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Stress causes breakdown, in people and in pipelines

The words ‘load’ and ‘stress’ are often but incorrectly used interchangeably within our industry. A good joint integrity specialist knows the difference and relationship between the two factors.

People in the workplace can be compared to pipelines. The number of tasks assigned an employee would be the load, with the stress coming from too many tasks or too few tasks.

Too much or too little stress can lead to failures to perform, affecting the staff member and colleagues. A balance is required between load and stress to achieve optimal performance.

Each joint component in the pipeline - the flange, the bolts and the gasket - must have sufficient load to make an adequate seal. Too much can lead to a breakdown of the component, while too little can result in leakage.

Hydratight wants components to act elastically, rather than plastically. A bolt with the correct load on it will stretch when torque or tension is applied, will utilize the material’s elastic properties in trying to return to its original state, but in doing so will compress the gasket to form a tight, clamping seal. However, if too much load is applied the bolt could become permanently stretched, no longer able to return to its original state and thus compromising its ability to form prolonged a seal.

How do we know the correct loads to apply and how much stress each component should be subjected to?

Load is the force acting between two components in contact, while stress is the effect of forces across a cross sectional area of an object. Insufficient load on one joint component can affect the others and even neighboring joints. Boundary conditions provide a framework of stress values, typically described as minimum, recommended and maximum.

Some components have a minimum stress determined by their material make-up. We use data provided by our manufacturing teams or external suppliers and make informed recommended stress judgments based on the type of flange and bolts in the configuration. We must also be aware of maximum stresses - this represents the maximum stress before the component moves out of the elastic range and into the plastic range.

Effective training from technician level onwards means everyone at Hydratight follows our Joint Integrity philosophy and practices. This ensures Load vs Stress is understood and practiced. Any person interacting with a joint will know the precise relationships between joint components and can protect them from unnecessary damage so they are right first time and long lasting.

Hydratight’s extensive track record in providing leak-free connections is a testament to employing industry recognized best practices.