Safety Lifecycle Management

How far does a heater explosion actually reach?

Tell us where to send it, and unlock the interactive blast radius calculator - modeled across 7 firebox volumes and 3 loss-of-flame scenarios, with screening-level BMS SIL targets.

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Safety Lifecycle Management

Blast Radius Calculator · Fired Heater Loss of Flame

How far does a heater explosion actually reach?

Model the blast overpressure distance for a natural-gas-fired heater loss-of-flame event - the same simplified, conservative consequence method process safety teams use in a PHA to size Burner Management System SIL targets in minutes instead of weeks.

1 · Configure your scenario

Loss-of-flame scenario

Regulator fails low

Fuel pressure drops below stable burner limits.

Regulator fails high

Fuel pressure exceeds stable burner limits.

Loss of combustion air

90% loss of air supply - generally worst case, independent of feed rate.

Firebox volume

Firebox falls between listed values? Select the next larger volume for a conservative estimate. Feed rate is fixed at the worst-case default (25 lb/min) for this screening tool.

2 · Your results

- ft

Fatality radius · 1.5 psi

- ft

Building collapse radius · 3.75 psi

Overpressure	Distance	Typical damage	Fatality risk

3 · LOPA Inputs

Target Mitigated Event Likelihood (TMEL)

1×10⁻⁴/yr (typical) 1×10⁻⁵/yr (stricter)

Occupancy

Low (0.1) — infrequent presence High (1.0) — continuously occupied

Regulator (PCV) failure frequency — low low fuel gas pressure

0.10/yr (typical) 3/yr (degraded/poorly maintained)

4 · LOPA Results

SIF	Hazard	RRF	SIL

Screening-level SIL targets from our LOPA methodology. Full cause breakdowns, sensors, and final elements are available when you talk to our team.

Modeling assumptions

Fuel modeled as 100% methane (CH4) for conservatism; typical natural gas is 80-95% methane.
Feed pressure basis: 3 psig (regulator fails low), 150 psig (fails high), 15 psig (loss of combustion air).
Fuel and combustion air at 80F. Combustion air at stoichiometric ratio, 17.19:1 for CH4.

Loss of combustion air modeled as a 90% loss of total supply.
10-minute release duration per EPA RMP section 68.25(e)(1); sufficient to reach steady state.
Equipment assumed at or slightly above grade (ground burst) - conservative. Open field; nearby structures not modeled.

This tool is intended for severity screening and PHA/SIL scoping discussions only - it is not a substitute for detailed consequence modeling, LOPA, or engineering design. Results are simplified and conservative by design and may not reflect site-specific conditions.
Methodology: Braedel, M. "Benefits of Simple Consequence Modeling for Burner Management Systems," Mary Kay O'Connor Process Safety Center, 2016 · Scott, M. "Burner Management System Safety Integrity Level Selection," aeSolutions · Scott, M. "Application of Functional Safety to a Burner Management System," aeShield, LLC.

Want a second opinion on your unit?

Our process safety team can help translate this into a defensible SIL target for your BMS - and walk you through the full interactive calculator live.

Talk to our team →