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  1. emalsyd

    Corroding pool ductwork

    No pictures. Will try to get some when we go back. The soil doesn't appear wet at all, at least the soil falling into the ductwork is dry. I could maybe see galvanic corrosion where the duct contacts the soil but I find it hard to believe it would corrode through the duct in under a year...
  2. emalsyd

    Corroding pool ductwork

    No,the corrosion is mostly up top, near the floor grilles, which are aluminum. The aluminum drops to the PCD spiral are about 18"-24" long. Most of the corrosion is maybe 12" and up. There is just dirt from the top of the PCD duct up to the bottom of the concrete slab surrounding all the...
  3. emalsyd

    Corroding pool ductwork

    Dirt is getting into the duct because the duct has corroded to the point where there are holes through the duct. The dirt outside of the duct is dropping into the duct and some is getting blown out the floor supply grilles. We used PCD coated spiral for the main trunk. We couldn't get sheets...
  4. emalsyd

    Corroding pool ductwork

    Last year we installed new underground pool duct at a long-time customers residence. Pool is indoors, at the same time we installed a new Seresco dehumification unit. Pool is salt water vs chlorine. The main underground duct was PCD coated spiral. Branch duct up to the floor grilles was...
  5. emalsyd

    Air Changes an Hour Confusion

    Thanks for the clarification and calculator.
  6. emalsyd

    Air Changes an Hour Confusion

    I will add, we installed bi-polar ionizers in all the rooftops units. Looking on the ionizer manufacturers site, they have an article and an excel sheet explaining and calculating ASHRAE 62 Ventilation Rate Proceduce and Indoor Air Quality Procedure. Reading through the article, it appears the...
  7. emalsyd

    Air Changes an Hour Confusion

    We are doing some work at a small private school. They've asked us to go through the school and determine the ACH in each classroom and if they are getting the required 4-6 ACH as suggested by the CDC based on the new Covid Requirements for schools. The document they gave us lays out the...
  8. emalsyd

    Cleaning the air

    We've installed quite a few of the ionizers. We've used Phenomenal Aire by Top Product Innovations. http://www.topproductinnovations.com/main.html I think they license the ionizer technology from GPS. They have independent 3rd party testing data on their website. They were also tested to...
  9. emalsyd

    Kitchen MUA heat calc

    Make up air, in the kitchen
  10. emalsyd

    Kitchen MUA heat calc

    Looked a small restaurant kitchen yesterday. The MUA is provided by a un-tempered supply fan directly into the front of the hood so the MUA blows into the hood. The owner wants to add cooling to the kitchen. Do I have to take the MUA into my calculations or is it negated since it goes right...
  11. emalsyd

    return duct entry to plenum

    If the duct and plenum are sized correctly, I don't think it's going to affect the performance of the cooling coil. We just installed 4 fan coils on a small job. 3 of the 4, the returns were installed similar. Airflow and supply air temps all came in at design so the ducting didn't affect...
  12. emalsyd

    Soldering lab ventilation

    A local tech academy we do some work for ask us to provide a rough budget price for a new soldering/brazing lab they are thinking of installing in the future. We're an HVAC contractor. They will end up hiring an engineer but were just looking for some rough numbers to get into their budget...
  13. emalsyd

    Kitchen Hood Exhaust Insulation

    Should have explained the installation a bit better. Building is about 18' high. Bottom of hood at 6'6", top 9'6". Wall hood is against ends at 10' high. Duct goes straight up from hood to roof. No combustibles within a few feet, except where we penetrate the metal deck at roof level.
  14. emalsyd

    Kitchen Hood Exhaust Insulation

    I'm installing a welded 16ga black iron duct for a commercial kitchen hood. Do I need to insulate the duct with firewrap. Wanted to make sure I'm reading the mechanical code correctly. 506.3. Grease duct clearances: Where enclosures are not required, grease duct systems and exhaust equipment...
  15. emalsyd

    Is Make up Air required in a kitchen

    A local boys & girls club is installing a small kitchen area. They are adding a 6 burner stovetop and a 4'x4' hood above. Exhaust is 1125 cfm. Is a MUA unit required or can they take in transfer air from the adjoining 4000sq ft activities room. The activities room is served by a rooftop unit...
  16. emalsyd

    Concentric diffusers box

    Just got hired to install the HVAC at a arcade/gaming facility. The engineer designed most of the rooftop units to utilize concentric diffusers. The owner let the engineer go a while back so I don't have him to ask. Took a walkthrough of the facility today. Most areas are 21' to the roof...
  17. emalsyd

    Fire pump room ventilation

    Does a fire pump room with an electric fire pump require ventilation. I can find ventilation requirements if using a diesel or gas powered fire pump but can't find anything for an electric fire pump. I wouldn't think any would be required since there is no combustion happening.
  18. emalsyd

    Maximum temp. in data closet

    Is there any way to predict what the temperature in a small data closet would get to if we didn't install any mechanical cooling? We have a 6'x4' internal room on the first floor, conditioned rooms above. The owner is saying the btu load of the equipment is 11,800 btu and the max temperature...
  19. emalsyd

    FLEXIBLE DUCT FOR PLENUM CONNECTION???

    You should be able to make a side takeoff rectangular to round transition with a 45* entry. Have them make it 150mm on the side then transition to 200mm round.
  20. emalsyd

    Class B Operating Room

    I just downloaded Ashrae 170. This is what I found. Table 7-1. Classes B&C operating rooms. Positive pressure, Min OA changes 4 Min total ACH 20 All room air exhausted outdoors N/R? Note J. I'm assuming that means not required. Air recirculated by means of room units No RH 20-60% Note...

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