Extremely unfortunate to see that happen. But it does reinforce the idea that being an RV owner is a hands-on thing that requires periodic inspection and maintenance. I haven't researched it, but I'd hazard a guess that the burn rate standards for RV's are similar to those for automotive interiors. 4 inches per minute, maximum. But the amount of synthetics and plastics used in them creates a hot chemical nightmare of toxic gases that can quickly incapacitate a sleeping victim long before the flames get them. Carbon monoxide is only one of them. FWIW, newer homes and retail stores are no better. Check your detectors frequently.