Instructions for Pexgol Above-Ground Installation

Pexgol pipes can withstand sunlight exposure for their entire lifetime. Above-ground Pexgol pipe installation is ideal in these cases:

  • Installation through areas with difficult access (e.g marshes)
  • When slurry lines are relocated frequently
  • Quick, temporary pipeline installation

Compared to steel pipes, the coefficient of expansion for Pexgol pipes is high, but the thermal stresses for Pexgol pipes generate much lower forces. This is because of Pexgol's low modulus of elasticity and the stress relaxation that Pexgol pipes feature.

Pexgol pipes that are installed above-ground tend to undergo “snaking” and increase in length due to increases in temperature. Due to the variation of the coefficient of friction between the pipe and the ground, pipe contraction and longitudinal elongation are not uniform. However, abrasion resistance and toughness of Pexgol pipes enable their movement across soil without affecting service life or strength.

 

Pexgol Above-Ground Installation Instructions for Pipes Laid on the Ground

Industrial pipes tend to contract when the installation temperature is higher than the design temperature. When the pipes contract, they experience axial stresses and tend to pull out from the fittings.

One way to reduce thermal stresses is to install the pipe above-ground with a calculated slack instead of installing it in a straight line. This method makes the pipe less likely to pull out of its fitting.

The slack, which is calculated according to the Pexgol coefficient of thermal contraction, is 0.2% or 2 millimeters for every meter per 10°C. The actual value is dependent on the difference between the lowest temperature and the installation temperature. Push the midspan of the pipe slightly to the side during installation to maintain the slack.

Secure and protect axially unrestrained fittings from pullout.

 

Maintain a Pexgol (PE-Xa) Pipeline in a Straight Line

In the case of a straight pipeline, control and limit thermal expansion and contraction by guiding the pipeline at intervals. The pipe length decreases when distance between the guides is smaller. The pipeline remains straight as a result and lateral deflections decrease.

 

Determine the Maximum Distance Between Two Guides

The following formula is used to calculate the distance between two adjacent guides:

L = F x D

where:

L = distance between the guides (in m)
D = outside pipe diameter (in mm)
F is a coefficient dependent on temperature.

Increase ΔT between the design temperature and the installation temperature.

This formula allows for a maximum sidewise deflection of 50 mm between two adjacent guides.

Example:

Pipe diameter: 200 mm
Installation temperature: 20°C
Maximum ambient temperature: 40°C
Design temperature: 20 + 40 = 60°C


ΔT= 60° – 20° = 40° F = 0.064  L= 0.064 X 200 = 12.8 m

 

Coefficients F:

above ground table1

 

Correction Factors:

above ground table2