Did they use liner programming? A brick should be easily handled (not too heavy), and small enough so that it can be fired quickly. the Romans used a thinner style brick; i imagine that this was to make them easier to fire. In any case, is the standard brick the optimum design? If they were larger, would bricklaying go faster?
If a wall was one giant brick that’d be a lot faster.
The size of a brick is that you want it as big as you can get it, but you still want to be able to pick it up with one hand so that you can have the trowel with the mortar in your other hand. That puts the width of the brick somewhere in the 4 inch range. As for length, if you make it roughly double the width, then you can overlap the bricks for strength (the joint between one row of bricks is at the halfway point of a brick in the next row) and can also easily make corners. So this makes your brick somewhere around 4 inches wide and 8 inches long. Bricks in the U.S. are slightly smaller than this (7 3/4 inch length). Bricks in some parts of the world are slightly larger than this. Russian bricks are 10 inches in length, for example. I guess the U.S. bricklayers are wimps and can’t carry the heavy bricks that the Russians use. 
The length of the brick should actually be double the width, plus the width of the mortar between two sideways bricks, so the length ends up being slightly longer than exactly double the width.
As for height, you again want something that is as big as possible, but it also needs to be light enough that your bricklayer can pick up the brick with one hand. In ancient times some folks liked perfect mathematical ratios, so some older bricks were a ratio or 4:2:1, so roughly 8 inches by 4 inches by 2 inches in height. These days we tend to use taller bricks.
If you made the bricks too much larger, then they wouldn’t be able to be handled with one hand, and you’d actually slow things down quite a bit.
I don’t know exactly where the various national standards came from.
I would assume that curing/hardening time of the brick is a factor. Too big a brick and the middle takes a long time to harden. And maybe doesn’t harden properly.
BTW - ‘Brick’ is also used in electrical engineering to describe standardized DC-DC converters. The standard ‘full brick’ looks roughly like a (quite small) masonry brick. Then there are 1/2, 1/4 etc size 'bricks.
So, one could answer the OP with “DOSA” (the defining organization)
The URL http://www.brick.org.uk/2011/03/brick-standards speaks for itself.
A certain number of bricks crack when drying or firing, due to shrinkage. The bigger the brick, the more likely that is to happen, and the more you lose when it does.
The standard three holes in a brick are partly to make it dry faster and more evenly, but have other functions as well. Solid bricks tend to be a bit smaller and thinner than the three hole sort.
There are a lot of different standard sizes for bricks. I don’t know how the standard came about but clearly it is difficult to construct buildings if you don’t know how many bricks to order based on their size. I will guess that the brick mason trade drove the standardization.
Probably one of those interminable English Parliamentary Royal Commissions that take 30 years to hear evidence from hundreds of bricklayers, builders, brick-makers, clay-diggers, furnace-makers and a few odd clergy, and then decide what they were told to decide before it started.
Come on, you can’t tease us like that. What other functions?
(My guesses:
- Help mortar adhere
- Provide a weak spot in the center, so it’s easier to break exactly in half
- Profit! That is, less material needed for the same strength
- Um, Masonic symbolism.
How did I do?)
I would argue that a larger brick would make a job fasterbut at a certain point, a large brick would be too slow to fire.
Three hole bricks in New England:
Me: I’ve got 50 of these <shows yardman the item number>
Yardman: Are they code bricks?
Me: <baffled> Code?
Yardman: Are you sure?
Me: No…
Yardman: Code bricks. You know with three holes in them.
Me: Oh! Cored bricks…
So you’re saying Jethro Tull was aware of this information?
(For the youngun’s: Jethro Tull - Thick As A Brick - YouTube)
Pretty much. Also :
Makes them a bit lighter, and uses less material (not a big deal, clay is almost free)
You can shove vertical re-bar down the holes to lend strength.
The holes give another place for excess mortar to go, so you have less to scrape/point, don’t have to be so careful buttering them, and makes it a little easier to level the course.
As a teenager in the late 50s I worked for a short time in a brick factory. We made mostly ‘commons’ which were simple solid bricks 3 5/8" x 2 1/4" x 7 5/8". My job was to cut off a length of extruded clay which was then cut into 12 bricks. (No holes)
The factory also made ‘handmades’ which were a lot more expensive as they were made by slapping clay into a wooden mould. These had a hollow on the top face to accept the mortar.
I was pais the equivalent of 12½p for every thousand bricks we made (we were a team of five) This meant that I could earn as much as £3.00 on a good day when the machinery didn’t break down.
FYI, the standard three-hole UK/American brick is not universal.
This is the typical Brazilian brick
And most structures resemble the building behind the fellow holding the bricks. They usually put on a coat of mortar and skim coat of plaster to make it pretty, but that’s how they do their walls there.
Not on the Dope it doesn’t. You expect people to click through and read a cite? Pshaw.
And £3 a day (no decimals in the old representation) was good money for a teenager in the late 50s.