A chilled water coil is installed on the outer wall of the pressure vessel – does this modification fall under the category of pressure vessel modifications?
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We have a pressure vessel whose heat-insulation capacity is insufficient; we plan to install chilled water coils on the outer wall of the vessel. May I ask whether this modification falls under the category of pressure vessel modifications? Are there any potential risks? Thank you~
According to the definition in Clause 5.2.1 of the Fixed Capacity Regulations, if none of the definitions of modification apply, simply adding coils to the external wall of the equipment does not constitute a modification.
If the coil uses half-tubes that are welded to the container, or if the medium inside the coil causes the operating temperature of the container to exceed its design temperature, then it constitutes a modification. If the coil is merely located outside the container without being connected to it, and does not cause the operating conditions of the container to go beyond its design parameters, then such change does not constitute a modification of the container
Design modifications are required; it is necessary to consider whether the addition of coils will have an impact on the material, medium, and operating procedures of the equipment itself.
It depends on the temperature of the chilled water and whether the material of the original container is suitable.
This does not fall within the scope of modifications; you can refer to the suggestions from the third floor. If welding is performed on the main load-bearing components, it constitutes damage to the equipment. If the equipment needs to be used again, it must be assessed according to relevant standards. In the absence of evaluation by a design firm, repair service, inspection agency, or regulatory authority confirming that it is suitable for use, such equipment is considered scrapped.
The definition of modification in TSG21-2016 can be seen as: altering the structure of the main pressure-bearing components, or changing the operating parameters of the pressure vessel, the medium it contains, its purpose, etc. If a coil jacket is added to the outer wall by welding, it obviously changes the structure of the main pressure-bearing element, and as a result, the stress conditions under which the container operates also change. If this isn’t considered modification, then there is no such thing as modification at all.