UL flame retardant standards: If any cable listed by UL has been tested and verified to meet a certain fire rating, the UL identification, fire rating and approval number can be printed on the cable.
1. Supercharged level-CMP level (supply air combustion test/Steiner tunnel test Plenum Flame Test/Steiner TunnelTest)
This is the most demanding cable (Plenum Cable) in the UL fire protection standard. The applicable safety standard is UL910. The experiment stipulates that multiple samples are laid on the horizontal air duct of the device and burned with an 87.9KW gas Bunsen burner (300,000BTU/Hr) 20 minutes. The eligibility criterion is that the flame cannot extend beyond 5 feet from the front end of the gas Bunsen burner. The maximum value of the optical density is 0.5, and the maximum value of the average density is 0.15. This kind of CMP cable is usually installed in the air return booster system used in ventilation ducts or air handling equipment, and is approved for use in Canada and the United States. FEP/PLENUM materials conforming to UL910 standard have better flame retardancy than low-smoke halogen-free materials conforming to IEC60332-1 and IEC60332-3 standards, and have a lower smoke concentration when burned. To
CMP: Filling grade communication cable, which is the highest cable safety grade. It has perfect flame retardant ability and emits very low smoke and toxins. According to UL definition, a bundle of CMP cables must be self-extinguished within less than 5 meters of the combustion spread under the condition of forced intensive combustion by the fan. CMP cables use Teflo-based chemicals to prevent the spread of combustion and minimize smoke and toxins. Compared with cables with lower UL ratings, this adds a lot of cost. CMP-class cables are used in buildings where cables are laid in the ventilation and return air passages. In the event of a fire, the building will not be filled with large amounts of smoke or hazardous toxins emitted by the cables. CMP-class cables must undergo a rigorous combustion test: UL910-"Fire propagation and smoke density value test"
2. Trunk level-CMR level (Riser Flame Test)
This is a riser cable in the UL standard, and the applicable safety standard is UL1666. The experiment stipulates that multiple samples are laid on the simulated vertical shaft, and the specified 154.5KW gas Bunsen burner (527,500BTU/Hr) is used for 30 minutes. The eligibility criterion is that the flame cannot spread to the upper part of a 12-foot-high room. There is no smoke density specification for trunk-level cables, and they are generally used for floor vertical and horizontal wiring. To
CMR: Trunk-level communication cable. This is the second-ranked cable. It has perfect flame retardancy, but it has not tested the smoke and toxins it emits. In addition to CMP and cables, CMR cables and all other communication cables use halide-based chemicals, such as chlorine, to prevent the spread of combustion. According to the definition, a bundle of CMR cables must be self-extinguished within less than 5 meters of the combustion spread under the forced combustion condition of the fan. The CMR cable jacket is generally made of a certain type of PVC, which emits chlorine in the combustion chamber, which will deplete the oxygen in the air and extinguish the flame. CMR cables are widely used in trunk line applications where the ventilation system is physically separated from the wiring system. This is very common in Asia and Australia. CMR-class cables must pass the intensive flame test: UL1666-"Test for the flame propagation height of cables installed vertically through the middle"
3. Commercial grade-CM grade (Vertial Tray Flame Test)
This is a general purpose cable in the UL standard, and the applicable safety standard is UL1581. The experiment stipulated that multiple samples were laid on a vertical stand of 8 feet high, and burned with a prescribed 20KW belt burner (70,000BTU/Hr) for 20 minutes. The qualification standard is that the flame cannot spread to the upper end of the cable and extinguish itself. UL1581 is similar to IEC60332-3C, but the number of cables is different. Commercial-grade cables do not have smoke density specifications and are generally only used for horizontal wiring on the same floor, not for vertical wiring on the floor.
4. General purpose-CMG level (Vertial Tray Flame Test)
This is a General Purpose Cable in the UL standard, and the applicable safety standard is UL1581. The test conditions of commercial grade and general grade are similar, and they are both approved for use in Canada and the United States. There is no smoke density specification for general-purpose cables, and they are generally only used for horizontal wiring on the same floor, not for vertical wiring on the floor.
CM/CMG: General communication wiring. This is common in the horizontal routing of buildings, and they are usually divided into smaller bundles than CMR-class cables. CM/CMG-class cables use halide-based chemicals when they are aligned. According to the definition, in a small bundle of cables, the CM/CMG cable must be extinguished by itself within less than 5 meters of the spread of combustion. The flame is not forced to burn with a fan. The CM/CMG cable jacket is usually made of some kind of PVC, which emits chlorine gas in the combustion chamber. CM/CMG grade cables are usually used in horizontal wiring in the United Kingdom, Asia and Australia. CM/CMG cable must pass CSA FT-4 "Vertical Burning Test"
5. Household level-CMX level (Vertial Wire Flame Test)
This is a Restricted Cable in the UL standard, and the applicable safety standards are UL1581, VW-1. The experiment stipulates that the sample should be kept vertical and burned with the test burner (30,000 TU/Hr) for 15 seconds, then stopped for 15 seconds, and repeated 5 times. The qualification standard is that the residual flame should not exceed 60 seconds, the sample should not be burned by more than 25%, and the surgical cotton pad on the bottom should not be ignited by falling objects. UL1581-VW-1 is similar to IEC60332-1, except that the burning time is different. This level also has no smoke or toxicity regulations, and is only used in home or small office systems where a single cable is laid. This type of cable should not be used in bundles, but must be sleeved. Smoke density, halogen content and toxicity level.
CMX: Residential communication wiring. This kind of cable is limited to residential or other small applications where the number of communication cables is very small, and these applications generally only lay one cable. CMX-level tools cannot be used for bundled cable applications. CMX cable must pass UL VW1 burning test
To summarize briefly (from low to high fire resistance):
CMX Auxiliary line restricted use, lowest fire resistance
CM/CMG Used in the same floor. Horizontal wiring can be bundled and used together
CMR Vertical wiring across floors
CMP Used in a forced ventilation environment with the highest fire resistance
In addition, in particular, LSZH/LS0H means low smoke zero halogen-low smoke zero halogen