Appropriate Live Load for File Cabinet Storage Room? 1

[JSA]

I have been getting questions from clients lately asking about potential tenants who want storage rooms full of filing cabinets. I'm talking about the standard ones that must be about 4 to 5-feet-high ... and I'm guessing 15" x 30", arranged for efficient use of the room as a file storage room.

What is the minimum floor design live load that would be acceptable? 80 + 20 [partitions]?; 50 + 20?: 100 non-reducible?; more?

 

[austim]

Hi, JSA.

I suspect that my answer should be 'maybe more'.

The Australian Loading Code specifies the following:

'File rooms'
- to be determined by the designer, but not less than 5.0 kPa UDL or Point load of 4.5 kN (1.045 kip/ft^2, 1.01 kip).
I read this as applying to your situation.

'Storage - stationery and packed books storage'
- again to be determined by the designer, but not less than 4.0 kPa per metre of usable height, 9.0 kN point load. (25.5 lb/ft^2 per foot heigh usable, or 2.02 kip local).
A similar UDL is specified for mobile file storage ('compactus units).

You would be doing the engineering world a great service if you were to fill a typical filing cabinet to the gunwhales, weighed it, and then posted the results as a FAQ on this forum.

 

[LPPE]

An excellent question. Has anyone noticed this question comes up often, but there really isnt anything in the code about filing loads?
I've always assumed that the filing cabinets are basically stuffed with paper, therefore I would take the dimensions of the INSIDE of the cabinet, find the volume, and figure its weight as if it were solid wood. Maybe something like a Doug-Fir at 30 pcf.

 

[steve1]

Per the Manual of Steel Construction, 9th ed. page 6-8 the unit weight of paper is 58 pounds per cubic foot.

 

[ishvaaag]

Estimate the actual weight of what is going to be used. If a mechanical on rails system is to be use contatct the system provider. For other estimate yourself the standing weight. 200 kgf/m2 may be enough for normal offices but if true compact filing is used one may be should jump to 400 or 500 kgf/m2 minimum directly, not without checking if that is enough.

 

[JAE]

For typical office loading in the U.S. (assuming your standard layout of file cabinets interspersed with desks, meeting rooms, etc. you would still use 50 psf live load and probably the 20 psf dead required by code for partitions in offices.

If, however, you have special rooms or areas with nothing but file cabinets, and these are laid out in a grid with narrow corridors between, then a higher load is justified. What that exact load is I'm not sure but austim has it right...you could copywrite your information by weighing various file cabinets and publishing the info!

We have had clients in the past ask about special filing systems which are rotating or sliding systems that avoid the corridors. These typically weigh between 200 to 250 psf (which matches the typical code live load of 250 psf for heavy storage.)

 

[DaveVikingPE]

I agree with JAE. For some reason, 250 psf sticks in my mind. UBC Table 23-A (from memory, don't have it in front of me now...) calls for 250 psf for "heavy storage" areas. Go with 250 psf, full files are heavy.

 

[Ingenuity]

Wow - talk about timing. I am working on a small project as I write this reply where we have an existing owner (insurance company) that occupies one of their old buildings but are relocating upstairs of the 2 story structure. Since they create lost of paper (insurance co!) they need to expand their file storage. It is a RC building, continuous beams with 1-way slabs. We asked for existing structural drawings etc but apparantly they only keep paper that is "insurance related" so we do not have any structural info. great! We undertook in-situ NDT, some invasive probing to determine rebar sixe and spacing to relevant elements, and did some concrete cores for confirming concrete comp strength etc. We are not too worried about the columns and foundations but the loads imparted from the storage are somewhat significant.

They are planning on using a proprietary sliding file system and a normal "fellowes" cardboard box is 16"x12"x10" high and with paper files the average weight comes in at about 25 lbs - mostly women work in company and this seemed to tally well with what a women could lift, or what i would probably want to lift anyway. The maximum you can stack is basically a little over the average human height (remember it is sliding and they do not want to have to use steps to get to the top boxes) so the file boxes alone at 8 No. x 10" high over a 16"x12" area gives us 150 psf (austim - basically 7.5 kPa in your and my "language&quot and this agrees real well with the what austim posted on 4kPa per m height. So i feel comfortable using 150 psf.

Also, using 150 psf with a LL factor applied for ultimate conditions also gives us a little extra F of S.

We are proposing using CFRP to slabs and beams to provide the required additional capacity. We have used CFRP's in the past with good success.

When i visited the project last week - they have already moved the boxes upstairs (temporarily) until the remodelling and structural work is completed. The files are stacked about 10+ high, mid span, over an area of 20' x 20 '. We asked them to reduce the height and spread the boxes out.

They then stated that since nothing happened with the boxes stacked so high that do we REALY need to do strengthening! And i thought insurance companies were involved in accessing and attempt to contolling risk! I guess they also like to save moeny too!

sorry for the long winded reply...but this forum is great for "validating" questions and stuff we all have from time to time. thank you.

 

[Taro]

Most building code require library stack rooms to be designed for 125-150 psf. This would probably be a reasonable starting place for most filing rooms unless you have very high-density filing or some other unusual condition.

 

[lshort]

Re filing cabinet storage
If you take paper a 56 psf ( assumed for this example)
For a filing cabinet height of say 6 ft
Load=6*56=330psf
In most cabinets the paper is 12" long whereas the cabinet is 18 " wide. therefore we are conservative in assuming 75% solid=330*.75= 250psf
Therefore weight per linear ft=250plf
If cabinet spacing =3 ft wt=250/3=85psf
now consider the human occupancy in between
If human live load at 50 psf reduces to roughly 40psf average because of filing cabinet space giving a combined load of 85+40=125 psf
Use a minimun loading of 125 psf (6kpa)

If back to back files (spacing 4 ft) are used this value will go up to 200psf(9.5 kpa)
=250*2/4=125psf+40=165 psf

Final note: Each condition may vary depending upon the type of storage. A professional Engineer should always check.
LLoydS

 

[JSA]

Thank you all for your input. Your responses have inspired me to go ahead and get some useful numbers.

I weighed my own filing cabinet (which is filled to the gunwhales) by tilting it onto a bathroom scale. I got 230 lbs, or 23 pcf, or 100 psf.

Then I went to Office Depot and measured file cabinets which were for sale. Available are the following:

Std Letter, 4-drawer, 15 x 25 x 49H
Std Legal, 4-drawer, 18 x 27 x 52H
Lateral 4-drawer, 36 x 19 x 53H
Lateral 5-drawer, 42 x 19 x 67H

I measured the drawer extensions and figured that an open file cabinet drawer plus 18" would be a good aisle width to assume for laying out a file cabinet storage room. I tried to maximize the use of the room by arranging in straight, back-to-back rows. Here's the resulting loads to the floor:

Std Legal, 4-drawer, with no added load = 56 psf
Std Legal, 4-drawer, with 30 psf on open floor = 70 psf

Lateral 5-drawer, with no added load = 66 psf
Lateral 5-drawer, with 30 psf on open floor = 80 psf

I made up the 30 psf.

I hope this helps you all in your work.

 

[steve1]

One point that has not been discussed is whether to consider file cabinet loading as dead load or live load. Most file cabinets, once full, are pretty much fixed in location - hence dead load. On the other hand, cabinets can be moved about - hence live load.

 

[JAE]

JSA - from your numbers, I would still use at least 125 psf for code required "light storage". This assuming you are indeed using "standard" file cabinets similar to what you measured.

I also agree that it ought to be considered a live load as it is not part of the fixed building but a load that can be moved, reduced, enlarged, etc.

 

[Ingenuity]

I think it should be considered as LL.

 

[LPPE]

I think it should be LL also.

 

[sc]

It should definitely be considered a live load as draws move and create a semi mobile load, redistributing the load (even though it is generally on a small area).

sc

 

[JSA]

JAE - My conclusion was that for a "normal" file cabinet room (file cabinets with a maximum height of 6'-7" & lateral files - worst case from my study) you would not need any more floor live load capacity than 80 psf, unreduced. For new office construction, considering that partitions will be needed, I would think that 100 psf non-reducible would be appropriate.

I agree that file cabinets are live load.