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  1. ElSid1

    Room Temperature Rise???

    Pump rooms/non-occupied rooms can get away without OA. Once the door is opened, there is your ACH. If it's a large enough room, it can be prop'd open. I did a similar room, but it was for elevator equipment instead of pumps. Run your calcs for the extreme hot. If you are still below 104 ...
  2. ElSid1

    4000 CFM fan with 3 in static - Please check

    Rumananoor, It is best if YOU post your work. Easier to correct and see your assumptions. Mech5 gave you the basics items that most forget.
  3. ElSid1

    4000 CFM fan with 3 in static - Please check

    Don't forget to specify if this is SCFM or ACFM! Major headache for me when reviewing others work. Their is a difference!
  4. ElSid1

    What version to use?

    PTC is implementing features with each release of MC Prime. I agree that, for now, MathCAD 15 is the way to go. For those that are knocking 15 and swearing by 14 ... Check your release. M035 is the last MC 14 but had a HUGE memory bug which I reported. MC 15 was their "bug fix" Kind of like...
  5. ElSid1

    Stairwell Pressurization

    Laugh all you want. It is a true story and currently being constructed for an underground light rail station where the AHJ criteria was Believe me, doing the calc was a pain and an even bigger pain was to set up the controls!
  6. ElSid1

    Heat Loss from uninsulated sch 80 CPVC

    It is an "insulation" style calculation ([link Pipe Insulation]http://www.raeng.org.uk/education/diploma/maths/pdf/exemplars_engineering/2_SteamPipe.pdf[/url]). Once you know the layer temperatures, you need to apply the glycol mixture specific heat to get a temperature rise. Basic thermodynamics
  7. ElSid1

    Stairwell Pressurization

    ChasBean1, ASHRAE, NFPA, IBC, etc ... they ALL reference a pressure and testing with the doors CLOSED. As an engineer, we follow these standards. In my case, the AHJ MANDATED an open door test. They didn't care what the standard was. Remember, all of the standards are guides and are not...
  8. ElSid1

    Modest Cryogen Compressed Air Process Pipeline - Materials Selection Question

    I recommend you follow the ISA IA standard for drying air. It is set at 19F below ambient for the dew point. You have not defined the conditions of the air, even if it's plant. If it is not dry enough and there are not enough drip legs with blow downs. I have seen SCH 40 piping in mining...
  9. ElSid1

    Pipework MAWS based on ASME B31.3

    Look at ASME B31G to calculate the life left on the pipe.
  10. ElSid1

    Modest Cryogen Compressed Air Process Pipeline - Materials Selection Question

    Compressed air has several options. You may want to look at Aluminum prepacked systems. If not, what about sch 80 CS? With air being dry (assuming a low dew point), it should not be a problem. I've worked on SCH 80 CS steam systems. Old ISA instrument air required -40d dew point ... so very...
  11. ElSid1

    ASME B31.3:2012 Effective Date

    I've seen it both ways. Typically, as the engineer, I just but B31.1. Div 1 usually states something to the effect of " the latest version at time of contract signature." Be warry though. On a nuclear project, I had B31.1 or section VIII change from 50% margin to 20% (over 10 yrs ago). A...
  12. ElSid1

    Humidity Issue

    Lower the temperature! This will bring the humidity ratio up. You mentioned some areas @ 68 while others were at 75 and a aet point of 72! Check the calibration on the T-Stats or lock them out. People will complain, but the placebo effect (people thinking they are controlling the T-Stat)...
  13. ElSid1

    A/C replacement for a load out room

    1) Ask the manufacturer of the transformer is always best. 2) Look up some tables in ASHRAE or other reputable publication to get an approximate value
  14. ElSid1

    pump performance curve for viscose lquid

    I agree with Pumpsonly. mirghaffari needs to specify the fluid. I always go back to TDH/Flow of H2O and put a NOTE on the bottom as to the actual fluid.
  15. ElSid1

    B31.1, 3, 9

    Does anyone have a "quick sheet"/synopsis comparing B31.1, B31.3 and B31.9? I'm liiking for something like: http://www.engineeringtoolbox.com/asme-b31-9-working-pressure-d_10.html Working on wastewater treatment and EVERYTHING is specified B31.1. Contractor is pushing B31.9. As a plant, we...
  16. ElSid1

    30" dia oil pipeline derating

    Correction ... B31G latest edition is 2012. (Do not know how to edit a previous post) Last one I have access to is 2009.
  17. ElSid1

    30" dia oil pipeline derating

    B21G latest edition is 2009. This link may help http://www.novanumeric.com/samples.php?CalcName=B31G
  18. ElSid1

    Mechanical Design of ball valve

    Attachment not working :( Did the specification did not call for a "blocked in seat"? I've been in a situation where the losing contractor had a way of badmouthing the winning bid. In short, if the specifications call for the blocked in seal, you can request new valves since the supplied...
  19. ElSid1

    Derating of Pump Motors at Higher Altitude

    An electrical may be better at explaining this, but here is how I learned it: As mentioned above, most motors operate at class B insulation and have class F. The SF "forces" the manufacturer to "add a little more" of the class F insulation into the motor. This allows a motor, with an SF, to...
  20. ElSid1

    GPM VS. PSI FOR A GIVEN PIPE DIAMETER

    cvg and bimr, I was tasked with estimating water supply for a mid-rise, no FP, that was a differned tap. My calculations showed a 14" line, was able to "justify" a 12" in my estimates. The main was 12". I was told that the city water mains are allowed to go to higher velocities since they are...

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