Characterization of a Residential Fire Sprinkler Using Phase Doppler Interferometry.
Characterization of a Residential Fire Sprinkler Using
Phase Doppler Interferometry.
Widmann, J. F.
NISTIR 6561; 36 p. August 2000.
Research and Practice: Bridging the Gap. Fire
Suppression and Detection Research Application
Symposium. Proceedings. Fire Protection Research
Foundation. February 7-9, 2001, Orlando, FL, 703-714 pp,
Available from: National Technical Information Service
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sprinklers; residential buildings; water sprays;
uncertainty; residential sprinklers; interferometry
The results of a feasibility study to determine if the
water sprays produced by residential fire sprinklers can
be accurately characterized using phase Doppler
interferometry (PDI) are presented. The large size of
the water drops produced by fire sprinklers, and the
relatively large coverage area of the spray, present
significant challenges when attempting to characterize
these sprays. These difficulties are especially relevant
when using PDI because large drops and large coverage
areas may result in trajectory dependent scattering
errors and attenuation of the transmitting laser beams.
For the residential sprinkler investigated, it was
determined that trajectory ambiguity was not a
significant source of error, but attenuation of the
laser beam resulted in over-counting of drops due to
burst splitting. This effect was minimized by properly
choosing the operating conditions of the PDI processing
electronics. For the spray investigated, the Sauter mean
diameter varied from approximately 360 mum to 560 mum.
Integration of the radial profile of the volume flux
resulted in a calculated flow rate that agreed with the
flow through the sprinkler to within 8%. The results of
this study demonstrate that PDI can be used to
accurately characterize the sprays produced by
residential fire sprinklers.