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Engineering Laboratory / Fire Research Division

National Fire Research Laboratory

Test_35

Table 1. Test Information
Name
Test_35
Date
Description

Low voltage switchgear cabinet (narrow) w/ 100kW natural gas burner below the breaker. Water cooled camera pointed at burner.
Specimen
Box Burner
Ignition
pilot flame
Project ID (s)
NRC Electrical Cabinet Experiments
Test Director
McGrattan

Timelapse Video with Heat Release Rate Plot

Table 2. Summary of Test Results
Measurement Value Uc Unit
Peak Heat Release Rate, PHRR
230
13
kW
Time to Peak Heat Release Rate
3.90
0.07
min
Total Heat Released, THR
251
17
MJ
Gas Burner Total Heat Released, NGTHR
24.73
0.35
MJ
Heat Release Quality Confirmation, HRQC
 Not measured -
MJ/MJ
Net Specimen Mass (gravimetric), NM = Mi-Mf
 Not measured -
kg
Total Fuel Mass Burned, TFM = THR / HOCf
5.02
0.37
kg
Net Effective Heat of Combustion = THR / NM
 Not measured -
MJ/kg
O2 Yield = O2 Consumed / TFM
3.95
0.32
kg/kg
CO2 Yield = CO2 Generated / TFM
4.02
0.33
kg/kg
CO Yield = CO Generated / TFM
0.185
0.015
kg/kg
Soot Yield = Soot Generated / TFM
0.075
0.023
kg/kg
Baseline Hood Exhaust Flow
17.18
0.52
kg/s
Test Duration = Time(Fire Out) - Time(Ignition)
54.02
0.03
min

Uc = Combined Expanded Uncertainty with 95% confidence level

Table 3. Summary of Test Input Parameters
Parameter Value Uc Unit
Fuel Type
Natural Gas
 - -
Hood Size
6
 -
m
Effective Duct Diameter
1.975
0.005
m
Exhaust Flow Correction Factor
1.055
0.034
 -
Net Heat of Combustion (per unit mass O2), Ef
12.54
0.50
MJ/kg
Net Heat of Combustion(per unit mass fuel), HOCf
50.00
1.50
MJ/kg
Initial Specimen Mass, Mi (gravimetric)
 Not measured -
kg
Final Specimen Mass, Mf (gravimetric)
 Not measured -
kg
Plot of Fire Heat Release Rate with event markers. Uncertainty bar shown at peak value.
Figure 1. Plot of Heat Release Rate data with event markers and error bars shown at peak.
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Table 4. Summary of Observed Test Events
Event Time (min) Description Video Snapshot Image
1
0.00
Ignition
Ignition
Download
peak
3.90
Peak HRR
Peak HRR
Download
2
4.05
burner OFF
burner OFF
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3
41.88
pilot OFF
pilot OFF
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4
50.92
water suppression
water suppression
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5
54.02
Fire Out
Fire Out
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Table 5. Supplemental Data Plots

Plot of Oxygen Dry Volume Fraction in hood exhaust stream.
Plot of Oxygen Dry Volume Fraction in hood exhaust stream.
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Plot of Carbon Dioxide Dry Volume Fraction in hood exhaust stream.
Plot of Carbon Dioxide Dry Volume Fraction in hood exhaust stream.
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Plot of Carbon Monoxide Dry Volume Fraction in hood exhaust stream.
Plot of Carbon Monoxide Dry Volume Fraction in hood exhaust stream.
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Plot of Radiant Heat Flux data with event markers. r= radial distance from center of hood, h=height above floor.
Plot of Radiant Heat Flux data with event markers. r= radial distance from center of hood, h=height above floor.
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Plot of Smoke Laser Extinction Coefficient in hood exhaust stream.
Plot of Smoke Laser Extinction Coefficient in hood exhaust stream.
Download
Plot of Exhaust Duct Mass Flow Rate.
Plot of Exhaust Duct Mass Flow Rate.
Download

Bryant, R. and Bundy, M. The NIST 20 MW Calorimetry Measurement System for Large-Fire Research, Technical Note (NIST TN) 2077, 2019
https://doi.org/10.6028/NIST.TN.2077(link is external)

NIST Fire Calorimetry Database (FCD)
https://doi.org/10.18434/mds2-2314(link is external)

Report Process Script Version
NFRL_Report_8.5.9
Last Updated January 17, 2025