- 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:
Given:
- Current # shelves in my library: 100
- Am adding 50 more new ones.
- 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 = 1,7500 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.
Yup, it works!
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 calcuations.
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. |
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.
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