it doesn't use frames or foundation
The space is created by the bees creating natural comb width and bee space..
if the bars are the wrong size there is no crushing as they still make bee space between the combs, but the combs eventually cross over the seam line between bars causing inspection issues

 

Yeah sorry I meant or was thinking a space along that top bar.

 

on the topic, why does this style hive frame not use a space between the frames so it would be easier (I am thinking) and save time to not hurt bees when servicing the hive?

 

on the topic, why does this style hive frame not use a space between the frames so it would be easier (I am thinking) and save time to not hurt bees when servicing the hive?

As a matter of fact - the touching bar feature is not mandatory.
Not it at all.

It is a feature that simplifies one aspect (no need for additional top covers since the bars ARE the top cover)
But creates the other problem - difficulty in management vs. the non-touching bar approach.

Here the idea of NON-touching top bars is squeezed to the max - simple sticks are used for comb support (no frames!).

 

Informative replies, thank you

 

In African countries, anything goes - whatever is at hand - but in first-world countries my understanding is that the convention is to use a Top Bar length the same as that of the country's dominant hive type - so in Langstroth country it would be 19", in British National country, 17". But as there are no rules involved, there may well be many other lengths used. Perhaps msl could kindly expand upon his 16" source ?

Regarding Top Bar width, Geoff Townsend in his 1984 seminal paper "Beehive Designs for the Tropics" specifies a width of 32mm (1 1/4") for the brood area, whereas Phil Chandler (if memory serves) uses 35mm (1 3/8"). Stores combs tend to be much wider, at 40-44mm, this width being usually achieved by inserting appropriate-width spacers between bars.

In less usual systems where non-touching bars are used, the bars are typically 22-25mm wide, with those bars placed appropriately to achieve the desired comb spacing. One well-known example of this being Phil Chandler's wanton destruction of British National framed brood combs to provide a ready-to-go TBH colony transferred directly from a framed hive - a process better known as "chop and crop"..
LJ

 

Perhaps msl could kindly expand upon his 16" source ?

to be clear, not saying its a standard, just giveing the OP my bar dementions

Back in the day there were 3 "big" names in Top bar beekeeping Marty Hardison, Phil Chandler, and Les Crowder.. each with a different designee

My 1st hive was a Crowder (19") that I built over the winter, later that spring I happened in to a full season of classes with Marty... one day a month for $5... all hands on/live demo in an apiary... a duild your own hive day, splits, queen rearing with cut comb strips and grafting, cut outs, all the seasonal mapulatoions, harvesting and processing honey and wax, candles, etc. one heck of an education for $30.... (times have changed) I credit much of my success to the straite forward mannor things were presented... this wasn't "advanced" beekeeping, this was just what beekeepers did, so its what I went and did. A few years down the road when I started geting involved in bee fourms and clubs I was a bit suprized that this wasn't "normal" for most hobby beekepers

any way marty had published his book, then made it free

https://www.beesource.com/attachments/the-appropriate-beehive-by-marty-hardison-pdf.61453/

and spent a bunch of time over seas with bees for development, kinda faded out of the scene.
Not suprizingly the next hives I build were of his design, marty felt that a 16" top bar led to less coss combing.
I have also run Crowder (19"), chandler (17"), and Backyardhive.com (18") topbar hives and my experience has been he is correct

 

Alternatively speaking....

With my free-standing framelet project - I have a very similar problem - how wide the framelets should be?

My answer - anything between 1.5" and 1" (inclusively) goes.
(In fact, intermixing the wood however it happened to be is fine).

Not to mention that one way to have the bars is to simply scavenge any wood material that generally fits the sizing (close enough).
Tree stakes/utility line markers are readily available everywhere - usually 1.25" in width - make very good bars.

The TBH and free-standing framelet hives are absolutely identical in this context - the width of the basic comb holding partition (a bar or a framelet).
No difference whatsoever.
Pictured is the mix of various widths in practical use.

 

I'm also interested in how wide people make bars, but I know that varies with bee race and so on.

And, does anyone use two different widths in the same TBH (for honey and brood)?

1 and 5/16" (1/2 way between 1 1/4 and 1 3/8 ) wide, 16" long 1/2"-3/4" triangle comb guide
all the same with, lots of checkerboarding and moveing brood combs to the back to keep "most" combs brood sized so they are interhcangbul for splits

 

And, does anyone use two different widths in the same TBH (for honey and brood)?

I tried (albeit in a different system - but the logic is the same).
Non-practical hassle.

I don't care for it anymore.
In fact, I am very loose with these so-called "requirements" anymore altogether.

 

Is there a standard length of bar for horizontal TBHs?

Of course - not.
The entire idea of the TBH - free will of people to do whatever and however.
What standards?

Do we have a large-scale manufacturer of the TBHs?
Rhetorically asking - because such manufactures usually publish end enforce de-facto practical standards.
Answer - no such manufacturers exist.