'Chemical Process Piping (CPP) Foray into Design, Manufacture and Installation of GRE Piping for Oil & Gas Industry'
Glass Reinforced Epoxy (GRE) piping has been used for the Marine & Offshore, Oil & Gas and Petrochemical markets. The article details about CPP foray into Design, Manufacture and Installation of GRE Piping for Oil & Gas Industry.

Oil & Gas industry has been using Glass Reinforced Epoxy (GRE) piping for several years now. These pipes are used in Fire Water service, Produced water, Brine, Hydrocarbon drains, Water/ Oil mixtures, Injection water, Process water, Sour water, NaOH, Potable water, HCL amongst others. The American Petroleum Institute (API) has two classes for GRE pipes namely API 15 LR and API 15 HR besides the API Monogram program. Several major Oil & Gas companies have their own specifications namely Shell DEP, Norsok, ONGC spec amongst others. Hence GRE has proven to be a reliable material of construction in the Oil & Gas industry.

CPP has been in the forefront of GRP and Thermoplastic lined GRP Piping for the Chemical, Power, Desalination and Water conveyance for over 50 years.

Our foray in the Design, Manufacture and Installation of GRE piping for the Oil & Gas industry is relatively new however we have had considerable success in this industry.

In the year 2015 CPP first delivered GRE piping for an LNG plant in India for Fire Water ser vice. The job involved Stress analysis, Surge analysis, manufacture, supply and installation along with excavation. This was the first project involving GRE piping executed entirely by an Indian vendor.

CPP followed by supplying over 50 kms of GRE piping for Fire Water service to Petronas for their RAPID project in Malaysia.

Several other projec ts in the Offshore as well as Shipping industry followed and CPP has made a mark in the industry as a reliable supplier and installer of GRE piping.

While carrying out these projects, CPP has done extensive cutting edge work in the field of design and manufacturing. We have used very efficient filament winding techniques which resulted in stronger laminates capable of sustaining very high pressures along with high chemical resistance. We have composite pipe designs that can sustain design pressures up to 60 bars.

CPP has developed fire retardant piping as per ASTM E 84 as well as ABS standards. These pipes can also be made electrically conductive to dissipate static charges.

Unlike metal, GRE material has a wide range of proper ties which changes with fibre orientation, lay up sequence, glass content etc.

CPP carries our Stress analysis, Surge analysis (wherever required) & Static calculations before start of manufacture.

Stress Analysis

This is done to calculate the stresses, displacements, forces and moments acting on the piping under various conditions/ cases (eg : sustained, operating, hydrotest) due to the combined effect of internal pressure, max differential temperature, bending, and ex ternal loads. The system is modelled and analyzed using Caeser II Pipe Stress Analysis software version 6.10 according to ISO 14692 or BS 7159.

Several design conditions are used for the analysis for eg : D esign Pressure, Hydro test Pressure, Design Temperature, Average Installation Temperature, Co- efficient of Friction.

Besides the above, Material Proper ties such as Pipe and fitting thickness, Tee dimensions, Elastic Modulus (Axial and hoop), Poisson Ratio, Shear Modulus, Long Term Axial Stress and Hoop Stress, Biaxial Stress ratio, qualified stress for Bends, Thermal fac tor are used as input for the stress analysis.

Surge Analysis
Water hammer analysis is carried out to investigate the following potential problems;
  • Surge due to Liquid Column Separation and Re-jointment:
    Simultaneous shut down of the water pumps may cause excessive water hammer due to liquid column separation and re-jointment, especially round outlet pipes of the elevated piping portions.
  • Pressure Surge due to Slam-shut of Tripped Pump Check Valve:
    Shut down ( or unintentional stop) of a water pump is followed by sudden closure of its discharge check valve Sudden closure of the check valve is likely to generate severe water hammer especially when one of the operating pumps shuts down and stand by pumps automatically starts.
Long-term Hydrostatic Design Basis (HDB)
Pipes are subjected to a long term hydrostatic tests wherein several samples are pressurized till failure over a period of time to derive the long term HDB and HDS. This is used in the Stress analysis and static calculations to come up with the thickness for each pressure class.

All pipes are manufactured on CNC controlled Filament Winding Machine which helically wind glass rovings at predetermined angles on a rotating mandrel. The rovings pass through a bath where they get impregnated with the epoxy resin. Thereafter the pipes are taken to an Oven to heat them up to temperatures ranging from 100o C upto 200o C depending on the type of system used.

CPP in-house laboratory can carry out the following tests:
  • Tensile Strength test
  • Stiffness Test
  • Ring Split Test
  • Beam Strength
  • Lap Shear Strength Test
  • Bond Strength Test
  • Peel Strength Test
  • Glass Content Test
  • Barcol Hardness Test
  • Hydro test
Oil & Gas industry in India is on the cusp of growth with constant capacity expansions and new refineries are being planned in Rajasthan and Maharashtra. With GRE being specified for Fire Water service and other areas of a Refinery by global EPC and Owners, we believe that the market for GRE piping will increase considerably.