scope:

NOTE 1-Use of the standard designation ISO 6944 refers to both ISO 6944:1985 and ISO 6944-1:2008. 

These test methods evaluate the fire-resistive materials and the HVAC duct systems surface burning characteristics, non-combustibility, fire resistance, durability, and fireengulfment with horizontal and vertical through-penetration firestops.

NOTE 2-The intent of these test methods is to provide authorities having jurisdiction a means to evaluate the fire performance of HVAC duct systems to enable their application and use. 

These test methods evaluate the fire performance of HVAC ducts, including both supply (pressurized: Condition A - Horizontal and Condition B - Vertical) and return (exhaust: Condition C - Horizontal and Condition D - Vertical). 

These test methods evaluate the ability of a HVAC duct system to resist the spread of fire from one compartment to other compartments separated by a fire resistance rated construction when the HVAC duct system is exposed to fire under one or more of the following conditions: 

Condition A-Fire exposure from the outside of the horizontal HVAC duct system without openings, 

Condition B-Fire exposure from the outside of the vertical HVAC duct system without openings, 

Condition C-Fire exposure from the outside with hot gases entering the inside of the horizontal HVAC duct system with unprotected openings, and

NOTE 3-Unprotected openings are openings that are not protected by fire dampers. 

Condition D-Fire exposure from the outside with hot gases entering the inside of the vertical HVAC duct system with unprotected openings. 

These test methods provide a means for determining the fire-resistance of vertical and horizontal HVAC duct systems, when subjected to the standard time-temperature curve of Test Methods E119. 

Condition A-These test methods provide a means for evaluating a horizontal HVAC duct system, without openings exposed to fire, passing through a vertical fire-separating element. 

Condition B-These test methods provide a means for evaluating a vertical HVAC duct system, without openings