the American Society of Mechanical Engineers (ASME) performance test code, PTC 4. A related component is the regenerative air heater. A major revision to the performance test code for air heaters will be published in 2013. Copies of the draft are available for review. The European standards for acceptance test of steam boilers are EN 12952-15 and EN 12953-11. The British standards BS 845-1 and BS 845-2 remain also in use in the UK. See also Glossary of boiler terminology References External links Steam engines