Related Legal Terms & Definitions. 1  COMPETENT WITNESS One who is legally qualified to be heard to testify in a cause. 2  RESPECTABLE WITNESS One who is competent to testify in a court of justice. 3  CREDIBLE WITNESS A credible witness is one who is competent to give evidence, and is worthy ofâ¦.
In general, combustibility of polymers depends on their chemical structures. Polymers with more carbon atoms in their macromolecular structure (e.g., PE, PP, PS, PMMA) are more combustible than polymers containing halogen atoms (e.g., PVC, PVDC, PTFE).
The color of PVC pipe is traditionally white or dark gray, with a technical description of the pipe printed on the side. PVC is available in both rigid form (commonly used in construction and piping applications) and flexible form (found in electrical cable insulation).1 It is safe to touch and handle, and does not leach chemicals when used as the manufacturer intended.