4.1.GeneralU.K.
4.1.1.Measures must be taken for assessing the presence of harmful and/or potentially explosive substances in the atmosphere and for measuring the concentration of such substances.U.K.
Where required by the safety and health document, monitoring devices measuring gas concentrations at specified places automatically and continuously, automatic alarms and devices to cut off power automatically from electrical installations and internal combustion engines must be provided.
Where automatic measurements are provided for, the values measured must be recorded and kept as stipulated in the safety and health document.
4.1.2.Smoking is forbidden in areas subject to particular fire or explosion hazards.U.K.
The use of any open flame and the execution of any work that may give rise to an ignition hazard is prohibited unless adequate safety precautions are taken to prevent the occurrence of fires or explosions.