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Garage Doors and How To Test Them
By Edward Robinson | July 11, 2008
I was reading the June ASHI Reporter and came across an article on the testing of garage door openers. The article basis was that inspectors were improperly testing door openers and causing damage to the overhead doors that the inspectors should presumably be responsible for due to an improper testing methodology. The point of the article was that inspectors should only test the reversing mechanism of garage door operators by placing a 2×4 board on its side under the door and allowing it to close against the board rather than stopping the door by hand at mid height. It also stated that the purpose of the auto reverse was not to prevent crushing injury. I, as many of you, have been testing doors using the hand method for years and was skeptical of the article which prompted me to look into this subject further. While I agree that the auto reverse would not be expected to prevent injury from crushing, the door adjustment related to this test should mitigate this problem. What I found was that many of us don’t do it so wrong after all, even according to the Door and Access System Manufacturing Association (DASMA).
In one of the postings on the DASMA website, posting TDS #369, DASMA states:
“Testing may, and should, be conducted at different heights to verify that the door reverses properly; however, the door MUST be tested to reverse off of a one-inch block or a 2×4 block of wood laid flat on the floor centered on where the door closes.”
This appears to contradict the ASHI article but confirms what many inspectors believe to be an essential test. One must be very careful not to cause the door to buckle or otherwise fail during a hand test. This is actually true regardless of whether you use your hand or a block as is indicated in the videos and literature provided by DASMA. The closing force of the door expected is the minimal force necessary to allow the door to close and any greater force should be considered in need of repair. The most minimal force is desirable to reduce the potential for a crushing hazards to persons or things in the path of the door as much as reasonable and is a judgment on the part of the inspector. You are cautioned that there is an inherent risk of injury to the inspector should the door fail and fall on the inspector, so keep it in mind when considering the hand test. The literature I read is clear that the hand test is not the only test that should be performed and that the 2-inch block test is essential in addition to any other testing to ensure that reversal works near the floor where the door is most likely to experience an obstruction.
When you get some time, visit the DASMA website and read their publications. They cover all aspects of door and opener evaluation and will provide a valuable resource to inspectors. Specifically, review document TDS #167 which is a checklist for inspector evaluation. You can also view the video presentation which is available as two videos on YouTube.com:
Video One
Video 2
You can damage an overhead door if you do your job without thinking about it using either test method, and the inspector should be diligent to inspect safely. Providing resistance for a closing overhead door by hand should not damage the door if you allow the door to proceed after it has exerted a reasonable load on your hand; however, if you hold a door under load to an unreasonable and foreseen failure, then perhaps you should be responsible for not using good judgment.
Topics: Real Estate Inspections |
July 16th, 2008 at 6:29 pm
Edward, I too read the ASHI article in wonderment. I too use the hand test. I too don’t want my hand torn off so I hold such that the door slides off easily.
As I read the article I found myself wondering what good is a 2×4 at ground level when a Mercedes parked across the opening is about 5 feet. I guess the doors are designed to crush anything in its path until is gets to the height of a 2×4…OR WHAT!
I have found a few, very few, that reverse at the touch of a feather. I am always impressed with those.
I use those to call for repair on those who don’t easily reverse. I guess I keep thinking of the toddler caught under a door, it doesn’t take much pressure to do them in.
I keep checking and calling for repair as needed. Don’t we all.
Mike Cothran
July 22nd, 2008 at 4:26 am
Edward and Mike,
As I read the article, several thoughts came to mind, one of which is “Maybe that’s why my back hurts all the time”, although it could just be the abuse over the years. Anyway, I too found it interesting that they would use a block of wood to test the reversing capability of the equipment. I also found it humorous that the “Reporter” recommended that this not be tried on the job. I guess some folks just have to be told.
I have heard, don’t remember where and cannot find a proof source, but this goes to Mike’s reference of a toddler being crushed, that OSHA uses a test with a roll of paper towels. The theory is that a roll of paper towels is approximately the same crush consistancy of a baby or toddlers body mass. Once the door contacts the roll, it should, compress slightly and then reverse. Again, I cannot find a proof source for this statement, however, it seems plausible. I always have a roll of shop towels in the truck and if nothing else, it creates a dramatic demonstration for the client on the value of having a proper adjustment on the doors throw strength or the proper installation of electronic sensors.
Jonathan Lang
July 22nd, 2008 at 5:29 am
It has been a while since I did the research for this article. I believe the paper towel roll test was mentioned in the DASMA literature somewhere. The issue was not that the test was not good in general but that rolls of paper were inconsistent and did not give a good test.