Section 69: Precautions with regard to explosive or flammable dust, gas, vapour or

69. Precautions with regard to explosive or flammable dust, gas, vapour or substance (1) Where, in connection with any process giving rise to dust, gas or vapour, there may escape dust, gas or vapour of such a character and to such an extent as to be liable to explode on ignition, all practicable steps shall be taken to prevent such an explosion by enclosure of the plant used in the process, and by removal or prevention of accumulation of the dust, gas or vapour that may escape in spite of the enclosure, and by exclusion or effective enclosure of possible sources of ignition. (2) Where there is stored or there is present in any plant any dust, gas or vapour of such a character and to such an extent as to be liable to explode on ignition, all practicable steps shall be taken to restrict the spread and effects of such an explosion by the provision, in connection with the plant, of chokes, baffles and vents or other equally effective appliances or measures, unless the plant is so constructed as to withstand the pressure likely to be produced by any such explosion. (3) Where any part of a plant contains any explosive or flammable gas or vapour under pressure greater than atmospheric pressure, that part shall not be opened, except in accordance with the following provisions— (a) before the fastening of any joint of any pipe connected with the part of the plant or the fastening of the cover of any opening into the part is loosened, any flow of the gas or vapour into the part or into such pipe shall be effectively stopped by a stopvalve or otherwise; (b) before any such fastening is removed, all practicable steps shall be taken to reduce the pressure of the gas or vapour in the pipe or part of the plant to atmospheric pressure, and where any such fastening has been loosened or removed, no explosive or flammable gas or vapour shall be allowed to enter the pipe or part of the plant until the fastening has been secured or securely replaced, as the case may be. [Issue 1] O2 – 48 Revised Laws of Mauritius (4) No plant, tank or vessel which contains or has contained any explosive or flammable substance shall be subjected to— (a) any welding, brazing or soldering operation; (b) any cutting operation which involves the application of heat; or (c) any operation involving the application of heat for the purpose of taking apart or removing the plant, tank or vessel or any part of it, until all practicable steps have been taken to remove the substance and any fumes arising from it, or to render them nonexplosive or non-flammable, and where any plant, tank or vessel has been subjected to any such operation, no explosive or flammable substance shall be allowed to enter the plant, tank or vessel until the metal has cooled sufficiently to prevent any risk of igniting the substance. (5) No plant, tank or vessel which contains or has contained a substance which, when heated may give rise to a toxic gas, fume or vapour, shall be so heated unless all practicable steps have been taken to remove such substance.