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Hi, Does anyone know of an organization that stores and sells estimating construction man-hour data for piping, electrical, structural, etc.? I know of the John S. Page manual for piping and the NECA manual for electrical... But are there any organizations that keep updated records and support...

Please, what is the purpose of STD, XS, and XXS pipe? Does this just give the designer a larger range of wall thicknesses for a given pipe size (at pipe sizes 10" and above for STD and XS, and for pipe sizes 6" and below for XXS)? There is no material difference or anything? Also, I have seen...

Hi, What is the purpose of a cut-sheet? Isn't all the information for fabrication on the actual ISO? Further, aren't you only supposed to build off of IFC ISOs? Is the sole purpose of the cut-sheet to show where the FWs are, and thus call out spool numbers? Thanks

Is this how centrifugal is pronounced?? I have been saying it cen-tri-fu-gal... But I have heard a lot of older guys say "centrifical", which isn't REALLY condusive to the spelling...

What is the functional difference between a stud and a bolt? I am not refering to obvious assembleability concerns. I have heard that studs eliminate (or greatly reduce) the torsional load and thus provide a more accurate clamp force... I don't quite understand this mathematically. Why are...

What is the real reason behind establishing a perfectly level (2 mils/ft) pump baseplate? I totally understand the reasoning for the tight tolerances on alignmnet but, functionally, if you achieve proper shaft alginment, soft foot, and pipe strain, why does it matter if the baseplate isn't...

Hi, I understand that head studs are generally prefered to head bolts because they "eliminate" the torsional force experienced by the bolt and thus provide a more accuracte clamping force... How does this work? Isn't the idea behind this that the nut "slips" on the threads thus "eliminating"...

Hi, I was just going through API 686 (2009 ed.) and I noticed in Chapter 5, Annex B, there is a table for "30,000 psi Internal Bolt Stress" which gives torque values, tpi, and compression. I am assuming the "30,000 psi" bolts they are referring to are Grade 36 F1554 anchor bolts... But why does...

I understand that it is necessary to perform a run-in on brushed D/C motors because the brushes have direct contact with the shafts and this could affect alignment. Is it necessary to perform run-ins on A/C induction motors? The stator and windings don't actually touch the shaft. The only thing...

I was reading on how a ARV (automatic recirculation valve) works and came across the following web page: http://www.wermac.org/valves/valves_arv.html It shows a cutaway of a valve that is similar to the one installed on the discharge of the LP BFW pumps in our plant. What I am having trouble...

My understanding of BEP is that it is based purely on geometry (and of course flow rate). Is this correct?

Hi, I have been reading through API 686, 610, 685, etc. and cannot seam to find any specification on baseplate/soleplate thickness. There is an appendix in 610 and 685 (Appendix M) on plan dimensions, but nowhere does it mention requirements for thickness. The reason I ask is, from a commercial...

I understand for storage and preservation a lot of larger electric motors have bearing heaters to keep the bearings in a certain termperature range in cold climate conditions. What exactly is the rationale behind this? I understand why shafts need to be rotated to avoid brinneling, but why do...

I am trying to understand 2 speed induction motors, so I figured the 2 speed, 2 winding, 3 phase induction motor would be simpler to understand. From what I learned in my electrical engineering classes a few years ago, the more times a conductor is wound, the stronger the magnetic field and thus...

Magnetizing current consumes no power. Reactive power is not real. However, the current in the wires is real. As I understand it, the reactive power DOES actually consume energy each cycle but it is like a spring. It compresses/decompresses/compresses, etc. providing the energy for the next...

I was talking to the electrical superintendent at my work. He was talking about VFDs and how they reduce your energy bill because they ramp up the current slowly rather than just applying full power right away. I was then told that this is how energy companies actually bill you: based on your...

Are there any instances of gearboxes, pumps, motors, etc. where the concept of a fixed and floating shaft end do not exist/are not implemented? How common is this approach to shaft design and bearing specification?

Hi everyone, just looking for some categorical clarification as I am writing a report on rotating equipment and giving brief overviews of the main types of rotating equipment. In my report I have basically categorized all rotating equipment into two classes: drivers and driven equipment. My...

Hi, How does a WAC exchanger work? Also, why is it called an exchanger or polisher (is it not just for precipitation of hard-water sulfates)? Does anyone have any section views of the internals? What is the purpose of "regeneration"? Thanks.

Hi, After a quality inspection it was noted that a sealless centrifugal pump was shimmed with adjustable chocks (underneath the baseplate pedestal between the pedestal and the skid!). The shims were almost 2 inches high providing a tiny bearing surface between the underside of the pedestal and...