SCH 10 and SCH 40 are both classifications for pipes based on their wall thickness, primarily used in the context of steel pipes. The "SCH" stands for "schedule," which indicates the thickness of the pipe walls. Here's the difference:

Wall Thickness: SCH 10 pipes have thinner walls compared to SCH 40 pipes. SCH 10 pipes are lighter and less robust, while SCH 40 pipes are thicker and stronger.

Pressure Rating: SCH 40 pipes can withstand higher pressure compared to SCH 10 pipes. This makes SCH 40 pipes suitable for applications where higher pressures are expected.

Application: SCH 10 pipes are typically used in low-pressure applications where strength and durability are not critical factors. On the other hand, SCH 40 pipes are commonly used in applications where higher pressures or heavier loads are involved, such as in industrial settings or for carrying fluids under higher pressures.

Cost: Generally, SCH 40 pipes are more expensive than SCH 10 pipes due to their thicker walls and higher pressure rating.

In summary, the main difference lies in the wall thickness, pressure rating, application, and cost between SCH 10 and SCH 40 pipes.