Some Factors Affecting the Design of a Furniture Calorimeter Hood and Exhaust.
Some Factors Affecting the Design of a Furniture
Calorimeter Hood and Exhaust.
Cooper, L. Y.
NISTIR 5298; 25 p. December 1993.
Journal of Fire Protection Engineering, Vol. 6, No. 3,
Available from: National Technical Information Service
Order number: PB94-139193
furniture calorimeters; exhaust systems; buoyant plumes;
calorimeters; fire plumes; flame length; wall flows
This work considers factors affecting the design of an
effective and versatile furniture calorimeter hood and
exhaust system. The purpose of the furniture
calorimeter, design functions, and inherent limitations
of a particular design are discussed. The interactions
between the hood structure and the fire and its plume
are analyzed in the context of avoiding: flame
impingement on the hood; enhanced combustion of a test
article, over and above that of a free-burn; loss of
combustion product plume gases due to "spill-over" below
the hood; and unacceptable dilution of plume gases in
the measurement section of the exhaust duct. The
concept of the ideally designed hood is introduced,
where, throughout the course of the burn of a test
article the hood is always immediately above the flame
tip and the exhaust rate always exactly matches the
hood-ceiling-elevation plume-flow rate. Methods to
partially or completely achieve the ideal design are
presented. These include the combined features of
adjustable hood elevation and adjustable hood exhaust
rate. The ideas and results of analyses developed are
applied in examples relevant to the existing furniture
calorimeter hood and exhaust system of the NIST Building
205 Fire Research Laboratory. Recommendations for
improvements to this facility are presented.