As per your man basket example of engineering problems, just because it was factory made does not mean it was rated for OSHA approved capacities. And, even if it was when originally built, the standards may have changed. There are many companies that make and market particular items but when proper research is done they are not rated by the correct and applicable organization for safety, strength, approved features, etc.
I say that to say this, be careful about how you judge engineering. They are often working off of incomplete information and/or applicable codes and quite possibly do not fully understand your application.
You need to start by coming up with a written project scope. You cannot be too descriptive. Don't try to leave things out in order to be cheap and not over involve your chosen engineer. This is a case of 'the more information the better'.
Have a Great Day, Brent
By Robert48
Date 03-29-2013 02:44
Edited 03-29-2013 03:09
Sorry for the delay. We just had a baby. I will clarify the man basket ordeal. The company I worked for was in the market for about ten new ones and they are extremely expensive. We took the guy a store bought one to give him an idea of what we wanted. After he came up with the drawing he called and made sure all the welding was to be done by qualified welders ( also noted on the drawings). After a few days and several thousand dollars he sent us the drawings. When I reviewed them I saw that he had went with 5/16 wall tubing instead of the 3/16 the factory one used. No big deal. We use fairly large cranes so a little extra weight is not a problem. The problem is that the information he gave us to have stamped on the tag was as follows Weight: 1000# Capacity: 500# NET Weight 25000# along with a serial number. I called him to make sure that the 25000# was a typo. He promptly told me that it was right and the crane operator would know what it ment. I told him I am an NCCO certified crane operator and know what it means. It means I have to treat that basket as if it weighs 25000# even if I know it does not. As per the new OSHA standards (ASME b30.5) I would have to use rigging that is good for 5x the NET weight stamped on the basket (125000#), and not exceed 50% of the cranes capacity at a given radius. So in short you could only pick it up with a 250 ton crane. After I explained about the crane side of it he would not budge. So we have a very expensive stack of papers and factory built baskets.
This is what I want to avoid. That company has plenty of money for screw ups like that, I dont. I understand fully the issue of liability and am willing to do it right. I already have one of these built and really want some one to look at it and tell me what I need to do for it to be right or maybe tell me I am wasting money over building it.
Hey Robert,
When it comes to safety, the product/part will always be "over designed". To use your man basket as an example, here's a couple of the factors that were probably considered:
The weight of heaviest person that might use the basket. (times 2 if there's a chance two people might use it) + The maximium weight of equipment that a person might put in basket. Add a safety factor for any unforseen factors. Add another factor for fatigue (especially if aluminum is selected). I've seen safety factors as high as 20X (crane industry).
I agree there are lots of over designed monstrosities out there, but I understand the reasoning behind them.
I'm sure you can get someone to design and rate the product at the low end, but you will end up assuming some responsibility if things go bad and fingers start pointing.
My 2 cents
Tyrone
Call Dr. Lee Guice @ 903-757-4701. He is in Longveiw Texas. He is one of the TOP Engineers in the Oilfield and ALL ofthe Majors know and recognize him. He has designed, Patented and built many items for the Oilfield thatare in wide use today. Tell him Cactus sent you
Thanks I will give him a call.
I've got an engineer I use up here and had him do the stuff for our bridge project. Looking at the steel being used for what it is doing you stand back and say what the heck? But when you consider that the river was 40 feet over it's normal height, flowing over the bridge and thousands of gallons of water floating and beating the pipe under the bridge you look at the steel again and say, that should take care of it.
We were considering ways to move our walkboards, aluminum to use and he called out using "T" aluminum, which nobody seems to have.....anywhere. Anyhow, talking to him about how to make our own walkboards and other things(for about 2-3 hours) and you can see where the engineer is coming from, mathematically when you consider loads and the forces that will act upon whatever it is your making.
I understand what your saying about "complications" as our bridge gig has been ongoing for over a year. We were just able to get started on the first phase this year. All of last year was engineering, measuring, TDOT approval and so on. Simple straighten and insulate the pipe at first went to $6000 in steel, 3 stage paint, removal of illegally welded brackets on the bridge (no, not something I did), brackets on the abutments to retain the pipe, it's a huge job. Then again on the engineers side he's designing it to withstand what has happened or what could possibly happen and in the end, like your CWI's he has to put his stamp on it. As welders we can design, build things all day long and usually build it in what I like to call "Farm built". We all know farmers, if a 1-1/2" pipe is good then a 2-1/2" will be better. Unfortunately if something we design and build fails, bye bye homestead and hopefully it don't kill somebody where we end up in the pokey with a roomate named bubba that has been in lockup for 15 years.
Getting an engineer stamp and design just means you get to raise the cost on the final product. The engineer got involved with our bridge and it went from a 3-4 week job to several months of work, all paid by the hour, thank you Mr. Engineer.
Good luck on your quest!
Ladies and Gentlemen,
Am a graduate engineer been in Texas and other oil fields. Bet y --- and ability to make a living on what you are selling me as a "trailer" for highway use? Texas P. E. stamp on drawings and I would see if there is any insurance concerns. I hope this is helpful.
Sincerely
Len Andersen weld@spemail.org
914-536-7101 / 212-839-6599 8-4 New York Time , 4042 FAX , Co-worker 6381 / 914-237-7689 (H)
POB 1529 / NYC 10116-1529 ( $1100 per year Caller Box GPO NYC / Most Secure Service At Largest Post Office