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  1. #1
    Join Date
    Dec 2010
    Location
    Goodyear, AZ
    Posts
    50

    Crane doesn't reach.

    My company is bidding on a big apartment complex job-replacing about 180 gas pack RTU's. Problem is the crane will not be able to access about 1/3 of them. Which means we would have to wheel them on a dolly over the roof, then lift them in to position.
    Other problem is there are many gas lines and water lines running across the roof, plus the roof is not flat and has a slight pitch to it.
    Anybody experience something like this before? Is there equipment out there that would help? Walk away, let the other guy go out of business?

  2. #2
    Join Date
    Mar 2007
    Posts
    3,071
    Quote Originally Posted by weebitdry View Post
    My company is bidding on a big apartment complex job-replacing about 180 gas pack RTU's. Problem is the crane will not be able to access about 1/3 of them. Which means we would have to wheel them on a dolly over the roof, then lift them in to position.
    Other problem is there are many gas lines and water lines running across the roof, plus the roof is not flat and has a slight pitch to it.
    Anybody experience something like this before? Is there equipment out there that would help? Walk away, let the other guy go out of business?
    The best solution is to use a helicopter to lift and set the units. The upfront cost will be more expensive than any crane you could use, but it will save many hours in labor, and will get the job done quickly, safely, and professionally.

    You could temporarily demo the gas/water piping and/or build ramps over them and use a gantry with big inflatable rubber tires to move the units from the edge of the roof to their final resting place. You'll still need a crane, and everyone on the site will have to work twice as hard to get the job done in the time allowed. This will also result in you having to purchase a lot of specialized equipment to move the units around, plus a lot of extra labor hours. This is not the preferred method. It may not even be possible at your site.
    "There is no greater inequality than the equal treatment of unequals."

    -Thomas Jefferson

  3. #3
    Join Date
    Jul 2007
    Location
    The Hot South
    Posts
    1,205
    I agree. A helicopter will be your best solution with that many units, even if the crane reached all of them. When you figure the amount of labor and crane time for tearing down , repositioning, and resetting up the crane for every couple of AC units the time will really add up. You can get all the units ready to go ahead of time and knock them out really fast with a helicopter.

  4. #4
    Join Date
    Mar 2007
    Posts
    3,071


    Here's a video of a helicopter lifting some rooftop units.
    "There is no greater inequality than the equal treatment of unequals."

    -Thomas Jefferson

  5. #5
    Join Date
    Jan 2003
    Location
    Kansas City
    Posts
    1,478
    What size RTU's?

  6. #6
    Join Date
    Jan 2003
    Location
    Kansas City
    Posts
    1,478
    Why isn't that tail rotor spinning Tech Rob?

  7. #7
    Join Date
    Mar 2007
    Posts
    3,071
    Quote Originally Posted by james mo View Post
    Why isn't that tail rotor spinning Tech Rob?
    The tail rotor looks like it's spinning to me... Those units are probably in the 20-25 ton range.
    "There is no greater inequality than the equal treatment of unequals."

    -Thomas Jefferson

  8. #8
    Join Date
    Aug 2012
    Location
    Gainesville, FL
    Posts
    325
    Helicopter lifting is pretty pricey...around $1,000/hr last time I looked into it, but it's fast...or at least it can be. You need a large, nearby parking lot for staging, experienced riggers that can get quick turns, and enough rigging to have 2 or 3 sets ready to fly from the parking lot and the old ones on the roof. With 180 units it will probably end up saving money over a crane to just use the chopper on all of them- chopper lifts are a lot faster unless there is a lot of overhead obstruction. After the first few and establishing a good rhythm you'll do one every 10-15 minutes. Just drop it on the curb and install it later. Time is money and it's all hands on deck.

  9. #9
    Join Date
    May 2002
    Location
    Baton Rouge, Louisiana
    Posts
    3,814
    Agree, helicopter all of them
    Quote Originally Posted by MatrixTransform View Post
    very soon it is you that will be pwned

  10. #10
    Join Date
    Jun 2010
    Location
    Indianapolis indiana
    Posts
    43
    Price out a helicopter, if you get the job, great, if you don't you're probably better off.

  11. #11
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    17,021
    What a great helicopter.

    It's probably one of the most recognizable rotary wing aircraft of the 50's and 60's. The Sikorsky S58T.

    The rotor speed and video scan rate get very close, so it can appear that the rotors are not turning. In reality, it's successive scans of video that catch the rotors in the same place in their rotation. This is also the reason that rotors seems to move slowly, or even backward, in TV and films.

    It was originally built as a radial engine piston craft, and then Sikorsky came out with a conversion kit to replace the expensive-to-maintain radial engine with a reliable turboshaft engine. In the video, you can hear that turbine whine.

    Most of the examples that are not in museums today are used for precisely the task this one is shown doing: lifting.

    You DO need multiple rigs, and guys on the roof for the settings, but this is DEFINITELY the way to go. Just don't try to rush so much to save a few minutes of time, because it is easy to get caught up in the moment and forget to favor the one end of the unit where the rails need to be up against the curbing to prevent air leaks. I'm amazed at how many units I find on an initial PM visit for a new contract, and I can look through the filter access and see the roof through a 1" wide gap!

    http://www.aviastar.org/helicopters_eng/sik_s-58t.php
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

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  12. #12
    Join Date
    Jul 2012
    Location
    Chicago, IL
    Posts
    20
    Quote Originally Posted by Tech Rob View Post


    Here's a video of a helicopter lifting some rooftop units.
    That looks like its Midwest Helicopter. We used them for a helicopter lift at Woodfield Mall in Schaumburg, IL .We swapped a couple 20 tons out and removed some abandoned units all in about 20 mins!!

  13. #13
    Join Date
    Nov 2002
    Location
    Pittsburgh
    Posts
    43
    Quote Originally Posted by MsiHvac View Post
    That looks like its Midwest Helicopter. We used them for a helicopter lift at Woodfield Mall in Schaumburg, IL .We swapped a couple 20 tons out and removed some abandoned units all in about 20 mins!!
    I agree on Midwest. Been under that orange Sikorsky before. One job would have required the largest crane in the city, a day to set it up, lift day, a day to tear it down.

    Went with Midwest. Seven lifts done in less than 25 minutes. I liked that they handled all the rigging also. All we had to do was guide the units onto the curbs.

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