Fireproof File Cabinets: What the Rating on a File Drawer Covers

A fire-rated file cabinet is a document safe with drawers

The search phrase is "fireproof file cabinet". What you'll find under it are fire-resistant cabinets: steel boxes with an insulating layer between the walls, sized for hanging file folders, and sold with a fire rating for a set time. Nothing in the category is immune to fire. Each one is rated, or claimed, to keep its interior below a temperature for a time.

This page covers any document box or fire-rated safe that holds hanging file folders. That includes:

• Vertical file cabinets with two to four drawers, built like office cabinets
• Lateral file cabinets, wider than they are deep
• File safes and file chests — single-compartment units with hanging-folder rails inside

If you don't need hanging folders, a document safe or a fire-rated document box may hold the same papers in less space. Our fire-rated safes page covers the wider category.

Who needs a fire-rated file cabinet, and who should skip one

It fits a home office or small business with active paper files you open every week: client records, tax years, contracts, property documents. The appeal is the drawer. You can work out of it like any filing cabinet, and the papers are inside a rated box every night.

The NFPA estimates US fire departments responded to about 329,500 home structure fires in 2024. A file cabinet with no fire rating gives you no stated protection for what's inside.

Skip it, or add something else, if:

• Your files are mostly digital. A Class 350 rating is intended for paper. Drives need a lower class, or a box built for media.
• You only have a few documents. A small fire-rated box or small safe holds passports and deeds without the weight of a cabinet.
• Theft is the main concern. A fire rating is not a burglary rating. If a cabinet has no burglary rating listed, assume it wasn't built to resist an attack.

What to look for: the class, the time, and the lab

File cabinet listings like the word "protection". It appears near the top, in large type, next to a photo of a burning building. Further down, in smaller type, is the part that matters: how long, how hot, and who said so.

The class. UL describes a fire rating as two parts: a class, which is the maximum interior temperature reached during testing, and a time rating. UL 72 Class 350 is intended to protect paper records. Class 150 covers paper and non-paper records. Class 125 is the strictest and is intended to also protect flexible computer disks. For a file cabinet holding paper, Class 350 is the baseline to look for.

The time. UL 72 time ratings come in fixed durations — for example ½, 1 or 2 hours. Longer is better for the same class, and the class plus the time is the complete rating. A time with no class, or a temperature with no lab, is half a rating.

The impact test. Products that claim an impact rating under UL 72 are dropped 30 feet while hot and then returned to the furnace. If the cabinet will sit on an upper floor, that test is worth having. Not every UL rating includes it.

Who tested it. "UL Classified" names UL. "ETL Verified" names Intertek, an OSHA-recognized Nationally Recognized Testing Laboratory. The tests aren't always identical: one Intertek verification for a line of chests and files uses a modified UL 72 fire endurance test, without the explosion and impact tests. A rating with no lab named is a manufacturer claim, and the table marks it that way. Our UL safe ratings guide explains each label.

Letter or legal. Check whether the rails take letter size, legal size, or both. Drawer width decides it.

Drawer count and depth. More drawers mean more paper and more weight. Check the interior depth of each drawer against how many folders you keep active.

Weight and floor. Fire insulation adds weight. A multi-drawer fire-rated cabinet can be very heavy, so check the listed weight against your floor and stairs, and plan delivery.

The lock. File cabinets may use a key lock or a keypad. A lock on a fire cabinet controls access. It isn't a burglary rating.

How these cabinets work, briefly

A fire-rated file cabinet puts an insulating layer between an outer steel shell and the space your files sit in. The goal is to keep the interior below a set temperature while the outside burns. That's why a UL rating is stated as an interior class — 350°F for paper — and not as the temperature of the fire.

The time rating is the other half. It's how long the product held that interior limit in the test. Nothing in the rating promises what happens after the time runs out, and a real fire doesn't follow a lab schedule. Treat the rating as a measured comparison between products, not a guarantee for your house.

What to file in it, and where to put it

A fire-rated cabinet earns its weight with papers you use and can't easily replace. A sensible split:

• In the cabinet: active client or household files, tax years you still need, property records, insurance policies, original contracts
• In a smaller rated box or safe: passports, birth certificates, titles — things you rarely touch
• Somewhere rated for media: drives and backups, or an off-site copy

Placement matters for a cabinet more than for a small box, because you can't move it easily later. A ground floor or a slab avoids the question of an upper floor giving way, which is where an impact rating earns its keep. A dry room keeps paper and drawer slides in better shape; a closed steel box holds whatever humidity is in the room. Check the floor can take the listed weight with every drawer full.

If you also want theft protection for the most valuable papers, keep those in a safe with a burglary rating and keep working files in the cabinet. Check both labels before assuming one product does both jobs; fire and burglary are tested under separate standards.

How to read the file cabinet table

The table lists every document box and fire-rated safe we track that holds hanging file folders. Products confirmed not to fit hanging folders are left out; products whose fit we couldn't confirm stay in with "—".

• Fire column first: time, class or temperature, and who tested it. "Rated" names a lab; "claimed" doesn't.
• Document fit: letter, legal or both.
• Capacity: interior volume in cubic feet. Compare it with the files you have now, plus a few years.
• Weight: check your floor and stairs.
• Water column: a separate rating, if any. See our waterproof safes page for products with a stated water rating.

When two cabinets have the same class and time, prefer the one with a named lab and an impact test. When ratings are equal, buy the one that holds your folders without forcing them.

Count your active files, measure them, and pick a cabinet rated for paper with a named lab. Then keep the drives somewhere rated for drives.