Overview of All Ratings (Ordered from lowest to highest level of protection)
Class 350 (1/2 hour – 4 hours):
- This is the most common class of devices and is suitable for storing most types of material. This includes paper products, jewellery, and guns.
- Fire Endurance Test – Maintains internal temperature of no more than 350°F during heating and cooling periods. Paper test material and mechanisms must maintain integrity.
- Explosion Test – Unit heated to 2000°F for 20, 30, 45, or 50 minutes (1/2 hour, 1 hour, 2 hour, 3-4 hour rating). Explosion must not occur when unit is opened and paper test material is placed inside. Test material as well as mechanisms must maintain integrity after cooling.
- Impact Test – Unit dropped 30 feet after endurance test or explosion test, then inverted and reheated. Paper test material and mechanisms must maintain integrity.
Class 150 (1/2 hour – 4 hours):
- Certification was originally introduced for the storage of computer data tapes or magnetic reel-to-reel tapes. These devices are capable of storing most types of delicate material including hard drives, compact disks, and photographs.
- Fire Endurance Test – Maintains internal temperature of no more than 150°F and 85% humidity during heating and cooling periods. Paper test material and mechanisms must maintain integrity.
- Explosion Test – Unit heated to 2000°F for 20, 30, 45, or 50 minutes (1/2 hour, 1 hour, 2 hour, 3-4 hour rating). Explosion must not occur when unit is opened and paper test material is placed inside. Test material as well as mechanisms must maintain integrity after cooling.
- Impact Test – Unit dropped 30 feet after endurance test or explosion test, then inverted and reheated. Paper test material and mechanisms must maintain integrity.
Class 125 (1/2 hour – 4 hours):
- Certification was originally introduced for the storage of floppy disks. These devices are capable of storing virtually any type of delicate material including floppy disks, compact disks, and photographs.
- Fire Endurance Test – Maintains internal temperature of no more than 125°F and 80% humidity during heating and cooling periods. Paper test material and mechanisms must maintain integrity.
- Explosion Test – Unit heated to 2000°F for 20, 30, 45, or 50 minutes (1/2 hour, 1 hour, 2 hour, 3-4 hour rating). Explosion must not occur when unit is opened and paper test material is placed inside. Test material as well as mechanisms must maintain integrity after cooling.
- Impact Test – Unit dropped 30 feet after endurance test or explosion test, then inverted and reheated. Paper test material and mechanisms must maintain integrity.
Heating Times and Temperatures
| Time | Temperature |
| 5 minutes | 1000 |
| 10 minutes | 1300 |
| 30 minutes | 1550 |
| 1 hour | 1700 |
| 2 hours | 1850 |
| 3 hours | 1925 |
| 4 hours | 2000 |
Impact Test Times
| Classification Time | Time Before Drop | Exposure Time After Drop |
| 1/2 hour | 20 minutes | 20 minutes |
| 1 hour | 30 minutes | 30 minutes |
| 2 hours | 45 minutes | 45 minutes |
| 3 or 4 hours | 60 minutes | 60 minutes |