Are it permissible to splice the suspension rods for boilers and pressure pipelines?

The suspension rods of boilers and pressure pipelines are generally not allowed to be spliced. Splicing may affect the strength and stability of the suspension rod, increasing safety risks. It is recommended to use a single suspension rod that is integral or meets the standards. .

Whether it is permissible to splice the suspension rods of boilers and pressure pipelines must be determined comprehensively based on relevant standards, design specifications, and actual operating conditions. The following is an analysis of the key points: 1. Main regulatory references: Domestic standards (GB/T/industry standards). GB/T 16507-2022 (water-tube boilers) or GB/T 16508-2022 (shell-and-tube boilers): It is generally required that load-bearing components (such as suspension rods) be made of a single piece of material, with no use of joined parts. If splicing is required, it must be approved by the design unit and meet strict technical requirements (such as full penetration welding and non-destructive testing). NB/T 47003.1-2022 (Technical Requirements for Boiler Steel Structures): Splicing is permitted, but equal-strength connections must be ensured, and the splicing locations should be avoided in high-stress areas. Pressure pipeline specifications (such as GB/T 20801 or SH/T 3059): The splicing of suspension rods generally needs to comply with steel structure standards, taking into account the effects of dynamic loads. International standards (ASME/EN): ASME BPVC Section I imposes strict restrictions on the joining of boiler load-bearing components; design approval and process qualification are usually required. EN 12952 (European boiler standard): Splicing is allowed, but the strength must be verified through calculations and testing. 2. Conditions permitting splicing: If the design permits it or if the regulations do not explicitly prohibit it, splicing must meet the following requirements: Material consistency: The material and specifications of the spliced sections must be identical to those of the original suspension rod. Welding process: Full penetration welding (such as groove welding) is used, and 100% non-destructive testing (RT/UT) is required after welding. Strength requirements: After splicing, the overall strength must not be lower than the original design value; moreover, the joint location should be kept away from high-stress areas (such as near threaded sections). Design approval: Written approval from the original design firm or a qualified engineer is required. Operating condition adaptability: Takes into account the effects of dynamic loads such as thermal expansion, vibration, and fatigue. 3. Cases where splicing is prohibited: Hoists that are directly subjected to alternating loads or high-temperature creep conditions. The design documents explicitly prohibit splicing or require overall forging. In small boilers or low-pressure systems, if the lifting rods are standard components (such as threaded rods), splicing may not be acceptable. 4. Recommended action: Review the design documents; prioritize compliance with the equipment’s technical specifications or drawing requirements. Consult the design party: If the specifications are not clear, written approval from the design firm is required. Strict process control: In case of welding, it must be performed by qualified welders according to the qualified procedure, and inspection records must be kept. Alternative: Consider switching to a single integral hanger to avoid the risks associated with splicing. Conclusion Under compliance with standards and design approval, the suspension rods of boilers and pressure pipelines can be carefully joined, but strict process and inspection requirements must be met. In practical engineering, it is recommended to prefer integral structures to ensure safety unless necessary.