During my career as a safety professional, I’ve often been asked whether a fire extinguisher can explode. People who ask are usually concerned about keeping a fire extinguisher in a car parked under direct sunlight or about what might happen if they accidentally drop one while handling it.
So, can a fire extinguisher explode?
The direct answer is yes, fire extinguishers can explode, but it's extremely rare when they're manufactured, maintained, and handled according to safety standards. (You’ve probably also seen some random fire extinguisher explosion videos on the internet.)
Like any pressurized equipment, fire extinguishers carry an inherent risk of explosion. However, the probability of explosion becomes very low when they comply with applicable standards such as
- NFPA 10 (US Standard for Portable Fire Extinguishers)
- BS EN 3 (European Standard for Portable Fire Extinguishers)
- UL 711 (Standard for Rating and Fire Testing of Fire Extinguishers)
A properly manufactured, maintained, and handled fire extinguisher can last decades, with explosion chances close to zero throughout its entire lifespan. To demonstrate this, our professional fire extinguisher inspection team and I conducted a series of tests. Let’s explore this in detail.
Fire Extinguisher Explosion Test
Test Subjects
We selected some remarkably old ABC dry chemical powder fire extinguishers manufactured in 2001 and 2002, which had endured harsh conditions on a drilling rig — exposed to direct sunlight, water, and occasional impacts.
These fire extinguishers were rated for Class A (ordinary combustibles), B (flammable liquids), and C (electrical fires) and are the most common extinguisher type found in homes, offices, and vehicles.
(If you're unfamiliar with fire classifications and the appropriate types of fire extinguishers, we recommend enrolling in our free Fire Safety Awareness course available on Alison.)
Our selected fire extinguishers were manufactured and approved to BS EN 3/BAFE, a European standard that specifies requirements for portable fire extinguishers, and were regularly inspected and maintained as per NFPA 10 guidelines.
Actual Test
We emptied them and measured their shell thickness. Originally designed at 1.6 mm, they still held at 1.6 mm after over two decades despite being in such a challenging environment.
To conduct the pressure test, we created a special manifold to seal the shell and pressurize it, along with a special safety box for protection in case of any explosion. For further safety, the test was conducted in an open environment at a considerable safe distance from any occupancy and under expert supervision.
According to the manufacturer’s guidelines, the standard operating pressure for these extinguishers is 12 bar (approximately 174 PSI). The shells were originally hydrostatically tested by the manufacturer to 26 bar (approximately 377 PSI).
During our test, we incrementally pressurized the fire extinguishers. We first applied pressure up to 17.9 bar (260 PSI) and then further increased it to 27.6 bar (400 PSI). This is significantly higher than the maximum pressure a fire extinguisher might experience even if left in direct sunlight or extreme heat for an entire day, which typically sees pressure increases to around 17 to 20 bar (250 to 290 PSI) in ambient temperatures ranging from 38°C to 60°C (100°F to 140°F).
Test Results
We maintained these elevated pressures for 30 minutes at each stage. The reassuring outcome? There was absolutely no sign of explosion, bursting, or structural failure from any of the extinguishers.
To push the limits even further, we intentionally deformed some of the extinguishers by hammering them, creating significant dents. We then subjected these highly dented and deformed units to the same rigorous pressure tests. Still, there was no sign of explosion.
This proved that if fire extinguishers are manufactured and maintained according to safety standards, the risk of explosion is negligible even after two decades.
Another important thing to note is that fire extinguishers are equipped with safety valves on their handle assembly. If exposed to extreme heat—say, 200°F (93°C)—in a fire, these valves release excess pressure gradually, emptying the extinguisher without an explosion. So, even in a fire, the risk of bursting is minimal.
For further reference, you can check the video by MythBusters where they tested three common types of fire extinguishers—CO₂, water, and chemical foam—by placing them in a fire to see if they would explode. None of them exploded.
When Can a Fire Extinguisher Explode?
If you're familiar with the "domino theory" of accident causation, you'll understand that for an accident to occur, a series of unfortunate events must align. For a fire extinguisher explosion to happen, these events could include:
- Poor design or manufacturing: Non-compliance with safety standards
- Neglected maintenance: Skipping hydrostatic testing or inspections
- Non-standard parts: Using incompatible components during repairs
- Over-pressurization: Exceeding the manufacturer’s limits
- Physical damage: Deep dents or corrosion weakening the shell
- Improper use/tampering: Attempting to modify the extinguisher for purposes other than its intended use
If these factors align, the risk of explosion would be high.
For more in-depth information, consider checking out "Why fire extinguishers must be routinely maintained."
Key Takeaway
Can a fire extinguisher explode?
Yes, like any pressurized equipment, they can explode—but it’s very rare if they are manufactured, maintained, and handled according to safety standards.