Vent Band (FRAS) and Its Use in Underground Mines

01 December 2019

A heavy emphasis is placed on worker safety when designing underground mines. Huge efforts are made to provide a risk-free environment down there among the tunnels and vaulted subterranean chambers. That’s why there are steel-laced supports in every passageway to stabilize the walls and ceilings. Following this line of safety-centric reasoning, a vent band’s job is to secure a mine’s ventilation tubes.

Protecting Environmental Lifelines

Above ground, walking around in the fresh air, we all take oxygen for granted. The air is maybe fresh, or it’s maybe a little stuffy, but it’s readily available. Divers can’t say the same. Swimming down into deep waters, they cautiously pay attention to their back-strapped oxygen tanks so that they can surface while they’ve still got plenty of breathable air. It’s much the same situation down inside an underground mine. There might be gas trapped in a chamber, clouds of dust choking a passageway, or simply a lack of breathable air throughout a deep subterranean level. Therefore, the ventilation tubing running through a mine is generally perceived as a life-giving umbilical line. The pipes provide clean, breathable air to miners. What, however, happens if the tubing develops a leak in a pipe joint?

Preventing Vent Leaks and Ignition Hazards

From one perspective, the tubing stays sealed so that oxygen pressure stays high and miners have access to a fully working ventilation system. Then there’s the other point of view to consider. Those gasses and powdered materials, the ones collecting and unable to disperse in a mine chamber, could very well ignite if they’re mixed with oxygen. For example methane gas is sometimes exposed and released from ground pockets, then there’s bituminous coal dust, which is also ignitable. To prevent joint leaks from feeding these ignitable atmospheric elements with fire-feeding oxygen, mining engineers wrap ventilation tubes in a special sealing rubber. This is Vent Band rubber, a Fire Retardant and Anti-Static medium (FRAS) that seals the tubing and, therefore, maintains a safe, pressure-verified vent line.

Spark hazards are significantly reduced when oxygen lines are wrapped in Vent Band rubber. The material features a static reduction attribute, so the possibility of a spark discharge is greatly minimized. The tubing seal also provides a high measure of flame retardation. Even if a conflagration does develop, it won’t receive any flame feeding oxygen from the tubing, not with the rubber resisting the heat. One more time, then, this material wraps snugly around oxygen line joints to create an impermeable oxygen barrier. Venting systems remain properly pressurized when the rubber wrapping eliminates potential leaks. Just as importantly, the flame and static immune material actually reduces sparks and suppresses mine ignitability conditions.