169. Determination of percentage of inflammable gas and of environmental conditions.
(1)Where electric energy is used in any ventilating district, determination shall be made of the percentage of inflammable gas present in the general body of air and the following provisions shall apply in respect of such determination, namely:-(a)the determination shall be made by a competent person either by means of an apparatus of a type approved for the purpose by the Chief Inspector, or by analysis of samples of air:Provided that if determinations are made by the analysis of air, the samples shall be analysed within three days of the taking thereof:Provided further that no apparatus as aforesaid shall be used unless it has been calibrated by its manufacturer or other approved agency within such period of time as specified from time to time by the Chief Inspector;(b)the determination shall be made or samples of air taken at suitable point fixed by the manager, on the intake side of the first working place and on the return side of the last working place in the district:Provided that where the Regional Inspector is of the opinion that the location of any such point is unsuitable, he may, by an order in writing, require the manager to fix some other point or points in substitution thereof;(c)the determination shall be made or samples of air taken, as the case may be, once at least in every seven days, so however that -(i)if any determination shows the percentage of inflammable gas to exceed 0.8, determination shall be made or samples of air taken at intervals not exceeding twenty-four hours for so long as such content exceeds that percentage and for the seven next following days, unless the Regional Inspector otherwise permits by an order in writing and subject to such conditions as he may specify therein; and(ii)if the determination made during the thirty days immediately preceding any day have shown the percentage of inflammable gas to be below 0.6, it shall be sufficient to make such determination or take such samples, once in every thirty days for so long as such content does not exceed that percentage:Provided that when any alteration is made in the system of ventilation so as to substantially affect or likely to affect the ventilation of the mine, such determination shall be made within period of twenty-four hours of such alteration;(d)particulars of every such determination under this regulation shall be recorded in a bound paged book kept for the purpose; and(e)if any determination in any ventilating district shows the percentage of inflammable gas to exceed one and a quarter, the supply of electric energy shall be cut off immediately from all cables and apparatus in the district, and a written report thereof submitted to the Regional Inspector forthwith.(2)If the Regional Inspector so requires by an order in writing in respect of any mine having workings belowground, determination shall, once at least in every thirty days, be made of temperature, humidity and such other environmental conditions at such points as the Regional Inspector may specify in the order.
