Butt Fusion Pressure & Time Calculation Guide per ISO 21307:2017 & DVS 2207-1:2025
Butt Fusion Pressure & Time Calculation Guide per ISO 21307:2017 & DVS 2207-1:2025To achieve high-quality, reliable welded joints for HDPE pipes, fittings and sheets during butt fusion operations, construction personnel must adopt accurate fusion pressure and duration parameters that comply with the welding specifications specified in project requirements.
This guide elaborates the manual calculation methods for core butt fusion pressure and time parameters, fully compliant with the ISO 21307:2017 and DVS 2207-1:2025 industry standards. All calibrated parameter values are validated for standard construction environments: an ambient temperature of 23±2°C for ISO 21307:2017, 20°C for DVS 2207-1:2025, and mild airflow conditions. Linear interpolation is required for unlisted intermediate specification values to ensure accurate welding results.
The butt fusion welding process features a complete pressure-time cycle, with all phase-specific parameters defined as follows (X stands for time, Y stands for pressure):
Time Parameters - t1: Bead forming time - t2: Heating soak time - t3: Heater plate removal time - t4: Pressure rising time to reach standard fusion joint pressure - t5: Minimum pressure-holding cooling time inside the welding machine
Table 1: Recommended values for the heated tool butt welding of pipes, fittings and sheets made of HDPE at an outside temperature of approx. 20 ° C and moderate air flow (interim values have to be interpolated).
Final Notes
The appropriate butt fusion process shall be chosen in compliance with project technical specifications, local regulatory provisions and the technical requirements specified by the pipe manufacturer. It is prohibited to intermingle parameters sourced from disparate standards or operating procedures.
Fusion pressure values are defined based on the pipe’s outer diameter, wall thickness and the piston cross-sectional area of the welding equipment. All time-related setting parameters are calculated with reference to pipe wall thickness and nominal diameter. For pipes with non-standard dimensional specifications, adopt rational interpolation calculation methods to ensure sufficient structural strength and reliable sealing property of the fused joints.
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