In the United States for applications for everything except underground coal mines, as published in the Code of Federal Regulations (CFR), is quite simple:
Bunsen Burner Test. (CFR Part 30 Section 18.65)
A small (approximately 150 by 12 millimeters) (6 by 1⁄2 in.) piece of a belt is held over a Bunsen burner flame for one minute, after which time the flame is removed and an airflow applied for three minutes. After a set length of time, the duration of the flames is recorded. The average of four samples must not burn for more than one minute or exhibit afterglow for more than three minutes.
This test, which was implemented per the 1969 Federal Coal Mine Health and Safety Act, is similar to a standard for underground conveyor belts that was in force in Europe until the mid 1970’s. However, with the advent of the more stringent regulations, flame-retardant belts have been allowed to be used in Europe only in applications above ground; self-extinguishing belts are required underground.
The United States now has a more stringent standard for flame-resistant belts in underground coal mines. In December 1992, the US Department of Labor, Mine Safety and Health Administration (MSHA), proposed a new rule for conveyor belt test requirements (Federal Register, Vol. 57, No. 248) that would bring safety standards up to the international level. Nearly ten years later, in July 2002, this proposed rule was withdrawn. The reasons cited for withdrawal were that the number of conveyor belt fires had significantly declined and that improvements in belt monitoring were being implemented.
Recommendations from the Mine Improvement and New Emergency Response (MINER) Act of 2006 resulted in a new rule for underground coal mines (CFR Part 30 Section 14.20) effective December 2008 that includes the Belt Evaluation Laboratory Test (BELT), a laboratory-scale flame resistance test based on the work done for the 1992 proposed rule. In order for a belt to pass the BELT method, it must have improved fireresistant capability, which greatly limits flame propagation.
The test requires that three belt samples, approximately 152 by 23 centimeters (60 by 9 in.), be placed in a test chamber 168 centimeters (66 in.) long by 456 centimeters (18 in.) square. After applying the burner flame to the front edge of the sample for 5 minutes and the flame is extinguished, each tested sample must exhibit an undamaged portion across its entire width.
At the time of this writing, the final rule published by MSHA requires conveyor belts placed in service in underground coal mines to be more flame resistant than those previously required beginning December 31, 2009. The rule also requires existing belting to be replaced within ten years. MSHA or a reputable belting supplier can be contacted for additional, updated information.
Other Belting Safety Concerns
Other standards are sometimes in place. Some countries have even more stringent requirements regarding, for example, the belt’s toxicity, hygiene, or cover roughness. The exact specifications can be found in the standards in a given geographic region or industry. Procedures and standards are offered under DIN, EN, ISO, BSI, CEMA and other standards. Of course, it is imperative that the belting be compatible with the materials to be transported on it.
See also: Conveyor Belt Fire Resistance Part 1
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