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  1. cwigg66

    Ventilation for Indoor Truck Wash Bays

    I am designing a facility in North Dakota that is to service large trucks all year round. The part of the facility in question is the indoor truck washing bays (two total), with roll up doors at each end. The bays are heated (ND winter design temp is -22F). Does anyone know what the...
  2. cwigg66

    When to Specify a Exhaust / Return Fans in AHU

    Here's where I am with this now - The plan is to incorporate a single return fan into the RTU, and place dampers at the main return ducts on each floor, to be controlled using static pressure sensors on each floor. The pressure sensors will allow the dampers to be adjusted to maintain neutral...
  3. cwigg66

    When to Specify a Exhaust / Return Fans in AHU

    Let me add a little to this problem. I have a single rooftop unit serving a two story building with fully ducted returns. If I use return fans, how do I control them? Should they both be driven simultaneously with the supply fan? The building is VAV controlled, so each floor will have...
  4. cwigg66

    When to Specify a Exhaust / Return Fans in AHU

    Hehe. Sorry for the confusion. First off, is there any way to change the field in my handle to Mech. Civil/Enviro is from a past life, and I can't figure out how to change it. I assure you I am an ME, and do alot of HVAC design work. This problem is just a little beyond my normal scope. To...
  5. cwigg66

    When to Specify a Exhaust / Return Fans in AHU

    Here's the siuation - 9000 CFM RTU w/ 2.5" ESP Ducted Return System Min O.A. = 4000 CFM to make up for constant exhaust requirements. Unit supplies air to VAV system for a two story wing of a hospital with isolation rooms, etc. Wing is connected to other portions of the hospital which are...
  6. cwigg66

    VAV Systems and Air Changes

    I am the HVAC designer for my engineering firm, and we frequently come across VAV systems in medical office buildings that pose a unique problem. Based on heat loads and standard practices, we supply enough flowrate to each room to cool the space using the 400 CFM per ton rule of thumb...
  7. cwigg66

    Marine Pile Lateral Resistance

    That is a fantastic paper, especially since I am from Charleston and got to see the effects of Hugo firsthand. Thanks so much for all your help on this... I think I have it reasonably figured out to do preliminary design. Chris
  8. cwigg66

    Marine Pile Lateral Resistance

    Thanks for the response, ishvaaag. The piling will be installed as single piles, serving as the anchorage for a system of floating docks making up a marina on a large inland lake. I would put the lateral soil bearing at 125 PSF/FT. The vessels tied up at the dock will impart lateral forces...
  9. cwigg66

    Marine Pile Lateral Resistance

    I am in the process of designing an inland (freshwater) marina on a lake in a 110 MPH wind zone. I am having some trouble locating information relating to the lateral force resistance of vibrated-in wood piles. The piles are 8"-10" in diameter, will be vibrated to a refusal depth approximately...
  10. cwigg66

    Calcium Chloride

    I am in the process of pouring a containment area in Mississippi. The slab (60'x70') is to be poured this week, with temperatures hovering around freezing at night and daytime highs around 45 degrees. My contractor would like to add 2% calcium chloride to the mixture. This slab cannot have...
  11. cwigg66

    Vertical 20K Tank on Stilts

    Could NOT be found.... sorry for the typo
  12. cwigg66

    Vertical 20K Tank on Stilts

    That was my first reaction this situation. The tank was most probably originally designed to be flat on the ground, although identification coudl be found on the tank which would indicate the method of construction (i.e UL, API, etc) The bottom was probably flat at one point, but with the lack...
  13. cwigg66

    Vertical 20K Tank on Stilts

    Simple question. Is it ever appropriate to take a 10' diameter vertical storage tank (34' tall)and weld I-beam stilts to the shell effectively raising the bottom of the tank 12-18" in the air. I have never seen this done. I believe the installer did it to prevent corrosion from standing water...
  14. cwigg66

    Static buildup in fuel piping

    I am designing a short piping run for some Jet A fuel. The run is 50'. I am looking to find out which API spec refers to the max velocity of the fuel in the pipe to minimize static buildup, or other reference which would supply guidance for this application. Is it API 5L? Thanks for helping...
  15. cwigg66

    Double Wall Tank Testing

    Anyone have any experience doing the integrity testing for a double wall, horizontal UL 142 tank (10K-20K range)? For single wall tanks, ultrasonic testing has worked well for us in the past. However, non-destrcutive testing of a double wall tank seems a bit tricky. Anyone with experience...
  16. cwigg66

    Help with USACE manuals

    thread194-5514 is closed. I am looking to find the USACE technical manuals referenced in it. How do I go about locating these? Are they free? Downloadable? Thanks all. CHris
  17. cwigg66

    Welding Tanks to Foundation

    I recently inspected three fuel storage ASTs in Florida, and found that all three tanks were welded to their foundation. That is, the concrete pedestal on which they stood had steel plates (probably small I beam pieces) cast into it, and the tanks were welded to those plates directly. Has...
  18. cwigg66

    Tank Inspection- Dents and Gouges

    Steve: You bring me back to my original point. I am trying to conduct the most complete inspection I can and give my customer the most for his money. For most of our clients, they don't even know they have to inspect their tanks at all until a regulator or myself tells them so and point them...
  19. cwigg66

    Tank Inspection- Dents and Gouges

    Great info JStephen... thanks. Got a link to the site you found the UT cert. requirements? I am interested in who the certifying agency is and what industries recognize the certification. I can't seem to find much on it online. Like you, I was also under the impression that equipment such...

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