The Lightning Safety Bag is not a reality, but rather an idea whose time has not yet come. It was first proposed as an on-the-spot idea by Ken Langford at the January 8, 1993 Lightning Data Center meeting.

The idea is basically the combination of two existing concepts: the “Shake And Bake” portable fire shelter, and the Faraday Cage.

A portable fire shelter is a large metallic bag that works by reflecting heat away from the human body when a firefighter is trapped by a fast-moving fire. A trained firefighter can deploy the shelter in seconds, and get inside until the fire passes. It is called a “shake and bake” because the firefighter shakes it to open it, and even though protected from direct burns, the internal temperature becomes very hot indeed.

A Faraday Cage is not a specific device as it is a type of shelter that protects the occupant from external electric fields. The name comes from the English scientist Michael Faraday, who first described the properties of such a shelter in the 1830s. The physics of a fully enclosed conducting cube or cage tend to keep all external electrical charge on the external surface of the conductor. An occupant of such a cage is surrounded by conducting material, and they are therefore protected from outside electrical sources – even those as strong as lightning. Fire towers and television transmitter shelters are examples of two structures that are commonly protected inside of a Faraday Cage.

The idea of the Lightning Safety Bag was to combine the two existing concepts to create a portable Faraday Cage – one small enough to be carried in a backpack. If an outdoor enthusiast were caught miles from shelter in an electrical storm, in theory they could pull out the Lightning Safety Bag and get inside, so that even if lightning were to strike them directly they might be spared serious injury or death.

The idea was never fully realized for several reasons.

First, there was the question of testing. One might easily design such a shelter, and initial testing might be easy enough with an instrumented mannequin in the bag. But sooner or later some live person would have to get in the bag, at first in a high voltage laboratory, and ultimately in a real lightning situation. Who would these test subjects be? How would the testers ensure the safety of the test subjects?

Even if the Lightning Safety Bag were thoroughly tested and deemed to be effective, there are huge questions about the correct use of the product. In an outdoor situation where an electrical storm is threatening, how early do you get into the bag? How long do you stay in there? When is it safe to get out of the bag?

Then there is the possibility that having such a bag would give someone a false sense of security. “I don’t have to worry about lightning storms. I have a Lightning Safety Bag.” It might encourage people to stay outdoors in stormy conditions rather than seek shelter. But of course just having possession of a bag would not protect you from anything. A person would have to be inside the bag before lightning strikes, and there is not always a clear warning that lightning will strike.

Finally, and not insubstantially, there is a question of liability. If any company did sell a product that encouraged people to stay outdoors in adverse weather, it would not seem far-fetched to imagine that the first person who was injured or killed because the bag was not fully or properly deployed would instigate legal action against the company in question.

And so the idea of the lightning safety bag is relegated to a modest web page. Unless you think you can address the above stated challenges and make it work.