My delay in getting back to this item and the comments is because I have been searching for the science behind the light bulb pointing in the direction of the source of fire.
It is in NFPA 921 part 4-20.1 (1995 edition) This NFPA document was the result of the lack of science that the news articles reference.
Titled "Distorted Light Bulbs" it goes on to state. Incandescent light bulbs can sometimes show the direction of heat impingment. As the side of the bulb facing the source is heated and softens the gases inside a bulb of greater than 25 watts can begin to expand and bubble out the softened glass. This has been traditionally called a "pulled" light bulb, though the action is really a response to internal pressure rather than a pulling. The bulged or "pulled" portion of the bulb will be in the direction of the source of the heating.
I wasn't aware of the 25 watt limit which is based on 25 watt or less bulbs being vacuum rather than inert gas filled, and the glass will be dimpled instead of pulled.
The NFPA is more than just the Electrical Code.
Alan--
