Abstract: This paper introduces in detail the performance of air conditioning insulation pipe material and the purchase guide. Firstly, the basic knowledge of air-conditioning insulation pipe is introduced, and then the material of air-conditioning insulation pipe is analyzed and interpreted from the aspects of material, insulation performance, anti-corrosion performance and reliability. Finally, some purchase suggestions and precautions are provided.

Basic knowledge of 1.
Air conditioning insulation pipe is a kind of pipe specially used for insulation, which is mainly used in the air conditioning system of buildings, industries and civil buildings. It is usually composed of inner and outer shell, thermal insulation material and waterproof material. The inner shell is generally made of galvanized steel sheet or stainless steel sheet, and the outer shell is generally made of high density polyethylene (HDPE) pipe or glass fiber reinforced plastic pipe. Insulation materials are generally polyurethane, polyethylene or polyvinyl chloride.

2. material
Air conditioning insulation pipe material can be divided into metal material and non-metallic material two categories.

1. Metal material
Metal air conditioning insulation pipe mainly has galvanized steel plate, stainless steel plate, aluminum plate and so on. Metal air conditioning insulation pipe has the advantages of high strength, pressure resistance, corrosion resistance, etc., but its thermal conductivity is poor, and the thermal insulation performance needs to be realized by thermal insulation materials. Metal air conditioning insulation pipe is relatively high price, not suitable for large-scale construction.

2. Non-metallic material
Non-metallic materials of air conditioning insulation pipe mainly polyurethane, polyethylene, polyvinyl chloride and so on. Non-metallic material of air conditioning insulation pipe has excellent thermal conductivity, excellent thermal insulation performance and other advantages, and the price is relatively low. These material products can usually be divided into two types of hard and soft, hard insulation materials are suitable for high temperature and high pressure areas, while soft insulation materials are suitable for low temperature and low pressure areas.

3. insulation performance
The thermal insulation performance of air conditioning insulation pipe is one of the important indicators of material selection.

1. Thermal conductivity
Thermal conductivity is an important index to evaluate the thermal insulation performance of thermal insulation materials, usually in W/m · K. The smaller the value, the better the insulation performance of the material. Polyurethane is the most cost-effective thermal insulation material, and its thermal conductivity is about 0.02 W/m · K, showing good thermal insulation performance.

2. Temperature resistance
The insulation material of the air conditioner insulation pipe must have high temperature resistance to ensure the stability of its service life in high temperature environment. Polyurethane material has a high stable service life under 150 ℃.

3. Water resistance
Air conditioning insulation pipe is often affected by rain, snow and humid environment, so its insulation material should have good water resistance, can resist water seepage, water absorption and so on. Polyurethane material has good water resistance and can achieve long-term heat preservation effect.

4. corrosion resistance
The anti-corrosion performance of the air conditioning insulation pipe is a necessary requirement for the project, especially in the construction of the industry and the square, it needs to be considered. The anti-corrosion performance of the material determines the service life and performance of the air conditioning insulation pipe.

1. Anti-corrosion coating
Galvanized steel plate and other metal materials of air conditioning insulation pipe, coated with a layer of anti-corrosion coating on the surface, can improve the anti-corrosion performance of the material. The coating is usually hot dip galvanized, organic coating or ultraviolet coating.

2. Special materials
In some highly corrosive and high sulfide environments, the protective performance of metal air conditioning insulation pipes is difficult to meet the demand. At this time, some special materials, such as chromium, molybdenum and tungsten, can be added to the material to improve its corrosion resistance.

5. reliability
The reliability of air conditioning insulation pipe is also one of the important indicators of material selection. Reliability means that the material will not fail during long-term use and can maintain long-term stable performance.

1. Anti-aging performance
The reliability of the air conditioning insulation pipe needs to consider its anti-aging performance, and the material should have good weather resistance and UV resistance. Polyurethane material has good anti-aging performance and can achieve long-term service life.

2. Vibration absorption performance
The air conditioning insulation pipe will be subjected to vibration and impact in the actual use process, so the material needs to have good vibration absorption performance, which can reduce the oscillation of the pipeline system.

3. Breaking strength
The fracture strength of air-conditioning insulation pipe is an important index of material reliability. The material needs to have high fracture strength and be able to bear certain loads during construction and use.

6. purchase suggestions and precautions
1. Selection of materials
Comprehensive consideration of the above indicators, according to the actual engineering situation to select the appropriate material. Polyurethane material has many advantages such as low cost, good thermal insulation performance and good anti-aging performance, which is an ideal choice at present.

2. Qualification of construction personnel
The quality of the air conditioning insulation pipe is not only related to the material selection, but also closely related to the technical level of the construction personnel. Therefore, when purchasing air-conditioning insulation pipes, it is necessary to take into account the qualifications of the construction team and choose a team with construction experience for construction.

3. Requirements for project warranty period
The warranty period of air conditioning insulation pipe materials shall meet the requirements of national standards, and the length of the warranty period of materials shall be paid attention to when purchasing. Material warranty period is too short will bring some trouble to the later maintenance.

4. Comparison of cost and value for money
In the process of purchasing, it is necessary to comprehensively consider the cost and cost performance, and select the appropriate air conditioning insulation pipe material according to the actual situation.

7. Conclusion
In short, the performance of air conditioning insulation pipe materials and purchase guidelines need to consider a number of indicators. When selecting materials, reasonable selection should be made according to the actual engineering situation. Generally speaking, polyurethane material has many advantages such as good thermal insulation performance and good anti-aging performance, which is an ideal choice at present.