LINEAR DIMENSIONS

The actual dimensions of individual regular units should conform to the declared work dimensions subject to the tolerances given below. Individual UKCSA cast stone manufacturers may specify tolerances that are tighter than those in the table given below.

Dimension (mm)
Up to 600
601 – 1000
1001 – 2500
2501 – 4000
Over 4000

Tolerance (mm)
+ / – 2
+ / – 3
+ / – 4
+ / – 5
+ / – 6

.

FLATNESS OF PLANE SURFACES

Where the surfaces intended to be exposed in the finished cast stone are declared by the cast stone manufacturer to be plane, they shall not deviate from a plane by more than the values given below.

Max permitted variation = 0.3% of the maximum dimension of the item or 2 mm, whichever is the greater.

The equipment required to perform this test shall be:

  • Straight edge of equal or greater length to the maximum dimension over which the flatness is to be measured or 1.5 m whichever is the lesser.
  • Feeler gauges (two sets).

Method

Concave Surfaces: Place the straight edge on the surface of the item to be tested. Insert a feeler gauge blade between the straight edge and the surface of the cast stone. Measure the deviation from the straight and compare with the value given above.

Convex Surfaces: Place the straight edge on the surface of the item to be tested. Insert two feeler gauge blades of identical size, one at each end of the straight edge such that contact is made between the feeler gauge blades the straight edge and the stone. Measure the deviation from the straight and compare with the value given above.

NB: The deviation from the straight is the thickness of one feeler blade not the sum of both.

BACK