I can't agree more with what you are saying. The school of hard knocks is a great way to learn, but the lessons can be very expensive.
More often than not, the best designs are collaboration between the people that use and install the equipment and the design team. Where I have an issue is when the welder takes it upon himself to modify or change the basic design without knowing all the parameters or without discussing the changes with the designer.
I have a lot of respect for welders. I earned my living under the welding hood for many years (over twenty). I also have respect for the engineers that design the structures and machines we use every day. I also respect the inspector who is tasked with verifying the welding and installation is done in accordance with the approved plans. None of these entities should be working in a vacuum. The effort of the team leads to successful installations and safety operations. It’s the lone wolf that knows more than anyone else that usually causes the most grief and problems. That lone wolf can be the welder, the mechanic, the inspector, or the designer. Sourdough isn't wrong in some of points he makes, but unless he or I know the whole story and all the facts before we act, the repercussions of our unilateral actions can be devastating.
I’ve worked in heavy industry all my life. I’ve been involved in accidents that have cost people’s lives because someone made a stupid decision that became obvious after the fact. In each case someone on the job site didn’t follow the plans or standard operating procedures. The result is that the family of the victim ends up paying dearly in terms of loss of earnings, the loss of a loved one, and the emotional stress that extends over a lifetime. The monetary loss can be easily compensated and over come. The loss of a loved one is something that cannot be fixed by the courts. Making an unauthorized change, fabricating pressure components without a design professional’s input is in my opinion criminal when it puts others at risk.
I have no problem when an individual builds something for his own use. When the people he or she puts at risk is his/her own, God bless them for having the initiative to try something new. I do it myself, but I’m not putting other people’s lives or livelihoods on the line. I don’t gamble with other people’s well being.
There is no teacher that provides better life lessons than experience. That experience can only go so far. The fact that you are experienced at building various components, systems, or structures is not a substitute for good engineering. It is difficult to know how a component is going to respond to a load if you do not have all the design parameters and if you are not knowledgeable of all the environmental conditions. Many of those details are not known by the welder and in some case they are not known by the designer. The designer at least has the resources available to make decisions based on the available data and “good engineering judgment”. A rule of thumb I subscribe to is: the greater the unknown, the greater the risk, the greater the need to be conservative. In this case it was evident that an individual was asking whether it was permissible to “design” a contraption without knowing all the design parameters. Giving advice that isn’t backed by good engineering principles is inexcusable. Taking short cuts that could jeopardize the well being of people working with the component or machinery is unethical and immoral.
If you have hung around the Forum for any length of time you know that there isn’t any profession, whether it’s the welder, designer, or the inspector, that is immune to being prodded with a sharp stick if they say something that is simply not factual or stupid. I’ll poke fun at anyone to make a point. It isn’t intended to humiliate anyone.
When a drawing specifies the use of standardized components it is the welder’s responsibility to weld it as shown by the approved drawing or by the manufacturer’s recommendations. The designer assumes the welder (fabricator) will follow the drawing and the manufacturer’s recommendations. The designer has no way of knowing the welder is going to take short cuts because “he” believes the component is over designed. The welder is in an indefensible position when he alters the design without consulting the designer or the owner. If there is any question about how something is to be welded it is incumbent upon the welder to ask questions. The welder is putting his employer at risk and may very well be putting other people at risk when he knowingly fails to follow instruction. In this post the individual stated that he was an hourly employee. I take that to assume he is not in a position to arbitrarily make design decisions.
If you own the company, if you are the individual that is responsible for the work produced by your company, if you have the knowledge and the experience to make design decisions, go for it. The situation is far different for an hourly employee on the production floor. As the latter, he should follow the directions provided or ask for direction when it isn’t sufficient to do the work in a competent manner.
By the way, those “nuts” as someone called them are suppose to be welded in a certain way to “reinforce” the run pipe, i.e., the weld and the design of the integrally reinforced branch fitting (IRBF) replaces the material removed when the hole is made in the run pipe. The “code” makes no distinction between low pressure and high pressure in relation to the welding of the IRBF. Is it overkill? Maybe, but if the designer specifies the use of the IRBF rather than a half coupling, there’s a good chance there is a reason for doing so. If the welder has a question, the answer is most likely a phone call away. Most designers would appreciate some feedback from the fabricator. If the run pipe curls like a banana, there are ways to correct it without depredating the mechanical properties.
Just my opinion on the subject.
Best regards – Al
FC,
