Fire safe or burglary safe?
From across a room they look alike, and they are built for opposite jobs. A fire safe keeps heat out with a thick, damp wall; a burglary safe keeps tools out with steel. Few do both well, and the label is the only reliable way to tell which one you have.
Read the label first
A burglary rating and a fire rating come from separate tests and appear on separate labels, usually on the inside of the door. Unless the maker says otherwise, a UL fire class is not a burglary rating at all.
| Label | Standard | What it resists |
|---|---|---|
| Grade 0 … XIII | EN 1143-1 | Burglary: tool attack, scored in resistance units |
| TL-15 · TL-30 · TL-30x6 | UL 687 | Burglary: net working time against listed tools |
| RSC | UL 1037 | Burglary: entry level, one person, hand tools |
| S 60 P · S 120 P | EN 1047-1 | Fire: paper, with a natural cooling phase |
| S 60 D · S 60 DIS and the 120 versions | EN 1047-1 | Fire: data media, and highly sensitive data media |
| LFS 30 P · LFS 60 P | EN 15659 | Fire: paper, light storage units, cooled artificially |
| Paper · Data · Diskette | NT Fire 017 | Fire: paper and data, cooled artificially |
| Class 350 · Class 150 · Class 125 | UL 72 | Fire: paper, magnetic media, sensitive digital media |
In the European fire labels the number is minutes in the furnace and the letters say what survives: P for paper, D for data media, DIS for highly sensitive data media. A UL class number is different — it is the temperature, in °F, that the inside must stay below. EN 1047-1 and UL 72 keep measuring through a natural cooling phase after the fire; EN 15659 and NT Fire 017 stop the test and cool the safe artificially — which is why they are the lighter labels. Burglary ratings in detail ›
No label: look at the wall
With the door open, look at its edge. A fire safe is two thin skins of sheet metal with a water-retaining filling between them — typically a mix of concrete and vermiculite. The skins are thin on purpose, to slow the heat, and the soft filling offers no real resistance to a direct attack: a professional can open most fire safes in minutes.
If the edge shows solid steel instead, the safe was built with burglary in mind. How well, only a certificate can say.
Old safes and old words
Nineteenth-century makers printed “fire-proof” and “burglar-proof” freely, and no laboratory stood behind either word — Cary, for one, described every safe it built as both. The archive keeps the period arguments, including a 1923 booklet on how safes were actually tested.
The filling of an old fire safe is also where asbestos turns up. Read this before anyone cuts ›
Where this comes from
- Silva Consultants — Introduction to burglar and fire safes
- Atelier Boonen — Fire resistance classes and test methods
- Brown Safe — fire safe buying tips
- Liberty Safe — Understanding UL and ETL ratings for your home safe
- Wikipedia — Cary Safe Company
- Health and Safety Authority, Ireland — Asbestos risks in safes and fire resistant cabinets
Every source above was read on 25 Sep 2026. If one of them changes or disappears, the line that rests on it is corrected or removed — see method.