Section 3.5.2 (b) is mandatory in respect of machinery or related products, which comprises highly flammable parts.
The braking system of machinery or related products intended for use in underground workings shall be designed and constructed in such a way that it does not produce sparks or cause fires.
Machinery or related products with internal combustion engines for use in underground workings shall be fitted only with engines using fuel with a low vaporising pressure and which exclude any spark of electrical origin.