Residential Flat Plate Concealed Sprinkler UL 1626 Compliance
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Solution Overview
Problem
Residential flat plate concealed sprinklers struggle to meet the minimum flow rate and pressure requirements of UL 1626 standards for larger room sizes, such as 5.46m x 5.46m and 6.1m x 6.1m, often requiring higher flow rates to pass fire tests due to their two-step operation and full recessed design.
Innovation Solution
A residential flat plate concealed sprinkler design featuring a body with a K-factor of 5, a thermally responsive trigger assembly, and a deflector assembly with an oval plate and telescopic guide members, allowing for fluid distribution over 13.38m² to 37.16m² with densities of 2.037 litres/min/m², and operating pressures ranging from 48.26kPa to 117.21kPa, accommodating minimum flow rates from 49.21L/min to 75.71L/min.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a flat plate concealed sprinkler is fully recessed into the ceiling for aesthetic appeal, then the visual appearance is improved, but the flow rate and pressure performance deteriorates
Solution Approach 1:
The sprinkler incorporates a two-step operation mechanism where the cover plate is first disengaged from the recessed ceiling, then the sprinkler head is activated. This dynamic operation allows the sprinkler to maintain a concealed aesthetic appearance during normal conditions while providing adequate flow rate and pressure performance when activated, resolving the contradiction between concealed design and performance.
2Quantity of substance
If the sprinkler cover is disengaged from the recessed ceiling for operation, then the flow rate performance improves, but the device complexity increases
Solution Approach 1:
The cover plate is pre-configured to be disengaged from the recessed ceiling before sprinkler activation. This preliminary action of cover disengagement prepares the sprinkler for optimal flow rate performance while maintaining a relatively simple operational sequence. The cover disengagement mechanism is integrated into the recessed mounting structure, reducing overall device complexity despite the two-step operation requirement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The sprinkler effectively meets UL 1626 standards for various room sizes by ensuring adequate fluid distribution and pressure, enhancing fire protection while maintaining a concealed, aesthetically appealing design.
Implementation Method 1
a thermally responsive trigger assembly that maintains the closure assembly adjacent the outlet
Implementation Method 2
the deflector assembly distributes a flow of fluid over a protection area
Implementation Method 3
distributes a flow of fluid over a protection area ranging from about 13.38m 2 to about 37.16m 2
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
A pendant sprinkler preferably includes a body having an inner surface defining a passageway. The passageway includes an inlet and an outlet spaced apart along the longitudinal axis and defines a K-factor of about 5. The sprinkler also includes a closure assembly adjacent the outlet to occlude the outlet and a thermally responsive support means for maintaining the closure assembly adjacent the outlet. Also provided are means for distributing a flow of fluid over a protection area ranging from about 144 square feet to about 400 square feet, the fluid distribution having a density of at least 0.05 gallons per minute per square foot (0.05 gpm/ft2) so as to define a range of minimum operating pressures ranging from about seven pounds per square inch to about seventeen pounds per square inch (7-17 psi.) and a range of minimum operating fluid flows ranging from about thirteen gallons per minute to about twenty gallons per minute (13-20 gpm.). The sprinkler preferably includes a thermally responsive plate means for maintaining a minimum spacing between the outlet and the means for distributing.