GRP Adhesive bonded Joints - water
GRP Adhesive bonded Joints - water
(OP)
Buried pipework within a water storage and pumping station facilities is specified to be GRP (glass reinforced plastic). Diameters 300mm to 1200mm. Rather than using standard spigot and socket (bell) joints with thrust blocks the designer has adopted to use tapered adhesive bonded spigot and socket joints: My concerns are
1) Time to make joints
2) Reliability - if pipe fails hydrostatic pressure test then it will be a major task to make repair ?
3) Quality control (we are in Africa)
4) Costs
5) Lack of flexibility
I have no experience of making adhesive bonded joints on large diameter GRP pipelines. (Pressure rating 16 bar) I would welcome any comments particualrly on costs compared to push in spigot and socket with thrust blocks and time to make joints.
Total length considering all facilities is over 20km.
1) Time to make joints
2) Reliability - if pipe fails hydrostatic pressure test then it will be a major task to make repair ?
3) Quality control (we are in Africa)
4) Costs
5) Lack of flexibility
I have no experience of making adhesive bonded joints on large diameter GRP pipelines. (Pressure rating 16 bar) I would welcome any comments particualrly on costs compared to push in spigot and socket with thrust blocks and time to make joints.
Total length considering all facilities is over 20km.





RE: GRP Adhesive bonded Joints - water
Hopefully, before it gets to the hydrotest stage, you will have put all the fitters, supervisors, and inspectors through the training and qualification programme detailed in ISO 14692-4; that way you will get a heads up on the feasibility and quality issues you will face when it comes to the actual pipe installation. During pipe installation, as well as having the manufacturer on site to supervise, it is advisable to perform hydrotest on 500 m sections as construction progresses in order to catch poor quality early. When consistency has been achieved you could agree to allowing longer intervals between hydrotests. I wish you much luck.
Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdoweb/
RE: GRP Adhesive bonded Joints - water
The contract is design and build. The contractor is not in control of his design consultant and the designer is producing inappropriate solutions, such as this one. The site labour is not highly skilled and I already have concerns of maintaining quality with GRP pipes using push in bell and spigot joints. There is little prospect of achieving quality using adhesive bonded tapered joints! We cannot prevent the contractor from adopting expensive inappropriate solutions. I need to make him aware of the quality problems, additional cost and potential programme delays. I have no experience of using GRP adhesive bonded joints and I cannot quantify these in comparison to push fit spigot and socket joints. Any advice is welcome.
Brian
RE: GRP Adhesive bonded Joints - water
Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdoweb/
RE: GRP Adhesive bonded Joints - water
I will otherwise only say that it is obvious that the basic pipe barrel material is not homogeneous/nor equally strong in all directions like some other pipes (it is instead obviously reliant on the actual amount and orientation of reinforcements within the wall, and of course on who designs this), and this can cause field inspection and uncertainty issues when actual loadings/deformation/settlements/movements etc. might not be predictable in all areas of a pipeline project. In other words it is much more difficult for the basic strength of a particular pipe etc., damaged or undamaged, to be independently verified in the field (e.g. by putting a caliper to the wall thickness etc.)!