The correct answer is: D. Sometimes greater than flange-way clearance.
Heel divergence is the difference between the inside diameter of the flange and the outside diameter of the pipe. Flange-way clearance is the minimum distance between the flanges of two pipes that are connected together.
Heel divergence can be greater than flange-way clearance if the pipe is not properly aligned or if the flanges are not properly installed. This can cause the pipes to leak or to come apart.
To avoid heel divergence, it is important to properly align the pipes and to install the flanges correctly. It is also important to use the correct type of flanges for the application.
Here are some additional details about each option:
- Option A: Heel divergence is always less than flange-way clearance. This is not always the case, as heel divergence can be greater than flange-way clearance if the pipe is not properly aligned or if the flanges are not properly installed.
- Option B: Heel divergence is equal to flange-way clearance. This is also not always the case, as heel divergence can be greater than flange-way clearance if the pipe is not properly aligned or if the flanges are not properly installed.
- Option C: Heel divergence is always greater than flange-way clearance. This is not always the case, as heel divergence can be equal to or less than flange-way clearance if the pipe is properly aligned and the flanges are properly installed.
- Option D: Heel divergence is sometimes greater than flange-way clearance. This is the correct answer, as heel divergence can be greater than flange-way clearance if the pipe is not properly aligned or if the flanges are not properly installed.