Abstract
Current methods of calculating hold time for a fire fighting gas assume that the enclosure is of uniform horizontal cross-sectional area and has horizontal upper and lower boundaries (a standard enclosure). The paper shows that the hold time equation for continuous mixing in standard enclosures may also be used for non-standard enclosures, presents exact and simplified equations for descending interfaces in non-standard enclosures, and discusses the accuracy of the simplified equation. Considering the error when the simplified equation is applied to standard enclosures, and that it is always conservative for an enclosure of any shape, it is suggested that it may be used as an approximation for non-standard enclosures. The paper also presents a hold time equation for a descending interface in a standard enclosure with laminar flow in the leaks.
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References
BS 5306, Section 5.1, 1992, “Fire Extinguishing Installations and Equipment on Premises, Halon Systems Specification,” British Standards Institution, 1992.
ISO 14520.1, “Gaseous Fire Extinguishing Systems-Physical Properties and System Design, Part 1: General Requirements,” Annex E, International Standards Organization, 2000.
[3] NFPA 12A, “Standard on Halon 1301 Fire Extinguishing Systems,” National Fire Protection Association, USA, 1997.
[4] NFPA 2001, “Standard on Clean Agent Fire Extinguishing Systems,” National Fire Protection Association, USA, 2000.
P.J. DiNenno and E.W. Forssell, “Evaluation of the Door Fan Pressurization Leakage Test Method Applied to Halon 1301 Total Flooding Systems,” Journal of Fire Protection Engineering, vol. 1, no. 4, 1989, pp. 131–140.
J. Dewsbury and R.A. Whiteley, “Review of Fan Integrity Testing and Hold Time Standards,” Fire Technology, vol. 36, no. 4, 2000, pp. 249–265.
J. Dewsbury and R.A. Whiteley, “Extensions to Standard Hold Time Calculations,” Fire Technology, vol. 36, no. 4, 2000, pp. 266–278.
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Dewsbury, J., Whiteley, R. Hold Time Calculations for Non-Standard Enclosures. Fire Technology 40, 75–89 (2004). https://doi.org/10.1023/B:FIRE.0000003317.39877.07
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DOI: https://doi.org/10.1023/B:FIRE.0000003317.39877.07
- integrity test
- hold time
- retention time
- standard
- airtightness
- air leakage
- airtightness measurement
- leakage measurement
- pressurisation test
- fan pressurisation
- leakage area
- leakage exponent
- lower leakage fraction
- bias pressure
- descending interface
- sharp interface
- wide interface
- continuous mixing
- Halon
- clean agent
- fire extinguishing
- fire fighting
- gas system
- standard enclosure
- non-standard enclosure