Re: optimum bale size

["Ann V. Edminster" <74200.746@compuserve.com>]

OK, Ron, I couldn't let that dig go by . . .

*I* didn't answer your question because it's actually a difficult one, and I was
waiting for somebody else to do the dirty work. But since the "answer" you found
was to another question ("what's the usual or typical bale size?"), not to the
one you actually asked ("what's the *optimum* bale size?"), I'll have a stab at
this.

Optimum bale size is (at present) unanswerable because:
a) there isn't a sufficient body of knowledge and experience in SB yet to draw
conclusions about optimum bale size, even if there were lots of sizes to play
with, which there aren't; and
b) there isn't *any* experience to speak of (of which I am aware) that is
specifically directed at answering that question, because nearly all SB work to
date has used the usual/typical 2- or 3-string bales

This is, however, a topic which comes up from time to time among SB'ers; there
is much speculation about the answer. Although speculation is about as far as it
ever seems to go, there are several factors that are touched upon in these
discussions. Among them are how balers work, local availability, handling
characteristics, design applications, and real estate considerations. A brief
treatise on these follows for your reading delectation.

It is relatively easy to change only one of the three dimensions for standard
rectangular bales that come out of mechanical balers; that, I believe, is the
longest of the three dimensions. It is commonly understood that it is desirable
to use local bales, for reasons having to do with sustainability; therefore, it
could be argued that "optimum" = locally available = whatever's standard
wherever you are -- or at least for two of the three dimensions, the third being
potentially negotiable with your supplier/farmer. (However, drawing from my own
experience, lots of SB'ers initially get excited about the prospect of obtaining
half-size bales -- should work well with the running bond, right? -- but in
reality, due to the variability of bale size within a single batch, even, there
isn't ever really a course that's exactly "n" bales long or ever uses only full
and half bales; it's always a custom bale 23-1/2" long, or whatever, that's
needed at the end of the course. So the value of probably paying more up front
for variable-length bales, when you don't truly know what you'll need, is
questionable.)

WRT handling characteristics, one of the reasons SB construction is "user
friendly" is that the size and weight of the building unit, the bale, have been
empirically found to be near-optimal in that the bale is large enough to
aggregate quickly into a sizable structure but small and light enough to be
handled relatively easily by one to two people.

One respect in which the unit is *not* optimal is that the larger the unit, the
greater the design constraints (in some respects). Bring to mind some of the
elaborate brickwork done in older buildings, with bricks conforming to curves
and intricate patternwork; then bring to mind the ways that other small units,
such as adobes, have been used in constructing arches, vaults, and domes. The
larger SB modules obviously do not lend themselves to these types of
applications (for other reasons, too, such as compressive behavior . . . ). 

Yet another facet to this discussion relates to the space occupied by the wall;
in urban, higher density contexts, there are many who believe (and probably
rightly so) that the footprint of SB walls is an obstacle to acceptance. Where
the cost of real estate is high and development is constrained by factors such
as standard front-side-rear setbacks, it may very well be so (but nobody's
actually tried it yet in these contexts, so we're only speculating again). In
such a case, the standard is certainly larger than optimum.

Given the above considerations, one might posit the notion that -- if one were
not constrained by the capabilities of existing baling machines -- the truly
optimum size might be different from the existing standard size(s), probably
smaller. Cadmon Whitty, among others, has created garden walls with custom-sized
(narrower) bales, and might offer some insight on the subject (I don't know if
he's on the list). But to my knowledge, there's been no experimentation to take
a close look at this question. In places where a high percentage of straw isn't
baled, but *might* be should enough demand arise, it is quite conceivable that
new baling equipment might be devised to supply "optimum" bales, should there be
some evidence of what that size might be.

Does that answer your question?

Happy New Year,
Ann V. Edminster