Is your metal roof prepared for 120 or 200 mile per hour winds? What about 45-105 pounds of pressure?

The way to know is by performing a wind uplift resistance test. There are three levels of performance a roof can achieve in the test: the UL Class 30, the UL Class 60 and the UL Class 90. The MR-24 roof is available at a UL Class 90 in its standard configuration! When you install an MR-24 roof in its basic form, you automatically have a UL Class 90 roof system.

What does a UL Class 90 mean for your roof?

Roof system classifications begin at a UL Class 30. In this Class, the uplift pressure the roof has to resist is approximately 45 pounds per square foot. This is the same pressure achieved by a 120 mile per hour wind! Although that seems very high, that is just taking the horizontal wind into account. The wind blowing into the side of the building moves up to the top as well, creating a force around the perimeter of the building. This 45 pounds of pressure can actually be achieved at a lower wind speed.

A UL Class 90 would be the next level. This Class tests at an uplift pressure of approximately 75 pounds per square foot. During this phase, Butler testing also runs a cyclic phase to simulate changing pressures and dusting. 

Lastly, a UL Class 90 tests at approximately 105 pounds per square foot. This is equivalent to a 200 mile per hour wind pressure. During this portion of the test, an MR-24 roof system’s seams do not come apart, and if any kinks occur, there is still a weather-tight membrane inside of the building. Typically, under this type of pressure, other seams would loosen and allow air to flow through. The MR-24, however, remains air and water tight and returns back to its original configuration.

The video below is a demonstration of the wind uplift tests on the MR-24 roof that Butler performs. In addition to the wind uplift, Butler also tests a variety of other standards, such as projectile penetration and more.

The test is performed on a 10 square foot piece of roof. It starts by evacuating the air on the top side of the roof and then lets the atmospheric pressure push on the bottom side. This creates an uplift form, which is then measured.

Now you know a little bit about wind uplift and the outstanding performance of the Butler Mr-24 roof system.

Watch the video below for an example: