GOST 31848-2012 Industrial gas-using equipment. Air heaters. General technical requirements
GOST 8.051-1981 State system for ensuring the uniformity measurements. Permissible errors of measurement of linear dimensions to 500 mm
GOST 8.549-1986 The state system of ensuring the uniformity of measurements. Permissible errors of measurement of linear dimensians to 500 mm with unindicated tolerances
GOST 31851-2012 history
2012GOST 31851-2012 Industrial gas-using equipment. Air heaters. Test methods