Eliminate risk and reduce your downtime - critical factors to consider to eliminate pipe deflection stress.

by Advanced Piping Systems
on June 18, 2019


Bracket Failure x 3Can the right support prevent your pipeline's shutdown?

In polyethylene pipelines, insufficient supports and bracketing can lead to unwanted shutdowns because it causes further problems. The primary cause of those problems is pipe deflection.

If a polyethylene pipe is insufficiently supported, you will face a range of issues, including:

 - buckling
 - kinks
 - stretching
 - tearing
 - air-locks

If you use elastomeric seals, excessive deflection can also cause leaks. Additionally, it can prevent the effective mechanical cleaning of your pipeline, and reduce its hydraulic capacity.[2]

To prevent these problems there are two critical elements to consider: Temperature, and weight.

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Critical factor 1: The temperature fluctuation of your pipeline

Temperature has a strong impact on polyethylene pipe installations. Consider it carefully, especially if your length of poly is replacing steel pipe.

The outcome is initially cosmetic: The pipes sag instead of running straight. Nevertheless, sagging pipe will reduce the performance of your pipeline.

Here at Advanced Piping Systems, we’ve seen all kinds of issues relating to temperature. In one extreme case, polyethylene pipe installed during winter, when it was cold, stretched once the weather warmed up. The sag was so significant that the pipeline ended up looping between the brackets.

Stretched pipelines aren’t your only risk. If you install your pipeline during higher temperatures, it can shrink when it gets cold, or transports cold media.

Factor in the temperature fluctuation of your pipeline when considering installation and support.

Critical factor 2: The weight of your pipeline’s load

The weight of your pipeline’s load also has a significant impact.

A simple example is a water pipeline, such as one that we have seen in irrigation.

By installing the pipeline dry, you aren’t going to get a complete picture of how the it is going to function. It looks like it will function perfectly—until you fill it with water. Once it’s full, then if it’s insufficiently supported, it will sag and impact your flow rate.

If you have a combination of poorly supported pipe, in a hot environment (or transporting warm to hot materials), with weight, then you have an accident waiting to happen.

Your pipe may end up tearing or shearing off if the issue isn’t addressed early enough.

Compensating for pipeline deflection

If you are used to working with steel pipe, then you might think that the bracketing needed for polyethylene pipe looks like overkill. In many situations that we have seen where insufficient bracketing has been installed, this has been the case: It wasn’t installed, because it seemed like too much.

There are other ways in which you can compensate for changes in length. For example, you can use change of direction as your absorbing mechanism, provided you use the appropriate deflection legs. You might also be able to use compensation loops, or expansion compensating joints. Contact us for more information about these.

The payoff of using the correct supports is that it prevents maintenance issues down the track, and preserves your pipeline’s high performance.

You’ll find that your pipeline’s media moves more efficiently and, if you clean your pipeline mechanically, that process will be easier. Over time, your pipeline will continue to exhibit peak performance, uninhibited by the deflection caused by poor support.

How to determine how many brackets your pipeline needs

Polyethylene pipe requires far more support than a steel pipe. As an example, let’s consider a 63 mm pipe. This pipe should have a bracket every 1.3 metres, if you follow the Standard Dimension Ratio.

Below is a full table that will help you to work out your pipeline’s required supports. It’s taken from the the Advanced Piping Systems catalogue, where you’ll find it on page 172.

Support Spans

In Conclusion

Making sure that your pipeline has the correct supports will prevent maintenance problems in the short term and unwanted shutdowns in the long term. Even if the bracketing looks like overkill, preventing unnecessary deflection will stop you running into bigger problems down the track.

When you need focused help fast, get it from a supplier who works to keep your plant moving. Call Advanced Piping Systems now on 1300 792 879.

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