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  1. Vellum

    cooling load calculation question...

    That is a tricky question that I don't think anyone could answer without looking at a drawing set. Things to keep in mind is that heat rises so the corridor at the top will probably be hotter then the other floors and that designing around a space with a lot of glass and air distribution is not...
  2. Vellum

    i transfer ducts

    Typically I would make a transfer duct out of an elbow or a 'Z', not a straight piece. The lining will absorb high frequency noise (e.g. talking). One other piece of advice is to watch where the return grilles are, if they are just on the other side of the wall from each other with a transfer...
  3. Vellum

    commercial PTAC manufacturers

    How big and what's the application?
  4. Vellum

    RTAA Sound Attenuation

    People can perceive a 2-3 dB difference.
  5. Vellum

    FACE AND BYPASS AHU APPLICATION

    What about adding electric Pre-heat to the units or adding a dedicated oa unit that supplies OA to all the OR units. Simsd is right, what is the cost of one life because of an improperly designed system?
  6. Vellum

    How much does the contractor really coordinate with other trades?

    It is important to bring your findings to someones attention ASAP. The sooner that the problems are addressed the cheaper the solution (possibly). It's easier to drop a ceiling or soffit before it's installed then after.
  7. Vellum

    diffuser in gypsum board ceiling

    I've seen lay-in kits or frames for square diffusers in drywall ceilings, they also double as access panels too. Typically though the border that comes with the diffuser (if ordered for surface mounting) will attach to the drywall. Also for balancing if you don't do a neck mounted damper, you...
  8. Vellum

    RTAA Sound Attenuation

    If you don't like the information from the manufacturer about the sound dampening then you need to install an acoustical screen wall on the roof this will allow for the sound to 'bounce' away from the houses. Note that high pitched frequencies are attenuated easily with mass. Do, however, keep...
  9. Vellum

    Chilled water expnsion tank commissioning.

    What type of expansion tanks are you setting up?
  10. Vellum

    What's the pressure needed for VAV box?

    Are you talking about pressure dependent or independent boxes? And what's the system?
  11. Vellum

    RTAA Sound Attenuation

    I've dealt with noise issues in the past and they are a pain. If the problem is noise complaints in adjacent occupied spaces then treating it at the source probably would be easier then treating it at the mechanical room wall. I would ask Trane what the dB difference is for the kit (make sure...
  12. Vellum

    electronic signatures on stamped drawings

    In Ohio the 'authority having jurisdiction' dictates what is required (stamped, embossed, signed etc.) but for smaller projects the state has started doing electronic walk-throughs involving the transfer of a single pdf drawing file that is then reviewed, stamped approved and then encrypted...
  13. Vellum

    FACE AND BYPASS AHU APPLICATION

    You will run into a problem with humidity if you by-pass the cooling coil while in the cooling mode. This would not be good IMO. Is the coil DX or chilled water?
  14. Vellum

    Construction Bid Review

    I've sat through a number of scope review meetings and it primarily turns into the contractor reaffirming everything that is in the job. If the MC is a prime then here are some of the questions that we ask (most of the first questions relate to the bid forms): -Verify Bid Amount -Verify...
  15. Vellum

    How long do you think this would take an entry level HVAC engineer?

    That is one heck of a project for an entry level engineer and it sounds as if you got little or no mentoring. The time you've spent will be a drop in the bucket if something was omitted in the design due to your inexperience. Hopefully, the project was well reviewed prior to being released.
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