There is not an ASTM standard for rotational lining of pipe and vessels. How can I ensure that the rotational lining will be properly installed by the contractor?
It is true that there are no ASTM or ASTM-type standards for rotational lining. However, there are standards that can be applied throughout the process of rotational lining. Below are the industry standards that contractors use to manufacture quality liners.
Before Lining
It is critical that the substrates surface is prepped prior to lining. This allows the liner to bond to the metal substrate without risk of delamination. Additionally, the surface roughness provides the right surface for mechanical bond to occur between the polymer and metal substrate. NACE Standard SSPC SP-5 is an internationally recognized standard that can be applied to this process. The substrate needs to be blasted to white metal maintaining a surface profile above 250 µm, which is sufficient for most applications.
Material
The resins used should have their properties tested to conform to international standards. For an example, please view the Tefzel 2195 datasheet. The contractor should have test certificates for the resin, as well as tractability on which lot or lots of material are used on your project.
Testing
There are quality standards that can be followed to check the liners integrity. A spark test, or holiday test, will be performed to determine sufficient thickness and continuity of the liner. For thick rotational liners, NACE SP-02-74 provides the correct voltages to test the liner. Additionally, a correctly calibrated ultrasonic thickness gauge can take local thickness measurements of the liner.
The mechanical bond strength itself can also be tested. One such test would be ASTM 3167, otherwise known as a float roller test. For roto-lining, test coupons should fail in cohesion, not adhesion, which means the bond strength is ultimately stronger than the tensile strength of the material. The contractor should be able to provide test data on the bond strength of their material.
As you can see, even without a published standard for rotational lining, many standards can be applied to the process. Check with your contractor to determine how standards are followed and how the roto-lining process is controlled within their company.
To learn more about the processes we use at RMB Products, please contact us.
