This Standard specifies safety requirements for diesel engine systems that are explosion-protected for use in underground coal mines, including use in explosion-risk zones.NOTES: 1 Compliance to this Standard implies a limited time safe operation in atmospheres containing up to 1 percent methane, including - (a) the control of surface temperature, to avert ignition of coal dust that could settle on a hot surface;(b) containment or elimination of flames and sparks that could ignite flammable gases and dust that may be present (such as in underground coal mines); and(c) control of diesel emissions.2 This Standard also addresses inadvertent short-term exposure to high methane levels and any consequent abnormal combustion.3 Appendix A gives guidance for demonstrating compliance with this Standard.