Fire Ratings
Fire Ratings Explained: What Safe Owners Need to Know
Table of Contents
- What Is a Fire Rating?
- Common Fire Testing Standards
- 350°F vs. 125°F: What the Numbers Mean
- House Fire Temperatures vs. Fire Tests
- Time–Temperature Curve
- Additional Fire Testing Methods
- Recommended Ratings by Use Case
- Fire Rating Comparison Table
- FAQ
- Need Help Choosing?
What Is a Fire Rating?
A fire rating tells you how long a safe can protect its contents from high heat during a fire. It’s usually expressed in minutes or hours, like 60 minutes at 1,700°F. These ratings come from either independent labs or factory-conducted tests.
Some safes are tested to protect paper, while others are designed to protect more sensitive items, such as hard drives or film.
Important: No safe is completely fireproof. Safes are designed to resist heat and smoke for a period of time, but cannot withstand fire indefinitely.
Also, most fire-rated safes are not waterproof unless specifically tested for those conditions.
Common Fire Testing Standards
Here are the most common types of fire certifications you’ll see on our site:
UL (Underwriters Laboratories)
Example of a UL Label on Gardall Safes
The most recognized and rigorous fire testing standard in the U.S., UL tests safes to 1,700–1,850°F and measures internal temperature rise. For paper protection, the temperature must remain below 350°F.
- UL Class 350: Contents stay under 350°F.
- UL Class 125: Required for digital media. Must stay under 125°F.
- (Used by American Security, Fire King, Gardall, Honeywell, Sentry Safe on select models)
ETL (Intertek)
- A globally recognized lab with similar protocols to UL. Their tests also heat safes to 1,200°F but may vary slightly in ramp-up speed or cooldown.
- (Used by American Security on select models)
JIS (Japanese Industrial Standard)
- JISS 1037 is Japan’s fire safety standard. Less common in the United States. Tests similar to UL but with slightly different temperature curves. Interior temps must remain below 350 degrees during the test and the cooldown period.
- (Used by Hollon Safes on select models)
KSG or KIS (Korean Industrial Standard)
- These safes are often tested to 927°C (1,700°F) with a 10-minute ramp-up period for 30 minutes. 1 hour or 2 hours. The safes interior must remain under 350 degrees. This rating is seen on many imported fire-rated safes.
- (Used by Gardall on select models)
GOST (Russia)
- GOST standards were established during the Soviet era and are still in use today. Their fire tests often use Celsius-based metrics and time intervals.
- (Used by Hollon Safes on select models)
MTC Grade B for Media
- Designed specifically to protect computer storage and backup tapes. These safes must remain below 125°F and have a humidity level of 80–85%.
- (Used by Phoenix Safes on select models)
RISE Research Institutes of Sweden AB
- RISE is a Swedish state-owned research institute that performs industry reserach and innovation, as well as testing and certification including fire testing.
- (Used by Phoenix Safes on select models)
Factory Tested
- Some manufacturers conduct their own internal fire tests. These may follow similar temperatures and durations, but are not verified by a third party. They can still provide meaningful protection, just with less oversight.
350°F vs. 125°F: What the Numbers Mean
- 350°F: The threshold at which paper begins to brown and eventually burn. Most residential fire safes are tested to stay below this mark. Paper chars at around 387°F and burns at 451°F.
- 125°F: The upper limit for digital media like hard drives and backup tapes. If you're storing digital files or electronics, look for a safe with this rating.
House Fire Temperatures vs. Fire Tests
Most structure fires in homes burn between 1,100°F and 1,300°F, peaking for 15–30 minutes in a given area. However, safes are tested under more extreme conditions:
- UL and KIS tests reach temperatures of 1,700–1,850°F.
- These temperatures rise fast, within 10 minutes.
- The internal temperature must stay below the rating for the full duration.
This means if a safe passes UL or ETL testing, it should perform well in a real-world fire.
UL fire-test curves hit 1,700–1,850°F quickly, well above a typical house fire peak of ~1,200°F.
This curve shows how fire test conditions compare to actual house fires. UL tests ramp up faster and stay hotter longer. That makes them a worst-case scenario model.
Additional Fire Testing Methods
What Is a Drop Test?
In addition to withstanding high heat, many fire-rated safes are also subjected to a drop test, an important part of UL and ETL certification.
Here's what it involves:
Heated Then Dropped:
After being baked in a furnace (usually at 1,550°F to 1,850°F for 30–60 minutes), the safe is immediately dropped from a height of 30 feet, simulating a two- to three-story fall, similar to what one might experience during a house fire if a floor collapses.
Why It Matters:
This test checks whether the safe's structural integrity holds up after extreme heat and physical impact. A safe that passes the drop test will:
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Stay closed
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Not burst open
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Maintain fire protection afterward
Not all safes include this test.
Look for models labeled with “UL Fire & Impact Rated” or “ETL Verified Drop Test” if this is important to you, especially in multi-level homes or areas prone to earthquakes.
Explosion Test: Handling Sudden Pressure Spikes
Some fire safes include an explosion test in which the safe is placed in a cold furnace that is rapidly heated to fire-test temperatures (typically 1,550°F in less than 10 minutes).
- Purpose: This checks if trapped moisture inside the safe turns to steam and causes an explosion.
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Outcome: If the safe remains intact and doesn’t burst open, it passes the test.
This matters because safes with extensive fire insulation (especially those made of concrete composite) can trap moisture that needs to be vented safely.
Recommended Fire Ratings by Use Case
Use this guide to match fire ratings to what you're protecting:
🏠 Home Documents
What You're Protecting: Birth certificates, passports, tax records
Recommended Fire Rating: 1 Hour at 350°F (UL or ETL)
Why It Matters: Most house fires last less than an hour. This protects against common fire durations.
💼 Home Office or Small Business
What You're Protecting: Client files, contracts, backup drives
Recommended Fire Rating: 1–2 Hours at 350°F
Why It Matters: For higher fire risk or longer emergency response times.
💾 Media & Electronics
What You're Protecting: USB drives, hard drives, photos, SD cards
Recommended Fire Rating: 1 Hour at 125°F (or less than 80% humidity)
Why It Matters: Electronics and digital media are far more sensitive. A 350°F safe won’t protect them.
💰 Cash or Jewelry
What You're Protecting: Currency, watches, heirlooms
Recommended Fire Rating: 1–2 Hours at 350°F + Burglary Rating (B‑Rate or higher)
Why It Matters: Cash burns easily. Fire resistance + theft protection is key.
🔧 Garage or Shop Tools
What You're Protecting: Service records, power tools, equipment docs
Recommended Fire Rating: 30–60 Minutes at 350°F
Why It Matters: Some protection is better than none; especially useful in detached garages.
🔫 Gun Storage
What You're Protecting: Firearms, ammo, accessories
Recommended Fire Rating: 60–90 Minutes at 350°F (plus anti-theft protection)
Why It Matters: Guns aren’t likely to melt, but heat can warp components and destroy optics.
🌲 High-Risk Zones
What You're Protecting: Remote cabins, areas with delayed fire response
Recommended Fire Rating: 2+ Hours at 350°F or higher
Why It Matters: Rural areas need longer protection times due to slower response times.
Quick Tip: 350°F protects paper and documents. 125°F protects media and electronics. Look for safes that list both time and temperature ratings from third-party labs like UL or ETL.
Fire Rating Comparison Table
| Certification | Common Duration | Peak Temp | Max Interior Temp | 3rd Party? |
|---|---|---|---|---|
| UL 350 | 1 or 2 hours | ~1,700°F–1,850°F | 350°F | Yes |
| UL 125 | 1 or 2 hours | ~1,700°F–1,850°F | 125°F | Yes |
| ETL | 30 min to 2 hours | ~1,200°F | 350°F or 125°F | Yes |
| JIS | 1 or 2 hours | ~1,700°F | 350°F | Yes |
| KIS/KSG | 1 or 2 hours | ~1,700°F | 350°F | Yes |
| GOST | 30 min to 2 hours | ~1,700°F | 350°F | Yes |
| Factory Test | Varies | Varies | Varies | No |
Fire Ratings FAQ
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Q: Can any safe be fireproof?
- A: No safe is truly "fireproof." They're fire-resistant for a specified time and temperature.
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Q: What’s better: UL or ETL?
- A: Both are respected. UL is older and more widely recognized in the U.S. ETL often tests to the same or similar standards.
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Q: Do higher temperatures mean better protection?
- A: Not necessarily. What matters is how long the inside stays below the critical threshold (350°F or 125°F).
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Q: Is a 2-hour safe twice as good as a 1-hour?
- A: It offers longer protection, but may also be more expensive and heavier. It depends on your risk level and the type of items you're storing.
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Q: Is smoke or water resistance included?
- A: Not by default. Always check if the safe has specific certifications for water or smoke protection.
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Q: Can I store USB drives in a 350 degree F safe?
- No. Electronics are much more sensitive and can fail around 125 degrees F. Look for a UL Class 125 safe specifically for media.
Need Help Choosing?
If you’re not sure what fire rating you need, give us a call at 800-207-2259 or start a live chat. Our team can guide you to the right fire safe for your valuables.