My forge is 44180cm3 inside diameter I was wondering if three half inch burners would let enough heat in?

t would be about 2696 cubic inches, a bit much.

If you made a typo and it is actually 4418 cubic cm that would be about 4.5 litres and a little under 275 cubic inches. Depending on the size and shape of your forge 2 might be enough. (roughly 150 cubic inches per 1/2 inch T burner). What dimensions does your forge have, what kind of burners do you intend to use? What are you going to heat and will you need to forge weld?

By my reckoning, that's around 2700 cu.in.

To be honest, it's so far out the normal range for homebuilt blacksmithing forges that many of the normal rules of thumb won't apply, if only because the surface area: volume ratio will be significantly different. It may be a 2:1 linear scaleup of a "normal" forge, which would give 4 times the area and 8 times the volume.

On the other thread (Firebrick Forge Questions), you say "it works great", so it seems fair to assume that whatever you have, it does what you need it to do.

For most "normal" applications though, the general consensus would be that three half-inch burners will probably not suffice.

As you are apparently in an industrial environment, there may be lots of things you've not told us (high-pressure-air-fed burners, for example) that move the goalposts.

Some pictures would be helpful.

80cm length 23.5cm tall 23.5cm wide and I don't know what the type is but it is not forced air the air comes from holes drilled in the pipe 

And timgunn I meant it holds heat great also it's just the brick I got off my uncle that is industrial the burners are home made. I will send you photo soon

due to stumps location less heat is needed, everything there is hot to start with ( he is in oz, NT )

Ha ha very funny.

 

It was 40 in Sydney yesterday, so I probably saved a bit of money on hot water too

 

So your saying even if I half the forge it is still to big

Depends on what you want to forge.

here it has been below 0 recently so our forges, stock, anvils and hammers are colder to start with, maybe we use at least 10% more fuel to get the same results

Wow ... I didn't think ambient temperature would play such a big role. 

After all between here and there it's only 40 C difference. So heating 900C or 860C wouldn't seem to be much of a muchness

So would that mean 40c increase efficiency by 10%

And I want to forge sword and knives weapons ect

To forge straight skinny stuff you only need a small forge. If you want to forge scrolls and large decorative work then you need a big one.

I notice the difference between summer and winter in how much heat the anvil sucks out of your work, not so much on the forge. But I don't have a gas forge. 

would depend on what you are doing but a forge here would take more to get it up to heat and would lose more due to lower ambient temp, stock will take more energy to heat it up initially and cool faster also affected by an anvil at 0c but the longer you work  the effects would gradually become lower

Do you have a picture of your super forge?

 

Yes, I agree initial heating would make a big difference

 

The weird thing is it does not look to big on the inside even though it is huge

I have a friend who sometimes posts here that once sent me some pictures of them forging 40"  (about 1 meter) *DIAMETER* stock and it wasn't considered especially large in their shop. Another was once forging a sewing pin using the powerhammer mounted on his hat... Huge/small is very very subjective