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Determine final amount of growth space per shelf when shift is done:
- Count new shelves being added to the collection.
- Multiply them by 35" (assuming each shelf is 35" long)
- Add the total number of current shelves to the number of newly added shelves for your final total # shelves.
- Add the total newly added growth space inches to the total current inches growth space available.
- Divide your grand total inches of growth space by the final total # of shelves. This tells you the average number of inches of growth space to leave per shelf.
- Double check yourself by doing it another way: there are several ways to do it. Divide your total inches of books by your grand total number shelves, and subtract that number from 35" (length of shelf).
Example:
- Current # shelves in my library: 100
- Am adding 50 more.
- Current inches of books in my library: 3400 (I'm absolutely cram-packed).
- My shelves are all 35" long.
- The total number of inches in my current library is 100 shelves x 35", or 3500".
- The number of inches of current growth space (does not include the new shelves) is 3500 minus the book inches (3400), or 100 inches.
- Count new shelves being added to the collection.
50 - Multiply them by 35" (assuming each shelf is 35" long)
50 x 35 = 1,750 new inches being added to my library - Add the total number of current shelves to the number of newly added shelves for your final total # shelves.
100 current shelves plus 50 new shelves = 150 total shelves. - Add the total newly added growth space inches to the total current inches growth space available.
1750 new inches plus 100 old inches of growth space is 1850" total growth space that will be available - Divide your grand total inches of growth space by the final total # of shelves. This tells you the average number of inches of growth space to leave per shelf.
1850 divided by 150 shelves = 12.3" growth space / shelf - Double check yourself by doing it another way: there are several ways to do it. Divide your total inches of books by your grand total number shelves, and subtract that number from 35" (length of shelf).
- 150 shelves x 35" = 5250 total inches available
- 5250 - 3400" of books = 1850 " growth space
- 3400" books / 150 shelves = 22.66 inches of books per shelf
- 22.6 inches of books + 12.3 inches of space = 34.9 " long shelf.
Now you know how many inches of growth space you need to leave per shelf in your completed library. You may choose to leave more space in faster-growing areas and less space in slower-growing areas.
To do this, count the number of inches of books in a call # area that is fast growing. Let's say you have 500 shelves of HJ's, and you're nearly 100 % full there. 500 x 35= 17,500 inches of fast-growing HJ's. If you were leaving the library-wide average 12.3 inches of growth space per shelf, you'd be leaving 22.66 inches of books per shelf, and you'd need = 772 shelves. That's if you were leaving the average.
But you want to leave 18 inches per shelf, instead because this section grows so quickly. That's 772 x (18 - 12.3)= 4400 extra inches. So this time, divide the total inches of HJ's into (35 - 18 = 17) 17" clumps to find out how many shelves you need for this collection (1029.4 shelves now). That makes sense: our original 500 shelves at 100% fill are going to be left a bit less than half full of books, so we should need a few more than twice the number of shelves, so 1029 sounds about right.)
Don't forget to decide which other area you can spare 4400 extra inches from, and adjust your calculations accordingly.
We've found, in pretty big and complicated shifts that are operating under time pressures, that it's easiest to leave the same # inches per shelf throughout the collection, and then later, shift as needed. Smaller or leisurely shifts, however, probably can incorporate these variations in growth space calculations.
On these web pages, we're leaving the same # inches of growth space per shelf, library wide.
When you're crunching numbers, don't let the calculator or the spreadsheet convince you against your better judgement. If you have a gut feeling that something is wrong, punch the numbers around until they feel better to you. Try to draw pictures in your head of what you're doing so you have an idea of where you'll end up, and if the numbers are in that neighborhood, you know you're on the right track. Double check your answers by doing the math a different way.
| Re-doing a shift on paper is a million times easier than re-doing it in real life. |
Transfer data from your measuring sheets to a spreadsheet:
| Floor: Range | Beg. Call# | End. Call# | # sections | hatch marks of empty space | # shelves | inches growth space | total inches available | inches of books | total inches needed - final | total sf sections needed - final | running total sections needed | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| a | b | c | d | e | f | g | h | i | j | k | l | |
| 1 | 1:1 | A | AP2.N7G43 | 11 | 8 | 148 | ||||||
| 2 | 1:2 | AP2.N7G45 | AP2.P4 v.11 | 11 | 11 | 150 | ||||||
| 3 | 1:3 | AP2.P4 v.12 | AP2.S3T99 | 12 | 8 | 165 | ||||||
| 4 | Totals | 34 | 27 | 463 |
Formulas for the spreadsheet:
| Floor: Range | Beg. Call# | End. Call# | # sections | hatch marks of empty space | # shelves | inches growth space | total inches available | inches of books | total inches needed - final | total sf sections needed - final | running total sections needed | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| a | b | c | d | e | f | g | h | i | j | k | l | |
| 1 | e1 x 35
see:(1) |
f1 x 35
see:(2) |
h1 - g1 | (i1/20)x35
see:(3) |
(j1/35) / 6.5
see:(4) |
|||||||
| 2 | k2+k1
see (5) |
|||||||||||
| 3 | ||||||||||||
| 4 | Totals | sum of
d |
sum of
e |
sum of
f |
sum of
g |
sum of
h |
sum of
i |
sum of
j |
sum of
k |
sum of
l |
(1): for measuring strings that are 35" long. If you use a 36" string, multiply by 36.
(2): for shelves that average 35" each.
(3): to find out how many inches you'll need for the books on this range, you'll have to have decided how much growth space per shelf you plan to leave.
- Assume you're leaving 15" growth space/shelf. That leaves (35-15=20) 20 inches of books per shelf.
- Divide your total inches of books into 20 inch clumps to see how many shelves you'll need: (g/20)
- then multiply the number of shelves by 35" to find out how many total inches of shelving this expanded collection will take up: (g/20)*35
(4): Look at your measuring sheets and the actual call number area to get an idea of the average number of shelves per section:
- They could be a bunch of tall journals and you know you can get only 6 shelves per sf section. They could be oversized materials and you can get only 4.5 shelves per single faced section. They could miniatures and you can get 10 shelves per sf section.
- Look at the area to see if you've tipped a whole bunch: if you are untipping and will lose a lot of space, maybe your average shelves per section won't be 7/sf section, after all.
So, remember that number (the average number of shelves per single faced sections); you'll need it in a second.
Now, divide your total inches needed by 35 (h/35) to find out how many shelves you'll need for this area. Then divide the number of shelves that you need by your ave # shelves/sf section: (ex: 6.5): (h/35) / 6.5. That should tell you how many single-faced sections you need.
We're using sf shelving because the next step is to do a "paper shift": color in sf sections on maps so we know exactly where a mini-shift begins and ends.
(5): Just so you know what your grand total sections are for this shift area, add the number of sections needed as you go along. I can't quite recall why this number is useful to us, but I found it on my spread sheet so I included it for you.
Maintained by: SChappell, chappell@uoregon.edu
Last Modified: 09/20/2006