A 1 in. nominal diameter steel pipe with its outside surface at 400F is located in air at 90F with the convective heat transfer coefficient between the surface of the pipe and the air (ho) equal to 1.5Btu/hft2F. It is proposed to add insulation having a thermal conductivity of 0.06Btu/hftF to the pipe to reduce the heat loss to one-half that for the bare pipe. What thickness of insulation is necessary if the surface temperature of the steel pipe and h0 remain constant? A 1 in. nominal diameter steel pipe with its outside surface at 400F is located in air at 90F with the convective heat transfer coefficient between the surface of the pipe and the air (ho) equal to 1.5Btu/hft2F. It is proposed to add insulation having a thermal conductivity of 0.06Btu/hftF to the pipe to reduce the heat loss to one-half that for the bare pipe. What thickness of insulation is necessary if the surface temperature of the steel pipe and h0 remain constant