FLEX PVC PIPE, TUBING, FLEXIBLE PVC PIPE & HOSE’
Products referred to as "pipe" conform to pipe standards as established by: IAPMO Other such agency ASTM NSF
Pipe size is "nominal" (means "in name only") and is approx. equal to the inside diameter (ID) of the pipe The OD (outside diameter) is held to strict tolerances, the inside diameter is not. Pipe wall thickness is set by the pipe's size and classification and usually expressed as a "minimum wall thickness", but it can vary. Pipe can be rigid or flexible. Pipe can be clear with a tint or solid colored, but the color is used to help identify the rating and classification of the pipe. Pipe wall thickness is set by the pipe's size and classification and usually expressed as a "minimum wall thickness", but it can vary.
Tubing does not conform to any standards and does not have any third party agency's ratings. Tubing is usually identified by it's OD (outside diameter) and ID (inner diameter) which determines the wall thickness. Tubing is not an engineered product for a particular purpose like pipe is. Tubing generally will not fit pipe fittings (there are exceptions). Tubing will have no printing on it and the color is clear like glass with no tint.
Flexible pvc pipe is identified the same way as rigid pvc pipe. Flexible pvc pipe can be colored or clear with a colored spiral. Flexible pvc pipe is a flexible material engineered to solvent weld INTO pvc pipe fittings with pvc glue or cement and primer. Flexible pvc pipe will be smooth on the inside and outside. Flexible pvc pipe MAY have a rating or certification from third party agency such as NSF, IAPMO, etc, but not all do.
Hose or flexible tubing is identified based up on both it's ID and OD. Hose or flexible tubing is terminates by going over the barbed end of an insert fitting and secured with a clamp. Hose or flexible tubing may have some rating or certification from a third party agency such as NSF, IAPMO or others but not all do. Hose or flexible tubing can be smooth or corrugated on the inside or outside.