The electric heating film heating system is composed of: electric heating diaphragm, T-type cable, insulated waterproof quick plug, thermostat and temperature sensor, automatic control reactor and other components. Although electric film electric floor heating has many advantages, there has been no relevant application regulations. In contrast, the heating cable already has the "Air Radiant Heating Technical Regulations" that all manufacturers must abide by. However, each electric heating film manufacturer can only adopt the application procedures of the enterprise version or local application procedures. What is more worrying is that most domestic electric heating film consumer manufacturers do not have the conditions for floor heating system design and construction, nor do they cooperate with relevant enterprises to discuss the construction process and daily maintenance measures suitable for their products, but they are eager to push their products to floor heating projects. Many technical leaders of enterprises even equate the leakage current of the electric heating film with leakage, and ridiculously claim that their product insulation is well done and there is no leakage current. Individual provincial electric heating film application specifications under the influence of electric heating film enterprises clearly stipulate that electric heating film can be maintained without insulation grounding and leakage. As everyone knows, only the metal shielding structure formed on the surface of the electric heating film can be used for wet paving methods such as tiles and marble floors. After some electric heating film manufacturers launched self-limiting temperature products, many manufacturers also followed the trend of publicity. If so many safety hazards cannot be limited from the national industry norms as soon as possible, I am afraid that it is not far off to present a chaotic situation similar to electric heating film ceiling heating, and its serious level may be even greater. If such problems occur, it will undoubtedly affect the reputation of the entire electric floor heating industry.
Issues that are not clear in the specification but seriously threaten the quality of construction
1. Local heat accumulation problem
Local overheating refers to the phenomenon that the electric floor heating system gradually accumulates heat and increases the temperature and produces certain hazards due to the poor heat transfer performance on the surface of the decorative layer during use, such as quilts, large floor-to-ceiling furniture, etc. Although the instruction manual of the electric floor heating system usually has instructions such as "prohibit large-scale coverage during use", it is difficult for users to completely avoid local overheating caused by coverage during use. Most manufacturers' electric heating film electric floor heating projects are not installed with overheating protection systems, and some manufacturers only install a metal fuse at one end of each electric heating film, which is difficult to really play the role of overheating protection.
(Some manufacturers advertise that their products have self-limiting temperature function and will not overheat, but this is not the case.) ）
2. Electrical safety issues
All types of electric heating films are surface electric heating bodies, and when the upper part is paved with cement mortar layer, a capacitive structure is formed and therefore an induced voltage and a corresponding capacitive leakage current are generated. The capacitive leakage current is related to the type of electric heating film and product structure, the conductivity of the electric heating film overlying material, the heating element area, the use voltage, the alternating current frequency and other factors, and its size can be calculated theoretically.
Capacitive leakage current is congenital and is not harmful, while leakage is a system failure and is harmful, such as leakage caused by poor sealing of terminal blocks caused by on-site wiring, leakage caused by system damage during use, etc. Safety grounding and leakage protection device is to ensure that the system will not be due to the failure of the electrical part of the safety hazards of important measures, its working principle is: due to the fault of leakage, leakage current through the system bonding layer in the metal mesh and equipotential connection into the earth, at the same time leakage protection device action, the power supply is cut off and give a signal in the control system, so as to ensure personal safety and give the system a prompt to facilitate fault handling. Without the above safety protection, even if the human body is attacked by leakage current, the power supply will not sense and power off.
The reality is that the vast majority of electric heating film manufacturers, including almost all imported brands, do not have complete electric heating film electric floor heating design and construction process specifications, and some even do not know the concept, generation mechanism and calculation method of electric heating film leakage current, but take risks and do electric floor heating without any safety protection measures.
Unfortunately, so far, there is no industry standard that deals with the provisions on "overheating protection, safe grounding and leakage protection", and large-scale electric heating film electric floor heating projects are constructed under the guidance of this regulation, which obviously has major safety risks. This is an unethical act that disregards the safety of customers' lives and property, and is even more harmful to the sustainable development of its own enterprise. Comparison of the development of electric heating film in various countries
In Japan, electric heating films have been used for floor heating for decades. Japan Equipment Design Office Association and Japan Floor Heating Construction Association jointly formulated the "Floor Heating Design and Construction Guidelines", which has clear provisions and requirements for the insulation level of heating elements, wiring requirements, overheating protection, number of overheating protectors per unit area, design and construction and acceptance standards, etc., and Japan will implement new standards in 2008, which has clear quantitative requirements for electromagnetic radiation. The process of making electric heating film into "electric tatami" by various Japanese manufacturers has gradually become the mainstream. It should be pointed out that there are no printing ink-type electric heating film manufacturers in Japan, and there are no relevant case reports in floor heating applications.
In South Korea, the demand for electric heating film floor heating is also growing rapidly.
In China, the use of electric heating film for heating was in the 90s of the 20th century, mainly printing ink-type electric heating film for ceiling heating. However, many projects of ceiling heating have problems such as indoor temperature not meeting design requirements and high operating costs in the application process, and users frequently complain, resulting in many legal disputes. At the same time, it has also led to many developers and building heating designers questioning and losing confidence in electric heating film products. Regardless of the heat transfer mechanism and the biological function of the human body to feel the temperature, ceiling heating is not a scientific heating method, plus most of the buildings at that time were not energy-saving buildings, and most of the heat had been lost before reaching the human body, so most of the project failure was an inevitable result.
With the rapid development of domestic floor heating, electric heating film heating environmental protection, easy behavior energy saving and other advantages will be more prominent than water floor heating, as long as the electric heating film manufacturers practice good internal strength, solve the technical problems of the electric heating film heating element itself, strictly implement the design standards, and establish a safe and complete construction process, do a good job in after-sales service, the market prospect of electric heating film applied to floor heating will be brighter.
At this stage, for electric heating film for floor heating, the state has just introduced standards.
Electric heating film is becoming more and more mature in floor heating projects. In the next few years, it will be a key stage in the development of the electric heating film floor heating industry.
