Here is a rapid breakdown of how PTC 4.1 quantifies losses:
Note: While PTC 4 is the current code, many legal contracts for boiler procurement were written decades ago and still legally require testing per PTC 4.1.
The air in the archives was thick with the scent of ozone and decaying glue, but didn't mind. He had finally found it: ASME PTC 4.1.pdf