During Dec 2000, Amchem executed a project for external coating of Approx. 5 Km of 24" Dia and 16" Dia New Oil & Gas Pipeline for a major Indian petroleum company at site in East India using Purethane^®386/9000 ,100% Solids Polyurethane Coatings.

The first of its kind project involved blast cleaning of the individual pipe sections using Granulated Copper Slag to SSPC SP-10 Near White Finish, Priming using Purethane^® AR Primer and coating with 1000 Microns of Purethane^® 386/9000 , 100% Solids Polyurethane Coating.

Amchem made extensive use of automation for the project to ensure high quality and output.
 

A 10 MT , Multiple Nozzle, Bulk Blasting Pot was deployed for the job. 3 No's X 11 mm Polyurethane - TC nozzles were used for simultaneous blasting. A surface profile of 100 Microns + ( Range 100-130 ) was obtained against the 50-75 specified.

Blasting output at 80-90 sq. metres / hour was 60% faster than manual blasting using similar sized nozzles. Blast cleaning obtained was very even and approximated a "White " finish. High precision variable speed drives controlled the pipe spinning and nozzle travel rates.

Immediately after blast cleaning, the pipes were primed using Purethane^® AR Primer, a modified two component polyurethane primer.

The primed pipes were coated on similar automated pipe beds using Graco Hydra Cat airless spray equipment. The coating speed selected was approx. 140 sq. metres per hour which translated to approx. 10 minutes / pipe. The applied coating was very even with a thickness of 42-44 Mils (1,050 to 1,100 Microns ) against the 40 Mil ( 1000 Microns ) specified. 100 mm wide areas was left on pipe ends for pipe girth welds at installation site.

A holiday free coating was provided. Adjacent picture on the left shows holiday testing ( at 6,000 V ) in progress .

After a short ( one or two day ) curing period, the coated pipes were transported to the nearby installation site. The operation of a mobile "pipe coating plant " near the installation site results in huge savings in transport and handling costs. Purethane^® 386/9000 has outstanding resistance to impact and abrasion damage and suffers virtually no damage during handling.

Picture shows the pipe strings after girth welds awaiting radiography / hydro testing. Purethane^® 386/9000 was manually sprayed on the girth welds areas after blast cleaning and priming. This is a very fast operation compared to conventional joint coatings such as shrink sleeves with several hundred joints possible in a day. The joint coating is a continuation of the pipe coating with no discernable discontinuity between the morphology of the two. Molecules of each link into a homogenous barrier affording equally strong protection over the field weld as well as over the pipe

The pipe was installed in adjacent marshy area. Due to its excellent Volume Resistance of > 4.0X 10 ¹⁴ Ohms / cm, Purethane^® 386/9000 requires the lowest current density for achieving protective potentials - thereby allowing large savings in cathodic protection costs.

Install the highest quality coating for your upcoming projects and save money too ! Purethane^® is ideal " on-site " coating for new pipelines as well as for re-habilitation of existing ones.