Pipe Tek Managing Director Myles Brannelly spoke with The Australian Pipeliner about hydrotesting and shared some tips for an efficient and effective process.
Hydrostatic testing is one of the last steps completed before putting a new pipeline into service, but it is also one of the most important.
Under Australian regulations, a new pipeline can’t be commissioned without a hydrostatic test. Despite this, there can be misconception and confusion around the process.
NATA-accredited hydrotesting specialist Pipe Tek has tested and certified over 700 pipelines throughout the Australia Pacific region, with diameters varying from 1 inch to 70 inches and pressures up to 45,000 kPa.
Understanding the steps involved
Hydrostatic testing is a specialist activity not usually completed by a pipeline contractor’s main workforce, according to Brannelly.
He said it is important to take extra care to make sure that all project stakeholders understand the steps involved in the process.
This includes making sure the team understands how to properly prepare the pipeline for hydrotesting.
To properly prepare:
- Determine where the test medium will be sourced and how it will be transported to the fill point.
- Ensure non-destructive testing (NDT) of all welds have passed.
- On new constructions, ensure a gauge plate pig run has been successful.
- Ensure the pipeline has been pre-cleaned.
- Once this is done, it is important to trust the specialist’s process.
“Hydrotesting isn’t just about filling the pipeline with water. It needs to be filled correctly using pigs to reduce the amount of residual air in the pipeline,” Brannelly said.
“Filling a pipeline from a water cart or standpipe results in air pockets throughout the pipeline, and if there are no high point vents, the pipeline won’t pressurise correctly.
“Too much residual air in the pipeline can result in the test failing or simulating a leak when there isn’t one.”
An experienced NATA- accredited hydrotest contractor will also understand, the importance of water stabilisation after filling the pipeline.
Providing the required information to the hydrotest contractor
To correctly quote and plan for hydrotesting works, the hydrotest contractor needs the following information at a minimum:
Pipe standard, type, grade, or class.
Pipeline length and diameter.
Any elevations in the pipeline.
Maximum allowable operating pressure (MAOP).
The hydrotest contractor will also need information on the parties responsible for associated hydrotesting works, including pre-cleaning, gauging, filling, dewatering, and drying the pipeline.
Some hydrotest contractors, like Pipe Tek, conduct these activities. In these cases, it’s important to let the hydrotest contractor know:
Where the water source is coming from.
If the water requires treatment.
Where the water is to be disposed.
The product that is currently in the pipeline before hydrotesting works – if any.
“Once we have this information, we can estimate the time that it will take to test the pipeline, the type of test required, how long we need to hold it at pressure for, how many temperature probes are required and where they should be located on the pipeline,” Brannelly said.
Keeping the lines of communication open
One recommendation is keeping the communication lines open between the engineer and project manager.
“Project details can change over time, which we completely understand,” Brannelly said.
“But a change in scope that hasn’t been communicated can cause delays to the start of your hydrotest works.”
Brannelly said jobs are quoted and planned based on the information provided by the project engineers.
“But often, we arrive on site and the scope of work is different based on the needs of the project manager,” he said.
“We’re flexible – but it does waste time.”
Include hydrotesting in budgets
Brannelly said most companies don’t allow enough funds in their budget for the hydrotesting process.
As it is often one of the last tasks completed in the pipeline construction process, funds can sometimes run low when it’s time for hydrostatic testing.
In these instances, contractors may try to complete some of the hydrotesting themselves.
This can lead to works not being completed correctly, putting further cost pressure on the project because a hydrotest specialist is required to fix the issues, as well as causing delays to the project.
“Every project is different, so it can be hard to determine how much to set aside for hydrotesting works,” Brannelly said.
“If you’re unsure about how much to budget, talk to a hydrotest specialist. We’re always happy to provide an estimate if we’ve got the information required to do so.”
Allowing for contingencies
Allowing for contingencies in the event that a leak is found during the hydrotesting process, is an important step.
“We conducted hydrotesting for a jet fuel pipeline to Sydney airport from terminals at Botany Bay,” Brannelly said.
“For that project, tankers were on stand-by to be filled with jet fuel to supply Sydney airport if the hydrotest were to fail.”
Schedule adequate time
Hydrotesting requires dealing with very high pressures, which means it’s important to manage the hazards and set up the appropriate safety or exclusion zones.
During a hydrotest, it is normal practice to have no other works conducted onsite, particularly on or above the pipeline.
“All personnel not involved in the hydrotest remain outside of the secondary exclusion zone,” Brannelly said.
“So it is important to make sure there is enough time for the hydrotesting process to occur in isolation from other works.
“Any landowners, business owners or other contractors working in the vicinity of the pipeline or close to the exclusion zones should be notified and, ideally, reduced during the hydrotesting works.”
Asking for advice
If operators are unsure about the information that is required to quote or plan hydrotesting and associated works, Pipe Tek can help.
Pipe Tek offers full-service pipeline integrity and maintenance turnkey solutions across NDT, pre-cleaning, gauging, filling, hydrostatic and pneumatic testing, dewatering, drying with either desiccant or refrigerant dryers, nitrogen purging, caliper pigging, and inline inspection (ILI) with dig ups and verification by phase array.
For more information visit www.pipetek.com.au.
This article featured in the November edition of The Australian Pipeliner.
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