Hello,

Regarding applicalbe code for GRP pipie design and stress analysis, I ordered vendor to apply below code.

- Design Code : ASTM and AWWA C950
- Stress Analysis : ISO 14692

Then, some vendors stated that pipes design required as per AWWA shall be ASME B31.3 for stress anaylsis not ISO 14692. It is not possible to make stress analysis according to ISO 14692 if pipes are not design according to ISO 14692.

Is it true? I thought the stress analysis for GRP pipe is always applied to ISO 14692 regardless of design code.

Please advise.

CAESAR II offers three codes that address GRP pipe - BS 7159, UKOOA & ISO 14692, the first two are more legacy codes than active codes. There's a new US code soon to be published (NPPS NM.2) that also is focused on GRP piping systems.
So, no, all GRP piping systems need not conform to the ISO standard but it is probably your best choice.

Hi Hiro,

My opinion is that those Vendors who objected for employing ISO 14692-3 Standard for stress analysis of "non-ISO" FRP/GRP piping are right, from some points of view.

Just for reference, you may have a look at this older post:
http://65.57.255.42/ubbthreads/ubbthreads.php?ubb=showflat&Main=9825&Number=44315#Post44315.

The fact is that ISO-14692-3 standard provisions regarding pipe stress analysis are based on the Design Stress Envelope which defines the allowable stress system.
If the FRP/GRP piping are NOT MANUFACTURED and TESTED in accordance with ISO 14692-2 & 14692-4 standards, then it is difficult for Manufacturer to provide all the definition parameters that "build" material's Design Stress Envelope.
I do not say that this is impossible, BUT, as customer or piping designer, you should ask to the "non-ISO" Manufacturer to provide and guarantee all the typical reference stresses that define FRP/GRP material's Design Envelope.

In addition, another problem of "non-ISO" FRP/GRP/GRE piping stress analysis might be Fittings' loading capacity and SIFs employment.

ISO-14692-2 Standard includes essential requirements regarding the FRP/GRP Qualified Fittings, which basically have same pressure strength/rate like the simple pipe spools. The related SIFs for additional bending loadings are specifically defined for FRP/GRP fittings manufactured in accordance with ISO 14692-2 standard.
If you intend to use ISO 14692-3 standard for stress analysis of "non-ISO" FRP/GRP piping, then you need to define the specific SIFs values for the FRP/GRP fittings that are manufactured as per other standards.
Trying to use ASME B31.3 Code's SIFs is not a correct approach, since limit states and failure mechanisms for metallic piping are essentially different than those corresponding to GRP/FRP piping.
Moreover, the actual fitting types (such as the intersections/tees, for instance), as provided by "non-ISO" manufacturers, may be different than the typology stated by ISO 14692-3 Standard.

As Dave stated above, BS 7159 is a "legacy" Code, but, in my opinion, has a more general applicability than ISO 14692-3 Standard.

If Manufacturer is not able to provide all the relevant parameters of the Design Stress Envelope, then BS 7159 employment for stress analysis purpose might be a solution. However, you need to read carefully BS 7159, identify all the required input parameters, and ask the Manufacturer to provide those parameters values.

FRP/GRP piping stress analysis may also be performed in accordance with ASME B31.3 Code. However, in such case, the analysis is likely much more complicated and time consuming. About 10 years ago I passed through such experience. In such case, Manufacturer should provide all Fittings' SIFs values and all Elbows' flexibility (k's) factors, which shall be introduced value by value, for each fitting/node, in Caesar II model. Loading cases that should be employed are likely different than those for B31.3 metallic piping - e.g. Sustained and Operating stresses are to be qualified.

Finally, please be aware that ISO 14592 standards have recently been revised (in 2016 or 2017). I've not been involved in GRP/FRP piping projects for the last couple of years, so that I am not aware how those standards look now. If you intend to proceed to stress analysis following ISO 14692-3, you need to read the latest edition in order to be able to ask to Manufacturer all the applicable input parameters.

Regards,