1. What material is the non-metallic compensator made of? Let's start with the conclusion: Not all non-metals are afraid of fire
When many people hear the word "non-metal", they automatically associate "plastic", "rubber" and "flammable" in their minds. This idea needs to be corrected quickly. Non-metallic compensator-to be precise, the one on our websiteNon-metallic expansion joint (fabric fiber expansion joint)— — The main material is a composite layer of high-strength glass fiber cloth, silicone rubber coated cloth and polytetrafluoroethylene film. Glass fiber itself is a Grade A non-combustible material with a melting point of more than 1000°C. What is really likely to burn is the rubber coating on the surface or the PTFE for sealing-but neither is at once. Silicone rubber is a flame-retardant material, which extinguishes itself from fire; Polytetrafluoroethylene (PTFE) is virtually nonflammable and only breaks down toxic gases in extreme heat. Therefore, the answer to the question "Can a non-metallic compensator catch fire?" depends on where it is used, at what temperature, and what medium it contacts. Think about it, if the material itself could be burned, then the thousands of degrees of smoke in the flue of the power plant would have set it on fire long ago, and it would have lasted for decades?
Second, under which working conditions the non-metallic compensator may indeed burn? Don't take any chances, these cases are worth watching
Seriously, the most common fire scenario for non-metallic compensators is the flue gas duct. For example, desulfurization system, cement kiln tail, power station flue and other places. The smoke often carries unburned sparks, oil mist or pulverized coal. Two days ago, a customer from a cement factory called and asked,Rectangular non-metallic expansion jointWill it burn through? I asked him if there were any sparks in the pipes and he said that the electrostatic precipitator occasionally ignites. This is dangerous. Once the surface coating of the fabric is continuously burned by high-temperature sparks, the silicone rubber will carbonize. Then, although the glass fiber cloth does not burn, it loses its sealing performance, the smoke leaks out, the temperature is higher, and finally the whole compensator will be scrapped. Another situation is that there is a leakage of flammable media in the pipeline. For example, the tail gas of chemical plants contains benzene steam, which may ignite when it touches high-temperature surfaces. Remember one sentence: the non-metallic compensator is not a source of fire itself, but it is a "carrier of combustion support"-if its surface is stained with oil and coal tar, it is equivalent to providing fuel for the fire. And guess what? At the end of many fire accidents, they were not burned by the compensator itself, but the ash and oil accumulated around them were ignited.
3. How do manufacturers prevent fires? Flame retardant coating, multi-layer structure, plus explosion-proof layer
Since there are risks, regular manufacturers must have countermeasures. When we make non-metallic expansion joints, we will select materials according to the medium temperature and composition provided by customers. For high-temperature flue gas pipelines (above 400℃), the structure of "ceramic fiber cloth + stainless steel wire mesh reinforced layer" is generally adopted. The refractory temperature of ceramic fiber can reach 1260℃, and it is okay to directly fight the flame. In the case of spark shock, the non-metallic compensator will be covered with a metal protective net or a metal skin-this is actually a bit like the one on our websiteHigh temperature axial expansion jointThe idea is that the high-temperature axial type is pure metal, and the non-metal type is only used as an inner liner. In addition, fluororubber or PTFE coating itself has good flame retardancy, which meets the fire protection requirements in JB/T 12235-2015 standard. Another point: when installing, it is necessary to ensure that no combustible materials, such as oil rags and cables, accumulate around the compensator. This is a problem of on-site management, but many accidents are precisely here. We often tell customers: You bought a fireproof compensator, and as a result, there is a pile of pulverized coal piled around, which is the same as not buying it.
Fourth, the easiest pit for users to step on: confusing rubber compensator and fabric compensator
We have a product list on our siterubber compensatorAndRubber PTFE compensator, there are alsoNon-metallic expansion joint (fabric fiber expansion joint)。 Although they are all classified as non-metals, the temperature resistance grade is much worse. The continuous working temperature of ordinary rubber compensators (such as nitrile rubber and neoprene rubber) generally does not exceed 120℃, and the instantaneous temperature resistance may reach 150℃. Beyond this temperature, the rubber will soften, decompose and even burn. However, the temperature resistance range of fabric fiber expansion joint (non-metallic expansion joint) is usually between 200℃ and 650℃, and it can be higher if the right model is selected. Therefore, if the user uses a fabric compensator in low-temperature pipelines (such as air-conditioning water systems), it is overqualified; But if a pure rubber compensator is used on a steam pipe at 300℃, it is a joke with your life. Before, a customer consulted, saying that the temperature of their flue gas pipe was only 180℃, and they used a rubber PTFE compensator. As a result, it burned through half a year later. Only after asking did I know that the actual temperature fluctuation peak of the pipeline reached 220℃, and the rubber layer had been carbonized. Therefore, when selecting the model, you can't only look at the average value, but also the peak temperature, duration and whether there are sparks in the medium. Is that the case?
5. Fire prevention starts from type selection: collect these three hard indicators
First, it is necessary to clarify the maximum operating temperature, instantaneous overtemperature temperature and frequency of the pipeline. If it is smoke with Mars, skip the rubber directly, choose a fabric fiber compensator and add a metal explosion-proof layer. Second, see if the compensator has flame retardant certification. The national standard JB/T 12235-2015 has clear requirements for the combustion performance of non-metallic expansion joints, such as oxygen index and horizontal combustion grade. On our stationRectangular non-metallic expansion jointAndNon-metallic expansion joint (fabric fiber expansion joint)Proof of flame retardant rating can be provided on demand. Third, don't ignore the installation environment. If the compensator is installed outdoors or has corrosive gases, the surface coating will age and the flame retardancy will decrease, requiring regular inspection and replacement. To put it bluntly, the deciding factor in whether a non-metallic compensator can catch fire is not whether there is "non-metallic" in the name, but whether you have put the right product in the right place. Choose right, it can hold thousands of degrees of high temperature; If you choose the wrong one, tens of degrees of oil fume can light it.