Does anyone know why that deminsion is consider a hazard and the familiar 4" spacing on decks is not.
Obviously, if it is a bunk bed, it is not a baby but a toddler that could be roaming the typical backyard deck.
Open for discussion.
Thanks. 
OK Marcel,
So what are the spacing requirements for interior stairway balusters/spindles??
4" for ballusters and 4&3/8" for stair railings.
Why do you ask? That was my question. Why does it differ?
Good point. I would like to know what “safety standard” that article is referring to.
This is a joke right! This is not even in the same category. You can’t get entraped on deck railings or stairs as easily as a bunk bed.
Outside decks fall under different codes because they’re outside.!!!
Same spacing codes go for inside guard and stair balusters.
Got a link?
It’s also missing a handrail. 
[http://www.cpsc.gov/Global/Images/Recall/2014/14016/Duo%20bunk%20DSC_3390%20%20800.jpg](http://www.cpsc.gov/Global/Images/Recall/2014/14016/Duo%20bunk%20DSC_3390%20%20800.jpg)
And the guards have the ladder effect.
You don’t know my grandsons. One of them stuck his head through my deck balusters and couldn’t get it back through. He was 2 at the time. Was constructed before the code changed.
Kids tend to roll around in bed. The adventurous will stick, or try to stick their head through just in play. If you compare this to the traditional crib, think about the spacing on those, which are designed to keep a child’s head from slipping through and causing some major injuries. What happens during sleep is uncontrollable. How many times have you seen a child turned, or at the other end of the bed, or moved crossways? Evidently there were some issues involved that sparked the recall.
Read close I said as easily Gregory and Christopher is correct on all points.
Linas, that link seems to be specifically for cribs and young infants and not necessarily for one old enough to climb the Bunk Bed and was not addressed in Juvenile Products Manufacturers Association (JPMA) .
Spacing between balluster on the crib are considerably less. Which would make sense.
The picture I posted does not have hand rail, guard rails at the top and far from meeting the requirements for a young baby.
Just seems odd. 