Notice from the General Office of the Quality Inspection Administration on Risk Warnings Regarding Gas Boilers, 2017

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On the morning of January 12, 2017, an explosion occurred in the furnace of a horizontal internal combustion boiler at a company in Zhijiang City, Hubei Province, during testing for ignition; this incident resulted in 2 deaths and 7 injuries. Preliminary analysis indicates that the accident occurred because the operating unit, while the burner’s program controller was functioning normally, illegally short-circuited and activated the gas safety shut-off valve, allowing gas to enter the furnace and mix with air before ignition, reaching the explosive limit. When the program controller reached the ignition stage, an explosion occurred in the furnace. In recent years, due to environmental protection requirements, the number of gas boilers in our country has increased rapidly, which in turn has heightened the risks associated with gas safety. To ensure the safe operation of gas boilers, the following risk warnings are hereby issued: 1. Selection of burners – Boiler manufacturers should specify the technical requirements for burner configuration in the technical documentation provided with the boilers, offer technically mature and safe burners, and attach warning labels in prominent locations on the boilers to outline the safety precautions regarding boiler commissioning and ignition. Under normal circumstances, the boiler burners should be selected and supplied by the boiler manufacturer ； In cases where special requirements necessitate selection by the boiler operator, the operator must ensure that the burner chosen meets the technical specifications for installation set forth by the boiler manufacturer. The boiler installation supervision and inspection unit shall verify whether the selected burners meet the technical requirements of the boiler manufacturer. II. Type testing of burners Burners shall meet the requirements of safety technical specifications and standards such as the \"Regulations on Safety Technical Inspection of Boilers\"; fuel and gas burners must pass type testing. Until the relevant safety technical specifications are revised, it is recommended that relevant entities use burners that have passed type tests in order to improve the safety performance of boilers as well as their energy-saving and environmental protection capabilities. III. Usage Requirements: The boiler operators are not allowed to modify or disengage the burner operation control programs without authorization. Boiler users shall conduct regular inspections of the burners, boiler safety accessories, and safety interlock devices in accordance with the requirements of the relevant safety technical specifications for boilers. When the burner needs to be repaired, it should be carried out by the boiler operator in consultation with the burner manufacturer or an authorized entity. IV. Commissioning: The system commissioning to be carried out after the installation of a newly installed boiler should be done jointly by the entity that will use the boiler and the boiler installation company or the boiler manufacturer. During commissioning, boiler operators with the appropriate qualifications must be responsible for operating the boiler. When it is necessary to adjust the burner, on-site guidance should be provided by technical personnel from the burner manufacturer or its authorized entity. During the commissioning of the boiler system and burner, the safety management department of the boiler operator shall ensure that unauthorized personnel do not gather near the boiler. V. Modification and Repair: The modification or replacement of boiler burners must follow the relevant procedures for notifying construction work as stipulated for boiler repairs. The modification, replacement, and calibration of boiler burners are to be carried out by the burner manufacturer or an authorized entity, with the boiler operator providing necessary cooperation. After the burner has been modified or replaced, the user entity shall conduct a self-inspection of safety accessories such as the boiler’s safety valve and safety interlock devices, and prepare a record of this self-inspection. Any modification, repair, or replacement of the burner must not reduce the safety performance and energy efficiency of the boiler, and must comply with environmental protection requirements. When conducting external inspections of boilers, the inspection agency shall also examine the aforementioned self-inspection records kept by the user unit, while paying particular attention to whether the burners have undergone type testing and whether the safety accessories meet the required standards. Coal-fired boilers should not be converted into boilers using gas, oil, or other liquid fuels. In cases where modification is required under special circumstances, the relevant regulations for boiler modification shall be followed. VI. Other matters: Before installing gas boilers, the relevant parties shall determine a safe and reliable gas supply method in accordance with standards such as GB 50028 \"Code for Design of Urban Gas Systems\" and other industry standards. The pressure vessels, pressure pipelines, and gas cylinders used in the gas supply system must meet the requirements of the safety technical specifications and standards applicable to special equipment. General Administration of Quality Supervision, Inspection and Quarantine, January 24, 2017