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  1. tlhoo

    MEP Design Fees

    Just started up my design consulting firm, looking for some rules of thumb for MEP design fees. What is typically used for creating proposals? A percentage of construction cost? $/SQ.FT? percentage of architectural fees? Thanks.
  2. tlhoo

    Air curtains in commercial kitchens

    Designing a new commercial kitchen with multiple grease hoods. Got a review comment stating the need for an air curtain (to prevent insects from entering) above the 3' side door. I assume this door would be used for supply loading, so it may be open for somewhat extended periods of time. My...
  3. tlhoo

    Grease Duct Connection to Upblast Fan

    Typical kitchen grease duct application, fully welded carbon steel. Is the connection to the roof-mounted fan welded as well, typically speaking of course. Or is it flanged and gasketed? Thanks Also, separate, but related question. In a fume hood application, with welded, stainless steel...
  4. tlhoo

    Dining Room Occupancy

    Trying to calculate dining room ventilation requirements for a commercial cafeteria. The most conservative occupancy count would be to simply count the number of chairs in the dining area. However, I've heard in the past that this number is discounted due to the fact that all tables are never...
  5. tlhoo

    Propylene Glycol vs Heat Trace

    Designing a job in Wash, DC area, with exposed chilled water piping (air cooled chillers on grade). Intially planned to use heat trace, but was directed to use propylene glycol due to the "reliability" problems with heat trace. Anyone have any experience with heat trace failures? Any...
  6. tlhoo

    Chilled Water Buffer Tanks?

    Yes, I have 3-way coils on a portion of the loads to maintain a minimum circulation in the secondary loop. The chillers will not be operating unless the secondary pumps are on, so the "system" volume should be the entire secondary system as well as the primary. Thanks for your help.
  7. tlhoo

    Chilled Water Buffer Tanks?

    General question regarding buffer tanks for chilled water systems. I have a primary-secondary system with two 70 ton air-cooled screw chillers. My total system volume is approximately 950 gals. The system is mainly serving fan coils units with 2-way modulating valves. Do I need a buffer...
  8. tlhoo

    Sound Insulation

    http://www.jm.com/insulation/technical_info/media_3020.htm Discussion of non-fibrous liner alternatives. They're out there, the VAV box manufacturer's also offer a non-fibrous liner in addition to the foil faced option.
  9. tlhoo

    Heat Gain Thru HEPA FIlters

    I'm looking for an equation to determine the heat gain (delta T) of an air stream passing through a HEPA filter. I have the flow rate, velocity, static press. loss, and I'm sure there's a way to determine the heat gain to the air from the pressure loss, I just can't seem to locate it. I...
  10. tlhoo

    Apartment Bldg, 4-pipe fan coil

    Desiging a building with 1 and 2 bedroom units. Using Air cooled chillers and modular non-condensing boilers. Trying to select coil delta-T's for the chilled and hot water, just wanted to get some opinions. Planning to use 44F-56F chilled and was hoping to get 30F delta-T across the hot water...
  11. tlhoo

    Armaflex pricing??

    Looking for total price (material, labor, O & P) for armaflex on refrigerant piping (for 3-ton split DX), probably 7/8" or 3/4". Contractor has it @ $14/LF, seems high. Note: looking for price of insulation, not piping. Thanks
  12. tlhoo

    sizing a/c for exhaust hoods

    Is the make-up air being introduced at the hood? With your numbers of 70%-80%, it sounds like you may be using a preforated plenum type of hood. If not, look into these. They provide good capture and containment, and have a low velocity make-up air stream that dumps air into the space right...
  13. tlhoo

    Elec. Transformer Heat Load

    What do you typically use for the heat rejection for transformers in elec. rooms? I've heard 5% of the kVA rating, but this seems to get my airflows a little high. I have an 10'x12' elec room with (2) 45 kVA and (1) 30 kVA transformers, and using the 5% rejection, I get a cooling load of about...

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