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They should be done as part of the same calculations. The stress analysis should calculate stress and deflection for all cases applicable to your system. So if your piping gets hot and is in a seismic area, then the load combinations should reflect that. I'm still an amateur compared to most...

@LI Good point, thanks for the wisdom. I've never gone through the pipe survey process, so I'll need to do some research.

LittleInch: It is a new connection, not repairing a broken piece. But I think your approach is a good one either way - it seems unnecessary to assume complete replacement from the get-go if we can properly qualify the system. Like you said, pressure testing would qualify the existing pipe, and...

Hi, I am working on a piping modification project that involves hot corrosive fluids (>200000 ppm chlorides, 200 F). The current piping is 1.5" sch 10, and the material is 6% moly (254SMO). Design pressure is 15 psig. As part of the project, we will need to tie in new piping to the old...

This might be a different topic, but I'm not a fan of music anywhere in the workplace. I was on a construction crew throughout college, and it always bothered me when people had earbuds in when working and I could never get peoples attention unless I walked over and tapped on their shoulder...

Snickster, That makes sense, for an on-off type there would just be a few sections that would be marked as N/A such as the positioner section.

Thanks LittleInch and Snickster. Those BP specs are a very good reference, I'll save them. Are these control valve datasheets typically filled out for on/off actuated valves? Or just for true control valves.

Hi All, I am trying to put together project documents for the control valves on a process piping project. The design will be issued to a number of contractors to bid on. I am trying to understand where the design responsibility is split between engineer and contractor for control valves, and...

It seems like the pressure thrust should not applied to the anchor that represents the pump nozzle. In reality, the pressure thrust would be applied in the pump casing and not at the nozzle. As in the pump manufacturer would have already accounted for any pressure thrust in the housing and it...

I'm trying really hard to discern if stxa's post is a joke or not. I keep telling myself it's satire, but then again posts on this website never cease to amaze me.

If you were to move the butterfly valve to the outlet of the pump, you would have issues with the system draining as the manufacturer states unless you put something there to hold back the fluid. I suppose you could put a high cracking pressure check valve where the butterfly valve currently is...

I would assume if the total volume of fluid in the system is larger than the volume of the tank, it has the potential of overflowing. In your case, I imagine it could burp air bubbles up the piping as the fluid fills back into the tank. Or siphon its way through. On a design I worked on, the...

Hi All, I wanted to see what others were using to do construction cost estimating for industrial jobs. We are a smaller EPC firm who usually hires an estimator to help bid jobs but we want to start taking this on ourself. I'm looking for techniques, methods, or software to start to learn this...

@ask Another good point. By going to 6" center with perimeter beams you're only saving ~6 yards of concrete (if i did my math right) vs the contractor having to do all the rebar details in the beams.

@brad I have come to agree that at this point its overkill. But my conclusion is if I want to change it any further, I need to understand the design and loading of the container. If I come to find out the load is supported at the edges, I could do perimeter beams and make the center much...

@dauwerda The shipper container supplier said that if piers were used that there would need to be 16 of them, so the client opted for a slab. I wasn't there for the conversation that's just what I heard.

@asktoomuch Its a fixed price job, and they certainly have had input about the costs of other parts of the job, so its interesting. From what I've heard there's not even a batch plant on the island. Yes, island. But anyways thats where my knowledge ends.

An update for everyone. My revised design will reduce thickness down to 14", which will maintain a 12" embedment with room for variation in grade and will keep the surface above grade a little bit (please chime in if this is flawed logic). The rebar will also be reduced to #6 @ 16"OC both top...

@BAretired, hokie, and human I appreciate the consensus. At this stage I certainly lack the gut-feel of what design should look like. It appears though that the minimum thickness will be governed by the geotech report which states that 'footings should be embedded to at least 12 inches below...

@driftLimiter aha! I think I see where I was mistaken. I calculated "minimum flexural reinforcement" using 7.6.1.1. Which got me my #8s @ 16". If I use section 9.6.1.2, I get an As,min that is significantly less, which would make a bit more sense. So would it be OK (with careful consideration)...