Pressure waves generated by the combustion of gas typically propagate at much lower speeds than pressure waves generated by explosives. The method therefore poses no danger for boiler tubes. The method involves no transfer or storage of explosives. The combustible gas mixture is prepared only moments before ignition. Several barriers of shut-off valves and non-return valves prevent gas leakage. All personnel involved in the pressure wave cleanings are trained on the equipment to help ensure no harm comes to any employee or customer’s property.