mechanical properties, high temperature resistance and low temperature performance. However, PE-X pipes have no thermoplastic properties and cannot be connected and repaired by hot-melt welding. PB is known as the soft gold in plastics. It has superior creep resistance and mechanical properties. It is the softest among several floor heating pipes and has the thinnest wall thickness under the same design pressure. Under the same use conditions, the same wall thickness series of pipes, this variety has the highest use safety. However, the price of raw materials is the highest, more than double that of other varieties, and the current domestic application area is small. The market will slowly popularize this kind of pipe in the future. PE-RT This floor heating mate