Hole Arrangement & Open Area Formulas

Open Area is the ratio between the total area of the holes and total sheet area, normally it is expressed by percent.


Round Hole, 60° Staggered

(R2 X 90.69) / T2 = %

Round Hole, Straight Row

(R2 X 78.5) / (U1 X U2) = %

Round Hole, 45° Staggered

(R2 X 78.5) / (K1 X K2) = %

Square Hole, Straight Row

(C2 X 100) / (U1 X U2) = %

Square Hole, Staggered

(C2 X 100) / (0.5 X Z1 X Z2) = %

Round End Slot, Straight Row

(R X L – 0.215R2) X 100) / (U1 X U2)
= %

Round End Slot, Z Type Staggered

(R X L – 0.215R2) X 100) / (0.5 X Z1 X Z2) = %

Round End Slot, K Type Staggered

(R X L – 0.215R2) X 100) / (0.5 X K1 X K2) = %

Square End Slot, Straight Row

(L X C X 100) / (U1 X U2) = %

Square End Slot, Z Type Staggered

(L X C X 100) / (0.5 X Z1 X Z2) = %

Square End Slot, K Type Staggered

(L X C X 100) / (0.5 X K1 X K2) = %

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