Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations MintJulep on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Search results for query: *

  • Users: daly1
  • Order by date
  1. daly1

    Fume Hood Face Velocity

    "...full height better protects the face of the scientist working" be very careful and read ANSI/NFPA-45 for yourself. OSHA requires you to provide adequate protection from vapors, explosion/blast,and splash. No where in any code or regulation does it state that a sash height of 16" or 18"...
  2. daly1

    Fail-Safe ventilation

    The fail safe design is to have the exhaust fan on emergency power (not a full stand by back up). Spring return open all dampers (or they fail in full open position). Fan defaults to max CFM/SP position
  3. daly1

    Heat recovery

    can you add some info on where the 25,000 cfm of exhaust comes from? If this is bathrooms, hallways, and similar areas I have used total enthalpy wheels with success (being sure to apply good filtration on both sides). For labs or areas with potential contaminants I would never use any wheel...
  4. daly1

    Low capture velocity @ lab hood

    don't fall for the 100-fpm myth. Look into the OSHA final ruling on Chemical Exposures in labs (1/31/00) to realize there is no OSHA requirement for 100-minute (or any other face velocity). Provide a fume hood that provides the required user protections from explosion (blast), splash, and...
  5. daly1

    AIR washer FOR DEHUMIDIFING

    I worked with several MEP contractors in North Carolina that have (had) extensive experience with Air Washers. With the loss of our textile industry experts with air washers are going to be fewer and harder to find. In North Carolina I worked with AC Corp, Environmental Air Systems, and LUWA...
  6. daly1

    "Custom" Air Handling Units

    custom ahu's used to onlyb use thermal breaks in the wall construction. Is that still something that spearates the MCC from the Des Champes--or does everyone do thermal break now?
  7. daly1

    Ductwork for laboratory exhaust

    The fume cupboard comment leads me to believe your in Europe and thus the possible use of PP. Need to approach this scientifically and relaying a 'I modified a lab last year where Galvanzied duct was used" should never be used to justify the next project's decisions. The chemistry changes...
  8. daly1

    MCC Room Ventilation

    My engineering firm had an account with a large pharmaceutical that allowed us to track and target issues like this. Not only is dirt the enemy to electronics build up on heat sinks forces the electronics to work harder-spend more energy. We always included 30/30 pre-filters and 95% bag...
  9. daly1

    How to calculate Air exchange in a room?

    Also make sure you account for the volume of the "stuff' in the space. to many of we engineers are tasked by customers with "give me 10 ACH" in the space. Casework vendors did studies years ago and found that most labs are 18-22% of the volume occupied by "stuff". Take the V x 0.85 for most...
  10. daly1

    Fume Hood Testing

    i've used a company named Precision Air Technology based in Raleigh, NC. Make sure whatever testing agency you use, uses an IR gas analzyer with a 0-20,000 cc/min sampling rate (usually set to match the isokenetic tidal volume of the average worker 15,000 cc/min). Do not use any testing...
  11. daly1

    HVAC Chiller Plant

    great stuff above and don't miss the opportunity to right size the pipe. All pipe charts are from the 30's or 40's when pipe was expensive and power was cheap. Now the converse is true. Evaluate the first cost and reduction in friction by oversizing pipe. I'd also strongly avoid the temptation...
  12. daly1

    Louver finishes

    Davebab--I agree the Kynar finishes are much better than most standard paints offered by manufacturers. You should also look into the painting/curing process and you'll learn something I did years ago--baked does not always mean baked. I was specifying a baked enamel finish and had repeated...
  13. daly1

    Maximum Air Exchange Rate per Hour

    Abbott has long eschewed vertical, Pfizer presented a paper at Labs21 touting (amongst other findings)the benefits of horizontal, added to literally hundreds of end users following this same approach. Do a goggle search and I think you'll be amazed at how far that movement has gone and how...
  14. daly1

    Air Separator in Chilled Water Systems?

    you might want to consider a smaller run around air separator. I've had similar concerns on a couple large chiller plants and we installed say a 6-8" air sep along with automatic air release valves at every change in elevation.
  15. daly1

    BAC cooling tower information

    I'm not a fan of the forced draft style towers mainly due to HP considerations and basin leaks. However, the lone applications where they shine over induced draft towers is ducted units and cold environments (both of which we only see in very cold environments like yours). The spray headers are...
  16. daly1

    Maximum Air Exchange Rate per Hour

    Lilliput1--regardless of how the FH industry sells fume hoods they are not designed to be operated safely, vertically. In your example you describe the major problem with working vertically. When you lower the sash below the operators face--then how do workers see their hands when they are...
  17. daly1

    Maximum Air Exchange Rate per Hour

    the ideal application for beams is where you have a low hood exhaust (say a min ACH of 4) and a thermal load of say 8 ACH. The induced air provides the added cooling affect without adding to the size of the AHU's. I have used beams on several good sized projects and generally I like them alot...
  18. daly1

    BAC cooling tower information

    assuming you get this information you need to also take a suspicious eye at the data. Prior to CTI being formed all the cooling tower manufacturers cheated--to varying degrees. As someone that designed hundreds of central utility plants I saw this cheating could amount from 20% to as high as 50%...
  19. daly1

    Maximum Air Exchange Rate per Hour

    You've asked a good question but without providing enough information to answer it completely. You also need to evaluate the system you offer for complete code and ANSI standard compliance--which sadly many are not completely up to date on. 1. 1500 cfm--6' FH's have approx 12 sq-ft opening x...

Part and Inventory Search

Back
Top