This practice covers microwave (MW) examination of butt fusion joints made entirely of high density polyethylene (HDPE) for the purpose of joining HDPE piping. MW examination detects differences between the dielectric constant(s) of the materials being examined. These differences may be due to material construction (expected) or defects such as voids, cracks, or foreign material intrusion (unexpected). MW examination detects the presence of improper fusion between the parts due to multiple factors, including improper fusion practice or inadvertent introduction of foreign material into the joint. This includes joints that appear fused but whose micro-structure is weaker than required, commonly called a cold fused joint.
The use of HDPE in critical applications is expanding because of the materials low-cost, ease of installation, and corrosion resistance. Critical applications include Nuclear power and oil and gas. The HDPE users do not currently have a standard that governs the type of examination and acceptance criteria to differentiate good from poor fusions. An ASTM standard would help the industry to specify routine examiantion of these critical joints.
non-destructive examination, nde
The title and scope are in draft form and are under development within this ASTM Committee.
Citing ASTM Standards
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