ANSI Z21.12-1990 (R2020)

Scope

1.1.1
This Standard covers separately constructed draft hoods for installation on appliances required to be vented. A draft hood supplied as part of a listed appliance is certified as part of the appliance under the applicable provisions of the individual appliance standard. 

1.1.2
This Standard applies to newly produced draft hoods (see Part IV, Definitions) constructed entirely of new, unused parts and materials: (a) For use with natural, manufactured, mixed and liquefied petroleum gases, and LP gas-air mixtures; or (b) For use with natural, manufactured and mixed gases. 

1.1.3
If a value for measurement as given in this standard is followed by an equivalent value in other units, the first stated value is to be regarded as the specification. 

1.1.4
Exhibit B contains a list of standards specifically referenced in this standard, and sources from which these reference standards may be obtained.