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Inspecting and Testing Overhead Garage Doors


hausdok
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Log onto any internet discussion forum for home inspectors and one of the most hotly debated topics is always how to properly inspect and test overhead doors and the automatic entrapment safety features of any automatic openers used to control them.

It's one of those topics that is usually initiated when an inspector laments the fact that an unhappy homeowner is demanding that the inspector pay for damages to an overhead door or an opener that were caused when the inspector tested the opening device. Though the inspector might have initially brought up the subject seeking advice on how to deal with the homeowner's complaint, the thread rarely stays on topic and these discussions usually end up focusing on whether the inspector's inspection/testing method is proper.

That's where the controversy begins. Being home inspectors and being used to offering opinions on all manner of things, there is never any shortage of opinions offered by respondents to the thread initiator on how to go about testing these devices and whether or not the inspector's actions actually led to the damage. Ultimately, the threads usually devolve into war stories about past experiences and no consensus ever seems to be reached about which is the proper method. In fact, instead of narrowing the scope of methods available, every new discussion on the topic seems to produce a new, and sometimes bizarre, testing method that is enthusiastically promulgated by one or two respondents.

My curiosity aroused by one of these debates, I decided to do a little research on my own in the hopes of finding a single standard on which to hang my hat for inspecting and testing overhead doors and their openers. I eventually found what I was looking for and since then have utilized what I believe to be the only defensible method for inspecting these devices.

A little bit of history

ANSI UL Standard 325 is the standard with which all automatic garage door and gate operating devices must comply. It was initially announced in 1973 and amended in 1982 to set initial requirements for residential garage door operators, sensing devices and motion sensors. Because those initial requirements were pretty rudimentary and didn't provide nearly as much protection for consumers as they do today, installers and consumers widely ignored precautions contained in the manufacturers' instructions and accidents were inevitable.

Consequently, On October 7th 1988 the Consumer Product Safety Commission (CPSC) issued a safety alert citing the death of 32 children, between the ages of 2 and 14, who'd died between 1982 and 1988 after being pinned by garage doors. In that initial release, CPSC urged parents to keep remote control devices locked up and door switches mounted high, out of arms reach for a child.

Six months later, after the deaths of four more children, CPSC issued another warning to homeowners, particularly parents and grandparents to replace any garage door opener that didn't have an automatic reverse function, with one which had been certified to meet UL 325 as amended in 1982. This is the first memo wherein CPSC recommended that consumers test these devices every 30 days by placing a 2 inch thick wooden block on the floor in the path of the door's travel. If the door didn't reverse, the CPSC release recommended repairing or replacing the device to bring it into compliance.

Roughly a year and a half later in October of 1990, after an additional 9 children were killed, CPSC issued another warning that cautioned homeowners that units manufactured before 1982 didn't meet the standards of UL 325. The notice went on to explain that some older openers were designed only to stop when encountering an object(clutch type) while others were supposed to reverse but didn't for a variety of reasons, and couldn't be repaired or adjusted to bring them into compliance.

Again, CPSC recommended that homeowners test their doors using the 2" thick wood block method and, if the door didn't reverse properly, to disengage the mechanism and call for repairs. In those cases where openers didn't have any auto-reverse feature, CPSC recommended disconnecting the opener until it could be replaced with one meeting the standard.

By then, CPSC had met with manufacturers to urge them to intensify their efforts at informing homeowners about the dangers of these devices and had published rules that specifically required any overhead door opener manufactured after January 1, 1991 to have entrapment protection. This was the first notice wherein CPSC informed the public that post-1982 units could be retrofitted with "electric eyes" "near" floor level, and, besides the usual warnings about switches and controllers, this notice warned homeowners to ensure they are periodically checking their track rollers and other hardware.

By October 1992, after an additional 3 children had been killed, CPSC published a final set of rules for all automatic residential garage door openers manufactured on or after January 1993 for sale in th Unites States. These rules included provisions for mandatory secondary entrapment devices as well as certification requirements and record keeping for manufacturers and subsequently became Federal Law (16CFR1211) and were published on December 3rd 1992.

So, Exactly What is the proper testing method?

16CFR1211 states that an automatic door opening device must stop and reverse the direction of the door within two seconds of encountering a 1-inch high object placed at the center of the door in the line of travel on the floor. Once it encounters the object, the opener must return the door to its full-up position. For testing purposes, the rule allows use of a 2 by 4 (1-1/2" thick) placed flat on the floor as an exception, but does not approve of any other method of testing, ie. standing and holding the door with one's hand; placing cardboard boxes, a roll of paper towels, weight-gauging devices or empty and capped plastic soft-drink bottles under the door's edge as it is closed.

Since this is the only method mentioned in the rule, anyone who is testing a door anywhere above the height of a 2 by 4, or with anything but a 2 by 4, is taking a chance on lightening his or her wallet. While other methods might be just as effective, these devices are built to comply with only this standard. So, if an inspector breaks a door or opener while testing it with another method, he/she might be hard-pressed to prove that those actions didn't directly contribute to the damage. Bottom line, the federal standard has been set - stick to it and consider it a gift to all home inspectors. Using any other method is foolhardy.

How much down-pressure is too-much?

Unless overhead door openers have been adjusted to exert only light pressure before reversing, at 1-1/2 inches off the floor they will not reverse and the 2 by 4 ends up trapped. When properly adjusted they kick back with hardly any back pressure at all. However, lighten the down-pressure adjustment too much and the door will go down, strike the floor and return to the upright position - even when the travel adjustment is properly set.

This is where home inspectors can get into trouble. Much is made by home inspectors of the down-force they feel when trying to hold one of these doors as it is being closed. Many inspectors actually write up doors for having what they believe to be excessive down-force, despite the fact that the door opener does stop and return the door within two seconds as required by the law. Are they right? Maybe not. 16CFR1211 does not specifically state there is an acceptable or unacceptable pressure or weight allowed before the door must reverse. What the residential standard does state is that, except for the first foot of it's travel from the fully-opened position, that a downward-moving door has to come to a complete stop and reverse within 2 seconds of contact with a 1-inch high object. So, a homeowner who pays an overhead door mechanic to adjust a door and is then told by the mechanic that the door is properly set might be completely justified in demanding that the inspector make reimbursement for an unnecessary service call.

There is one paragraph in 16CFR1211 wherein the parameters for UL testing have been set forth by CPSC where one might infer from the text that there is a quasi-standard of 15 pounds (66.7 newtons) pressure for these devices. That section deals with doors equipped with a bottom edge sensor that doubles as a door gasket and states that testing must be done along the entire edge of the door. Since it must initiate reversal with 15 lbs of pressure on a door equipped with an edge sensor, logic seems to dictate that this standard should apply to other doors as well. However, these are only testing parameters for UL. The rule doesn't say anything about homeowners, installers or home inspectors utilizing this as a means to gauge whether a door is closing with too much force or not. So, though one might be able to infer that more than 15lbs of down-pressure is unacceptable, unless the door is equipped with edge sensors it probably won't stand up in court.

Bottom line, the door must stop and re-open itself within two seconds of striking the object on the floor and, unless the entire bottom edge of the door is equipped with a 15lb. sensor strip, the amount of down-force can exceed 15lbs. If the opener can't meet this requirement, write it up.

How about secondary entrapment devices and controls?

The rule also sets standards for the photo-electric sensors commonly used as secondary entrapment safety devices. According to the rule, the maximum height at which they should be placed is what the manufacturer's instructions state. However, the rule also states that they must be able to detect a vertical object 6-inches high by 1-ft. wide placed at the center of the door and one foot from each end of the opening.

Since I often find these devices mounted anywhere from one foot to several feet off the floor - and even found one set mounted on the ceiling of a garage - I spoke with Allen Claxton, the UL Standards Tech at Genie Overhead Door Corporation to see what height they recommend. According to Claxton, Genie recommends installing them between 4 and 6 inches off the floor, since mounted any higher they won't be able to meet the object standard.

The rule also goes into graphic detail about the placement height and location for door operator controls and mandatory placement of instruction sheets - including the colors of instruction sheet and even the size of the font to be used. Switches must be installed no closer than 5' to the nearest standing surface - not the garage floor - so a child can't reach them from either the floor of the garage or the floor of the room leading into the garage. I find them installed 5' off garage floors all the time, right next to a step-up from the garage to the house where a child can reach them easily.

Look for the red, black, orange and white safety decal that is supposed to be mounted near the wall-mounted control button. It might seem like a quibble, but I often find them missing - even on brand new homes - and the law says they are required. I once asked a builder if he knew where one of these stickers was. "What sticker?" the builder asked. "You know, the one that federal law says is supposed to be on the wall next to that control," I answered. His face went blank. "Where's the instruction booklet for the opener," I asked? He led me into the kitchen to a drawer full of literature, dug around and came up with a plastic bag full of instructions for the door and opener, including the sticker. When I explained that a federal law requires that the sticker to be installed near the controls, he asked me, "How come the guy who installs my openers and the code guys don't know that?" "Good question," I responded, "Why don't you ask them?" It seems home inspectors aren't the only ones who are still poorly informed about these devices.

What about the rest of the door?

There's more to inspecting a garage door than just testing the opening device. The first thing one should look at is how the mounting brackets for the opening device, tracks and springs are secured to the walls and ceilings and how each component is bolted to these. It's not unusual to find them loose or damaged. Ensure that the opener is solidly bolted to the brackets and that the bracket holding the other end of the opener is properly and securely anchored to the wall/header above the overhead door? If there a dedicated outlet for the opener, ensure that it is close enough to the opener that an extension cord isn't necessary. If the hardware is loose or missing, write it up. If there isn't an outlet within reach of the cord, write it up.

If the door is wood or a wood composite, before opening it, determine whether it has ever been primed and painted properly on the inside surface and all edges. Every single wood or wood byproduct overhead door manufacturer requires these doors be primed and painted before installation or the warranty is void. You can usually find the instructions clearly printed on a label attached to the door or stenciled on the inside surface.

Why is priming and painting them so important? Well, when a car is driven into a garage in rainy or snowy weather and the rain or snow ends up on the garage floor, it evaporates and then condenses against the thinnest membrane in the garage - usually the door - and then begins to foster mildew growth. The mildew feeds on and softens the glue in the finger-jointed stiles and rails of the door, or in the lamina, and causes the joints to separate and the panels to delaminate. So, if the door isn't properly primed and painted on all surfaces, write it up.

With the door in the down position check the lift cables for fraying and examine the torsion spring and axles for cracks in the axle, signs of slippage where the torsion springs are anchored to their axles or broken spring segments. If any fraying or broken spring segments are found, write it up.

It's very important to check the tightness of the nuts and bolts that secure every hinge to the door. These are loose 9 out of 10 doors that I check and will re-loosen in only about 4 months, if lock washers or star washers aren't used. I was explaining this to a client once when she interrupted me and said, "You don't need to explain this part to me. My grandfather is paralyzed from the neck down because he failed to properly maintain his garage door. He walked into his garage one day, hit the opener button and began walking over to his car. Just as he reached the side of the car, that 18ft. wide wood door jumped it's track, fell on him and broke his neck." There was kind of an awkward silence for about five seconds as I absorbed that, at which point I expressed my sympathies and we moved on. So, if the hardware is loose or missing, write it up.

Run each door up and down a couple of times. Ensure the door is moving smoothly and isn't hanging up in the track. Check every dolly axle while doing so. It's amazing how many of these are missing ball bearings and are ready to pop off the track. Check the doors balance by disengaging the emergency relief handle with the door in the down position and manually raising the door and ensuring that it will remain in several positions along the length of it's travel without slamming shut. The door needs to be neutrally balanced, so it should not be difficult to lift and should remain in whatever position you leave it at any height. Check the height of the emergency release handle and ensure that it is at least 6' above the floor. If the door binds, there are bearings missing, the door isn't neutrally balanced or the handle is less than six feet off the floor, write it up.

When the door is in the full-up position and uses side springs instead of torsion springs, examine the springs for weak over-stretched sections, and look for safety wires in the side springs. Any loose dolly wheels or axles, weak springs and missing safety wires should be written up.

In conclusion, these doors are often the single largest and heaviest moving object in a home and no home inspector can afford to screw up this part of the inspection. Making a mistake here can place a homeowner or client's safety at risk and might ultimately jeopardize an inspector's reputation and financial well being. Doing the job right means doing it to a published standard and no published standard is more defensible than the law.

A copy of 16CFR1211 can be located and downloaded here. A technical data sheet (#167) that summarizes these rules and can be used as a handout for clients, as well as periodic maintenance instructions for overhead doors and their openers, can be downloaded free at the Door & Access Systems Manufacturers Association (DASMA) website.

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http://www.dasma.com/safetygdmaint.asp

quote

Force Setting Test

Test the force setting of your garage door opener by holding the bottom of the door as it closes. If the door does not reverse readily, the force setting may be excessive and need adjusting. See your owner’s manual for details on how to make the adjustment

Captain

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Hi Mitchell,

As the article states, there is no actual established force by which the door must reverse, but that is not the reversal test. The reversal test requires the 2 by 4.

Read the paragraph above that:

Test the reversing feature every month.

1. First, test the balance of the door. If the door is properly balanced, then proceed.

2. With the door fully open, place a 1-1/2" thick piece of wood (a 2" X 4" laid flat) or a full roll of paper towels on the floor in the center of the door.

3. Push the transmitter or wall button to close the door. The door must reverse when it strikes the obstruction. (Note that the bottom part of "one-piece doors" must be rigid so that the door will not close, but will reverse when it contacts the obstruction.)

4. If the door does not reverse, have it repaired or replaced. Have a qualified technician adjust, repair, or replace the opener or door.

A home inspector might criticize the door and state that in his/her opinion the force is excessive, but that's a subjective opinion only without the weight of law behind it. Without an established down-force parameter it does not constitute a defect.

The force test and reversal test are two different things and the force test musn't be substituted for the reversal test. The 2 by 4 test is still the only test that can't be misinterpreted.

OT - OF!!!

M.

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Mike

This is how I write it up:

"The garage door did not stop when meeting resistance, and did not reverse. The opener should be repaired or replaced Recommend having item(s) corrected by a competent professional licensed garage door technician. Cost Estimate: $75 - $350"

Now what does that do (hopefully)? It brings in a technician to check the door, repair the door, cover my axx, and my client has someone to sue.

Captain

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Hi Mitchell,

Sure, that'll work, but is the resistance that you've tested done with a 2 by 4 or with your hand?

If by hand and not with a 2 by 4, what happens when the fellow from the garage door company arrives, asks the homeowner what the problem is, is told it's that the door didn't reverse, tests it with a 2 by 4 - which is the standard set down in law - and the door reverses as it should?

Here's what happens: You end up with the phone call that 1. wastes your time arguing with someone 2. may damage your credibility with your client and the garage door companies in your area.

I've never gotten one of those phone calls and I've had doors damaged using the 2 by 4 test and was never asked to pay for them. I make it a point to ensure that the client as well as the client's realtor watch me test the door. I have a copy of the DASMA instructions in a notebook in my truck. If the door is damaged, I pull it out and show it to them, to show that I did the test exactly as prescribed. Then I leave an extra copy with them.

If there were a specific down-force set in law - say the 15lbs used for the full-edge sensor, for instance, but for a door without the full-edge sensor - and a mechanical means to test that reliably, I would agree 100% with using such a mechanical device to test the door's down-force and then stating something like:

"The garage door did not stop or reverse at less than XXlbs pressure as required by law. The opener should be repaired or replaced. Recommend having item(s) corrected by a competent professional licensed garage door technician. Cost Estimate: $75 - $350"

However, since we don't actually have that in law it isn't a defensible argument. So, the door reverses when you feel that the down-force is excessive. What if the door is tested by someone who is stronger or weaker than you are? Might they not have a different interpretation of what constitutes excessive force?

I was a cop for more than 20 years - nearly 10 of that as an investigator. I'm acutely aware of how stepping outside the technicalities set down in law, no matter how little, can really hurt your credibility. Defense lawyers make it their mission in life to try and tear apart a cop's credibility by picking at every little nuance of procedures set forth in the law in the hope of getting a cop to admit that he/she has stepped out-of-bounds. I've testified hundreds of times in criminal cases and have had to endure more hours of cross examination than I want to contemplate.

I've never had to go to court in nearly 10 years in this business, but I'm pretty certain that if/when I do that the side opposing my testimony will attempt the same tactic. I can assure you that if it is ever about a garage door that they'll never be able to say that I was at fault because I used a test method not prescribed by law.

ONE TEAM - ONE FIGHT!!!

Mike

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Mike

I really hate this topic because it can go on forever.

The prescribe test for garage doors is dumber than dirt. Place a 2X4 in the "middle" of the door, that sure tells you a lot. If you can find a human or pet 2" tall that will be in the center of the door that test will work great. However their are not too many 2" people running around.

I've been testing garage doors by hand pressure for ten years, broke a couple never paid for one. Never had a call from a technician and never paid a service call because I made a wrong call.

Just because something is law doesn't make it right. It just dumb. And if I ever went to court I would set up a demonstration were by the door would reverse with a 2X4 in the center but not 2' from the sides. Then I would put a kids bike with a big doll as a rider on the bike. I would then push the button and as the door crushes the doll and the bike, the defense rests.

Captain

If

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Okay,

Well, it's not my intent to stay here and slug it out with you. It's was my intention to post an article that was based on defensible facts, not supposition or inspector folklore based on a subjective unproven opinion. I'm afraid, your demonstration, until proven, is just that, and constitutes the kind of folklore that gets folks in trouble.

However, that's just my opinion and you are welcome to your's. Just as it's obvious I won't convince you, you aren't liable to convince me. I guess we'll have to just agree to disagree on this one and hope that neither one of us ever has to be challenged in court.

ONE TEAM - ONE FIGHT!!!

Mike

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Some times common sense should prevail. When I catch the door with both hands and the pressure is so great in my opinion that it would break the neck of a child before kick back to me it is not operating properly. If it kicks back quickly with little pressure to me it is operating properly. With the 2X4 method it is impossible to know whether the pressure is great or slight before kick back. If pressure is great before kick back if could do damage to a child even if it does kick back.

In other words I trust what I can feel rather than what I can't feel if I use the 2X4 method.

Just my 2 cents worth,

Paul Burrell

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"And if I ever went to court I would set up a demonstration were by the door would reverse with a 2X4 in the center but not 2' from the sides. Then I would put a kids bike with a big doll as a rider on the bike. I would then push the button and as the door crushes the doll and the bike, the defense rests."

I am curious as to how you would accomplish this. Not saying that you couldnt, but I am curious.

Standards are not intended to be comprehensive. They are developed considering historical data (failure modes), design data, practicallity, trial and error, and ability to be documented, among other considerations. These standards were not pulled out of someones arse. They were developed by engineers taking into account design variables among different manufacturers, variables considering improper installations, variables considering differences in materials, etc.

An inspector who relied on feel in the face of a documentable procedure would be eviscerated on the stand IMO. If an inspector trusts his 'feel' over all else, by all means use your hands for self edification, but sliding the 2x

under the door as well and testing to procedure would be an easy way to CYA.

Tim

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Good article, thank you, but some of the garage stuff starts to sound moldy to me @ times.

Personally, I don't EVER test garage doors w/ a 2x4, or anything else. Over several years, I've had 2 doors splinter, and a third dropped in it's entirety on top of an '87 Buick Skylark. I got tired of paying for doors & body work. There is no good argument for us testing doors if the industry and gov't. can't come up w/an acceptable standard.

The doors got electric eyes which are installed properly & functional, or I recommend a new opener. Period.

Personal story; I recently got a brand new overhead door for the old garage. Good install, he set the opener, and when I tested it the next day, it was out of adjustment. I readjusted it, finally tweaked it into position, hit the button, put my foot under the door for the acid test, & got my foot painfully trapped until I hit the remote button to get the damn thing off my toe. IOW, it's almost impossible to get the stupid things adjusted properly.

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The Cap'n and Paul are two inspectors that I would want to inspect the home where my family will be living. They have enough sense to ignore a published test procedure that does nothing to adequately measure a potential life safety issue. When they are testing that automatic feature, they are picturing my children and pets laying under the door and not fearing potential claims if the door is damaged or some installer disputing their opinion.

This is just one example of HIs not daring to point out potential issues because there are no published standards or codes to support their opinion. Is ignoring the potential for injury or death to an occupant of a building you inspected more important than having the possibility of defending your "subjective" opinion?

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Originally posted by inspecthistoric

The Cap'n and Paul are two inspectors that I would want to inspect the home where my family will be living. They have enough sense to ignore a published test procedure that does nothing to adequately measure a potential life safety issue. When they are testing that automatic feature, they are picturing my children and pets laying under the door and not fearing potential claims if the door is damaged or some installer disputing their opinion.

This is just one example of HIs not daring to point out potential issues because there are no published standards or codes to support their opinion. Is ignoring the potential for injury or death to an occupant of a building you inspected more important than having the possibility of defending your "subjective" opinion?

Not trying at all to be argumentative Bill, But how did you come to the conclusion that the ANSI standards do nothing to adequately measure a life safety issue? It is my understanding that the standard was developed in response to deaths caused by improperly adjusted/maintained doors. I am relatively new to Home Inspections, but quite familiar with ASTM, UL, and ANSI standards and how they are developed. They are developed through rigorous testing by some of the top engineers in the world. If grabbing the door were the best way to verify the reverse mechanism, the standard would likely call for you to grab the door. For me personally the issue has nothing to do with "ignoring the potential for injury or death to an occupant of a building you inspected more important than having the possibility of defending your "subjective opinion", it is considering the possibility that I do not have all the answers and that deferring to experts on matters of life and safety IS the right and responsible thing to do. I have been using my hands and will continue to do so, I will also use the standard now that I know it exists.

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Thank you for a very informative and well written articale. I have found it to be very useful.

I can understand now why you prefaced it with an overview on your observations on how the subject is handled in forums. hehe . Was tickled by all the responses. We inspectors are an opinionated lot. But that is probably one of the attributes that make us good inspectors.

Keep them coming.

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Damn, now I'm confused again. I guess in 8 years I haven't had any issues come up with the "hand pressure" method and should continue to use it. Kurt's point is valid though, the adjustment is tough, particularly on heavy doors and rarely stays properly adjusted. I do find that most installers adjust the down force much too heavily, probably to avoid callbacks. I cant see any real value in the 2x4 test for above mentioned reasons. Maybe there is no "easy way out" on this one. Kurt's recommendation to replace any opener without electric eye reverse makes sense but would probably not work for me. Sellers and agents raise hell about having to install a $15 GFCi receptacle, I can imagine what would come of a recommendation to replace a $400 garage door opener that was functioning properly. Sort of like recommending installing AFCI breakers in a 1980 home bedroom circuits. "OK, it may take some re-wiring but it will be safer". At some point we have to just deal with this older equipment and accept that it is not as safe as a new home. I do realize from this thread that at least the consideration of an upgrade should be recommended, IMO to be paid for by the buyer, not the seller.

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There was a big discussion about this sometime ago on the ASHI forum. Mike wrote an excellent article, same as the one here, on how to inspect a garage door and the opener. Then came the debate of legalities.

In testing the auto-reverse feature on a garage door I place a 2x4, on the ground, and in the center of the door. Why? Because this is the way the manufacture recommends that I test their opener. This is the same manufacture that has degreed engineers on their design team.

I am not an engineer, nor do I profess to be, so why on earth would I even think to deviate from the manufactures recommendations. Moreover, why would I climb out on that limb without any written documentation, from the manufacture, giving sanction to my methods? That would be considered the “Ya butâ€

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Hi Terry,

I actually interviewed several folks about this issue years ago when doing research for the article. I cited one of them in the article. Just for everyone's information, yesterday I called DASMA to ask why their maintenance instructions conflict with 16CFR1211 and spoke with their technical guy, Joe Hetzel.

He didn't seem to realize there was a conflict with the law in the instructions when I described it to him, but after he read it himself he agreed that it is confusing and saw how it could be misleading to home inspectors. He agreed that the only legally valid test is the 2 by 4 method and promised to present this issue to DASMA's information committee to see what the consensus was - whether it should be left the way it is or that 'force test' should be deleted. He then came over here and signed up as a member, so I'm hopeful that, once he's done so, he'll come onto TIJ and provide us with an update from his organization.

This is a good debate - one that I expected when I wrote the article. That is, after all, why TIJ is here - to get inspectors talking to each other and sharing information and opinions so that, ultimately, we all get better at what we do, little by little by little.

By the way, the next issue of TIJUpdate will feature mostly articles and information about plumbing issues. If any of you have expertise in something related to that and would like write an article that can be featured in the next update, shoot me an e-mail at hausdok@msn.com so we can talk about it.

ONE TEAM - ONE FIGHT!!!

Mike

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Originally posted by inspecthistoric

The Cap'n and Paul are two inspectors that I would want to inspect the home where my family will be living. They have enough sense to ignore a published test procedure that does nothing to adequately measure a potential life safety issue. When they are testing that automatic feature, they are picturing my children and pets laying under the door and not fearing potential claims if the door is damaged or some installer disputing their opinion.

This is just one example of HIs not daring to point out potential issues because there are no published standards or codes to support their opinion. Is ignoring the potential for injury or death to an occupant of a building you inspected more important than having the possibility of defending your "subjective" opinion?

Pshaw! I'm amazed to see so much misunderstanding of this subject. Really, I though you guys would know better.

The auto-reverse feature on a garage door IS NOT INTENDED TO PREVENT SOMEONE FROM BEING KILLED, CRUSHED, DENTED OR OTHERWISE HARMED by the door as it travels downward. Its ONLY PURPOSE is to prevent entrapment. That's all that's being tested by the 2x4. It's not sensitive enough or consistent enough to hold an adjustment to the degree of precision necessary to prevent injury. As I explain to my customers, if the door reverses with the 2x4 under it, this only means that you'll be able to retrieve the body or, if it’s you, that you might be able to crawl for help.

The test is done low to the floor because that's the place where the armature is changing from a horizontal to a vertical position and its leverage greatly increases at that point. That is, the motor exerts the least effort to impart the most force on the door at that point. A door that reverses easily at waist height might not reverse at all at a point 2" off the floor. The opposite is rarely true because of the geometry of the armature.

Feeling for resistance with your hands is not going to achieve much. First of all, you would be amazed, really amazed, at how little force is necessary to kill a kid with one of these things. With the mass behind a garage door, I'd guess that it takes about 15 pounds of force to seriously injure or kill a small kid if it hits them in the right spot. Many adult men that I know can resist that force with one hand. If you don’t believe me, get a few cats from the shelter and do your own experimenting.

Second, as Kurt pointed out, there's a lot of latitude in these things. Anyone ever taken one apart? They're ridiculously primitive. They rely on amp draw from the motor to decide when to reverse. This is about as inaccurate as you can get, even the old clutch systems were better. There’s enough consistency there to reverse reliably with the 2x4, where the amount of force can vary widely, but the design isn’t sophisticated enough to reverse reliably at a specific level of force. They’re NOT DESIGNED TO BEHAVE THAT WAY. A hand test that you do today is worthless tomorrow, but a 2x4 test today will be very, very similar to a 2x4 test tomorrow.

Look at it from a design point of view. The force necessary to open and close a door while overcoming uneven rails, sticky rollers, and ornery tracks is almost always going to be greater than the force necessary to injure or kill a person. A resistance-to-pressure based safety reverse is not a valid design goal. Even if you could get it to work while the door was new, it would likely fail as the door aged. That’s why we have to rely on other means to achieve real safety.

If you’re concerned about injury, a photo sensor mounted near the floor is the most reliable safety feature out there today. Second runner up is a leading edge sensor on the door. If I wanted a truly safe door, I think I’d install a leading edge sensor on the door and three photo sensors, one at 4â€

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Jim wrote: "The auto-reverse feature on a garage door IS NOT INTENDED TO PREVENT SOMEONE FROM BEING KILLED, CRUSHED, DENTED OR OTHERWISE HARMED by the door as it travels downward. Its ONLY PURPOSE is to prevent entrapment. That's all that's being tested by the 2x4."

That last part is correct. The 2x4 test only verifies the functionality of the reverse feature. That's why manufacturers' instructions I've read describe the "Force Setting Test" immediately after describing the "Reversal Test" Those instructions are similar to the ones listed in the DASMA guide.

Tim wrote: "Not trying at all to be argumentative Bill, But how did you come to the conclusion that the ANSI standards do nothing to adequately measure a life safety issue?"

Again, the 2x4 test does nothing to evaluate the amount of force it takes to reverse the door. I'll describe an experience to help illustrate this point.

I grabbed a shovel and used the handle to do the reversal test. After snapping the 1.25" ash handle, the door reversed in at least a second. This would have easily passed the 2x4 test. Using a force gauge at 12" from the floor, the door reversed at about 130 lbs. After simple adjustment, the door reversed at 11 lbs.

I just can't walk away from a home after only using the 2x4 to test the safety of pre '93 automatic garage door opener.

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Originally posted by Jim Katen

The auto-reverse feature on a garage door IS NOT INTENDED TO PREVENT SOMEONE FROM BEING KILLED, CRUSHED, DENTED OR OTHERWISE HARMED by the door as it travels downward. Its ONLY PURPOSE is to prevent entrapment.

I'll fess up. I've always done the hand test, even after I read Mike's original article and tried the 2 x 4 test a couple of times, and I do find myself lacking understanding on this topic. I don't know lots about garage doors, openers, etc., but I can't help thinking there are gigantic holes in the base logic of the ASTM 2 x 4 test. The simple fact that no attempt was made to create a standard that might prevent someone from killed, crushed, or dented (otherwise harmed is far too fine a line) calls the whole project into question in my mind. Why not? It can't be done? From what Jim says that may be the case, but that seems like cause for a serious re-thinking of the basic design of garage doors and/or openers, not a capitulation to a silly standard that addresses almost none of the worst possibilties. To be perfectly frank, I don't buy can't be done for a second...it just isn't being done for the same reasons we're still sealing toilets down with a wax ring while we build motors that get lost on a hair and a space station....status quo rules (cheapest, easiest to produce, the way we've always done it, etc.).

What is a 2 x 4 equal to? A wrist? An ankle? Is that really what we're worried about? It doesn't make sense to me, except that it's published standard.

My personal silly idea is to check it about knee high, roughly between the height of a car hood and a prone body. I know I'm out on my own little limb there legally, but I'm just flat-out uncomfortable and unsatisfied with the 2 x 4 test. Nothing I'm concerned about is 1 1/2 inches thick. Maybe Tim has the best idea; do both, just because.

This discussion does make me think I need to lean a little harder yet on the photo sensor end of the deal though. Thanks to all for that at least.

This must be one of those things God chose to confound the wise.

Brian G.

I Don't Know How Wise I Am, But I'm Definitely Confounded by the Standard [:-boggled

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Great article and discussion. Jim Katen's post made some very good points. I am a PE with 20 years of engineering experience but I am by no means an expert on garage doors. After reading this thread and thinking about it for a bit I think there are two areas to consider.

First, the 2x4 protocol tests whether the reverse mechanism functions under a set of very standard and easily created conditions, and, as Jim states, really only addresses the issue of entrapment. However, injury may be caused by the force exerted by the door as it approaches the floor, and the 2x4 test does nothing to measure this force. In other words, the force applied by the door could kill you but at least they will be able to pull the body out because the door will be up and not pinning you down. ;)

If what Jim posted about using amp draw on the motor to kick the reversing mechanism is true (and I have no reason to doubt it), then trying to set a standard based upon force applied wouldn't work very well .... there's just too much slop in the system between the business end (the door bottom edge) and the measurement point (amp draw) to develop a force which was constant along much of its length of travel and which would be the same each time the door closed. With the amp draw 2x4 method, the motor is trying to drive the door that extra 1 1/2" down to the floor and will keep cranking and the amps will build until it reaches the amp set-point for the reverse (or the circuit breaker, whichever is less) -- force applied at the door edge can vary widely and has little to do with the actual reversing of the door in this system.

To base the reverse mechanism on the force applied, would probably require either fitting the entire door bottom edge with a pressure sensor, or a redesign of the linkage between door and motor so there is very little "slop" in this linkage, and then in some manner measuring the strain being placed on the linkage.

Either of these methods would probably add considerable cost to your door/opener. So you approach the safety problem a different way. Keep the existing opener/door design, and add the photo eyes down by the floor which reverses the door before it could travel low enough to crush or suffocate somebody. Now, any object down by the floor will cause the door to reverse without even needing to touch it.

If I decide to make the jump and become a home inspector, I think my procedure would be to first test the reverse with the 2x4 method, and then repeat the test with the hand test (down near the floor, keeping the 2x4 in place to keep fingers from being crushed) in order to feel the pressure. I would report my observations of both tests. I would call the door/opener a defect if it failed the 2x4 test. I would recommend photo eyes as a safety upgrade if they were not present. I might even go so far as to have my client do the hand test and feel the pressure themselves as I explained why having the photo eyes installed would be a good idea.

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Originally posted by inspecthistoric

. . . I grabbed a shovel and used the handle to do the reversal test. After snapping the 1.25" ash handle, the door reversed in at least a second. This would have easily passed the 2x4 test. Using a force gauge at 12" from the floor, the door reversed at about 130 lbs. After simple adjustment, the door reversed at 11 lbs.

Unfortunately, that adjustment is unlikely to be good for more than a short while after you adjust it. The down-pressure adjustment on these things just isn't intended to prevent someone from being squished. It'd be a nice idea, but it isn't so. About the only thing you'll achieve by creating this correlation is a false sense of security.

I just can't walk away from a home after only using the 2x4 to test the safety of pre '93 automatic garage door opener.

Well geez, if it's a pre-93 opener it's, by definition, unsafe. You might as well guarantee that if someone's hit by it that they'll be hurt or killed. How could you walk away from that without an unreserved recommendation to upgrade to the safer modern equipment?

Once again -- if you're worried about being crushed by one of these things, the downforce adjustment alone ain't gonna protect you.

- Jim Katen

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Originally posted by Brian G.

. . . The simple fact that no attempt was made to create a standard that might prevent someone from killed, crushed, or dented (otherwise harmed is far too fine a line) calls the whole project into question in my mind. Why not? It can't be done? From what Jim says that may be the case, but that seems like cause for a serious re-thinking of the basic design of garage doors and/or openers, not a capitulation to a silly standard that addresses almost none of the worst possibilties. To be perfectly frank, I don't buy can't be done for a second...it just isn't being done for the same reasons we're still sealing toilets down with a wax ring while we build motors that get lost on a hair and a space station....status quo rules (cheapest, easiest to produce, the way we've always done it, etc.).

What, you've never heard of photo eyes? If installed properly, they do a pretty darn good job of preventing the kill-crush-dent thing. What's the matter with those?

What is a 2 x 4 equal to? A wrist? An ankle? Is that really what we're worried about? It doesn't make sense to me, except that it's published standard.

The 2x4 just represents a 2x4. Nothing else. There's no reason to equate it with a body part. That part of the safety system is only intended to prevent entrapment. From a design standpoint it'd be foolish to use the amp-draw auto reverse any other way.

My personal silly idea is to check it about knee high, roughly between the height of a car hood and a prone body. I know I'm out on my own little limb there legally, but I'm just flat-out uncomfortable and unsatisfied with the 2 x 4 test. Nothing I'm concerned about is 1 1/2 inches thick. Maybe Tim has the best idea; do both, just because.

In addition to the limb you're going out on, the danger is that you'll create an unrealistic expectation in the mind of the buyer. He might see you do that and think, reasonably, that you "tested" the pressure and determined that it was safe. He might even think that, because you approved it, there was no real danger to his kids.

This discussion does make me think I need to lean a little harder yet on the photo sensor end of the deal though. Thanks to all for that at least.

I agree. I think that, from this day forward, I'll be reporting that pre-93 openers that lack photo eyes are flat-out unsafe because they could crush someone and that if the buyer wants a door that's less likely to crush someone, he should replace the opener with a new one that includes modern safety features.

- Jim Katen, Oregon

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Originally posted by Brandon Chew

. . . To base the reverse mechanism on the force applied, would probably require either fitting the entire door bottom edge with a pressure sensor, or a redesign of the linkage between door and motor so there is very little "slop" in this linkage, and then in some manner measuring the strain being placed on the linkage.

Either of these methods would probably add considerable cost to your door/opener. So you approach the safety problem a different way. Keep the existing opener/door design, and add the photo eyes down by the floor which reverses the door before it could travel low enough to crush or suffocate somebody. Now, any object down by the floor will cause the door to reverse without even needing to touch it.

In one of my past lives, before becoming a home inspector, I designed machines that moved large, heavy objects up, down, sideways and round & round as well as the safety features that accompanied them. If someone hired me to design a safer garage door, the first thing I'd do would be to install a spring-loaded leading edge sensor with several inches of travel. It could be calibrated to respond to ounces of pressure consistantly and would remain consistent regardless of resistance and slop in the rest of the system because it would be entirely independent of the rest of the system. I'll bet that I could design one that you could test with a carton of eggs.

If I decide to make the jump and become a home inspector, I think my procedure would be to first test the reverse with the 2x4 method, and then repeat the test with the hand test (down near the floor, keeping the 2x4 in place to keep fingers from being crushed) in order to feel the pressure. I would report my observations of both tests. I would call the door/opener a defect if it failed the 2x4 test. I would recommend photo eyes as a safety upgrade if they were not present. I might even go so far as to have my client do the hand test and feel the pressure themselves as I explained why having the photo eyes installed would be a good idea.

The only problem with that approach, as many other inspectors have learned, is that the door, motor, or drive system sometimes breaks while you've got your hands under it. Sometimes a door section or a track or motor even falls on your head.

- Jim Katen, Oregon

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Thanx to Mike and others for the info and input.

“There is a principle which is a bar against all information, which is proof against all arguments and which cannot fail to keep a man in everlasting ignorance—that principle is contempt prior to investigation.â€

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