Typical Geometrical Characteristics of fused silica tubes

At Heraeus Conamic we have been dealt with tubes for a long time. Over the years we developed our own vocabulary for talking about the geometric properties of tubes. Not all are intuitively understood, therefore, we help you visualize them below. Please note, not all properties are part of a specification, but they might be and tolerances are a key factor in determining the price of your product.

Find an overview of the available tubes on our product pages

Outer Diameter (OD)

Outer Diameter Tolerance

Maximum deviation of real 

OD from nominal OD in mm.

Inner Diameter (ID)

Inner Diameter Tolerance

Maximum deviation of real ID from nominal ID in mm.

Wall Thickness (WT)

Wall Thickness Tolerance

Maximum deviation of real WT from nominal WT in mm.


Maximum wall thickness minus minimum wall thickness in mm.


Difference of Maximum OD and minimum OD at one ring in mm.


Maximum displacement of tube center when both ends are on the axis of rotation in mm.

Cross Sectional Area (CSA) variation

Variation of CSA in one tube: Difference of Max. and Min. CSA normalized to avg. CSA of tube in %.