Manufacturers can have their appliances/devices tested by a recognized third party testing agent for uses that are less stringent than the code.
For example while an unprotected metal wood burning stove may require 36" clearance from combustibles, a manufacturer can incorporate protectives or clearance reduction and show they're as safe at the reduced distance, via the independent recognized testing agency.
Manufacturers can have their appliances/devices tested by a recognized third party testing agent for uses that are less stringent than the code.
For example while an unprotected metal wood burning stove may require 36" clearance from combustibles, a manufacturer can incorporate protectives or clearance reduction and show they're as safe at the reduced distance, via the independent recognized testing agency.