Introduction of UL flame retardant grades CMP, CMR, CM, CMG, CMX

Booster stage - CMP stage (air supply combustion test / stair sodium air duct test)

The cable with the highest requirements in the UL fire protection standard (Plenum Cable), the applicable safety standard is UL910, the experiment stipulates that multiple samples are laid on the horizontal air duct of the device, and the 87.9KW gas Bunsen burner (300,000BTU/Hr) is burned for 20 minutes. Eligibility criteria is that the flame does not extend beyond 5 feet (1.525m) from the front of the gas Bunsen burner flame. The peak value of the optical density is 0.5 maximum, and the average density value is 0.15 maximum.

CMP cables are typically installed in ventilation ducts or in air return booster systems used in air handling equipment.

Mainline grade - CMR grade (Riser Flame Test)

The commercial grade cable (Riser Cable) in the UL standard, the applicable safety standard is UL1666. The experiment stipulates that several 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 must not spread to the upper part of the room at a height of 12 feet (3.66m).

CMR trunk-level cables have no smoke concentration specifications and are generally used for vertical and horizontal wiring on floors.

Commercial grade-CM grade (Vertical Tray Flame Test)

The commercial grade cable (General Purpose Cable) in the UL standard, the applicable safety standard is UL1581. The experiment stipulated that multiple samples were laid on a vertical 8-foot-high rack and burned with a prescribed 20KW ribbon torch (70,000BTU/Hr) for 20 minutes. The eligibility criterion is that the flame shall not spread to the upper end of the cable and extinguish itself. UL1581 is similar to IEC60332-3C, but the number of cables is different.

CM commercial grade cables do not have smoke density specifications and are generally only used for horizontal wiring on the same floor.

General class-CMG class (Vertical Tray Flame Test)

General Purpose Cable in the UL standard, the applicable safety standard is UL1581. General-purpose and commercial-grade test conditions are similar. General-purpose cables do not have smoke concentration specifications, and are generally only used for horizontal wiring on the same floor, not for vertical wiring on the floor.

Household grade - CMX grade (Vertical Wire Flame Test)

This is a Restricted Cable in the UL standard, and the applicable safety standard is UL1581, VW-1. The experiment stipulates that the sample is kept vertical, burnt with the test torch (30,000 TU/Hr) for 15 seconds, then stopped for 15 seconds, and repeated 5 times. The qualified standard is that the residual flame should not exceed 60 seconds, the paper label on the upper part of the sample should not be burned by more than 25%, and the surgical cotton pad at the bottom should not be ignited by falling objects. UL1581-VW-1 is similar to IEC60332-1, but the burning time is different. This grade also has no smoke or toxicity specifications and is only used in single-cable home or small office systems. Such cables should not be used in bundles and must be sleeved.

Overview, ranked from low to high fire resistance:

CMX Auxiliary Line Restricted Use Minimum Fire Resistance

CM/CMG can be bundled together using horizontal wiring on the same floor

CMR vertical routing across floors

CMP for use in forced ventilation environments Highest fire resistance