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Up Topic Welding Industry / Inspection & Qualification / High pressure VS low pressure welding
- - By jeremycuningham Date 04-09-2018 13:59

The context is hot water and steam piping in a heating network. The pipes are sometimes steel, sometimes stainless steel.

Is there a difference between High pressure welding (above 150psi) and low pressure (below 15psi) for steam or hot water pipes or do they fall into the same standards?

My concern is regarding the procedure AND the testing. Is X-ray necessary?

I've been searching in the B31.9 Building Services Piping and in the ASME Boiler & Pressure Vessel code and haven't found any clear distinction concerning the procedures and quality testing between high pressure and low pressure heating networks...


Parent - By 803056 (*****) Date 04-15-2018 17:29
There is considerable overlap between the different pressure piping codes. It is the Owner's responsibility to determine which piping code is suitable for the application.

There are minor differences depending on the specific piping code selected by the owner. The loosest acceptance criteria is probably B31.9 which is intended for institutional piping that for the most part is small diameter and low pressure compared to B31.1 for power piping and B31.3 process piping. The latter has several fluid service categories that have different restrictions for qualification and acceptance criteria.

Generally, the employer is responsible for the qualification of the WPS and the welders. In some cases the construction code may required Charpy Impact Testing and in some cases PWHT is required.

It all depends on the construction code and the particulars of the job.

As for B31.9, I do not recollect there is a distinction between low pressure and high pressure with regards to welder qualification.

Parent - By Joey (***) Date 04-24-2018 01:15
Here in Smokey Mountain you can't install a steam piping without following the statutory regulations.
The inspection and test requirements set by the goverment may be more stringent than the applicable construction code (e.g. B31.1).
Up Topic Welding Industry / Inspection & Qualification / High pressure VS low pressure welding

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