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What do I need to consider if I want to suspend a 1/2 ton chain hoist from this type of ceiling Joist? I would never even come near 1/2 ton, maybe 50Kg tops.

I want to connect an I beam with a trolly between two spans, to lift slaps of wood up to a second level.

enter image description here

[Edit] This picture is not of the space I'm in, its just a clear example of the type of joist I'm dealing with

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  • For 50kg would use a small rope hoist so that your friend does not see the I beam and chain hoist and decides to pull his car engine out.
    – crip659
    Nov 8 '21 at 21:19
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    I’m voting to close this question because it's a commercial structural engineering issue and not home improvement.
    – isherwood
    Nov 8 '21 at 21:57
  • Do you have a suggestion of where I should post @isherwood, It's for a personal workspace in a communal studio. I just want to give the other's peace of mind that it's realivly safe.
    – Lpaulson
    Nov 8 '21 at 22:09
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    I don't, but it's not a question for the internet. It's a question for a local professional with suitable credentials. Generally speaking, you can hang 50kg from such a ceiling, but only if you do it correctly (using the right hardware), and depending on dynamic loading. We don't have nearly enough information to answer. Good luck.
    – isherwood
    Nov 8 '21 at 22:09
  • You could say that about half the question on this site. I'm not asking for someone to sign off on this; I'm looking for a general direction or terms to research.
    – Lpaulson
    Nov 8 '21 at 22:14
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Sanity check, 1 metric ton = 1000 kgf, one half of it is 500 kgf, gar exceeds your need (that's good though). Even at 50 kgf, plus some dynamic lifting force, it is not a small load for a typical roof joist. For the safe bet, you should:

  1. Carefully look around the joists to find whether there is a tag that lists the name of the manufacturer, the type and series of the joist (serial number), and possibly the date it was produced.

  2. If no such tag was found, if you know the approximate year of the installation, then you can contact the professional institution that deals with steel joists for help to identify the joist and to see whether the manufacturer is still in business, or they happen to have the historical joist information that matches yours. (In the US, contact SJI - Steel Joist Institute)

  3. Engage a structural engineer to perform inspection and make recommendations.

The roof joist has a very slim margin for additional load, especially for the concentrated load, which would require special attention or may require modification. No one can tell the capacity of your joist but the above-mentioned sources mentioned. Please do not take it lightly.

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Those are top chord bearing steel trusses. Their capacity is based on the span, spacing, size of steel webs, spacing of steel web connectors, etc. You’ll need to find a steel truss manufacturer to run the calculations based on size, spacing, etc. of your trusses. (It may not be exact, but they can get close.)

Steel trusses are like spaghetti without lots of blocking and bracing between trusses. Your steel truss manufacture will be able to give you blocking and bracing requirements too.

However, no matter what, do not attach to bottom chord between web connection points. Steel trusses are different from wood trusses because they’re so light and have very little safety factor.

Btw, I’m surprised their aren’t horizontal bracing on the bottom chords at about 12’ on center, based on their depth, span, etc. Be careful.

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  • Thanks for the specific name, that's helped a lot with reference material. When you say do connect between the web, do you mean don't connect to the base of the triangle, formed by the webs, instead connected to the point where the two webs meet?
    – Lpaulson
    Nov 9 '21 at 0:16
  • Yes, add blocking, bracing, etc. only where the two triangles meet on the bottom chord. If add a load between the connection points, you’ll be adding “double bending” to that section of the bottom chord. Webs in trusses are either in compression or tension. When you apply a load between the points where the triangles meet you will add “bending” to the bottom chord. This will add additional compression to the top of that section or tension to the bottom part of that section. Those kinds of loads are not accounted for in the design of these types of trusses and the truss will fail.
    – Lee Sam
    Nov 9 '21 at 0:53

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