how big a space for a 150w?

so i have a 150w hps floralux system that i bought not to long ago that i am using for my flowering at the moment. the specs are 14'' long, 11'' wide, and 4'' tall. but when my other plants are done flowering i wanna make a flowering box to put other plants in and i am wondering what is the smallest space i could put that in without having to worry it catching fire or getting too hot in the box...i have intake and exhaust fans so that wont be an issue. but whats the smallest safest size to have this box for that light?
im just trying to collaborate so i can get this box togather by about 5-6 weeks so i can make a box.
suggestions?
peace

ive seen people use them in pc cases... so you can make the box pretty much as small as you want! I personally have a 150w hps in my mother/clone box that is 48x18x36in. just make sure the air exchange is good, and it sounds like youve got that covered... so you should be fine. if its too hot you can cool tube it but i doubt youll have to

mine has the ballast built in to the back of the lamp so i wouldnt be able to put it in a pc case but thats legit though lol. sick do you ave a picture of yours?

nope unfortunately i dont have a camera haha. i used all pc fans to exhaust it though so you really shouldnt have an issue with heat. i mean dont get me wrong the bulb gets hot, but if you just do what everyone on here says and exhaust at the top with fresh air coming in at the bottom you should be fine. ill try to get some pics though to show you what im talkin abtou

word just PM me or somthin