Improving Safety of Crude Oil and Regional Water System Pipeline Crossings Pipeline Safety Conference November 5, 2010 Delvin E. DeBoer, Ph.D., P.E. South Dakota State University

Outline Who is the affected community? What is their safety concern? What is needed to address the concern? What is the project approach? What do we hope to accomplish?

South Dakota Regional Water Systems

Pipeline Crossings in SD Crossing characteristics – PVC pipe through steel casing – PVC pipe through fusible PVC – PVC pipe through restrained joint PVC – Ductile Iron – Restrained joint PVC – PVC No Single Standard for design Desired elements of the crossing – Protect oil pipeline from water pipe maintenance and repair activities – Protect the water pipeline in a spill event High cost of environmental liability insurance

AwwaRF (2008) study Focused on polyethylene and PVC pipes Exposed to pure gas and BTEX along with water/solvent mixtures Studied gasket joints and ungasketed pipe Focused on permeation (exceeding drinking water standards) under field conditions (flowing water and stagnant water)

Conclusions - AwwaRF (2008) Permeation through Pipe Wall – PE Pipe Rapid permeation (also documented in case studies) – PVC pipe Depended on concentration of BTEX Pure solvents permeated in a matter of days (toluene 16 days, benzene 20 days) – pipes noticeably swollen Gasoline (BTEX) did not permeate in 2 years (due to lower concentrations of BTEX than in pure solvent)

Conclusions - AwwaRF (2008) Hydrocarbon Permeation through gaskets in PVC pipe – IS a source of contamination – NBR more resistant to permeation than SBR gaskets – Under stagnant-flow conditions, can exceed MCL for Benzene when submerged in free product gasoline – Water flow through pipe dilutes benzene below MCL (required flow depends on pipe size) – Less potential for contamination if ground water dilutes the gasoline

Unknowns What is the impact of crude oil products on permeation through PVC pipe and gaskets? What are the permeation characteristics of restrained joint pipe configurations (joints and fittings)? What is the impact of crude oil on pipe strength characteristics?

Scope of Project Assumption - restrained joint casing is likely the low cost crossing option with good potential for approval as a local design standard. Determine impacts of crude oil on small diameter PVC pipe characteristics – Permeability through PVC pipe wall and through joints – Impacts on strength and physical characteristics Convene a committee to review results and develop a local design standard

Rural Water System Number of crossings Water Pipe diameters Water Pipe material Casing material Casing Provider Total Casing length Vertical Distance from water pipe to oil pipe A141.5" - 8"Yelomine PVC Winwater Works Company300 ft7 ft B42" - 12"Yelomine PVC Yelomine PVC, SteelDSG ft6 ft C71.5" - 4"Yelomine PVC DSG100 ft7 ft D112" - 6"Yelomine PVC C900 fused PVC Underground Solution200 ft ft E132" - 12"Yelomine PVC DSG100 ft ft F211.5" - 18" Bell/Spigot PVC, Yelomine PVC, ductile ironnone 1.5 ft or more

Tensile Strength Tests

Tension Test Data

Parallel Plate Compression Test

O-Ring Tension Test

O-Ring Test

Next Steps Obtain Crude Oil Sample Conduct tests (6-10 months) Interpret results Convene Design Standard Committee – Draft a local design standard – Agency review