The hood test
standard specifies an ejector system that releases 4 L per minute (0.14 cfm) of tracer gas inside the hood.
For example, a wetlaid filter material that tests at 99% gravimetric efficiency in an automotive air filter flat sheet test ma y very well have about 60-65% dust spot efficiency in an AHSRAE hood test
. Also, just because a filter material tests well in a flat sheet test does not mean that it will work in the filter.
consumers, found capture efficiencies from less than 15% to greater than 98%, depending on both the hood tested
and the burners used (front versus rear).
soldiers around the world take a new piece of gear to the field, either wearing it, driving it, or firing it, the Operational Test Command at Fort Hood tests
it to make sure it meets Army standards and can be used in the field functionally by the everyday soldier.