What does the set the fire to the third bar by snow patrol mean?

have you guys heard the song set the fire to the third bar? can anyone tell me what the song mean? especially the “set the fire to the third bar”.

I find the map and draw a straight line
Over rivers, farms, and state lines
The distance from A to where you’d B
It’s only finger-lengths that I see
I touch the place where I’d find your face
My fingers in creases of distant dark places

I hang my coat up in the first bar
There is no peace that I’ve felt so far
The laughter penetrates my silence
As drunken men find flaws in science

Their words mostly noises
Ghosts with just voices
Your words in my memory
Are like music to me

I’m miles from where you are
I lay down on the cold ground
I pray that something picks me up
And sets me down in your warm arms

After I have travelled so far
We’d set the fire to the third bar
We’d share each other like an island
Until exhausted, close our eyelids
And dreaming pick up from
The last place we left off
Your soft skin is weeping
A joy you can’t keep it

I’m miles from where you are
I lay down on the cold ground
And I pray that something picks me up
And sets me down in your warm arms

I’m miles from where you are
I lay down on the cold ground
I pray that something picks me up
And sets me down in your warm arms

http://www.youtube.com/watch?v=084l5-SA_nU