Tnemec Company Inc. has introduced a specialized ceramic epoxy lining to protect carbon steel and ductile iron pipe used to transport domestic wastewater.
Series 431 Perma-Shield PL is a 100% solids, ceramic-modified polyamine epoxy developed for carbon steel and ductile iron pipe and fittings.
“When properly applied at 40 to 50 mils dry film thickness, Series 431 provides an impenetrable barrier to the elevated levels of hydrogen sulfide gas (H2S) and other sewer gases, which can rapidly corrode ductile iron pipes and fittings used in wastewater environments,” said Vaughn O’Dea, Tnemec’s director of sales for water & wastewater treatment.
The lining is for use on new pipe “by specialty applicators who understand the unique surface preparation and application process for this product on the pipe and fittings,” O’Dea said.
Series 431 was extensively tested for permeability resistance to sewer gases in accelerated laboratory environments using the Standard Practice for Rapid Evaluation of Coatings and Linings by Severe Wastewater Analysis Test (SWAT), the manufacturer said.
“The older ceramic epoxy technologies no longer offer sufficient protection given today’s higher levels of sewer gases, which are the leading causes of coating failure in severe wastewater environments,” O’Dea said.
Abrasion Resistance Testing
Abrasion resistance was tested in accordance with BSI BS EN 598: 2007 + A1 2009 for ductile iron pipe, fittings, accessories and their joints for sewerage applications.
For this test, a section of ductile iron pipe lined with Series 431 and containing a slurry of pea gravel and water was capped at both ends and placed in a mechanical rocking device, which causes the aggregate to slide back and forth within the pipe to simulate abrasive flow conditions.
After 50,000 cycles, the average loss of film thickness along 15 points was 0.6 mil (0.01 mm) for Series 431. After one million cycles, Series 431 had an average loss of 5.5 mils (0.10 mm).
In ASTM D 4060-07 (Test Method for Abrasion Resistance of Organic Coatings by the Taber Abraser), coating erosion is determined by the milligrams of film loss when subjected to 1,000 cycles under a coarse abrasive wheel loaded with 1,000 grams of weight. After 1,000 cycles, Series 431 had an average film loss of 76 mg based on three tests performed by Tnemec.
Chemical Resistance Testing
Series 431 was also tested for chemical resistance using the NACE TM-0174 Laboratory Methods for the Evaluation of Protective Coatings and Lining Materials in Immersion Service.
“After six months of immersion in various concentrations of hydrochloric acid, sulfuric acid and sodium hypochlorite, Series 431 showed no signs of deterioration,” O’Dea said.
“There was no blistering, cracking, checking, erosion or delaminating of film. Gloss and general appearance of areas that were immersed in chemicals were the same as areas not immersed.” Series 431 also passed the British Standards Institute (BSI) BS EN 598: 2007 + A1 2009 Chemical Resistance to Effluents test.
Established in 1921, Tnemec (www.tnemec.com) is one of the largest privately held companies in North America, manufacturing more than 120 industrial and architectural coatings products for steel, concrete and other substrates for new construction and maintenance.