5901 23RD DR W ZAP ENERGY 2024-04-12

Discussion of Results - Capacitor Room Hold Time Compliance with Annex C of NFPA 2001 (2012 Edition) It is predicted that the leakage measurement in this enclosure of 263 sq in would allow an extinguishing agent loss rate of 2.04 lb/min. The extinguishing agent discharge system is designed with an extended discharge rate of 0.00 lb/min for 10 minutes, which is less than the extinguishing agent loss rate. Therefore, the minimum concentration of 42.16% cannot be maintained and therefore the enclosure FAILS this acceptance procedure. Peak Pressure Compliance with section 5 of NFPA 2001 (2012 Edition) 5.3.7: The protected enclosure shall have the structural strength and integrity necessary to contain the agent discharge. If the developed pressures present a threat to the structural strength of the enclosure, venting shall be provided to prevent excessive pressures. And that the following shall be submitted for approval to the authority having jurisdiction: 5.1.2.2 (10): maximum positive and the maximum negative pressure... expected to be developed upon the discharge of agent 5.1.2.2 (28): pressure relief vent area... to prevent development of a pressure difference across the enclosure boundary that exceeds a specified enclosure pressure limit. Calculations for peak pressure, based on leakage area of Enclosure Only at a standard reference condition of 125 Pa and using no pressure relief vent (PRV), determined: • The enclosure would represent a free vent area during discharge of 334 sq in with the enclosure set up in the condition expected to occur during the positive pressure pulse caused by the agent discharge which is predicted to be 589 Pa. This pressure is less than the specified maximum of 1,000 Pa, therefore the enclosure PASSES this acceptance procedure. Vents should be installed high in the enclosure so that mostly air is exhausted, instead of the heavier extinguishing agent. Additionally, the vents should be rated to fully open between 80-130 Pa. Once a vent is installed or it is decided to use leakage of the enclosure only to relieve pressures during discharge, the chosen venting situation is used to calculate expected peak pressure, and the available free vent area must be enough to relieve this peak pressure in order to pass. All leakage areas are extrapolated to a standard reference condition of 125 Pa which is representative of conditions where most of the peak pressure will be relieved Peak pressure calculation detail Using the leakage area of Enclosure Only and equations from the Fire Suppression Systems Association (FSSA) "Pressure Relief Vent Guide": • A peak positive pressure of approximately 589 Pa would form. • Peak negative pressure will not form with agent Nitrogen [IG-100]. Free vent area required calculation detail Assuming an Enclosure Pressure limit of 1,000 Pa, this enclosure requires a total free vent area of 206 sq in in the positive direction to maintain the enclosure's structural integrity. Page 5 of 12