Every hangar door leaf has two top guide rollers at the head. The primary job of a roller is to guide the door leaf along the top guide rails, but it also defines the deflection capabilities of the door.
When we use the terms wind or live load deflection in horizontal rolling hangar doors, we’re talking about how many inches of vertical movement (+/-) a door can tolerate from wind or snow.
There are two types of top guide roller available to choose from and it’s critical the right one is paired for your building.
Here’s what we’re covering in this article:
- Fixed Rollers
- Telescoping Rollers
- Rollers in Summary
Fixed Rollers
A fixed roller will be manufactured with a fixed deflection limit. This could be as low as 1-inch or as much as 6 inches.
If a fixed roller is used in an environment where wind could lift the building roof more than the door roller’s deflection capabilities, the door is at risk of lifting off its bottom rails and falling down.
On the other hand, heavy snow loads or downward winds could jam the door in place making it strenuous or impossible to operate.
Telescoping Rollers
A telescoping roller is visually very easy to distinguish because it has a long pogo tube. This tube allows the door rollers to move up or down as the deflection loads of the roof space change. These rollers can be designed to wider levels of deflection than a fixed roller, often upwards of 15-inches (+9 inches/-6 inches), making them the most sensible and safest roller for large horizontal rolling doors.
Rollers in Summary
The telescoping roller is considerably more expensive than a fixed roller, but you’re protecting yourself from the hazards I explained earlier. You’ll also upgrade to a floating weather seal, which prevents airspace appearing between the head of the door and roller as positive deflection is encountered. Talk to your building manufacturer about the load limits of the roof space within the hangar door opening. Relay this information back to your hangar door manufacturer and the right choice of top guide roller and deflection capability can be specified. If you’re retrofitting a door to an existing building structure with no load calculations to determine deflection limits, I recommend you err on the side of caution and use telescoping rollers.
Paul Blake is project director of AeroDoor International, Eustis, Fla. For more information, visit https://hangardoors.aero/or call (866) 226-3667.