Pipeline & Coatings

Pipelines have a very real risk of damage. As such, they often require pipeline casings, a powerful method for mitigating the risk of breaking due to ground movement and collision. These casings are protective sleeves or conduits made from steel, concrete, or high-density polyethylene (HDPE), and they are typically pumped full of a petrolatum-based compound to protect against pipe corrosion.

Petrolatum fillers function by displacing water, soil and other external elements in the casing and preventing them from re-entering the pipeline casing. The annular space between the pipeline and the casing is often backfilled with suitable petrolatum-based material to provide additional stability and protection. This is particularly important when the pipeline is buried underground or submerged in water, as it helps prevent damage and to extend the lifespan of the pipeline. 

This article will define the important steps installers must take to ensure success when filling a pipeline casing. We are including a downloadable checklist to take on-site so that projects may run smoothly.

 

How to Fill Pipeline Casings

A petrolatum-based, liquid-filler wax is pumped into the low-end, bottom casing vent using an insulated, heated tanker truck and factory-trained installers. The pumping continues until the filler is discharged from the high-end casing vent (it's nice to know ahead of time how to calculate the amount of filling required for a pipeline casing). The manufacturer’s application guide, product data sheet, and SDS provide additional information. 

The general process goes as follows:

1. The vents must be clear and open into the casing 
2. Make certain there are vents on both ends 
3. Conduct a pressure check to ensure the end seals are in place and there are no leaks  
   • Pressure check boot seals to a minimum of 5-psi  
   • Pressure test link seals to a minimum of 10-psi 
     • Failure to pressure test the end seals ahead of time could result in a downtime of crew and added expenses 
4. Water within the casing pipe must be removed 
5. The casing must be clear and free of any debris 

 

Casing Filler Checklist 

Key information regarding the casing fill project is gathered and reviewed prior to submitting a proposal. Creating a checklist of actionable items leading up to the scheduled fill date will help the project run smoothly. For those directly associated with the casing fill work, having a pipeline casing checklist of critical processes aids in preparedness. 

Prior to filling the pipeline casing, ensure you know:

• Are the vents clear, and have the end seals been pressure tested? 
• Was water blown out of the casing to ensure a good fill on the morning of arrival? 
• What type of connection are on the vent pipes? 
  • Flange or threaded pipe 
    • What is the diameter of the threaded pipe? 
• Have you conducted pressure tests on the end seals?
  • Tests should run for an hour and read 5-psi for boot seals and 10-psi for link seals
• How close can the wax pump truck get to the end vent connection? 
• What length of hose is needed? (Cold weather conditions require shorter distances to prevent wax from cooling in the lines)
• Have we met the following:
  • PPE requirements?
  • Safety meeting requirements  
• Do we require contractors to supply traffic control?

• Point of contact(s) onsite and cell number(s) 
• Physical address for the crew to report and check-in 
• Set meeting location and time. (Is a site escort required?)  
• Procedures for signing in, getting badged, etc. 

In summary, filling pipeline casings is no easy feat. Taking the proper measures goes a long way in making sure jobs are successful. With a lot of manpower and costs on the line, small mistakes can quickly escalate into major disasters. These guidelines serve as a good general guide to making the project run smoothly on the day of; but remember, each job is different and may pose unique challenges. 

The specific pipeline corrosion protection measures employed may vary depending on factors such as the type of pipeline, environmental conditions, and regulatory requirements. It’s advisable to consult with corrosion engineers or pipeline experts to determine the most suitable corrosion protection strategy for a particular casing. 

Filling the pipeline casing is just the first step. We have helpful guides on backfilling a pipeline and conducting peel adhesion tests on pipes you may be interested in checking out. We even have a guide on pipeline color coding.

Tapecoat and Royston tape coating systems provide corrosion protection to critical pipeline infrastructure. Our technical representatives can assist you with product information to meet your coating needs. Please contact us.