Many people may have encountered the situation of freezing and cracking PE pipes in winter - when they woke up in the morning, they unscrewed the faucet and ran out of water. When they got closer, they saw that the pipeline was bulging, and even cracked directly. This not only affected the daily water use, but also had to knock on the wall and dig the ground for maintenance, which was expensive and troublesome. In fact, these are all pots that have not been well insulated. Although PE pipes are corrosion-resistant and tough, their low temperature resistance is limited. When the ambient temperature is lower than 0 ° C, the water in the pipe freezes and expands, and it is easy to burst the pipe; even if it is a hot water pipe, it will quickly lose heat without insulation, resulting in a drop in water temperature and affecting the use. So how should PE pipes be kept warm? Today, I will explain the practical methods and precautions at one time.

1. Thermal insulation material wrapping method (the most basic and most commonly used)

This is the most common thermal insulation method in households and small projects. The core is to "wrap" the pipeline with thermal insulation materials to block the contact of cold air outside. There are three commonly used materials:

- Rubber and plastic sponge: soft and elastic, with its own stickiness, the construction is super simple - just measure the diameter of the pipe, cut it to the right size, wrap it directly on the pipe, align the seams with tape and stick it firmly. Its waterproof performance is very good, even if it is damp, it will not reduce the thermal insulation effect, suitable for hot and cold water pipes in humid environments such as bathrooms and balconies.

- polyethylene foam (EPE): high density, small thermal conductivity, thermal insulation effect is better than rubber and plastic sponge, the disadvantage is poor elasticity, need to be fixed with tape or clamp, suitable for industrial pipes or pre-treatment before burying.

- Glass wool: high temperature resistance (can withstand temperatures above 100 ° C), suitable for hot water pipes or industrial high temperature pipes, but its fibers are easy to get rid of, wear gloves during construction, and must do a moisture-proof layer (such as a layer of aluminum foil), otherwise the thermal insulation effect will be greatly reduced after water absorption.

#2. Electric heat tracing system (essential in extremely cold areas)

If the temperature in the area is often lower than -10 ° C in winter, ordinary thermal insulation materials may not be enough, this time you have to use electric heat tracing. The principle is very simple: wrap the electric hot wire on the surface of the PE pipe to generate heat through the current and maintain the temperature of the pipeline above 0 ° C. Three points should be paid attention to during installation: ① The electric hot wire should be spirally wound to cover the entire pipe surface to avoid local overheating; ② Wrap it with thermal insulation materials (such as rubber and plastic sponges) after winding to reduce heat loss; ③ The electric heat tracing system should be equipped with a temperature controller to avoid damage to the pipeline due to excessive temperature.

#3. Buried thermal insulation method (suitable for outdoor buried pipelines)

If the PE pipe is buried underground, in addition to meeting the "burial depth exceeding the local permafrost layer" (generally buried below 1.2 meters in the northern region), thermal insulation materials should also be filled around the pipeline. Commonly used fillers are foam concrete, perlite or foamed polyethylene - these materials block the conduction of cold energy in the soil, while acting as a buffer to prevent the pipeline from being crushed by heavy objects. It should be noted that before burying the pipeline, a waterproof film should be wrapped to prevent the moisture in the soil from penetrating into the insulation layer.

Second, how to choose the insulation material? 4 key indicators

choose the right material is half of the success of insulation, focusing on these 4 points:

- thermal conductivity: the smaller the value, the better (generally 0.04W/(m · K)), such as rubber sponge thermal conductivity of about 0.034, thermal insulation effect is better than glass wool (0.04);

- waterproof: PE pipe is afraid of water, thermal insulation material must be moisture-proof (such as rubber sponge is a closed cell structure, will not absorb water), otherwise once damp, thermal conductivity will double, thermal insulation is equal to white;

- temperature resistance: hot water pipe to choose high temperature resistant material (such as glass wool can carry 120 ℃), cold water pipe to choose conventional temperature resistance (-20 ℃~ 50 ℃) on the line;

- construction convenience: family use choose its own sticky rubber Plastic sponge, no additional tools; industrial use can choose prefabricated insulation pipes, directly on the pipeline, saving time.

Third, construction precautions: details determine the effect

Even if the right materials are selected, the construction will fall short if it is not done well. These points must be noted:

1. Pipeline pretreatment: wipe the pipeline clean before wrapping - oil, dust will affect the viscosity of the insulation material; if the pipeline is cracked or damaged, it must be repaired with PE electrodes first, otherwise the insulation layer will leak;

2. Seamless fit: When wrapping the material, align the seams, and do not leave gaps (for example, the seams of rubber and plastic sponges should be cut into 45 oblique angles, and glued with tape after docking); elbows and valves should be cut and wrapped separately to avoid leakage;

3. Fix firmly: use special aluminum foil tape or stainless steel clamp to fix the insulation layer, do not use ordinary transparent glue - it will age and fall off over time;

4. Acceptance inspection: After construction, take a closer look: Is the insulation layer damaged? Is the seam cracked? Is the electric heating circuit exposed? Especially for outdoor pipes, a layer of tarp should be wrapped to prevent wind and rain.

In fact, PE pipe insulation is not as complicated as imagined. As long as you choose the right method according to your own scene (such as rubber and plastic sponge for home use, electric heat tracing in extremely cold areas), choose the right material, and pay attention to details in construction, you can completely solve the problem of freezing cracking and heat loss. After all, taking some time to do insulation is better than climbing ladders to repair pipes in winter - do you think so?