Metric floor loading calculations

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Data center design and infrastructure
Raised floors
If the building floor loading is 3 kpa and the equipment is 2,000 kg (950 x 600 mm), and is located in a computer room with raised floor environment, can the building and environment support that 2,000 kg equipment?

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First, forgive me if I translate this for our non-metric readers. kPa is “KiloPascals” which is the Pressure Equivalent of Pounds per Square Foot in the English System. Therefore, the question could also be paraphrased: “If building floor loading is 62.7 Pounds per Square Foot, and the equipment is 4,410 Lbs in a37.4 inch x23.6 inch cabinet, can the building and raised floor support that 4,410 pound load?”.

The bottom line is, I wouldn’t try it, and here’s why. The cabinet is 0.57 Square Meters (SqM), or 6.13 Square Feet (sf). The loading on the raised floor is therefore 3,509 kb/SqM, (719 Lbs/sf) or 45 kPa. The raised floor should not be the problem. Most any decent raised floor panel should support that, depending on how the cabinet is supported, the Point Loading capacity of the tile, and where on each tile the cabinet weight is actually concentrated. If it is on the frame base, the raised floor is probably fine, but if it is on small leveling feet or casters that are close to the centers of tiles, it could be a problem on a low capacity or poor quality floor system. But an extra pedestal under the cabinet support point can easily solve that. (The Rolling Load bringing it into the room could be another matter.)

The problem is the building slab. 34.45 kPA (719 Lbs/sf) is clearly way beyond the 3 kPA (62.7 Lbs/sf) capacity of the floor slab, but we have to look farther. A Raised Access Floor, particularly one with a Bolted Stringer under-structure (which is what should be used in any Data Center) has the effect of spreading or transferring the load to multiple pedestals around the concentrated load. So let’s assume for the moment that this is just one cabinet in a row of cabinets of more normal weight, sitting between two other rows of cabinets, also of more normal weight. And let’s assume your floor is standard 600mm tiles (the Metric equivalent of American standard 24-inch tiles), and that the cabinet is sitting on two tiles with some tile left over in front, back or both. Let’s also assume there are two full tiles between cabinet rows.

The “Cabinet Footprint”, then, is one tile in front and one in back (half the aisle each because there are other cabinets loading the floor as well) plus the two tiles under the cabinet for a total of 2,400 mm depth. Since this is a 600mm wide cabinet sitting on 600mm tiles, and we are assuming other cabinets on both sides, the effective width is still 600mm. This makes the “Cabinet Footprint” 1.44 SqM or 15.5 sf. Dividing 2,000 kg by 1.44 SqM (4,410 Lbs by 15.5 sf) gives 1,389 kg/ SqM (284.5 Lbs/sf) which is 13.62 kPa. This is still more than four times your slab capacity. Even if you could provide five times the clear floor area around the cabinet, I wouldn’t depend on the raised floor structure to spread the load evenly enough and widely enough to be safe.

If it is important that you install this unusually heavy cabinet in your room, you could have a licensed Structural Engineer examine the total situation and advise you as to how it might be done. (There might be a specific location in the room, or the use of supporting beams or steel plating, called “dunnage”, to better spread the load.) But I would not advise you, based on the information provided, to try this.

This should also illustrate why we specify at absolute minimum of 100 lb/sf (4.79 kPa), and often 250 lbs/sf (11.97 kPa) or more for modern Data Centers, and why most equipment cabinets are designed for only 2,000 Lbs (907 kg), which of course is in addition to their own weight of generally 300 – 600 lbs (136 to 272 kg).

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  • Dave mc
    I agree with the above comments, If you want to install heavy equipment you MUST ENGAGE A RECOGNISED STRUCTURAL ENGINEER. I have seen cases where the data centre manager installed heavy equipment that didn't fall though the floor but it did permanently deform the slab. In one case it cost the data centre tenant a very large amount of money to rectify and the floor had to be reinforced to bring it back to design capacity. On the other hand you can some times place larger loads than the design depending on where they are placed in comparison to the building structural design. This may include an allowance of reduced weight for a certain distance around the higher load. Bottom line is pay the money for the structural engineer checks and written advice. David mc
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  • Datacenterdesignload
    what is the floor design load per kN/m2 for data center?
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