157. Bulk head and air-locks.- The employer shall ensure at a construction site of a building or other construction work that- (a) a bulk head or air tight diaphragms retaining compressed air, when used within a tunnel or a shaft, is constructed to withstand the maximum pressure at one point two five times the maximum working pressure of such bulk head or diaphragm and such bulk head or diaphragm is tested before its each use by a responsible person referred to in rule 121 to ensure that such bulk head or diaphragm is in proper working order; (b) such responsible person keeps the record of each test referred to in clause (a) and such record is produced for inspection to the Inspector having jurisdiction on demand; (c) the bulk head or diaphram referred to in clause (a) are made of sound material of adequate strength and are able to withstand the maximum pressure on which they are subjected to at any time of their use; (d) a bulk-head anchorage and air lock is tested at its work place at an excavation or tunnelling work immediately after their installation at such place. | 
