Abstract: A heat resistant protective coating is comprised of a composition including 14 to 21 percent by weight of an alkali metal silicate; 20 to 35 percent by weight of magnesium silicate; a blowing agent; and water. The composition upon heating intumesces to form a closed cell structure which provides insulation to a coated substrate.The coating composition is particularly useful in coating steel pipe to form an intumesced closed cell composition on the steel pipe. The pipe can be used as an oxygen lance in producing steel or as an aluminum flux rod.