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Engineering Laboratory / Fire Research Division

National Fire Research Laboratory

Test_34

Table 1. Test Information
Name
Test_34
Date
Description

Low voltage switchgear cabinet w/ 100kW natural gas burner below the right 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
172
10
kW
Time to Peak Heat Release Rate
5.80
0.07
min
Total Heat Released, THR
235
16
MJ
Gas Burner Total Heat Released, NGTHR
45.05
0.64
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
4.70
0.35
kg
Net Effective Heat of Combustion = THR / NM
 Not measured -
MJ/kg
O2 Yield = O2 Consumed / TFM
3.91
0.32
kg/kg
CO2 Yield = CO2 Generated / TFM
3.86
0.32
kg/kg
CO Yield = CO Generated / TFM
0.218
0.018
kg/kg
Soot Yield = Soot Generated / TFM
0.0506
0.0075
kg/kg
Baseline Hood Exhaust Flow
15.82
0.47
kg/s
Test Duration = Time(Fire Out) - Time(Ignition)
57.60
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.
Table 4. Summary of Observed Test Events
Event Time (min) Description Video Snapshot Image
1
0.00
Ignition
Ignition
peak
5.80
Peak HRR
Peak HRR
2
6.48
Adjust Burner from 100 kW to 50 kW
Adjust Burner from 100 kW to 50 kW
3
8.50
Burner OFF
Burner OFF
4
15.82
Pilot flame OFF
Pilot flame OFF
5
55.88
water suppression
water suppression
6
57.60
Fire Out
Fire Out

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.
Plot of Carbon Dioxide Dry Volume Fraction in hood exhaust stream.
Plot of Carbon Dioxide Dry Volume Fraction in hood exhaust stream.
Plot of Carbon Monoxide Dry Volume Fraction in hood exhaust stream.
Plot of Carbon Monoxide Dry Volume Fraction in hood exhaust stream.
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.
Plot of Smoke Laser Extinction Coefficient in hood exhaust stream.
Plot of Smoke Laser Extinction Coefficient in hood exhaust stream.
Plot of Exhaust Duct Mass Flow Rate.
Plot of Exhaust Duct Mass Flow Rate.

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

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

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