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# Structural integrity of a welded steel stand for two condenser units8

## Structural integrity of a welded steel stand for two condenser units

(OP)
I've recently bought two mini split heat pumps and want to build a stand to hold the outdoor units. I would like to obtain an E-shaped cantilever structure but am unable to determine whether the beams will hold the units safely in place without adding some form of additional support (e.g. diagonal braces).

I plan to use 50mm x 50mm x 2mm (2" x 2" x 14ga) square steel tubes which are going to be welded together as shown in the drawing above. The small cylindrical shapes are rubber-metal mounts that will go underneath the condenser units to prevent vibrations from being transferred to the steel frame. I might also use some larger rubber-metal buffers to decouple the stand from the concrete foundation on which it will be mounted, so any unmitigated vibrations don't find their way into the nearby walls of the house.

The weight of the outdoor units is 43kg (95lb) each, and the way this weight is distributed on each corner is shown on page 11 of LG's product data book (i.e. page 13 of the PDF) linked below.

Since this stand is only going to be secured to the ground (and not to a wall), my main concern is stability, i.e., supporting the weight and stress from the two condensers without bending, breaking, or tipping over, while enduring the fluctuating weather conditions.

Any thoughts or advice would be greatly appreciated.

### RE: Structural integrity of a welded steel stand for two condenser units

Really, you are coming back for more?
I like stacked cinderblocks for your project.

### RE: Structural integrity of a welded steel stand for two condenser units

Without looking into any detail, I suggest to locate a solid wall to provide lateral stability, tipping/roll over is the main concern. Do you know the design wind speed for the local, and are you in an earthquake zone, which one (A thru E).

### RE: Structural integrity of a welded steel stand for two condenser units

Well, if I was building it I would add some angle braces or gussets. Cantilevering the arms is a bad idea. Same for the base to side rails. And I would attach the units to the frame, not just sit them on the bumpers.

### RE: Structural integrity of a welded steel stand for two condenser units

And in the engineers with hobbies forum.....

Now double posting really isn't allowed so please choose one forum or the other.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

### RE: Structural integrity of a welded steel stand for two condenser units

#### Quote (Well, if I was building it I would add some angle braces or gussets. Cantilevering the arms is a bad idea. Same for the base to side rails. And I would attach the units to the frame, not just sit them on the bumpers.)

works without gussets. Loads are relatively small.

Dik

### RE: Structural integrity of a welded steel stand for two condenser units

#### Quote (Now double posting really isn't allowed so please choose one forum or the other.)

LittleInch is correct... this is a good forum... not really a hobbie item...

Dik

### RE: Structural integrity of a welded steel stand for two condenser units

If I am doing it, I'll add quite a few members as shown in sketch below (Black - HSS, Red - rod/plate/HSS diagonal). The upper cantilevers may require kickers too. Do you think you can handle all calculation required? Although it is small, the concept is the same as a building frame.

### RE: Structural integrity of a welded steel stand for two condenser units

retired... the framing is robust and the loads are relatively small.

Dik

### RE: Structural integrity of a welded steel stand for two condenser units

(OP)
Sorry for the double post, that was a mistake. I wanted to delete the other one but it's just now that I am noticing the "delete" button at the bottom of the OP. I want to respond to the replies I got there, too, so I will replace the content of the OP with a link to this thread instead of deleting it. Or if a moderator can merge the replies into a single thread (this one) and delete the other one, that would be awesome.

I am busy now, but will post more later. Thank you all for your replies.

### RE: Structural integrity of a welded steel stand for two condenser units

I was thinking a space frame to hold a person's weight:) But at least attach it to a wall, or something solid.

Watch out, the weight is off the center of geometry. You need to ensure later stability (leaning tendency).

### RE: Structural integrity of a welded steel stand for two condenser units

My greatest concern is with the welding of 14 ga. material. It is easy to burn through. Here are a couple of videos about stick welding thin gauge steel.

Good welds are difficult to achieve if the members have the same width. As Dik said, it may be better to use 1.5" HSS members for the horizontal arms, but the welding is still tricky and you can't develop the full strength of the cantilevered arm when welding across the wall of the 2x2 HSS. The load is fairly light, so it may be strong enough, but would need to do a yield line analysis to prove it.

Also,the base needs to be tied down so that the whole thing can't blow over in a strong wind.

BA

### RE: Structural integrity of a welded steel stand for two condenser units

(OP)

#### Quote (LittleInch)

What is it sitting on?
Concrete foundation surrounding a brick veneer house.

#### Quote (LittleInch)

Why two one on top of another?
Because I don't have sufficient space to put them side by side in the location I want to utilize. Clearance requirements suggest a lot of open space around them — they will have to be placed at least 1 meter apart and be clear of any surrounding obstacles.

#### Quote (SWComposites)

And I would attach the units to the frame, not just sit them on the bumpers.
Of course I will do that. It will look something like this (the one on the left), except I'll need to use longer bolts on the bottom to pierce through the steel tubes and come out from below.

#### Quote (retired13)

Do you know the design wind speed for the local, and are you in an earthquake zone, which one (A thru E).
Not sure. I think I'm in the "moderate" seismic hazard zone. There's been a few short bursts of unusually strong winds over the past two years or so.

#### Quote (dik)

retired... the framing is robust and the loads are relatively small.
This is why I quoted the weight and posted the link to the technical specs. :) I would like to keep the design as minimalist as possible, but if attaching a few braces or gussets in the right (or most critical) places would strengthen the build significantly, I wouldn't mind doing it.

#### Quote (retired13)

Watch out, the weight is off the center of geometry. You need to ensure later stability (leaning tendency).
Yeah, most of the weight (around 72% if I'm reading the specs correctly) falls on the right mounting brackets, and I have no idea whether and how to address this.

### RE: Structural integrity of a welded steel stand for two condenser units

Parker,

On top of machine weight, you need gather the wind load, snow load and seismic design coefficients, which will be used for frame member sizing, connection design, and fastening of the whole unit.

The off center weight creates a moment (rotation) about the center of the frame, which will resolve into a couple at the support legs. The net support reaction is the sum of effect of the weight plus the couple. See sketch below (Red - moment, force couple).

### RE: Structural integrity of a welded steel stand for two condenser units

BART:

With the weld, you can develop about 80% of a CJP if properly done... about 3x what is needed, if prelim calcs are OK. Didn't need to complicate the welding by using fillet and flare bevel welds, therefore reduced dimensions of the horiz and vert tubing. I'd prefer to see 1/8" wall thickness, easier and safer weld and not much more costly. He should still add mounting tabs at the bottom and use TEKS 3 or TEKS 5 for mounting the equipment to the 'arms'. A vibration isolator can be placed between the equipment and the HSS. He really needs to check the design... or have a real engineer do it.

Also tie the top to keep the frame from translating.

Dik

### RE: Structural integrity of a welded steel stand for two condenser units

#### Quote (Yeah, most of the weight (around 72% if I'm reading the specs correctly) falls on the right mounting brackets, and I have no idea whether and how to address this.)

The product cut sheet has the actual reactions at the four legs and I used these for the preliminary check.

Dik

### RE: Structural integrity of a welded steel stand for two condenser units

(OP)
Dik, the vibration isolators have independent top and bottom threading so you can't really screw through them: https://www.dinex.net/rubber-buffer-silencer_p-809...

Considering the specifics of the weight load distribution, would you still say there's no need to put any diagonal braces or gussets?

#### Quote (dik)

He should still add mounting tabs at the bottom

What's the reason for avoiding fastening through the steel tube? I dislike the idea of using mounting tabs at the bottom because of the off-center positioning of the vibration pads. More than half of their "supporting" surface will inevitably stay clear (no matter which direction the tabs are facing) and the tubes will end up resting only on the remaining portion of the pads.

### RE: Structural integrity of a welded steel stand for two condenser units

(OP)
Following some of the suggestions provided in this and the other thread, I have updated my design to the following:

Not sure if this would be the right type (or size) of gussets to use, so if anyone has a different/better idea, please let me know.

### RE: Structural integrity of a welded steel stand for two condenser units

Those gussets are installed as what I refer to as "can opener." The sharp ends are in the middle of the thin wall. In this case they perform no function as the rest of the structure is stiffer, but I've seen similar gussets just punch through.

Typical gussets would be cutting tubing to fit so the flat side walls have structural continuity.

If you like, I'd recommend the James F. Lincoln Arc Welding Foundation book on Design of Welded Structures. https://www.jflf.org/ProductDetails.asp?ProductCod... It's $25, so it's a good deal, probably the best ever for engineering. I'd rather not do a full analysis or explain what the book details vs the$25 book which does a more complete job. The target for the book is people in your situation re weldments.

### RE: Structural integrity of a welded steel stand for two condenser units

#### Quote (dik)

With the weld, you can develop about 80% of a CJP if properly done... about 3x what is needed, if prelim calcs are OK

When I said you can't develop the full strength of the 1.5" HSS outriggers, I was not thinking about the weld. No matter how good the weld is, each outrigger is fastened to the thin wall of the vertical HSS which is incapable of resisting the maximum fibre stress in the attached member. The deflection of each outrigger will be almost impossible to predict because of the flexible support. One thing for sure, deflections will not be equal because the loads are not equal on each side of the unit.

The triangular gussets suggested by the OP are not much use as noted by 3DDave.

BA

### RE: Structural integrity of a welded steel stand for two condenser units

concurr with your weld comment, and I wouldn't use gussets, either...

Dik

### RE: Structural integrity of a welded steel stand for two condenser units

#### Quote (Dik, the vibration isolators have independent top and bottom threading so you can't really screw through them)

I didn't realise they were true vibration isolators. I thought they were 'rubber bushings'

Dik

### RE: Structural integrity of a welded steel stand for two condenser units

(OP)
So it's be better to use HSS with thicker walls (e.g. 2" x 2" x 11ga)?

The reason I want to use 2" x 2" for the horizontal arms is because the condensers' mounting legs are 2" wide and I can get rubber buffers with the same diameter so everything fits neatly on the 2" square tube.

One more question: is it better to weld the upper and lower (base) horizontal members like in my drawing or have the verticals stretch to full height? Consider that I will most likely be using rubber pads like in the picture below and the vertical members will not be touching the ground if they extend to the bottom.

I can get ones locally that look a lot like these: https://www.polymax.co.uk/anti-vibration-rubber-mo...

### RE: Structural integrity of a welded steel stand for two condenser units

Why don't you just copy this design and make it a bit taller?

Even now, all your weight is going through one small fillet weld on the top angle with a huge stress concentration. All your other welds are there for effect only.

Why weld it? Use bolted angle brackets.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

### RE: Structural integrity of a welded steel stand for two condenser units

Unless those rubber isolators/mounts are gummi-bear soft AND selected based on static deflection and the units' frequencies of interest I think there is high likelihood that welded frame is going along for the ride, as if the mounts were aluminum biscuits.

In addition, all the electrical connections and "refrigerant" ping must be very flexible in 3 dimensions, and anchored to the building, lest the units' vibrations sneak into the building.
https://qph.fs.quoracdn.net/main-qimg-6c734999ac53...

### RE: Structural integrity of a welded steel stand for two condenser units

For what it's worth, if you make that using SHS 3mm thick (11ga), it won't go anywhere. Those are airco units ffs.
I'd have the bottom (horizontal) members full length for ease of mounting purposes, the rest doesn't really matter in a practical way. Whatever you can weld easiest/best is good enough.

### RE: Structural integrity of a welded steel stand for two condenser units

Extend two verticals as shown below and delete the triangular gussets and you should be okay. If you want to use 2x2 HSS for all members, that should be okay too. Make sure you have a skilled welder.

BA

### RE: Structural integrity of a welded steel stand for two condenser units

(OP)
Thanks, BA. The reason I don't want to have those verticals on the front is because: (1) It will look ugly and restrict airflow to the bottom unit (minor concern) and (2) It will make it difficult to install (and service?) the bottom unit, which will have to be "slid in" from the side.

And to address LittleInch's post, I initially designed it a similar way with the units to be mounted on the front and back horizontals (as opposed to the right and left) but there is an obstacle on the ground right around 10cm inward from where the right verticals should be (the solid concrete basically ends there [dotted line in the drawing below]). A stand with a narrower footprint solves this issue.

P.S. Now that I am thinking of using anti-vibration mounts underneath the stand, the above might not be an actual issue anymore. A remaining issue would be leveling, since the ground is slightly sloped downward towards the right and front.

### RE: Structural integrity of a welded steel stand for two condenser units

I understand your operation concern to not to restrict the way to set the units in, but with merely a few inches wider than you detail shown above, you can done the BA's way, which is preferred. Then, add a few surface mount triangular brackets, you might have eliminate the stability concerns and stand free by its own.

### RE: Structural integrity of a welded steel stand for two condenser units

(OP)
By the way, the only floor/ground anti-vibration mounts I can easily obtain are of the following kind: https://4.imimg.com/data4/JY/UG/MY-2836580/kpn-typ.... Makes me wonder how long they would last outdoors before the rubber starts degrading and falling apart due to sun exposure and other environmental factors.

I want to do my best to eliminate vibration transference, but these things don't look like a permanent solution to me. The condenser mounts could easily be swapped for new ones if need be, these might be harder to replace.

### RE: Structural integrity of a welded steel stand for two condenser units

If you are using 14 ga, doesn't that put you into AISI design land? Different set of rules.

### RE: Structural integrity of a welded steel stand for two condenser units

For modern heat pump, the vibration is rarely a concern, if it is on solid ground, such as concrete. You can add a raised concrete pad, if necessary, you can sandwich a vibration absorbing pad between the concrete elements.

### RE: Structural integrity of a welded steel stand for two condenser units

The lower level is not a problem now. It's only the upper shelf that needs a little help. I suggest a couple of knee braces as shown in the sketch below. If it's a bit wobbly, add diagonal braces in the bottom tier. The whole structure must be fastened down to something solid to prevent overturning.

BA

### RE: Structural integrity of a welded steel stand for two condenser units

(OP)

#### Quote (BAretired)

The whole structure must be fastened down to something solid to prevent overturning

Are you suggesting I don't use the anti-vibration mounts and secure the stand directly to the concrete or something else?

I was thinking of doing something like this:

### RE: Structural integrity of a welded steel stand for two condenser units

If you use this arrangement, the bottom shelf needs support. Mitering the corners of the base frame is one option. If they are butt welded, end plates would be required.

If the structure is just sitting on rubber mounts, with no attachment to a foundation, it cannot resist serious lateral forces such as strong winds or seismic events.

BA

### RE: Structural integrity of a welded steel stand for two condenser units

Parker87,

Our posts crossed in cyberspace. I don't know how much vibration condensers have but you are getting vibration isolation under each unit. Do you also need it under the structural frame? I was thinking of just bolting down to a concrete base to prevent overturning. It would have been my preference to extend the vertical members down to a base plate anchored in the concrete. In that case, the bottom frame would not be required and we would not have the issue of columns partially bearing on 14 ga. HSS walls.

BA

### RE: Structural integrity of a welded steel stand for two condenser units

The unit should be connected on top, if possible. It will be more stable than mounting on the ground alone. Also, up to this point, the frame looks great, but will it stands against wind and earthquake, it's head heavy laterally.

### RE: Structural integrity of a welded steel stand for two condenser units

(OP)
With all these options and details to consider, I feel like I keep getting further and further away from making any final decisions. :)

If I do the boxed bottom and diagonal braces for the top shelf, do I still need to miter the joints?

I would refrain from messing with the concrete for various reasons... and I can't really know if the rubber buffers under the units will do a good enough job of isolating the vibrations and keeping them away from entering the house. I've had bad experiences with mini-split ACs in the past and it can be extremely annoying when you feel the walls or floor underneath you trembling ever so subtly. In other words, I don't want to let it get to this and then regret not having taken sufficient measures against it. Once the stand is mounted, it will be harder to tackle any vibration/noise issues or do any revisions with regards to the way the stand was initially constructed and mounted.

### RE: Structural integrity of a welded steel stand for two condenser units

#### Quote:

With all these options and details to consider, I feel like I keep getting further and further away from making any final decisions. :)

That's the punishment for asking expert opinion/advice on the open space. I think from this point on, you already have adequate idea to talk to a local structural engineer to develop your project. If you willing to risk the investment on the equipment and the framing material, you can experiment on your own, but at least talk to a metal fabricator/welder to be realistic. After all, you might change your mind, and finding it is better just to purchase a preassembled rack/shelf instead of the troubles. Sorry to pour cold water on an enthusiastic mind.

### RE: Structural integrity of a welded steel stand for two condenser units

The bottom frame members are mitred together at each corner in a 2-way mitre. The post is square cut to sit on top. On the picture below, the post is to the left and we are seeing the underside of the base to the right.

I don't know anything about vibration isolation, so I won't comment on that.

If the top of stand can be supported laterally by a wall as suggested by retired13, that would be more positive than relying on the base connection alone.

BA

### RE: Structural integrity of a welded steel stand for two condenser units

This is my preferred method for providing the corner of a tube frame if you can tolerate the extra plate sticking out - especially for thin tube (or for backyard welders).

### RE: Structural integrity of a welded steel stand for two condenser units

I don't think welding HSS is an idea project for DIY. You'll need professional welder and pay the top dollar. With the unit fastened to the wall, put a thick rubber door mat beneath to get ride of vibration.

### RE: Structural integrity of a welded steel stand for two condenser units

The consequences of failure are not life threatening, so I guess Parker87 is free to take his chances with abnormal lateral forces.

BA

### RE: Structural integrity of a welded steel stand for two condenser units

#### Quote (retired13)

I don't think welding HSS is an idea project for DIY. You'll need professional welder and pay the top dollar.

DIY of HSS is not too difficult, especially if your tube wall thickness is > 1/8" - provided you have the right equipment. I am a self-taught welder and built this mobile welding table in a few hours - 1.5" x 3/16" wall, square tube - very strong - supported many thousands of pounds of steel fab on this unit. Took me longer to paint it than to cut and weld it up. I hate painting!

### RE: Structural integrity of a welded steel stand for two condenser units

He's free with deep pocket, are we free of our obligation? His question turns out quite interesting, but it is still a DIY project, I prefer to draw a line somewhere....But it's up to anybody's judgement when to call end.

### RE: Structural integrity of a welded steel stand for two condenser units

Ingenuity,

Good job, I couldn't have picked it out from professional works, but you would agree, it takes time and practice to be a capable welder, though the OP can be one too. I learnt soldering myself, however, it can not compare with electrode welding though.

### RE: Structural integrity of a welded steel stand for two condenser units

The wall thickness in ingenuity great example makes it a better starter project. The other gauges discussed burn thru easily and it takes more skill. Aluminum takes far more skill and understanding of prep to weld well. What do you have for tools? If only a few, I would price out what you need as you could spend more than hiring someone. McMaster carr sells a number of fittings to make this easier, but they add up quickly. They have some that eliminate welding, but they are not as neat.

### RE: Structural integrity of a welded steel stand for two condenser units

(OP)
I had a recently retired architect friend of my parents look at my sketches and he said that if I use the 2"x 2" HSS, I won't need any supporting braces/struts and could probably do without the front corner posts in the bottom as well, because the load is very light. For the vibrations, he suggested I cut a rectangular hole in the concrete with a circular saw, dig out some soil and pour a new concrete slab that won't be touching the surrounding one. Anchor the verticals in the new concrete and drop the bottom frame, similarly to what BAretired suggested. But as I already said, I would rather not mess with the concrete as I would probably need to hire someone else to do it and wait for it to dry for weeks before I can mount the whole thing. And it's too close to the walls of the house, which might open a new can of worms.

I can get a local welder to execute the build, but I want to at least finalize the design (including the basic details of the welding process) myself.

### RE: Structural integrity of a welded steel stand for two condenser units

..."retired architect friend of my parents"...hmmm, I am surprised he did not suggest you curve the steelwork and paint it mauve.

### RE: Structural integrity of a welded steel stand for two condenser units

#### Quote (BUGGAR: If you are using 14 ga, doesn't that put you into AISI design land? Different set of rules.)

Great comment... I don't know, and I should. I have checked with Canadian Code S16 and CISC 'Handbook of Steel Construction' and couldn't find an answer. I posted the CISC a query about this.

Looking at the latest rendition... it looks like a Horse designed to military specs... aka Elephant.

Thanks

Dik

### RE: Structural integrity of a welded steel stand for two condenser units

dik,

I like your comment. It is fool proof for DIY project.

### RE: Structural integrity of a welded steel stand for two condenser units

#### Quote:

Because I don't have sufficient space to put them side by side in the location I want to utilize. Clearance requirements suggest a lot of open space around them — they will have to be placed at least 1 meter apart and be clear of any surrounding obstacles.

Page 47 of the manual you linked says otherwise. If the units are outdoors and have only ground and one wall and no overhangs, the clearance requirement is more like 250 mm, minimum. This suggests that your upper unit does not need to be so high; eliminating 400 mm from the height would drastically reduce the tipping and bending concerns.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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### RE: Structural integrity of a welded steel stand for two condenser units

Ingenuity... Mauve would be nice, or maybe candy apple green (the colour of my first bookcase that I made)... I'm thinking of a hammer-beam truss for the 'arms'...

Dik

### RE: Structural integrity of a welded steel stand for two condenser units

#### Quote (IRstuff)

...eliminating 400 mm from the height would drastically reduce the tipping and bending concerns.

Tipping, yes. Bending, not really. The problem with the outriggers supporting the units remains the same. They would still need more support than the two posts at the back.

BA

### RE: Structural integrity of a welded steel stand for two condenser units

BART... have you actually run the moments?

Dik

### RE: Structural integrity of a welded steel stand for two condenser units

(OP)

#### Quote (IRstuff)

Page 47 of the manual you linked says otherwise. If the units are outdoors and have only ground and one wall and no overhangs, the clearance requirement is more like 250 mm, minimum.

Good catch, but the normal/preferred clearance is actually 600mm, which is the minimum I would aim for.

Page 10 of another, more generic LG manual (http://web.mit.edu/parmstr/Public/hvac/LGelectroni...):

My '1 meter' claim was erroneous — I was adding up 30cm and 60cm and giving it an extra 10cm 'just to be safe' which was obviously a mistake.

#### Quote (IRstuff)

This suggests that your upper unit does not need to be so high; eliminating 400 mm from the height would drastically reduce the tipping and bending concerns.

No, the 250mm-600mm figures are for the sides only. The top clearance should be greater than 600mm as shown in the picture above, or 1000mm if there are surrounding walls like in Case 1 in the other manual. (That is, unless I'm missing something.)

### RE: Structural integrity of a welded steel stand for two condenser units

(OP)
If I use the rubber mounting feet and raise the frame a couple of centimeters off the ground, I might be able to go with a simpler design, something like this:

In this scenario, the rubber feet will have to be positioned further away from the corners (either close to or exactly where the condenser mounting points would be) because the solid concrete ends at the dotted line and I can't place the stand any further to the left:

But I have no idea how clever it is to use the rubber feet (regardless of which design I go with), both because of rubber degradation concerns (lifetime/need of replacement down the road) and reduced stability (as opposed to securing the stand directly to the concrete).

### RE: Structural integrity of a welded steel stand for two condenser units

These units are about 200 pounds or less are they not?

### RE: Structural integrity of a welded steel stand for two condenser units

(OP)
95 pounds each, 190 total.

### RE: Structural integrity of a welded steel stand for two condenser units

The design looks good. Get plastic table/chair leg floor pad from store, they are cheap, replace as often as required.

### RE: Structural integrity of a welded steel stand for two condenser units

#### Quote (dik)

BART... have you actually run the moments?

Yes, but the geometry may change. (see 9 Aug 20 02:35 post by OP).

BA

### RE: Structural integrity of a welded steel stand for two condenser units

(OP)

#### Quote (retired13)

Get plastic table/chair leg floor pad from store, they are cheap, replace as often as required.

Is this supposed to be some kind of a funny joke?

In case you misunderstood what I was saying, I was referring to the ones I want to put between the stand and the concrete which, just like the smaller ones for the condenser units, are specifically designed to kill vibrations. The stand needs to be bolted down to them (or vice versa if I use the threaded variety) and they need to be bolted down to the concrete, as shown in one of my earlier posts (which has the 7 Aug 20 23:24 timestamp).

### RE: Structural integrity of a welded steel stand for two condenser units

95 lbs each? We are structural engineers. Not furniture designers.

At 95 lbs a piece... the structure itself will probably weigh And cost (fabricating in time and materials) more than both units combined.

### RE: Structural integrity of a welded steel stand for two condenser units

Parker87,

You shall find a way to fasten the unit on a wall, the connection shall be high (top shelf level) to make the unit stable in any situation (wind/earthquake), without the need to bolt to the concrete floor. So a cheap chair leg pad, or rubber pad, can dampen the vibration.

### RE: Structural integrity of a welded steel stand for two condenser units

I really think you're worrying excessively about the vibration thing.

Too much compliance and the stand will wobble.

The feet of these things and the motors inside them are usually already on compliant mountings.

Bolt the frame to the concrete flat and as hard as you can to stop the thing falling over and just get on with it!

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

### RE: Structural integrity of a welded steel stand for two condenser units

I think this is all you need. Note, you have find a way to fasten the upper unit for lateral stability. Otherwise, you might kill a cat, dog, or even a small kid. This is no joking when you stack weights vertically.

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This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

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