AXISHK
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Size of server rack and raising floor
Suppose I have a full 42" server rack with 800mm wide and put in the middle of two 600mm x 600mm raising floor. How to calcuate the load need to support by each of the raising floor if
1. the server rack is just put in the middle of two raising floor
2. a steel plan is put under the two raising floor in order to distribute the load evenly across the two floor. Will the thickness of the steel need to be considered ?
1. the server rack is just put in the middle of two raising floor
2. a steel plan is put under the two raising floor in order to distribute the load evenly across the two floor. Will the thickness of the steel need to be considered ?
Our datacenter is raised 36" from the ground to run cables, cooling, etc, and we happened to use wood with metal braces. It's about 5 years old and haven't had any problems with it. We hired a local construction firm, although they had never built something like that before, we explained the weight of what we were going to place above it, and they designed a floor system that would work. I think currently we have 12 racks, plenty of UPS units and the floor is stiff as a board. It looks like they used 6x6's and 2x4s, but I'm no builder.
ASKER
Most server racks shouldn't go beyond 1200lbs for 24U of space (50lbs per U).
- Are you talking about the height of the rack ? My server rack is 42U".
"It looks like they used 6x6's and 2x4s".
Are you talking about the dimension of each tiles ?
Thanks
- Are you talking about the height of the rack ? My server rack is 42U".
"It looks like they used 6x6's and 2x4s".
Are you talking about the dimension of each tiles ?
Thanks
Sorry yes, 50lbs per U, so 2100lbs for your rack, or about 1000kg. I did a search online and most 42U racks have a max weight capacity of 2000lbs/900kg, so that's about right.
It would be best if you know what your rack is actually going to weigh since you only have 1.
They used 6x6's and 2x4's for the wood construction under the tiles to raise them, I am not sure on the dimension of the actual tiles, I think they are around 2'x2', or around the same 600x600mm. I'm not a builder though, and I never go down there so I'm not sure. I do know it's made of wood though. Sorry about the 24U calculation, I misread your post; that was an error on my part. 24U would only be about waist high, our racks are probably 42U as well.
Are you talking about raising the rack from the ground as well?
It would be best if you know what your rack is actually going to weigh since you only have 1.
They used 6x6's and 2x4's for the wood construction under the tiles to raise them, I am not sure on the dimension of the actual tiles, I think they are around 2'x2', or around the same 600x600mm. I'm not a builder though, and I never go down there so I'm not sure. I do know it's made of wood though. Sorry about the 24U calculation, I misread your post; that was an error on my part. 24U would only be about waist high, our racks are probably 42U as well.
Are you talking about raising the rack from the ground as well?
If you are just going to put a steel plate under the rack to distribute the weight across the two 600m tiles, the steel plate would have to be plenty thick, yes.
For example think about putting foil underneath; if the weight of a single tile couldn't support it; of course the foil would bend under the wheels and it would come crashing down.
You will have to have a plate thick enough so that the weight wont be transmitted directly underneath. A solid plate will need to be quite thick in order to do this as the entire bottom surface is a contact point where weight can escape; if all the weight can escape directly underneath, it's not going to travel very far outward.
I would use a corrugated tile so that there are fewer contact points with the ground. Picture placing the rack on a bench on top of the two 600mm tiles; the weight of the rack would distribute evenly across all 4 legs, as they are the only contact points with the floor. The fewer contacts you have the less weight can escape directly down.
For example think about putting foil underneath; if the weight of a single tile couldn't support it; of course the foil would bend under the wheels and it would come crashing down.
You will have to have a plate thick enough so that the weight wont be transmitted directly underneath. A solid plate will need to be quite thick in order to do this as the entire bottom surface is a contact point where weight can escape; if all the weight can escape directly underneath, it's not going to travel very far outward.
I would use a corrugated tile so that there are fewer contact points with the ground. Picture placing the rack on a bench on top of the two 600mm tiles; the weight of the rack would distribute evenly across all 4 legs, as they are the only contact points with the floor. The fewer contacts you have the less weight can escape directly down.
If your 800mm wide rack has locking casters, you might just be safe as it is as long as each 600mm tile can support at least 500kg; each wheel will be distributing around a max of 250kg (so each 600mm tile will have 2 weight points of 250kg each max), or if you can place each caster on a different tile, you can support only 250kg per tile.
If you go with half inch steel (about 12mm), you should be able to distribute the weight evenly, with casters or not. In the US, a 1200mm square 12mm thick plate is only about $100.
If you go with half inch steel (about 12mm), you should be able to distribute the weight evenly, with casters or not. In the US, a 1200mm square 12mm thick plate is only about $100.
A lot of this is determined by the building. Where I am, none of the above advice would be allowed by code. You can't use wood for construction in a highrise. Nor can you load up a single rack freestanding on caster. Can't even do it without substatial bracing to the wall. The smallest run of racks without lateral support is 2x full racks with anchor plates bolted to the structure itself. (APC will give you engineering documents for seismic areas.)
Have you consulted the building engineer, or someone familiar with the slab? You need to keep the weight below the max rating (pound/sq.ft.) of the slab. So, if your object is 2,000# and your slab loading is 100#/sq.ft, then you need placement over a beam and/or steel plate to distribute the weight over 20sq.ft. That would be a 1/2" steel plate 4-1/2 foot square. All of that would have to be approved by the building engineer and local authority.
We have seismic requirements, and the highrise means the engineering requirement have to be better than best guess. We also had some heavy gear to put high up, so we worked with the original engineer who designed the building as well as the city. YMMV depending on the type of building and local codes.
Have you consulted the building engineer, or someone familiar with the slab? You need to keep the weight below the max rating (pound/sq.ft.) of the slab. So, if your object is 2,000# and your slab loading is 100#/sq.ft, then you need placement over a beam and/or steel plate to distribute the weight over 20sq.ft. That would be a 1/2" steel plate 4-1/2 foot square. All of that would have to be approved by the building engineer and local authority.
We have seismic requirements, and the highrise means the engineering requirement have to be better than best guess. We also had some heavy gear to put high up, so we worked with the original engineer who designed the building as well as the city. YMMV depending on the type of building and local codes.
Awesome information aleghart! What area are you in?
Los Angeles. Highrise building.
Ah I see. I'm on the east coast with mostly 3 stories max. Just about every rack I've seen is on casters here.
ASKER
Rise an interesting question :
"if your object is 2,000# and your slab loading is 100#/sq.ft, then you need placement over a beam and/or steel plate to distribute the weight over 20sq.ft. That would be a 1/2" steel plate 4-1/2 foot square. "
So, how to estimate the steel plate with 1/2" thickness with area of 4-1/2 foot square ?
"if your object is 2,000# and your slab loading is 100#/sq.ft, then you need placement over a beam and/or steel plate to distribute the weight over 20sq.ft. That would be a 1/2" steel plate 4-1/2 foot square. "
So, how to estimate the steel plate with 1/2" thickness with area of 4-1/2 foot square ?
Seismic areas make that a problem...it will move during an earthquake, even if the wheels are locked. Seen it, and had to retreat from the room while 2 racks danced.
In this install, we could have stacked everything into a single rack (every slot filled), but two racks are so much more stable, and left room for moving/adding equipment. Also spread the load over more square feet and gave more anchor points.
The additional cost was not much at all. I assembled the racks myself, and the extra time for a contractor to drill anchors was about 20 extra minutes.
The considerations for raised flooring...we would've had to have twice as much flooring as the space used right not on the bare slab. The supports under the flooring had to be steel because of the weight, and would have needed far more concrete anchors for each support. Once attached to the building, it become property of the building anyway, so I didn't want to sink that much money in for the sake of a few more hidden wires. A/C was being installed overhead, so we didn't that space for ventilation.
In this install, we could have stacked everything into a single rack (every slot filled), but two racks are so much more stable, and left room for moving/adding equipment. Also spread the load over more square feet and gave more anchor points.
The additional cost was not much at all. I assembled the racks myself, and the extra time for a contractor to drill anchors was about 20 extra minutes.
The considerations for raised flooring...we would've had to have twice as much flooring as the space used right not on the bare slab. The supports under the flooring had to be steel because of the weight, and would have needed far more concrete anchors for each support. Once attached to the building, it become property of the building anyway, so I didn't want to sink that much money in for the sake of a few more hidden wires. A/C was being installed overhead, so we didn't that space for ventilation.
ASKER
Just back to my previous question, how to estimate the steel thickness and size ?
Tks
Tks
2000# / 100#/sq.ft (max loading from your engineer) = 200 sq.ft
sqrt 20 = 4.47
It doesn't have to be square...just round up the square footage. So 4.5sq or 4x5 would be the same.
You get the slab loading specifications from the building's engineer or architect. Some web sites advertising building space (offices, tech, manufacturing) will tell you the slab loading on different floors. For example, lobby/ground floor loading may be greater if it's on solid ground. Highrise can be as low as 50# per sq.ft unless you get your plans drawn up by an engineer. Then you might go up to 100-120#/sq.ft.
Steel plates are an easy (and cheap) fix. Next would be locating loads over existing beams, but that's not always convenient for floorplan.
More radical installations require reinforcement by installing new steel structural members, tying new beams into existing beams & columns in the building. You wouldn't need to go that far for a couple of racks.
sqrt 20 = 4.47
It doesn't have to be square...just round up the square footage. So 4.5sq or 4x5 would be the same.
You get the slab loading specifications from the building's engineer or architect. Some web sites advertising building space (offices, tech, manufacturing) will tell you the slab loading on different floors. For example, lobby/ground floor loading may be greater if it's on solid ground. Highrise can be as low as 50# per sq.ft unless you get your plans drawn up by an engineer. Then you might go up to 100-120#/sq.ft.
Steel plates are an easy (and cheap) fix. Next would be locating loads over existing beams, but that's not always convenient for floorplan.
More radical installations require reinforcement by installing new steel structural members, tying new beams into existing beams & columns in the building. You wouldn't need to go that far for a couple of racks.
http://onemetlifeplaza.com/
Click "building specs" and you'll see they allow 100#/sq.ft. at lobby level. 50#/sq.ft. for their higher floors. That's all nominal, I'm sure. Getting an architect and engineer could get approvals for higher loading, as long as building codes are satisfied and the owners are OK with it. Computer equipment racks are becoming "standard" office equipment, so I don't think many modern building managers would have an issue with it. You'd be surprised how much you can do to a building with the proper permits.
Click "building specs" and you'll see they allow 100#/sq.ft. at lobby level. 50#/sq.ft. for their higher floors. That's all nominal, I'm sure. Getting an architect and engineer could get approvals for higher loading, as long as building codes are satisfied and the owners are OK with it. Computer equipment racks are becoming "standard" office equipment, so I don't think many modern building managers would have an issue with it. You'd be surprised how much you can do to a building with the proper permits.
ASKER
Thanks, but thickness of the steel need to be taken into account , correct ? How to estimate this ?
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Tks
Most server racks shouldn't go beyond 1200lbs for 24U of space (50lbs per U). There aren't many configurations that could possibly create that much weight either. So you should be safe at 750lbs per raised floor panel.
This could easily be done with a well made wooden floor, if you want to use steel for some reason, I would check with a builder, as building depends a lot on how the pieces are positioned, not just the thickness of the material, just tell the builder it needs to support 1200-1500lbs. He will probably tell you you can go with wood.