The critical design parameter in any pneumatic conveying system is the conveying line inlet air velocity. With different grades of the same material care must be exercised in design and specification of the plant and components. Emphasis is given to system design and system operation and so problems are considered in two ways. For a new system the conveying variables are highlighted so that they should be taken into account in the system analysis an design process. For existing systems chapters are devoted specifically to troubleshooting. Numerous equations can be used to check operating parameters.