Piping Design

What are you trying to pipe?

we are one of the boiler installer,one of my my job is to make an PI diagram,to estimate pipe,valves etc.now i need more knowledge or advance technique in piping design.thanks

I would love to help you. Unfortunately the vague nature and phrasing of your question render that extremely difficult and suggest that you wouldn't understand the technical assistance in any case in your present state of ignorance.

If changing jobs is not an option, you have a great deal of work ahead of you, since it would seem you have little relevant technical knowledge to build on.

You will be dealing with a variety of piping issues and applications for all the different parts of the boiler system. Pipes, valves, fittings, etc have to specified as to size, pressure rating, material and so on based on their application. To accomplish that you need some understanding of the boiler, its operation and the associated equipment's function and specifications. Routing and pipe supports come into play because in piping, the shortest distance between two points almost always consists of a series of straight runs and right angle turns, generally horizontal and vertical, but with some runs pitched as may be required. There are also code issues to satisfy. One place to start is with the boiler manufacturer: they likely will have general piping diagrams for that type of boiler in various applications. A trip to the local library, stopping at the research desk, should point you in the right direction to learn much relevant information. Of course web searches will be useful also, but at this point you need some hands on guidance which is best gotten at a library.

After some research, you will then be in a position to get more meaningful technical help here.

I hope my ramblings are of some help to you but questions such as yours are not amenable to meaningful technical answers. Hopefully some other posters will have handbooks or guides they can refer you to.

Good Luck.

what greag says all of us should agree one cant except spoon feeding through this fourm

It's really scary when you consider that many of these types of questions involve actual installations somewhere that could put innocent lives in harms way.

We should have a followup bulletin board to track explosions, crashes, fires, electrocutions, maimings and other catastrophies and mishaps that involved some of the participants asking for help here. And this question posting was better than many.

Talk about getting in over your head ..... depressing, isn't it?

Well said

I think it would be worth your while to get to know a very special company in the piping and pipe joining technology, namely http://www.t-drill.fi/

If it proves to be productive, say hello for me: olli.eloranta@pp.inet.fi.

Rgs, Olli

You might start your work with the ASME piping, boiler, and pressure vessel codes.

Get real engineers involved before you hurt yourself or others!

I have to agree with other posters here. You sound like you don't have any experience in the piping and instrument design area. There are many factors to consider, some already mentioned and others such as temperature control, insulation, steam traps, condensate recovery, etc.

There is also a need to have a good feed water system to control boiler make-up water quality. This is key to the longevity of your equipment / system.

I strongly suggest you contact a professional chemical engineer with process engineering experience. This is the type of thing my firm does here in Montana, but a local person might be better / easier for you to work with. Look up engineering firms with "process engineering" in the title or description. Try the American Institute of Chemical Engineers (www.aiche.org).

If you need more help or wish to bid this work out, I am happy to bid on it as I imagine many people who participate here would be, but there is no way to teach you years of engineering and years of practical experience in this forum.

Stephan Bradley, PE

www.bradleyventures.com

Steven,

Sorry, but I have to disagree with you on one point. If you read Junrey's post number two you will see that he is a "boiler installer". Since he is working with water and steam, he would not need the services of a Chemical Engineer doing process engineering work. This is really the domain of Mechanical Engineers who do this kind of thing all the time for power plant, HVAC, and process steam applications. After all, the piping, boiler, and pressure vessel codes were developed and are maintained by the ASME, not AIChE!

No doubt, an experienced Process ChemE could do this type of work, but you must be pretty hard up for contracts if you are going after this type of job instead of chemical industry work!

I guess there aren't that many chemical plants in Montana. You should move South. We've got plenty of work here!

Anyway, my guess is that he is not even located in our hemisphere, else they would not be trying to put piping design work onto a "boiler installer". That smacks of Third World "make-do" human resource policies, and the primary reason why many US companies that tried to "Outsource" or "Off-shore" white collar work are finding the experience less than satisfactory and bringing many of those jobs back home to the USA.

STL,

Point well made and ASME is clearly the governing athority in this case. I suspect you are also right about the location of the project. Too bad.

The point you made that is a little more personal is also true - there are only a couple of chemical facilities in MT. I have some refinery clients and some specialty plants, but I mostly do water treatment design. That is often what gets me into the piping design for the associated systems.

I was born on the Texas coast, got my BSChe at Texas A&M, worked in Houston until I couldn't stand it, moved to FL, then met my now wife who is from Billings, MT!!! Damn I am cold!!! It is -6F right now and I have no idea what the hell I am doing up here!

Stephan

Steven,

I feel for you! It is a relatively balmy 67°F at the moment here in STL, although we are expecting a winter storm to bring freezing rain and snow and temperatures down in the 30's by Friday. We just had several weeks of "Indian Summer", with temps in the mid to upper '70's. Earlier in the fall we had one night where the temp dropped below freezing. Normal temps have been in the 50's and 60's.

6°F below ZERO? People here would think the world had come to an end! We rarely get sub-zero temps, usually only in January or early February, and then only for a day or so. Our worst time is when the temp hangs in the '20s and we get icy streets after a heavy snow, with a melt/refreeze cycle that can last for weeks.

On the other hand, July and August have killer temps and humidity that rivals Houston. I'll bet your Montana summers are wonderful, the whole month!

Steven,

You said, "Damn I am cold!!! It is -6F right now and I have no idea what the hell I am doing up here!".

Well, they always said at Rolla that Aggies weren't too smart. I didn't believe it until now!

Love will do that to you not an Aggie degree!!

A piping designer can do a certain amount of work without advanced engineering knowledge. Typically, routing and connecting major pieces of equipment can be done, as well as estimating fairly accurately, especially with CAD, the lengths of pipes and numbers of standard fittings, such as tees, elbows, ends, unions, wyes, etc.

The key knowledge here is that pipes must go in straight lines unless a fitting is used that changes the direction or splits flows apart or joins flows together. An elbow changes direction and is measured by the angle from straight (0 degrees) to a right angle (90 degrees), usually a function of 90 divided by an exponent of 2, i.e. 2⁰,2¹,2²,2³ giving angles of 90°, 45°, 22.5° and 11.25°. with 90° and 45° being most common. With this knowledge it is easy to route pipes around obstacles, including other pipes, conduit, building columns, impenetrable walls, unmovable equipment, or underground including utility pipes, sewers, cables, culverts, foundations, etc. and connect them between components like boilers, heat exchangers, meters, and various types of flow controls (valves).

Tees and wyes get their names from the shape of the fitting, T or Y, and are ways to split or unite multiple pipe flows. A tee has a 90 degree take-off from a straight section, while wyes have angled take-off, and can be thought of as angled tees. The key here is that flow should not be forced to bend more than 90 degrees, so care should be taken that the wyes are not installed backwards.

Unions are used to connect lengths of straight pipe and ends are used to cap off short branches, which might be created for future expansion or other usage. Consult a manufacturers catalog for specifications and size of various types of fittings.

However, unless you have advanced engineering knowledge, when dealing with high temperature and high pressure systems like steam boilers, you might have "just enough knowledge to be dangerous". Calculating pressures and flows in a piping system can be as complex as electrical circuit design. Complicating this further, in steam systems you often have a mix of gaseous and liquid flow, and condensate drains and traps are often needed in conjunction with other devices like expansion or throttling valves, used to change pressure and flow rates. Piping materials, wall thickness, diameter, and many other design features must be selected based on planned pressure, flow rate, and temperature. If this is not done properly, excessive pressure or heat can cause explosions and damage to the system, components, other equipment, and people!

Mechanical Engineers typically take three semesters (half-years) of courses to prepare for even the most basic of pressure systems design and analysis, including Introduction to Thermodynamics (Thermo I), Applied (or Advanced) Thermodynamics (Thermo II), and Heat Transfer or Thermofluid Mechanics (Thermo III). This coursework also depends on a foundation of university level general Physics, and Math, including Calculus.

Some rudimentary system design may be learned in technical training at trade schools, but should always be checked over thoroughly by a qualified engineer. Experienced designers who have worked with engineers over many years also develop some basic skills that allow them to plan out basic systems before submitting to the engineer for approval or modification. This type of knowledge cannot be transferred in a forum like CR4 but requires a classroom environment or years of elbow-to-elbow mentoring.

I have to agree with all of those that warn to error on the side of caution. As a retred I was a steamfitter/welder for over 20 years and have seen what steam can do. In the old days the steamboats would get to racing and tie the safety valves down to get more pressure and speed. They exploded with sime regularity and were known to scatter body parts for miles in all directions. This was with what is now considered low to medium pressure steam and never exceeded 250 psi. Now we regularly have superheated boilers that can have pressures in excess of 2000 psi and more. I just happen to be familliar with Montana's booiler as that is where I started at Colstrip plant 1&2. On an aircraft carrier they use steam to throw a 50+ton airplane off the end of the boat and if they get the settings wrong, it will litterally pull the plane in two.

The thing to remember is that of all forms of energy that man has tried to harness, steam is the most powerful and a nuclear power plant is only a fancy way of booiling the water.

RL Hurd