Features

High installation location: Elevated ducts are generally installed at the top of buildings, above ceilings, or on steel structures at high elevations to provide ventilation or air conditioning coverage for specific areas.

Efficient use of space: It can deliver air to the required areas without occupying floor space. This is particularly important for places with limited space, such as industrial plants, large warehouses, and gymnasiums, as it can effectively utilize vertical space and improve space utilization.

Long air delivery distance: Due to the high installation position, the air duct can utilize natural air flow and pressure differences to deliver air over long distances, thereby achieving large-area ventilation or air conditioning coverage.

Aesthetically pleasing: Elevated ductwork is typically installed at a height where it is not easily visible to people, thereby minimizing its impact on the appearance of the building and keeping the interior neat and attractive.

High construction difficulty: Installation at high altitudes requires specialized high-altitude work equipment and technical personnel. Safety issues must be addressed during construction, which also increases the difficulty and cost of construction.

Maintenance inconvenience: Due to its elevated position, maintenance personnel need to use professional climbing equipment to perform repairs, maintenance, and other tasks, which increases the difficulty and cost of maintenance and places higher demands on the skills and safety awareness of maintenance personnel.

application scenarios

Industrial plants: Used to remove exhaust gases, dust, and heat generated during production, provide fresh air, improve the working environment, protect workers’ health and safety, and also help protect equipment and improve production efficiency.

Large warehouses: such as automated multi-level warehouses, which can control the temperature and humidity of different areas within the warehouse to ensure proper storage conditions for goods and prevent them from becoming damp, moldy, or spoiled.

Commercial buildings: such as shopping malls, supermarkets, shopping centers, etc., used to regulate indoor air temperature, humidity, and air quality, providing customers and employees with a comfortable shopping and working environment.

Sports venues: Able to meet the ventilation and air conditioning needs of large numbers of spectators and athletes in sports venues, ensuring fresh air and comfortable temperatures inside the venue, thereby enhancing the spectator experience and the competitive performance of athletes.

Transportation hubs: such as train stations and airports, can effectively regulate the air environment in areas such as lobbies, waiting rooms, and waiting areas, providing passengers with a comfortable waiting space.

Installation points

Construction plan formulation: Based on the specific conditions of the construction site, including building structure, duct installation location, height, quantity, specifications, and models, formulate a detailed construction plan, clarify construction objectives and construction sequence.

Safety measures: Set up safety warning signs at the construction site, cordon off the construction area, and prevent non-construction personnel from entering. Set up a suitable aerial work platform, ensure that the platform legs are evenly distributed, install guardrails and anti-slip boards, and set up safety nets below the work platform.

Duct inspection and hoisting: Inspect the ducts before construction to ensure that they are free of damage, deformation, and other issues. Set hoisting points based on the length and weight of the ducts, generally at both ends and in the middle, and use special lifting lugs to secure them firmly. During hoisting, a designated person should be in charge to ensure that the ducts are lifted vertically and do not hit nearby obstacles.

Duct connection and sealing: Align the duct ends and ensure that the interface is flat and straight. Use sealing tape, sealant, or flanges to seal the duct system and prevent air leakage. For duct bends and diameter changes, use special elbow components and diameter change pipes, and pay attention to the sealing of the interface.

Installation Quality Inspection: After installation is complete, inspect the installation quality of the ductwork section by section, including whether the ductwork is straight, whether the connections are secure, and whether there are any air leaks. Use professional testing instruments to conduct airtightness tests, airflow and air velocity tests, etc., on the ductwork system to ensure that it meets design requirements.

In the chemical and electroplating industries, the production process often produces various gases with strong corrosive properties, such as sulfuric acid, hydrochloric acid, sodium hydroxide, etc. PP ducts can easily cope with these “acid and alkali attacks” by virtue of their excellent chemical resistance. In the sulfuric acid plant, PP ducts are used to transport high concentration of sulfuric acid vapor, and after a long time of use, the inner wall of the ducts is still smooth as before, without the slightest trace of corrosion. While the traditional metal duct, in the same environment, may be just a few months will appear serious corrosion, resulting in pipe leakage, not only affect the production, but also may bring potential safety hazards. According to relevant data, in the chemical industry, the use of PP duct equipment maintenance frequency than the use of metal duct equipment reduced by more than 50%, greatly improving production efficiency.

(ii) Sealing: “zero air leakage” guarantee

PP ducts are connected by heat fusion connection, flange connection and many other advanced connection methods. These connection methods can ensure that the ducts are tightly bonded to each other and realize “zero leakage” of air. In hospital operating rooms, good sealing is crucial. If there is leakage in the ventilation system, it will not only affect the air quality in the room, but may also lead to an increased risk of surgical infections. the excellent sealing of PP ducts can effectively prevent the leakage of harmful gases, providing a safe and clean environment for patients and healthcare workers. In industrial production, for some processes that require high gas purity, such as electronic chip manufacturing, the sealing of PP air ducts can ensure that the production environment is not interfered by external impurities, ensuring the stability of product quality.

(iii) Low noise: quiet ventilation system

PP material has good damping properties, which is the key to its noise reduction. As air flows through the duct, the PP material absorbs and attenuates sound waves, thus reducing the transmission of noise. Compared with metal ducts, PP ducts are significantly quieter in operation. According to professional tests, under the same conditions of air speed and air volume, the operation noise of metal ducts can be over 60 dB, while the noise of PP ducts can be controlled at about 40 dB, which is about 30% lower. In hospital wards, school classrooms and other noise-sensitive places, PP ducts can provide a quiet and comfortable environment, which is conducive to the recovery of patients and students’ learning.

(iv) Thermal insulation: energy saving and comfort

PP ducts can be equipped with specialized insulation, which effectively reduces heat loss. This feature is especially important in HVAC systems. In winter, PP square ducts with insulation can better retain heat in the room and reduce the energy consumption of heating equipment; in summer, it can prevent cold air from escaping and reduce the power consumption of air conditioning. Comparisons of real-world examples show that buildings with insulated PP ducts use 15% – 20% less energy for their HVAC systems than buildings with ordinary ducts. This not only saves energy costs for users, but also helps to reduce carbon emissions and realize green environmental protection.

(v) Long life: durable

PP material ages slowly, mainly due to its stable molecular structure and good chemical stability. Under normal operating conditions, PP ducts have a practical service life of 30 – 50 years. In some large industrial plants, PP ducts have been in continuous use for more than 30 years and are still performing well and do not need to be replaced. From a long-term cost perspective, although the initial investment in PP ducts may be slightly higher than some common ducts, the overall cost is lower due to their long service life and low maintenance costs. For example, while metal ducts require regular anti-corrosion treatment and repairs during use, PP ducts require little or no such additional costs, greatly reducing the operating costs of the enterprise.

In the ventilation system of all kinds of buildings, the suitability of air volume and duct size is crucial, which is directly related to the ventilation effect, energy consumption and the stability of the operation of the whole system. Imagine a large shopping mall or factory, if the ventilation system duct size is unreasonable, either can not meet the indoor ventilation needs, resulting in dirty air, stuffy, affecting people’s comfort and work efficiency; or will cause energy waste, increase operating costs. Today, we focus on a specific problem: when the air volume is 20000, how big should the air duct be? This seemingly simple question involves a series of complex calculations and consideration of various factors. Let’s dig deeper and solve the mystery for you.

二.Duct Basics

(1) Role of air ducts

Duct, as a key component of the ventilation system, undertakes the important mission of conveying and distributing air . In the ventilation system, it is like the trachea in the human body’s respiratory system, which is the channel for air circulation. Fresh air is introduced into the room through the air ducts to provide people with sufficient oxygen and maintain a comfortable indoor environment; at the same time, indoor dirty air, harmful gases, and excess heat and moisture, etc., also rely on the air ducts to be discharged outdoors to ensure indoor air quality and hygiene. For example, in the operating room of a hospital, the air duct continuously sends in purified sterile air and discharges the exhaust air that may carry germs to create a safe air environment for the smooth operation; in the factory workshop, the air duct can timely discharge the dust, smoke and other harmful pollutants produced during the production process to protect the health of the workers.

（2）Classification of air ducts（Classified by cross-section shape）

• Round Duct: Round duct has superior aerodynamic performance, air flows in it with minimum resistance, which makes the round duct can effectively reduce the energy consumption of the fan under the same air volume, and the operation cost is lower. At the same time, it has good sealing performance, which can reduce air leakage and ensure the efficient operation of the ventilation system. Circular air ducts are widely used in places with high ventilation requirements and where space permits, such as the central air conditioning ventilation system of large shopping malls. However, the production process of round air duct is relatively complicated and occupies a large space height, so the installation may be restricted in some buildings with limited space.

• Rectangular Duct: The biggest advantage of rectangular duct is that it can better adapt to the building structure and combine closely with the walls and ceilings of the building, which makes it easy to install and layout. In most office buildings, residential and other places, due to the characteristics of the space layout, rectangular duct is more common. It is relatively simple to fabricate, and the fittings are easy to make and connect. However, the air resistance of rectangular duct is relatively large, in the case of conveying the same amount of air, it requires a more powerful fan, and the energy consumption will increase accordingly, and its air leakage rate is relatively high.

• Flat round duct: Flat round duct combines part of the characteristics of round duct and rectangular duct, it reduces the height size of round duct to some extent, and less resistance than rectangular duct. In some of the space height has some limitations, but also on the ventilation resistance requirements of the occasion, such as some of the lower level underground parking lot ventilation system, flat round air duct can play its advantage. However, the production difficulty of flat round duct is between round and rectangular duct, the application scope is relatively narrow.

Polypropylene is a high-density, side-chain-free, high-crystalline linear polymer with excellent comprehensive properties. Common products: basins, barrels, furniture, films, woven bags, bottle caps, car bumpers, etc.

pp plastic, chemical name: polypropylene, English name: Polypropylene (abbreviated as pp) specific gravity: 0.9-0.91 g/cm3, molding shrinkage: 1.0-2.5%, molding temperature: 160-220 °CPP is a crystalline polymer, and the comprehensive performance of PP is better than that of PE material. PP products are lightweight, tough and chemically resistant. The disadvantages of PP: low dimensional accuracy, insufficient rigidity, poor weather resistance, it has the phenomenon of post-shrinkage, and after demoulding, it is easy to age, become brittle and easy to deform. In engineering projects, the commonly used air duct is made of PP material.

In the PP material inside the high-purity propylene as the main material, including a small amount of ethylene copolymer, after drying, mixing, extrusion, granulation, screening and homogenization into polypropylene particles, this particle is cylindrical particles, the particles are very smooth, without any mechanical impurities, it has good mechanical properties and heat resistance, in the temperature range of minus 30 degrees Celsius to 140 degrees Celsius is not toxic.

Mechanical properties PP has high crystallinity and regular structure, so it has excellent mechanical properties. However, at room temperature and low temperature, the impact strength is poor due to the high regularity of its molecular structure. The most outstanding performance of PP is its resistance to flexural fatigue.

Chemical stability PP has good chemical stability, in addition to being eroded by concentrated sulfuric acid and concentrated nitric acid, it is relatively stable to various other chemical reagents; However, low molecular weight aliphatic hydrocarbons, aromatic hydrocarbons and chlorinated hydrocarbons can soften and swell polypropylene, and its chemical stability is improved with the increase of crystallinity, so PP is suitable for making various chemical pipes and fittings, and the anti-corrosion effect is good.

Electrical properties PP has excellent high-frequency insulation properties, and since it hardly absorbs water, the insulation properties are not affected by humidity. It has a high dielectric coefficient, and with the increase of temperature, it can be used to make heated electrical insulation products. It also has a high breakdown voltage, making it suitable for use as an electrical accessory, etc. It has good voltage resistance and arc resistance, but has a high degree of electrostatic electricity. Due to the presence of the side methyl group in PP, tertiary carbon atoms alternately appear on the molecular chain, and the tertiary carbon atoms are very easy to oxidize when in contact with copper ions, resulting in poor oxidation resistance and radiation resistance of polypropylene. Therefore, copper inhibitors must be added in applications that come into contact with copper.

The performance can be changed through additives: PP can change its performance by adding various fillers, plasticizers, antistatic agents, etc., so that it has the characteristics of flame retardant, antistatic, antibacterial, and reinforcing. For example, adding glass fiber can enhance the rigidity and strength of PP, adding carbon black can make PP have anti-ultraviolet and antistatic properties, adding antioxidants can extend the service life of PP, etc.

Physicochemical properties

1. Odorless, tasteless and non-toxic. It is one of the lightest resins commonly used;

2. Excellent mechanical properties, including tensile strength, compressive strength and hardness, outstanding rigidity and bending fatigue resistance, the movable hinge made of PP can withstand more than 7 × 10 to the power of 7 folds and bends without breaking, and the impact strength is poor at low temperatures. The tensile strength of PP is generally 21-39 MPa; The flexural strength is 42-56 MPa, the compressive strength is 39-56 MPa, the elongation at break is 200%~400%, the notched impact strength is 2.2-5 kJ/m2, and the low-temperature notched impact strength is 1-2 kJ/m2. Rockwell hardness R95~105;

3. Good heat resistance, continuous use temperature up to 110-120°C;

4. Good chemical stability, except for strong oxidants, it does not interact with most chemicals; The solvent cannot dissolve PP at room temperature, only some halogenated compounds, aromatic hydrocarbons and high boiling point aliphatic hydrocarbons can make it swell, and the water resistance is particularly good;

5. Excellent electrical properties, good resistance to high-frequency electrical insulation, and good electrical insulation in humid environments;

6. Since there are many tertiary carbon atoms with methyl groups on the backbone of PP, the hydrogen on the tertiary carbon atoms is susceptible to oxygen attack, so the weathering resistance of PP is poor, and antioxidants or ultraviolet absorbers must be added

7. Mice were gavaged 1~5 times at a dose of 8g/kg, and no obvious poisoning symptoms were caused. The decomposition products of polypropylene heated to 210~220 °C were inhaled 30 times for 2 hours each time, and the symptoms of ocular mucosa and upper respiratory tract irritation appeared. As with polyethylene, it is forbidden to use its recycled products for food.

Polypropylene modification

In view of the poor impact resistance, poor weather resistance, poor surface decoration of polypropylene at low temperatures, and the gap between the functionality and actual needs in electricity, magnetism, light, heat, combustion, etc., the polypropylene has been modified, which has become the most active and fruitful field in the current plastic processing development.

• PP chemical modification

Through copolymerization modification, cross-linking modification, grafting modification, adding nucleating agent, etc., the polypropylene polymer components and macromolecular structure or crystal configuration are changed to improve its mechanical properties, heat resistance, aging resistance and other properties, improve its comprehensive properties, and expand its application fields.

(1) Copolymerization modification

Copolymerization modification is the modification of propylene monomer synthesis stage by using catalysts such as metallocene. When the monomer is polymerized, the added olefin monomer is copolymerized with it, and the random copolymer, block copolymer and alternating copolymer are polymerized, and the mechanical properties, transparency and processing fluidity of homopolymer PP are improved. The complexes formed by metallocene catalysts are used as a single active center in a transition state with a certain restriction of irregular shape, so as to achieve precise control of the relative molecular weight and its distribution, comonomer content, distribution on the backbone and the crystal structure of the polymer.

(2) Grafting modification

The PP (polypropylene) resin molecule has a non-polar crystalline linear structure, low surface activity, and no polarity. Poor surface printability; Poor coating and adhesion; Difficult to blend with polar polymers; Disadvantage that it is difficult to be compatible with polar reinforcing fibers and fillers. Graft modification is to introduce polar groups to its macromolecular chain to improve the blendability, compatibility and adhesion of PP, and to overcome the shortcomings of difficult blending, incompatibility and bonding. When the active free radical encounters the unsaturated carboxylic acid monomer, it promotes the unstable bond of the unsaturated carboxylic acid monomer to open and react with the PP active free radical to form the free radical, which is then terminated by the molecular chain transfer reaction. The common grafting modification methods of PP are: melting method, solution method, solid phase method, suspension method, etc. The hydrogen atoms in the grafted modified PP molecular chain are replaced and show strong polarity, and these polar groups enhance the compatibility of PP, and the heat resistance and mechanical properties are greatly improved.

PP flame retardant pipe and PVC pipe are both common pipe materials, and they each have unique advantages and application scenarios. PP flame retardant pipe is widely used in specific occasions due to its flame retardant performance and good durability, while PVC pipe is used in many fields due to its excellent corrosion resistance and low cost. When these two materials are connected, although they are connected in different ways (PP flame retardant pipes are usually connected by hot melt, while PVC pipes are connected by adhesive), they can be used together in practical use, especially in occasions where flame retardant properties are required, such as the protection of electrical circuits.

• Connection of PP flame retardant pipe: Since the PP flame retardant pipe adopts the hot melt connection method, this connection method ensures the firmness and tightness of the pipe connection, so as to ensure the safety and durability of the pipeline system. The hot melt connection melts the pipe end by heating it, and then quickly connects the two sections of pipe, which when cooled to form a strong connection.
• Connection of PVC pipes :PVC pipes are usually connected by adhesive, which is suitable for the connection of PVC pipes and fittings, which can provide a certain degree of tightness and durability. Adhesive connections require the use of specialized glue to apply glue to the ends of pipes and fittings, and then butt them to cure them under a certain pressure and time, thus forming a strong connection. Although PP flame retardant pipes and PVC pipes are connected differently, they can be used together in practical engineering applications, especially in occasions where flame retardant properties are required, such as the protection of electrical wiring. In addition, if you need to make a connection between PP flame retardant pipe and PVC pipe, you can consider using a special PP adhesive PVC plastic glue, which can effectively solve the bonding problem between these two materials, provide strong adhesion and firmness, and can maintain its performance and quality for a long time in different temperature environments

PP flame retardant air duct and PPH air duct

With its excellent corrosion resistance and mechanical properties, PPH pipes are widely used in chemical industry, environmental protection and other fields. Both materials can be joined by hot melt welding, including hot plate welding, hot air welding, and hot melt butt welding, which allows them to be flexibly combined in practical applications.

• The properties of PP flame retardant pipe make it ideal for fireproof occasions. It has good flame retardant properties, which can effectively stop the spread of flames and protect the safety of people and property.

• PPH pipes are known for their excellent corrosion resistance, wear resistance and high temperature resistance, and are suitable for chemical, electronics, pharmaceutical factories and other fields. The β modification of PPH tubing gives it a uniform and delicate Beta crystal structure, which improves its chemical resistance and mechanical strength.

Since both can be joined by the method of hot melt welding, this means that in engineering projects, PP flame retardant pipes and PPH pipes can be combined according to specific needs, and they can be joined together by welding technology to form a complete system. This combination not only increases the safety and reliability of the system, but also expands the range of applications for materials that meet the special needs of different engineering fields. In summary, PP flame retardant pipes and PPH pipes can be used together to achieve a seamless connection through hot melt welding technology, providing more options and possibilities for various engineering applications

The flame retardant performance of flame retardant PP material is mainly due to the addition of flame retardants. Flame retardant is generally a kind of combustible material processing products, with flame retardant, inhibition of combustion diffusion, flame retardant PP material added flame retardant can decompose a large number of inert gas, thereby reducing the temperature of the combustion area. At the same time, flame retardants can also consume oxygen in the combustion area, thereby inhibiting the combustion reaction.

Flame retardant PP material has good fire performance. When burned by an open flame, the flame-retardant PP material does not ignite, but automatically extinguishes the fire. This can effectively reduce the occurrence of fires and protect the safety of people’s lives and property. In addition, the amount of smoke produced by flame retardant PP material when burning is less, the smoke is white, and does not contain toxic and harmful substances, which reduces the secondary disaster caused by fire.

Flame retardant PP material also has good flame resistance properties. Due to the addition of flame retardants, its combustion performance is greatly reduced, and the combustion rate is slower. After a fire, it can give people a certain amount of time to escape and improve the survival rate of personnel. In addition, the flame-retardant PP material does not drip when burned, preventing the expansion and spread of the fire.

Flame retardant PP material has a wide range of applications. First of all, in the construction field, flame-retardant PP materials can be used in building materials such as walls, roofs and floors, improving the fire safety of buildings. Secondly, in the field of electronics, flame-retardant PP materials can be used as insulating materials for wires and cables to effectively prevent accidents caused by fires caused by wires and cables. Finally, in the field of electric power, flame-retardant PP materials can be used in the shell and wiring harness of power equipment, etc., to improve the safety of power equipment.

In the industrial field, PP flame retardant materials are widely used in electrical equipment, auto parts, building materials and other fields. In electrical equipment, PP flame retardant materials can effectively improve the safety performance of equipment and reduce the occurrence of fire accidents. In auto parts, PP flame retardant materials can effectively improve the safety performance of automobiles and protect the lives of passengers. Among building materials, PP flame retardant materials can effectively improve the fire performance of buildings and reduce the damage to buildings caused by fire accidents.

In daily life, PP flame retardant materials are widely used in home appliances, furniture, toys and other fields. In household appliances, PP flame retardant materials can effectively improve the safety performance of household appliances and protect the lives and property safety of consumers. In furniture and toys, PP flame retardant materials can effectively improve the fire performance of products and protect the lives and property safety of users.

All in all, PP flame retardant material is a material with good flame retardant properties and mechanical properties, which plays an important role in the industrial field and daily life. With the continuous improvement of people’s requirements for safety performance, PP flame retardant materials will be more widely used, bringing more convenience and safety to the development of society and people’s lives.

• PP Flame Retardant Fuel: This material adds a certain amount of flame retardant masterbatch to make the PP material achieve the effect of self-extinguishing from the fire. Flame retardant PP material is suitable for aerospace, chemical, electronic and electrical, machinery, automobile and railway industries, and is used to make machine parts with high strength, high temperature resistance and insulation with various high-performance requirements. The properties of flame retardant PP are affected by flame retardants and are more complex than ordinary PP. Almost all flame retardants will have a certain impact on the mechanical properties and melting index of PP, and if too many flame retardants are added, it may also lead to increased toxicity of products, and even cause serious pollution to the environment. Therefore, the selection of suitable flame retardant PP materials also needs to consider its performance and cost and other factors.

• PP material: This refers to polypropylene (PP for short) material, which is a semi-crystalline thermoplastic. It has the characteristics of thermoplasticity, light specific gravity, chemical corrosion resistance, etc., and is widely used in injection molded parts, pipes, films, fibers and other fields. Ordinary PP sheet is a semi-crystalline material with a high melting point and good heat resistance, but it is very brittle at temperatures above 0°C. In order to improve its properties, a certain proportion of ethylene is usually added for copolymerization to improve its impact strength and transparency.

About PP material

• Abbreviation for Polypropylene (PP). Together with polyethylene (PE), polyvinyl chloride (PVC) and polystyrene (PS), it is known as the four major general plastics. With the continuous progress of polymer modification technology, PP has shown better comprehensive properties than other general-purpose plastics, and its application is becoming more and more extensive. Electronic and electrical devices, auto parts, plastic pipes, films, fiber non-woven fabrics and other fields have traces of PP.
• There are many ways to classify PP, and the commonly used PP in the market can be boiled down to two types: homopolymer polypropylene (HOMO-PP) and copolymer polypropylene (COPO-PP). The molecular structure of homopolymer polypropylene is regular, high strength, and transparent or translucent particles, while copolymer polypropylene is milky white particles because of its structure containing ethylene components and good toughness.

About the performance modification of PP

• There are many ways to blend and modify PP, such as reinforcement, filling, toughening, flame retardant, electrical conductivity, coloring, etc., according to the different needs of the product, one or more functions can be superimposed to give PP excellent comprehensive properties.
• The oxygen index (the minimum oxygen concentration required to maintain its combustion under specified conditions) of PP is very low, only 18, so its positive combustion modification is a trend and inevitable. Flame retardants on the market: brominated flame retardants (decabromodiphenyl ether, decabromodiphenylethane, octabromoether, tetrabromobisphenol A, octabromoS ether, bromotriazine, hexabromocyclododecane, etc.), phosphorus-based flame retardants (coated red phosphorus, triphenyl phosphate, BDP, RDP, APP, MPP, etc.), nitrogen-based flame retardants (MCA, melamine, etc.), inorganic flame retardants (magnesium hydroxide, aluminum hydroxide, zinc borate, etc.), composite N-P intumescent flame retardants, etc., all have a certain flame retardant effect on PP. It is only because of the comprehensive cost, the flame retardant requirements of related PP products, and the shortcomings of the flame retardant itself that we must choose different flame retardants or composite flame retardant systems in different applications to meet the different needs of customers.

Differentiation of PP flame retardant materials

• The main difference between PP flame retardant materials is whether flame retardants are added or not
• The difference between PP flame retardant material and ordinary PP material is that flame retardant PP material is added in the production process, and these flame retardants are usually composed of bromine, oxygen, phosphorus, titanium, aluminum and other elements, which are designed to provide fire and flame retardant functionsThe presence of flame retardant makes the flame retardant PP material inhibit the open flame combustion and slow down the spread of the fire when it encounters the fire source, so as to achieve the purpose of fire controlThis material has been widely used in building materials, electronic appliances and other fields, because it can significantly improve the fire safety of products
• In addition, the flame retardant effect of PP flame retardant material not only depends on the type of flame retardant added, but also affects the proportion of flame retardant addedDifferent flame retardants have different properties and costs, and the selection of suitable flame retardant PP materials needs to consider their performance and cost and other factorsFor example, the fire resistance grade of PP flame retardant board is usually B1 grade, and some can reach A2 grade, depending on its production process and the amount of flame retardant addedThe addition of flame retardant will also affect the mechanical properties and melt index of PP materials, so it is necessary to weigh their fire performance and possible environmental impact when using flame retardant PP materials
• To sum up, the difference between PP flame retardant materials and ordinary PP materials lies in whether flame retardants are added, as well as the type and amount of these flame retardants, which together determine the fire performance and safety level of the material

PP air duct flame retardant grade classification

The flame retardant grades of PP air ducts mainly include A, B1, B2 and B3

• Grade A: Indicates non-combustible material, barely combustible
• B1 grade: It is a flame-retardant material, with a good flame retardant effect, it is not easy to spread quickly in case of fire, and it can be extinguished by itself after leaving the fire source
• Class B2: It is a combustible material with a certain flame retardant effect, but it is still a flammable material
• Class B3: It is a flammable material, has no flame retardant effect, and is extremely flammable.
• PP flame retardant ducts should generally achieve a fire rating of at least B1 to ensure that the spread of fire can be slowed down in the event of a fire, providing more time for personnel evacuation and extinguishing the fire.In addition, for the fire rating of plastics, there is also the UL-94 flame retardant plastic standard, in which the flame retardant grade is divided into HB, V2, V1, V0, 5VB, 5VA, etc., these grades are divided according to different test standards to divide the flame retardant performance of materials.For example, a V0 rating indicates that the material has high flame retardant properties, and the flame is extinguished within 30 seconds after two 10-second burn tests, and no combustibles can fallThe V2 rating indicates that the material has certain flame retardant properties, and after two 10-second burn tests, the flame is extinguished within 60 seconds, and some combustibles can fall.
• To sum up, the flame retardant grade classification of PP air duct not only considers the combustion characteristics of the material, but also covers the detailed definition and test standards of different grades to ensure that the material can play an effective flame retardant role under specific conditions