Students, faculty, researchers, and engineers from fire safety programs around the world are invited to join a competition to predict the burning behavior of Balsam Fir Christmas Trees. The highest individual and highest group scores - i.e., the average scores of all submissions from a single research team or program (at least 3 team members) - will be announced to all competition participants.

2023 Winners


For a second year in a row, the University of British Columbia won the first place in our competition, leading the predictions with an average score of 56.4. The team was succeeded by the University of Edinburgh, who earned the second place with a mean of 53.8 points. Teams of at least 3 individuals from the same University or Research Institution are needed for a chance to win best team prediction. The first and second place teams of this competition earn our coveted golden and silver pinecones.

See the Invitation to Participate.



Species:     Balsam Fir (3x, pictured right)
  Tree 1 Tree 2 Tree 3
Height 10.96 kg 10.76 kg 10.70 kg
Weight 2.05 m 2.18 m 1.77 m

Figure 1. The 2023 competition trees (Balsam Firs)






Storage: Trees will be kept, unwatered, for 24 days in laboratory storage at approximately 50% relative humidity and 12°C.

Ignition:  A 6 cm diameter pan filled with 40 mL of heptane will be placed below the lowest branches of the tree, approximately 15 cm away from the outermost edge of the tree. Ignition (time, t = 0 s) will be defined as the earliest time at which calculated HRR exceeds 50 kW. Note: this procedure moves the ignition source farther away from the center of the tree as compared to previous competitions (i.e., 2020 and earlier). Also note the variability in 2023 tree dimensions, despite similar initial weights. Experimental results and the best predicted HRR curves from the 2022 Competition are shown in Fig. 3 of the Invitation to Participate.

Data: Christmas tree mass loss rate will be measured continuously at 1 Hz using a mass balance with a 0.1 g precision. If possible, cone calorimeter measurements will be performed to determine a representative heat of combustion, ΔHc, for each tree. If not, a constant value will be assumed – ΔHc = 17.7 kJ/g [Mell et al. 2009] – to convert this to HRR.

HOW TO PARTICIPATE: Generating and Submitting your Predictions

This year, the submission (and generation of) predicted heat release rate (HRR) curves will once again be made possible by visiting the National Institute of Standards and Technology Christmas Tree Heat Release Rate page. Here, you can use a custom-made app that allows you to ‘build’ (and submit) your own fire by adjusting just four parameters that define:

  • Fire Growth Rate
  • Peak Heat Release Rate (Peak HRR)
  • Duration of Steady Burning
  • Fire Decay

In this app, after you click submit, an email will be generated that contains the four parameters defining your HRR curve. In this email, please remember to add your name, email and lab affiliation if you wish to receive credit (and final competition results) and CLICK SEND so that we receive your submission.

A video guide to using this app to create HRR curves and submit predictions is available on Youtube.

The 2023 event will be livestreamed here:


The burn tests will be repeated in triplicate and your predictions will be scored with respect to the average and standard deviations (with explicit considerations for measurement uncertainty) of experimentally measured burning behavior (i.e., peak HRR, time to peak, fire growth time and duration, and total energy release).

Points (100 possible) will be awarded in 5 categories as listed below. Our scoring system will give up to 20 points for each category so long as the predicted values are within two standard deviations considering the calculated uncertainties. 



Uncertainty, Calculated as:

Peak Heat Release Rate

Propagation of error including uncertainty in time-resolved balance reading and heat of combustion. 

Total Energy Release

Propagation of error including uncertainty in time-resolved balance reading and heat of combustion. 

Time to Peak Heat Release Rate

Standard deviation of time to peak HRR values measured in each of the 3 repeated tests. 

Duration in which HRR exceeds 70% of peak HRR

In each test, a lower and upper estimate of the duration of burning in which exceeds 70% of peak HRR can be made based on the uncertainty in measured HRR. These two values are shown graphically in Fig. 1.

Uncertainty in 70% duration is thus calculated as the standard deviation of all 6 of these values measured from each of the 3 repeated tests.

Duration in which HRR exceeds 200 Kw

Calculated identically as the uncertainty in 70% duration. 


QUESTIONS?  Please contact the fire safety demo leader,  Dr. Isaac Leventon (

Dr. Leventon would like to thank Dr. Anthony Hamins of NIST for his thoughtful comments and helpful suggestions regarding relevant uncertainty analysis for the scoring of this event.