New York Codes, Rules and Regulations
Title 10 - DEPARTMENT OF HEALTH
Chapter II - Administrative Rules and Regulations
Subchapter I - Environmental Health
Part 71 - Requirements For Vent-free Gas Space Heating Appliances
Section 71.2 - Definitions

(a) Sizing guidelines means printed instructions provided by the manufacturer that contain information on selecting vent-free gas space heating appliance with appropriate heat output.

(b) Vent-free space heating appliance, also known as a gas-fired unvented room heater, means an unvented, self-contained, gas-burning appliance for connection to the house fuel supply system and for furnishing heat to the space in which installed, directly from the appliance without duct connection. These appliances may be free-standing, wall mounted or for insertion in a noncombustible fireplace.