Playing with fire!? - Belt conveyors are sophisticated equipment widely used in the transportation business. Most often, nevertheless, their function is of paramount importance for the plants they serve: If the belt conveyors fail, the plant (or port) might be paralysed, so their weaknesses should always be kept in mind.
If a belt does not perform according to the manufacturer’s claims by wearing prematurely, ripping too easily or disintegrating due to excessive heat or because of oil penetration, the risk to life and limb is relatively small.
Yes, it can be very expensive but hardly life-threatening. But if a conveyor belt that is specified as being fire retardant catches fire but does not resist the fire the way that it should do then it will literally ‘convey’ the fire throughout the site. The consequences can be catastrophic.
Is Cost being put before Safety?
Due to the financial pressures on the cargo industry caused by the uncertain economic climate, more and more organisations are being forced to examine their day-to-day running costs and, almost inevitably, seek cost savings. The pressure to cut costs now seems to be influencing buying decisions concerning fire retardant conveyor belts.
Is price being put before safety? Or to put it another way, is the operator being lulled into a false sense of security by conveyor belt manufacturers and suppliers? The discovery that a belt is not sufficiently fire retardant is only likely to be made when it is too late.
Anecdotal as well as factual evidence gained from laboratory testing certainly indicates that even some of Europe’s biggest users of conveyor belts, including some major ports, may be using belts that are not as resistant to fire as they are supposed to be. In a growing number of instances, many sites that should be using fire resistant belting are operating with non-fire resistant belts simply because of ‘economy’.
Poor quality fire resistant belt can be expensive!
At the same time, insurance companies are becoming increasingly concerned. According to at least one major insurer, claims for fires directly involving convey-or belts are costing an average of nearly USD 8 million per claim.
No Conveyor Belt is Fire proof
Fire retardency standards on specifications and test methods applied to conveyor belts are becoming increasingly stringent and can be very confusing. The first and most important thing to bear in mind is that conveyor belts cannot be totally fire proof. Using special additives and chemicals, the rubber used in the top and bottom covers that protect the carcass of the belt and the rubber skim between the fabric plies of the carcass can be engineered to resist fire but the complete structure of the belt cannot be made fire proof. The fabrics used in the carcass of the belt most commonly contain polyester and nylon, which have little or no resistance to fire. In other words, every belt will burn when it is exposed to a naked flame that has sufficient energy to ignite the belt. When choosing a fire retardant conveyor belt, deciding on the actual level of fire retardency needed for a specific application or environment is of crucial importance.
Environments with inflammable Dust and Gas
EN 12882 is the standard for safety requirements for conveyor belts for general-purpose use (not underground). The most basic electrical and flammability safety requirement is EN 12882 Category 1. For environments where coal dust, gas, fertilizer, grain or other potentially combustible materials are involved, it is essential that the conveyor belt cannot create static electricity that could ignite the atmosphere. Belts need to be able to allow static electricity to pass through the metal frame of the conveyor structure down to earth rather than allow static to build up. At Dunlop we decided some time ago that the safest approach was for all of our belts to be anti-static and conform to EN/ISO 284 international standards.
This means that they can all be used in ATEX 95 (94/9/EC Directive) classified zones. Some people mistakenly believe that all belts used in ATEX classified zones must be flame retardant but actually this is not the case.