About the FireCred Fire Dynamics Calculators

Notice — These calculators are provided for educational and training purposes only. Results depend on the validity of the underlying correlations for your specific scenario. FireCred makes no warranty as to the accuracy or fitness of these tools for any particular use.

What this is

This site is a web-based, interactive version of the FireCred Fire Dynamics Spreadsheet. The original spreadsheet bundles fourteen small fire-engineering calculators — flashover, conductive heat transfer, pool-fire radiation, solid-material ignition, heat release rate from burning fuels, t² fire growth, Heskestad flame height, gas amount needed to reach LEL/UEL, open-pipe gas flow, gas concentration over time, oxygen depletion, upper-layer gas temperature, sprinkler activation, and a units-conversion reference — into a single workbook intended for students learning fire dynamics.

The web site rebuilds each of those calculators as its own page. Every page lists the inputs (with per-field unit selectors), shows the underlying equation with its source citation, explains the calculation in plain language, and includes at least one worked example. The math runs in your browser, so you can plug in numbers without an Excel licence and share a specific scenario simply by copying the URL — the inputs are encoded into the page address.

Authorship and maintenance

The original spreadsheet was authored by James Lord, co-founder of FireCred. The web version preserves the spreadsheet's equations bit-for-bit — every calculator on this site has been wired up to produce results that match the spreadsheet, using the same lookup tables (wall lining materials, fuel properties, gas properties, sprinkler RTI values, fire growth rates) and the same unit-conversion factors found in the workbook's Conversion Factors sheet.

The site is maintained by FireCred. Bug reports, suggested calculators, or content corrections are very welcome — see the feedback section below.

Methodology

Each calculator on this site is a direct port of a single tab from the spreadsheet:

Inputs and units — Every input the spreadsheet exposes is exposed on the web. Each numeric input has a unit selector so you can work in whatever units are convenient; values are converted to SI internally before the equation is evaluated, then converted back for display.
Lookup tables — Material thermal conductivities for wall linings (NUREG 1805 Chapter 13), thermal inertia and ignition temperatures for solids (Quintiere Table 4-3), fuel mass-flux and heat-of-combustion values (Quintiere Tables 6-2 and 6-3), gas properties (engineeringtoolbox.com and SFPE Handbook), sprinkler RTI categories (NFPA 13), and t² growth rates (Quintiere Table 6-6 and NFPA) are all populated from the original spreadsheet so the dropdowns produce identical results.
Equations — Each calculator's underlying equation is shown rendered with KaTeX, along with the citation it came from. The same equations are evaluated in JavaScript; for time-series calculators (t² fires, gas concentration, oxygen depletion, sprinkler activation) the integration matches the spreadsheet's per-row approach.
Sprinkler activation — The original spreadsheet uses Excel's manual Goal Seek (the user adjusts a cell until a "difference" cell is approximately zero). The web version automates that by solving the ceiling-jet/bulb-response ODE numerically and returning the activation time directly.
References — Every calculator's "References" section lists the source of each equation and lookup table, with page and equation numbers from the SFPE Handbook (3rd ed., 2002), Quintiere's Principles of Fire Behavior, NUREG 1805, NFPA 13, and Harris's Investigation and Control of Gas Explosions as cited in the spreadsheet's accompanying instructions document.

The calculators do not require an internet connection once a page is loaded — calculations run entirely client-side. Saving or sharing a calculation is done by copying the URL: the page address contains every input value you have entered.

Audience

These tools are aimed at students learning fire dynamics. They are deliberately not a substitute for a full fire-protection analysis. The spreadsheet was originally built as a teaching aid alongside coursework based on Quintiere's Principles of Fire Behavior, the SFPE Handbook of Fire Protection Engineering, and NFPA standards. The website's content (equations, examples, references) follows the same teaching-first style, with every page including a worked example and a discussion of when the underlying correlation does and does not apply.

Branding and substitutions

The FireCred branding (logo, colour palette, body type) is used throughout. The brand-guide heading typeface, Neology Deco W03 Bold, is a licensed Monotype web font; to keep this public-facing site simple and licence-clean, the heading typeface on the website is set to Montserrat 700 served from Google Fonts. Montserrat is a similar geometric sans, free for unrestricted web use, and reads cleanly alongside Poppins (the body font specified in the brand guide).

Feedback and corrections

If you spot an error, want a new calculator added, or have a question about how a particular equation has been implemented, please email info@firecred.com. The site does not require an account and does not store any of your input values on a server.