China PVC Network Cable Material Suppliers - CM, CMR, CMP Factory Certified for Performance & Quality
Product Features
Scope of Use
How to Distinguish CM, CMR and CMP
1. Commercial Grade - CM Grade (Vertical Tray Flame Test)
This is a UL standard commercial grade cable (General Purpose Cable), applicable to the safety standard UL1581. The test requires multiple samples to be mounted on a vertical 8-foot stand and burned for 20 minutes with a prescribed 20KW strip burner (70,000 BTU/Hr). The qualification criterion is that the flame cannot spread to the upper end of the cable and must extinguish itself. UL1581 and IEC60332-3C are similar, only the number of cables laid is different. Commercial grade cables do not have smoke concentration specifications and are generally only applied to horizontal wiring on the same floor, not to vertical wiring between floors.
2. Main Line Class - CMR Class (Riser Flame Test)
This is a UL standard commercial grade cable (Riser Cable), applicable to the safety standard UL1666. The experiment requires laying several samples on a simulated vertical shaft and using a prescribed 154.5KW gas Bunsen burner (527,500 BTU/Hr) for 30 minutes. The eligibility criterion is that the flame does not spread to the upper part of the 12-foot high room. Trunk level cables do not have smoke concentration specifications and are generally used for vertical and horizontal floor wiring.
3. Booster Stage - CMP Stage (Plenum Flame Test / Steiner Tunnel Test)
This is the most demanding cable in the UL fire protection standard (Plenum Cable), and the applicable safety standard is UL910. The test stipulates that a number of samples are laid on the horizontal air duct of the device, burning with an 87.9KW gas Bunsen burner (300,000 BTU/Hr) for 20 minutes. The qualification criterion is that the flame must not extend beyond 5 feet from the front of the Bunsen burner flame. The maximum peak optical density is 0.5, and the maximum average optical density is 0.15. This CMP cable is usually installed in air return pressurization systems used in ventilation ducts or air handling equipment and is approved for use in Canada and the United States. The flame retardant performance of FEP/PLENUM material conforming to the UL910 standard is better than that of low smoke halogen-free material conforming to IEC60332-1 and IEC60332-3 standards, and the smoke concentration is low when burning.