Final answer:
To ensure fire resistance in rigid insulation, factors such as material, thickness, and the R factor (ratio of thickness to conductivity) are critical. The larger the R factor, the better the insulation. An example of effective fire-resistant insulation is the material on the Apollo heat shield, which dissipates heat through burning and expansion.
Step-by-step explanation:
In order to ensure that rigid insulation is fire resistant, it's important to consider the combination of material and thickness in the insulation. This is often manipulated to develop good insulators. The ratio of thickness (d) to conductivity (k) is called the R factor, and a larger R factor indicates better insulation. The rate of conductive heat transfer is inversely proportional to R.
A good example of fire-resistant insulation is the material coating the Apollo heat shield, developed by Avco Corporation. This material was designed to dissipate energy through burning and form a protective, insulating layer to block heat penetration. In a fire situation, this material expands to provide an insulating barrier and dissipates heat through burn-off, making it ideal for fire resistance.
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