FIRE-RESISTANT CONVEYOR BELTS
Major mining losses from the last few years have shown that conveyor fires can cause significant damage and have a large impact to client's supply chain. Over the past seven years the industry has seen individual losses as high as USD 125m. (1) Sites must prioritize the protection of critical conveyors as only a short outage can generate very large Business Interruption impacts. FRAS conveyors belts can help reduce this risk but it is not the only means of protection.
FRAS conveyor belts - what are they?
Fire Resistant Anti Static (FRAS) conveyor belts are engineered so that the top and bottom covers of the conveyor belt meet local fire retardancy standards. This means these belts are difficult to ignite and should never be the cause of a fire. Additionally, if ignited by an external fire source, they should minimize the propagation of the fire. These conveyor belts are also Anti Static, meaning they provide electrical resistance to avoid the build-up of static electricity. FRAS conveyors belts allow more time for an existing protection system (fire detection/fire sprinklers) to respond. Flame spread can be reduced therefore increasing the effectiveness of the protection system. While FRAS belting can reduce fire exposure, it should not be relied on as the sole means of fire protection.
"Fire Resistant" not fire proof. The top and bottom covers of the conveyor belt can be engineered to meet local fire retardancy standards.
"Anti Static" provides electrical resistance to avoid the build-up of static electricity. Internationally recognised acceptance criteria is 3.0 x 108 Ohms.
There are a wide range of standards, so careful consideration must be taken when selecting a FRAS belt for your application.
Types of FRAS
There are many FRAS standards available to meet country standards and regulation. This paper refers to the European Norms (EN) as it is widely accepted but local requirements should always be adhered to.
Under EN12882 (for above ground belts) there are 10 FRAS categories offering a different degree of protection according to their application.
Under EN14973 (for underground installations) there are 5 categories available. For further information refer to Appendix 1 and 2.
FRAS belts used for underground coal are typically the highest standard C1 (EN14973).
Various industries do not only have a need for conveyor belts that are resistant to high temperatures, but also require a product that can actively extinguish or restrict fire. After all, fire can quickly cause damage at the location where it starts, and if not controlled in a timely manner, it can spread in no time and lead to explosions.
That is why fire-resistant conveyor belts are absolutely essential. Especially mining companies, power plants, and businesses in the steel, recycling, and cement industries, make ample use of the fire-resistant conveyor belt.
Noted:
Know your risks
Conveyors are designed to transport material, so they can also transport a flame. A conveyor can travel more than 40m in 15 seconds which coincides with the flammability test (EN/ISO 340) for FRAS conveyors.
Smoke detection can have a slow response time especially when air velocity is increased. A fire can then be transported a considerable distance before being detected.
Burning rubber can produce large amounts of black toxic smoke which can be particularly hazardous in underground environments.
Loss of a critical conveyor can have a large impact on a business due to the replacement time.
Intervention time is very important in controlling conveyor fires as high heat can quickly lead to conveyor structural collapse. As mentioned FRAS will buy you more time but will still ultimately burn.
FRAS can allow more time for an existing protection system (detection/sprinklers) to respond. Flame spread can be reduced therefore increasing the effectiveness of the protection system.
Ignition Sources
Restrict hot work and smoking. Use a formal hot work permit system when this activity is absolutely necessary.
Mechanical failure of drives, pulleys, scrapers, belt alignment and tracking can lead to localised heating and ignition.
A guide when considering a FRAS conveyor belt
1. Its application will depend on the material conveyed, conveyor structure, control interlocks in place and fire protection installed to control and therefore reduce the inherent risk to an acceptable level. Regulation and safety codes will also dictate how the use of FRAS conveyor belting is applied.
2. Is your material abrasive? As the belt cover wears so does the fire-resistant cover. ISO340 standard makes the distinction between fire resistance with covers (EN12882 Class 2A) and fire resistance with and without covers (EN12882 Class 2B). In the case of Class 2B grade (fire resistant without covers), the rubber skim should be thicker than the skim used for Class 2A grade belts.
3. Using the highest-grade FRAS is always preferred for added protection however this needs to be balanced with cost and wear characteristics.
4. All sites should consider conducting a risk assessment on their conveyor infrastructure and determine the necessary controls to put in place. The risk assessment should assess risk not only to people but also infrastructure. Controls should lower the residual risk to acceptable levels in accordance with company guidance and regulation.
5. Do you have the required mechanical protection (slippage, friction, misalignment, belt rip detection and pulley RTD's). And is it regularly checked and tested?
6. Are conveyors accessible for fire fighting and if not should more protection be added? FRAS conveyor belt when combined with fire protection can assist in lowering the risk.
7. Is the conveyor difficult to access - greater than 10 m from the ground or enclosed? The correct grade of FRAS conveyor belt when combined with fire protection can assist in lowering the risk.
8. Is the conveyor a production bottleneck with a production impact greater than 30 days? If so FRAS should be considered if fire protection is not provided to the length of the conveyor.
9. Retrofitting existing conveyor structures with FRAS must take into consideration the change in properties of the belt to ensure the structure is fit for purpose. FRAS belting can be higher in weight and have varying mechanical properties.
Testing : There are many standards but the basis of most tests for belting used in normal industrial application is EN/ISO340.
Gallery Test- Designed to replicate an enclosed conveyor and requires the belt to remain undamaged over a specified length.
Drum Friction Test -This is one of the most important tests designed to show how friction can ignite a belt. The test simulates a stalled belt and a driven rotating drum or pulley resulting in friction and heat build-up:
` Measured over a set time period
` Drum temperature is monitored
` Presence or absence of flame and glow is noted
Laboratory Flame Test- Testing to see if a mass of conveyor belt is ignited with a small ignition source (Bunsen burner). The time taken for all flame or glow to self-extinguish is noted.
Electrical Resistance Test -Possible build up and discharge of static electrical charge on moving conveyors. 3.0 x 108 Ohms.
Concerns
FRAS belts can wear faster and as they wear their resistance to fire also decreases. Abrasion resistance is therefore an important consideration when selecting a FRAS belt. In operation sites need to ensure maintenance plans are consistent with the wear properties of the belt to ensure that the required FRAS properties are maintained for which it was installed.
FRAS specification can vary greatly. Be diligent and don't be afraid to test your supplier. Manufacturers are required to test every 800m of conveyor belt by removing a sample. This means that the belt you receive onsite may have not been tested. You can therefore test your own belt prior to use through accredited laboratories.
Housekeeping
Conveyor spillage should be reduced and daily belt walks should be used to address poor housekeeping and to prevent against rapid deterioration of the building structure or contents.
Heating systems should be routinely inspected. Consider monitoring temperature remotely.
Fire is one of the biggest hazards in a manufacturing systems. Therefore, flame retardant conveyor belts should be used to decrease or even prevent risk of flame damage to individuals and assets.
Our fire-resistant conveyor belts have a structure that automatically extinguishes and prevents the spread of flame throughout its length. We carry out numerous tests according to the ISO standards to guarantee the fireproof characteristics of those fireproof conveyor belts. These experiments cover drum friction tests, fire tests, electric strength tests, etc.
Fire-Resistant Conveyor belts can be divided into three major grades:
K quality: flame-retardant rubber conveyor belts with cover plate
S quality: flame-retardant conveyor belts with or without cover plate
V quality: self-extinguishing Fire Resistant Rubber Textile Conveyor Belts
Our fire-resistant conveyor belts are ideal for prevention of fire hazards in coal mines and for reducing maintenance of conveyors susceptible to flame damage in the metalurgy furnaces. Furthermore, they can be used in thermal power stations, mining, coal-cleaning, and other sectors.
Appendix 1
EN12882 is the standard for safety requirements for conveyor belts for general purpose (above ground). Under EN12882 there are 10 classifications depending on the hazards.
| Category |
Application according to EN12882 for general use and above ground conveyors |
| 1 |
General use, risk only through electrostatic discharge |
| 2A |
As for category 1, additional hazards from small open flames on the cover stock (additional causes of fire) |
| 2B |
As for category 2A, the additional risk is smaller open flames on the carcass |
| 3A |
As for category 2A, however with the additional risk of heating due to localised friction |
| 3B |
Same as category 2B with the additional risk of heating due local friction |
| 4A |
Same test as category 1 however with a fire propagation test |
| 4B |
Same as category 4A however with additional risk of heating due to local friction |
| 5A |
Same as category 4B however there is an increased risk of frictional ignition (no secondary safety device) |
| 5B |
Same as category 5A however there is an additional risk if the belt is glowing |
| 5C |
Same as category 5B however there is an additional risk if the conveyor is in a combustible atmosphere |
Appendix 2
EN14973 is the standard for safety requirements for conveyor belts for underground installations. There are 5 classifications that take into consideration the material being conveyed. FRAS belts used for underground coal are typically the highest standard. C1 (EN14973).
| Category |
Application according to EN14973 for use underground |
| A |
General use, only hazards being limited access and means of escape. |
| B1 |
as class A, but potentially flammable atmosphere.No secondary safety device. |
| B2 |
as Class A, but potentially flammable atmosphere. With secondary safety device. |
| C1 |
as Class B1 plus combustible dust or material conveyed. No secondary devices |
| C2 |
as Class B1, plus combustible dust or material conveyed and additional fuel sources. With secondary safety devices. |
Reference Data
EN12882 standard for safety requirements for conveyor belts for general purpose. EN14973 is the standard for safety requirements for conveyor belts for underground installations. Note 1: Major mining losses 2013-19 from Willis Towers Watson, WTW-Mining-Risk-Review-2019
Founded in 1980, Shandong Weifang Zhenxing Group has more than 40 years of production experience. We are a large-scale comprehensive joint-stock enterprise with myriad industries and diversified operations. Adhering to the business philosophy of"Innovation & Progress, Multi- cooperation, High Quality, Credible Service, Mutual Benefit, Brilliant Future" and the quality policy of "Survival by Quality, Development by Reputation", we strive to develop high-quality products. Our business involves international trade, rubber conveyor belt manufacturing, plastic packaging product design, and production, large automobile maintenance, etc. Weifang Zhenxing Rubber Co.Ltd. covers an area of 80,000m2, with both output value and assets of over 100 million yuan. We have always been in line with the purpose of "Customer First, Remarkable Performance" to serve our customers wholeheartedly.
Diversified products
The main products are various types of conveyor belts including conveyor belts of general cotton canvas, nylon (NN), polyester (EP) whole core (PVC, PVG), steel cord, high-temperature resistance, acid and alkali resistance,anti-static, fire resistance, oil resistance, cold resistance, high strength, and high wear-resistant conveyor belt high-intensity corrugated sidewall conveyor belt, and pattern conveyor belt. Special pattern models and various types of conveyor belts can also be manufactured according to customers' requirements.
The products have excellent shock resistance, abrasion resistance, high strength ductility, and long service life, which can better meet the demands of the transport of materials in such industries as large coal mines, metallurgy, chemical industry, port, and so on.
Product Capacity:
Equipment production capacity
Mixing equipment
Equipment Name Specification Model Production Capacity
Internal mixer F-270 500kg/hour
Internal mixer XM-250/140 200kg/hour
Calendering equipment
Equipment Name Specification Model Production Capacity
Three-roll calender XY-3T/610×1730mm Rubber material 10000kg/8h, adhesive cloth 2100m/8h
Four-roll calender XY-4T/610×1730mm Rubber compound 15000kg/8h
Molding equipment
Equipment Name Specification Model Production Capacity
forming 2600mm×15000mm 25000 m2day
1600mm×9000mm 25000 m2/day (layered 1000M)
25000M/day PVG lagging
Vulcanization equipment
Equipment Name Specification Model Production Conveyor Belt Product Type
1# Flat Vulcanizer B2600×11000 ST, CC, EP, NN, PVG
2# Flat Vulcanizer B2400×10000 ST, CC, EP, NN, PVG
3# Flat Vulcanizer B1600×8000 ST, CC, EP, NN, PVG
4# Flat Vulcanizer B1600×6000 CC, EP, NN, PVG
5# Flat Vulcanizer B1400×6000/2 CC, EP, NN, PVG
6# Flat Vulcanizer B1400×3200 CC, EP, NN, PVG
7# Flat Vulcanizer B1200×1800 CC, EP, NN, PVG
8# drum vulcanizer ¢ 1500×1800 CC, EP, NN,
9# flame retardant whole core with raw material
A set of production lines
1400×P
PVC, PVG
10# sidewall with vulcanization B2400×4000 CC, EP, NN, ST
machine
11# sidewall with vulcanization B2000×4000 CC, EP, NN, ST
12# sidewall belt vulcanizer B1800×3000 750000 CC, EP, NN, ST
13# sidewall belt vulcanizer B1600×2000 600000 CC, EP, NN, ST
Q1: What types of Conveyor Belt you can Produce?
A: Hello,Dear We can produce Sidewall,Flat,Chevron,Steel Cord Conveyor Belt,Heat Resistant,
Oil Resistant,Acid-Alkali Resistant Cold Resistant and PIPE Conveyor Belt etc.
Q2:Does your Company have ISO Certificate?
A: Yes of course we have ISO9001:2008 Certificate.
Q3:Can you Provide FORM E Certificate of Origin for us?
A: Yes we can do Normal CO,FROM E,FROM F,FORM A etc.
Q4:What is your Delivery Time?
A:Normally Within 10-20days after getting your Prepayment or L/C.
Q5:Can you give Guarantee if I buy your belt?
A:Of course,we must give Guarantee for all of our Products,Please tell me your Details of Requirement.
We will be appreciated if you can provide the following specification:
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1. Conveyor belt type
2. Top cover thickness
3. Bottom cover thickness
4. No.of plies
5. Width of the conveyor belt
6. Grade:
If you are not sure for any of above,we can recommend for you.WELCOME INQUIRY US
Once we get above information we will quote exact price at soonest time.
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