Codes for Penstock Installation
Codes for Penstock Installation
(OP)
Good afternoon
We´re starting a steel penstock installation in Panama with this features:
Material: ASTM A-506 gr70
Plate thickness: 1"
Penstock Diameter: 5m
Lenght: 300m
Which codes should I follow for this installation?
Does ASME B31.1 Power piping covers this application?
Does ASME Pressure Vessel Code covers this application?
Thanks
We´re starting a steel penstock installation in Panama with this features:
Material: ASTM A-506 gr70
Plate thickness: 1"
Penstock Diameter: 5m
Lenght: 300m
Which codes should I follow for this installation?
Does ASME B31.1 Power piping covers this application?
Does ASME Pressure Vessel Code covers this application?
Thanks





RE: Codes for Penstock Installation
RE: Codes for Penstock Installation
Surely you should check which Code was used for design ??
Yes, and don't call me Shirley ! RIP Leslie Nielson.
RE: Codes for Penstock Installation
Shop fabrication of pipe and fittings for this type of penstock shall conform to either "ASME Boiler and Pressure Vessel Code-Section VIII, Division 1, covering fabrication, inspection and tests or ANSI AWWA C-200 and ASTM A-139 Standards plus additional requirements.
Some additional requirements might be needed to ASME VIII for example for qualification of welders, welding procedures and radiographic inspection.
I recommend that you look for "buried steel penstocks-Steel plate engineering data,volume4" by American Iron and Steel Institute and "welded steel penstock-engineering monograph No.3" for further info.
RE: Codes for Penstock Installation
Basically my problem is this:
In a project we are finishing right now,the penstock diameter is 4500m. We measured the roundness of the pipes, 4 measures in total to know the OUT OF ROUNDNESS, and it must comply with this:
Dmax - Dmin <= 45mm (1%) - based on ASME VIII UG-80
The problem is that some penstocks have an out-of-roundness over 1%, like 2% and 3% the most critical. I think that ASME VIII UG-80 is very rigorous, with the tolerance of 1%, for the specific case of high diameter penstock as it is for pressure vessels with much critical conditions like higher pressures and temperatures, so I was looking for a standard that may give me a little more tolerance, let's say till 3%. A lot of literature refers ASCE MOP#79 but I's been impossible for me to find it. Any ideas???
greetings
RE: Codes for Penstock Installation
Please make sure where you are making your measurements. if it's buried then the bed preparation and compaction is of great importance to control the ovality and the measurement should be made after the backfill.
for the ASCE manual, contact them through their site.
May I ask why 4 measurements and how you decide where to make the measurements along the penstock lenghts? this might give a better insight to your problem.
RE: Codes for Penstock Installation
RE: Codes for Penstock Installation
RE: Codes for Penstock Installation
Regarding AWWA, steel penstock is a large diameter water transmission pipe and could be covered by AWWA. That is why AWWA is referred as the standard in many penstock design books including the references I mentioned previously. At any rate, follow the designer specified requirements whatever they are.
Achieving under 1% deflection is tough for a 4.5 m pipe unless it has really a tick wall thickness with high grade steel. Considering the normal pressures in hydro power, I think thickness calculation is dominated by penstock weight (and external loads)in your case and if buried, compaction is highly important.
RE: Codes for Penstock Installation
RE: Codes for Penstock Installation
That being said, and perhaps contrary to the inference of another response, I don't believe that AWWA M11 really says out-of-roundness of steel water pipes of 3-5% is allowed. At least at one point, what this manual in fact said was, "When required, the design, installation, and performance of pipe bracing during transportation and installation is generally the responsibility of the contractor." While I am not going to hold myself out as any sort of expert in matters involving five meter diameter pipes, this phraseology may be due to the quite job-specific complexity of bracing etc., i.e. exactly what e.g. is expected of or by internal bracing, including what it is intended to accomplish upfront and/or in some cases even while/after pipes are buried in the specific applications. This statement may also reflect that there could be different abilities of contractors, in different areas and with different fitting-up equipment and expertise etc., to practically deal with whatever pipe shapes or bracing is involved in the specific application (maybe kind of alluded to by Mr.cvg). As to ultimately what is acceptable, I guess the desired shape should be available and affordable (to build the project in the time frame when it is needed, and with available money), and it can certainly be argued ultimately would be most helpful if it will also work!
Everyone have a good weekend.
RE: Codes for Penstock Installation
Regarding what AWWA M11 really says, please take a look to the manual under "6.2.deflection determination":
RE: Codes for Penstock Installation
Some applications include the water conduction for hydropower generation (fall water), if it is your case, the pressure difference (by level difference or high) is the main risk. You could be install the penstock sections with problems on the top of system (low pressure zone). I coincide with CVG about the difficulty for assembly the sections with problems, because to penstock thickness added to the site difficulties.