So according to this article, the garage door requires more pressure to reverse as it approaches the floor and testing it 3 or 4 feet off the floor is not going to give a realistic idea of what the door might do to a child lying beneath it.
Seems to me that if an inspector is going to actually report on the safety of the automatic reverse response, the door ought to be tested at 6 or 8 inches off the floor with one of these. Anything over 15 pounds gets reported as needing adjustment. I know that’s practically every door out there, but what does that tell you? How many pounds would you want your child or grandchild to be subjected to?
I just got off the phone with Genie (big garage door opener mfgr) and they recommend the 2x4x test (Chuck wins! #20, good post). They said that if the weatherstripping were extra large it might not work correctly.
I asked about the height difference (6 inches as opposed to 1.5 inches) and he admitted that he’s supposed to stick to company policy and not start agreeing with alternatives.
So the 2x4 test is the industry standard but imo it doesn’t do what it should to protect children and toy poodles. I don’t think anyone’s going to break a door with a fish scale if they release after about 20 lbs AND they can use the 2x4 too.
I don’t think you can be required to pay for performing an industry standard test and identifying a condition that could kill a child. Nick has a good point in the article on that link.
Of course there will continue to be inspectors who insist on using the okra/ruler/gum/ball-bearing test.
I certainly wouldn’t object to using a scale. I think it’s a great idea if you can come up with a manageable method. I think I would still do the lower clearance test because the operator travel adjustment will factor in too.
BTW: I use the heel of my shoe laid on its side rather than drag a block around with me. It has enough give that if the door pressure is too high the shoe will just squash (it’s not calibrated for 15# though).
Someone should explain how pressure increases significantly as the door descends, I am not understanding that, I don’t see any increase in mechanical advantage other than possibly the weight of the door. Using a fish scale is great tho, because now you have a number. People who use it should report if there really is a difference checking at various door heights.
The geometry of the trolley arm to the direction of movement changes as it pivots during the final few inches. The door slows in the final few inches. It slows because it is gaining mechanical advantage not because the drive has slowed.
At our monthly chapter meeting last week we had a very well respected garage door company rep do a presentation.
He said the only accepted method of testing is the 2x4 laid on it’s side. They as a company will not test any other way.
It appears that Liftmaster recommends a 3/4-inch board instead of a 1.5-inch board.
I don’t think inspectors are going to keep track of what different testing protocols are recommended by each company if there is one testing protocol recommended for all doors by a Federal agency or one similar to UL.
The guy I spoke from Genie with couldn’t remember the name of the relevant agency. So I’ll make some more calls on Monday. It’s time that as inspectors, we clearly understand our choices and limitations in making recommendations that relate to a system that has the capacity to kill children.
Actually, it says the 2x4 laid on it’s 1.5 inch dimension, which to me means flat, not on it’s side. Obviously terms mean different things to different people. Liftmaster, Genie, and the federal agencies responsible for public safety, all recommend a 2x4 placed so that the door is required to reverse at 1.5 inches above the garage floor.
Unfortunately, they don’t specify a pressure at which the door is required to reverse, which seems pretty important, since no inspector wants to say “yeah it’s fine” about a garage door that kills a client’s kid right after his clients move in.
I don’t think determining the amount of pressure it takes to reverse a garage vehicle door at a certain point above the floor (6 inches) at which a child might be at risk of being injured or killed is difficult or a guessing game. I think no one has bothered to do it. But I think without the backing of federal regulatory agencies, inspectors who us specific methods to identify deficiencies in these systems to call out inadequate automatic reverse systems may lose work because they’re perceived as alarmist by real estate agents.
