Dynamic Leach Analysis
Harvel LXT piping was subjected to on-line dynamic flow analysis with 18.2 megohm UPW to evaluate particles, TOC, resistivity, anions, and trace metals. This testing used solvent-cemented flange assemblies (spool piece) to see the effect that the cement had on TOC, resistivity and particle generation in a freshly assembled pipe section. Grab samples were also pulled periodically (at start-up, five minutes, 50 minutes and five hours) to analyze anions and trace metals under flowing conditions. Harvel LXT flanges were assembled using Harvel LXT One-Step Cement and allowed to cure 24 hours prior to testing. Dynamic testing revealed that Harvel LXT piping assemblies did not contribute significantly to particle generation or leachable contamination under flowing conditions throughout the test duration
Dynamic Test Description
Ambient temperature dynamic leach utilizing 18.2 megohm UPW and flowing at 9.35 GPM (turbulent flow) was conducted. One-inch diameter pipe 30” long with solvent-cemented flanges on each end (approximately 82 square inches wetted surface contact area) was assembled. Approximately 11⁄2 grams of Harvel LXT solvent cement was used in assembly of the components. The solvent-cemented assembly was allowed to cure 24 hours prior to start-up. Dynamic testing was conducted for a period of five hours.
As seen in the chart, resistivity measured 17.95 megohms at the start of the leach and rose quickly to 18.12 megohms during the first 6 minutes. Resistivity readings continued to rise until reaching the theoretical maximum level of 18.2 megohms after five hours of leaching.
Total Oxidizable Carbon (TOC)
Dynamic testing revealed that after four hours of leaching, TOC readings reached and maintained the background levels throughout the test duration. This data confirms the fast cure time of Harvel LXT One-Step Cement as opposed to conventional solvent cements and primers used for joining. PVC, TOC contamination can leach for up to 30 days.
Dynamic testing revealed that average particle counts decreased rapidly during the first six minutes of the flow. After 12 minutes of flow, the average smallest particles measured (0.05 size range) were equivalent to the background levels.
Anions/Cations – Ion Chromatography (IC) grab sample analysis revealed low levels of sulfate (0.15 ppb) five minutes into the test, and low levels of ammonium at 50 minutes (0.05 ppb) and five hours (0.07ppb) into the test. All other IC contaminants were below the limit of detection.
Trace Metals – Of the 68 trace metal contaminants evaluated using Inductively Couple Plasma - Mass Spectroscopy (ICP-MS), all were below the limit of detection with the exception of aluminum, detected at 0.012 ppb at the five-minute interval. This element remained below the limit of detection throughout the remainder of the extraction test.