FRAS (Fire Retardant Anti Static) Vent Bands are being used for wrapping around vent tubes in underground mines.
What is Vent Band?
In an underground mine, a vent tube is beneficial in dealing with the high concentration of gas emitted from the drilling site and borehole. Vent band, also known as vent tube rubber is used for wrapping around the ventilation tube, to seal the joint thus maintaining air pressure. Further, the vent band can be used to repair damage to the vent tube.
Given that the operation of underground coal mines poses a high number of risks of fire and explosion, materials used as vent band are required to be certified fire retardant and anti-static (FRAS). That means, they need to be able to control ignitability and flame propagation. Further, they also require the capability to reduce static electricity, which could lead to possible sparking.
To comply with the requirement, some manufacturers produce polyurethane systems with the ability to self-extinguish in the case of fire and also provides excellent antistatic protection. These materials have been documented to possess a highly durable, longer lasting, wear and abrasion resistance characteristic; and most importantly, they comply with all relevant Australian FRAS standards.
What is FRAS?
FRAS (Fire Retardant and Anti-Static) requirements exist in numerous industries. In mining, the conditions specifically apply to non-metallic materials such as vent band, as stated in the Mine Design Guideline MDG 3608 non-metallic materials for use in underground coal mines. To be FRAS certified, the manufactured materials undergo assessments with regards to antistatic and flammability properties.
When tested, the materials’ antistatic property must fall within the acceptance criteria stated in clause 7.4 of AS/NZS 60079.0:2012 Explosive atmospheres Part 0: Equipment – General requirements. This clause specifically applies to external, non-metallic materials of electrical equipment, as well as to non-metallic parts, which are applied to the external surface of an enclosure.
For flammability testing, materials must be within the acceptance criteria as specified in sub-clauses 19.3.1. And 19.3.2. of AS/NZS 60079.1:2015 Explosive atmospheres Part 1: Equipment protection by flameproof enclosures ‘d’. These sub-clauses require the materials tested to comply with IEC 60079-0 and IEC 60695-11-10 (Method V2).
Only with the proper FRAS certification can one ensure safety use and quality of vent band in underground mining.