# Relief Devices

FluidFlow contains a database of relief devices that can be used when building a network. The user can choose from either a relief valve or a bursting disk relief device. New devices can also be easily added to the software database. When using database components, it is good practice to check with the manufacturer to ensure the values entered match the current test data available. To access this database, select the Database | Relief Devices menu item:
Actions
Add | Add a new relief valve to the database.
Delete | Delete the currently selected relief valve record from the database. Note: There are certain records, added by Flite, that you will not be able to delete.
Clone | Makes a copy of the currently selected relief valve record and adds it to the database. For example: cloning 'JBS' will result in a new record 'JBS (2)'. Note: This action is only available via the context menu when you right-mouse click on the current record.
Import | Import relief valve records from a FluidFlow2 database.
Load | Loads a ".comp" file - containing a relief valve record - and adds it to your current database. See 'Save' below for more information.
Save | Saves the currently selected relief valve record as a ".comp" file type. This means that if you have created a new relief valve in your local database (stored in your "DATA" Folder), you can save the relief valve file and share it with another user. The user can then use the "Load" button to select the file and add the new relief valve data to their local database.
Relief Valve Data Entry
Name | A descriptive name for this element.
Manufacturer | The name of the relief valve manufacturer.
Materials | The materials used to manufacture the relief valve may be defined in this field, e.g., Steel, Stainless Steel, Bronze, etc.
Applications | The specific applications in which the relief valve may be used, e.g., Chemical, Power, etc.
Inlet Size | Diameter of the valve inlet.
Outlet Size | Diameter of the valve outlet.
Size Unit | Diameter/size units used in the two entries above.
Valve Type | There are three options to choose from: ▪Standard ▪Balanced Bellows ▪Pilot Operated
Usage | Allows you to define the type of systems where the relief device may be used. There are three options to choose from: Gases, Liquids, and Steam.
Design Coefficient (Kd) | This is the ratio of measured relieving capacity to the theoretical relieving capacity, i.e., Actual Flow Capacity/Theoretical (Ideal) Flow Capacity. The actual mass flow rate through the relief valve is diminished from the theoretical value by the existence of a fluid boundary layer. Therefore, a "discharge coefficient" (Kd) is applied to the theoretical value required to obtain the actual flow rate.
Max Backpressure (%) | In a conventional relief valve application, built-up back pressure should not exceed 10% of the set pressure at 10% allowable overpressure. A higher maximum allowable built-up back pressure may be used for allowable overpressures greater than 10% provided the built-up back pressure does not exceed the allowable overpressure. Note, check this value with the relief valve manufacturer's data sheets. Refer to API 520 for further information.
Bursting Disk Data Entry
Name | A descriptive name for this element.
Manufacturer | The name of the bursting disk manufacturer.
Materials | The materials used to manufacture the bursting disk may be defined in this field, e.g., Steel, Stainless Steel, Bronze, etc.
Applications | The specific applications in which the bursting disk may be used, e.g., Chemical, Power, etc.
Usage | Allows you to define the type of systems where the bursting disk may be used. There are three options to choose from: Gases, Liquids, and Steam.
Certified Resistance Coefficient (Kr) | The resistance of the bursting disk is modelled using a certified resistance coefficient "Kr". The flow resistance for bursting disk devices can be obtained from the manufacturer. The flow resistance is expressed in terms of velocity head loss "Kr". ASME Code certified values should be used where available.
If any of the above is unclear or you require any further information, please contact us at: support@fluidflowinfo.com.