Tubing Technical Information
Working Pressure Information
Thermoplastic tubing is affected by temperature. Careful consideration must be given to the reduced pressure capabilities of tubing as temperatures are increased.
Working pressure is calculated as a ratio of the burst pressure by dividing the burst pressure by an appropriate safety factor. Commonly used safety factors are three to one or four to one, depending on the severity of the application.
Formula: Burst pressure / Safety factor = Working pressure
Example: 450 PSI @ 75°F / 3 to 1 safety factor = 150 PSI working pressure
Example: 450 PSI @ 75°F / 4 to 1 safety factor = 112 PSI working pressure
Terms to Know for Tube Coil:
Material memory: Polyurethane and nylon offer superior thermoset memory, however, Polyethylene or PVC may be used for reasons such as cost or chemical compatibility.
Retractability: Material memory leads to retractability including factors of wall thickness and mass weight (heavier the coil weight, the more difficult for the coil to retract).
Coil Diameter: An important factor in retractability; a tighter coil diameter produces a more retractable coil. Coil diameter minimums are limited by tubing flexibility. Balance between retractability and usability results in a self-storing easy to stretch and use coil.
Working Length: Of a coil is usually a percentage of the total tubing length. It may be necessary to experiment with working lengths to produce a coil that can be stretched and used comfortably. Polyurethane features flexibility allowing a working length of 80 - 90% the actual material length; nylon, a more rigid tubing, has a working length that is 67 - 75% the total tubing length.
Retracted Length: Length of coil not including 'pig' tails. Retracted length or outer coil diameter may be important in applications where the coil rests over a pole or retracts into a box.
Tails: Standard sized Polyurethane coils have two straight "tails" (8" and 16"). Tails ease use of coils with small diameters. Nylon tails are not standard - rather coils are produced from 100 foot bulk length coils, if tail length is required - supply measurement for quote.