A flange connection is a complex mechanical device, therefore, engineering that provide leak-free solutions are the result of many selections/activities having been made/performed within a relatively narrow band of acceptable limits. Each joint assembly procedure should be subject to an appropriate review by qualified engineers.
Fitting flange connections requires knowledge and expertise. Determining how the flange connection has to be fitted requires knowledge of the all parts of a flange connection such as materials, forces and stresses, temperature influences and among numerous other factors.
One of the activities essential to leak-free performance is the joint assembly process. The guidelines that are needed has to cover the assembly elements essential for a high level of leak-tightness integrity.
Asset owners are coming under ever increasing pressure to reduce fugitive emissions for a number of reasons including environmental (legislation) and safety and commercial (plant efficiency). A number of the resultant costs are often difficult to quantify such as loss of product, cost of labour/materials to repair leaks, cost of cleaning the affected area, environmental fines, and image. Flange Management is the total package of services that provides the best possible chance of achieving a leak-free start-up.
Correct assembly of a critical flange connection requires that the connection is calculated and the correct bolt preload, lubricant and the allowable alignment tolerances to seal the joint is established. It requires the most suitable gasket to be installed for the service, flange face condition and bolt and nut condition to be inspected and for the determined bolt perload to be applied in a controlled manner. Incorrect bolt loads, flange distortion, inappropriate gasket selection and uncontrolled flange assembly/bolt tightening methods are the main reasons for joint leaks. By taking some simple steps these potential causes for failure can be eliminated.
The integrity of flange connections is often insufficiently known to the asset owner. Mechanical failure of construction (parts) or materials in general is the second cause of failure of incidents with flange connections. In general, fugitive emissions occur due to non-or incorrectly closed flanges. Fugitive emissions are emissions of gases or vapors from pressurized equipment due to leaks and other unintended or irregular releases of gases, mostly from industrial activities.
In the design phase, the client makes demands on the flange connections. In the construction phase, the flange connections are tested by means of inspections and various tests by the executing Party. To ensure sufficient safety, these flange connections must also be maintained and inspected during the management phase. On the basis of the above it is important that attention is paid to flange connections. Flange Management helps asset owners with manage the flange connections.
Legal frame of reference
The legislation requires an asset owner to do everything that can reasonably be expected of him to prevent leaks and the consequences thereof (duty of care).
Standards such as ASME provide guidelines to an asset owner for dealing with condition monitoring of flange connections during the management or operation of the pipeline system.
Our goal is to make asset owners aware of the presence and the specific risks of flange connections in their pipeline system and the way in which they can carry out systematic checks in the management phase. It also contributes to a better awareness of high-risk issues among the asset owners in terms of (external) safety and thus compliance with the legislation.
A specific technical investigation must be carried out into flange connections. When applying flange management the following is tested: Environmental management systems (Requirements with guidelines for use) or own company guidelines for flange connections, with which the asset owner can comply with the lesislation. The use of a method, such as the PDCA cycle for the flange connections of the pipelines, in the management phase. The risk management system (RMS) must be based on the method of the PDCA cycle. This must be conclusive, controlled and guaranteed.
Flange management is intended for asset owners. The results of and recommendations provide an indicative view of the working method.