On trailers with a LQ, the extinguisher is accessible and mounted within reach of someone standing outside or near to the entrance door.

As far as interior mountings and fire extinguishing, a friend of mine and I came up with the following scenario. Most LQ fires are caused by galley related events, and most flammable items are used in this area. The gas and electrical utilities are many times also involved in sharing this space. The galleys are often installed between the door and the main sleeping area, the bunk.

If you are in the bunk, and there is a galley fire, it will block you from reaching the very extinguisher you need to put it out. You should have a bunk exit, whether it is an overhead emergency vent or a kick out window. But by the time you egress and can reach the outside of the door to reach the extinguisher, the flames undoubtedly will have spread dramatically. When you open the door to access the extinguisher, more air will be supplied to the fire, and it will intensify even more.

If a second extinguisher were placed in the bunk area, it could afford the opportunity to suppress the flames before they are totally out of control. In addition, it may lengthen the time you have to escape. I now have extinguishers installed on the side of the bunk cabinets in my trailers, and my friend has made the same installation in the LQ of his trailer.

To mount an external extinguisher for a possible vehicle fire is difficult. Having it readily available for immediate usage, invites theft. I don't know the placement per the law, but having one handy just inside the door seems to be a good alternative. The original smaller LQ extinguishers can be easily upgraded and replaced with larger sizes. The original one can then be reused in the bunk area.

Gard

We have fire extinguishers mounted in our trailer in the living quarters, pickup and another in the storage underneath the mangers.  I had a friend that she burned up her lq trailer in a matter of minutes.  Her generator caught a bail of hay on fire and with in ten or fifteen minutes the trailer was destroyed.  Of course I’ve never heard of a tire catching fire. 

Thos little fire extinguishers have a lot more power to stop fires than you think.  Couple years ago I was working on our Honda generator that still had a carburetors and it and I went to add little gas to the carburetor and before you know it I had a fire started.  I was away from the trailer but I was on some grass, I grabbed the little fire extinguisher out of the trailer and put out a pretty good sized fire (the gas made things burn pretty good).