Let’s Learn: What is a Bearing?

By Nick Thiessen

Bearings are an essential part of fans at S&P USA that keep a fan at its optimal performance. In this blog, we will learn more about this critical piece that keeps things running smoothly.

A bearing is an element that constrains the movement motion to only the desired action and reduces friction that occurs between the rotating shaft and the part that supports the rotation, in our fans, a pillow block mount. Bearings are used between these two components. Thus, the bearings serve to reduce friction and allow for smoother rotation. This is the single most crucial function of bearings.


Commonly referred to as L50 200,000 hours and L10 100,000 hours. These numbers symbolize the lifespan of the product.

The first term, L50 or L10, denotes the type of lifespan that is being specified. L50 is commonly known as the average life, and it is the amount of time for 50% of bearings to fail. L10 denotes 10% of the bearings will have fatigued after a specified amount of time.

L10 is the better way to specify bearing life because it denotes a 90% reliability, which can be used for planned maintenance and repair.

The second term in the bearing life is the number of hours. In our example, L50 200,000 hours. This number represents the hours of continuous operation that will lead to either 50 or 10% failure for L50 and L10, respectively.


These two numbers relate to each other in equivalency. L10 40,000 hours is the equivalent of L50 200,000 hours, and L10 100,000 hours is equivalent to L50 500,000 hours!


At S&P USA, you will find all of our fans are rated for a minimum bearing life of L50 200,000 hours, and many are rated to L10 100,000 hours (L50 500,000 hours).

Bearings are used in every belt drive fan we sell including Belt Drive Centrifugal Downblast Roof Exhaust Fan, Upblast Belt Drive Centrifugal Roof/Sidewall Exhaust Fans, High Temperature Upblast Belt Drive Centrifugal Roof Exhaust Fans, Belt Drive Upblast Propeller Roof Exhaust Fan, L2/LS Belt Drive Sidewall Propeller Exhaust/Supply Fans, and L3E and L3S Belt Drive Sidewall Propeller Exhaust/Supply Fans.

Tags: Commercial