Insulations Design Rules of the Thumb

1. Up to 650˚F, 85% magnesia is most used.
2. Up to 1600―1900˚F, a mixture of asbestos and diatomaceous earth is used.
3. Ceramic refractories at higher temperatures.
4. Cryogenic equipment (―200˚F) employs insulants with one pores in which air is trapped.
5. Optimum thickness varies with temperature 0.5 in. at 200˚F. 1.0 in. at 400˚F, 1.25 in. at 600˚F.
6. Under windy conditions (7.5 miles/hr). 10―20% greater thickness of insulation is justified.