Formulas

Our basic formuals below will help you choose the correct Raci Spacer element.

Formula One To Determine Height Required

Casing pipe ID - Carrier pipe O.D. / 2 will give you the desired range for element height.

Go to the table that best addresses the carrier pipe O.D. and load carrying capacity to determine the different heights that are available within that style.

Formula Two To Clear The Bell

(carrier pipe O.D.) + (2 times height of element) > O.D. of bell + clearance factor*

*Clearance factor is .6 inches or 15 mm and ensures bell clearance.

Formula Three For Insertion Ease

(carrier pipe O.D.) + (2 times height of element) + clearance factor* < the I.D. of casing pipe

*Clearance factor is .6 inches or 15 mm and ensures insertion ease.

*When working in inches the clearance factor is .6

Once you have determined the element type and the height necessary return to the table to determine the number of elements required to complete a ring.

Formula Four Number Of Rings Required

Length of application / distance between rings + 3*

*The spacing of Raci spacer rings must ensure that the carrier pipe is fully supported throughout its length.

To guard against the effects of differential loading at the entrance and exit points of the casing, two rings are used at the beginning and end of the each casing, regardless of pipe size or length.