The 3.1.1. Rule
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If you've flown a plane recently, you've no doubt encountered the 3-1-1 rule. 3 bottles, no more than one once each in size, in one container that the inspector can see through. Have you ever thought about why this particular restriction is used? Why not 4 bottles, 2 oz. each? Why not one 3 oz. bottle? Well, the staff at the Homeland Security Department faced with many complaints about the inability of passengers to take on the plane small quantities of cosmetics, first aid supplies, etc. finally decided to apply some science to this question as opposed to arbitrarily ruling out the carrying of all liquids on a plane.

How much explosive material was really required to cause a dangerous explosion on a plane? Is there some level of material that would not cause an imminent danger? The answer is not zero! It's some small quantity in a critical mass. Now we don't know what the exact calculation was, but suffice it to say that someone calculated that 1 oz. of known explosive materials was insufficient. And further, that 3 of these small quantities was insufficient together to be an explosive hazard.

What's all this got to do with TRIZ? Well, resource use and identification is a KEY aspect of TRIZ analysis. Without sufficient resources, a system cannot accomplish certain things (that's how the TSA used this concept). When we are doing TRIZ problem solving, we are always looking for additional (preferably free or low cost)resources to achieve and accomplish additional functionality. In the case of the TSA, they were using a form of Predictive Failure Analysis or TRIZ in reverse, to figure out how little resource is required to accomplish a negative function.

There are a number of ways of using these concepts. First, if you are trying to accomplish something, consider ALL of the available resources that you have, including those available in the raw materials you use and the super-systems into which your product is used. Consider not only the materials you have, but their impurities and defects as positive resources. Consider time during our process as well as time before and time after (in transit, in storage). Consider all the fields you have and those which those fields generate (an electric field can always generate an electric field, whether you like it or not!). A thermal field ALWAYS generates a mechanical field (whether you like it or not!).

When considering potential failure routes for process or product failures, do this resource thinking in "reverse". If you wanted to cause your process or product to fail, what would you do or cause to happen? Are there resources available to accomplish this? Could they be created? How? From the activities and fields you are already using? How would you prevent? Consider how and what the TSA did and broaden the concepts to apply to your situation: improve a product you have or prevent a product or system from failing.