Plenum, Riser, CM and LSZH Ratings Cables by Arindam Bhadra
What are Plenum, Riser, CM and Low-Smoke Zero Halogen Ratings, and What are the differences between them? Plenum (CMP) Rated Cable: Complies with NFPA-262 and UL-910. Allowed in spaces defined as "air plenums", such as raised flooring systems and air handling ducts. Must self-extinguish and not reignite. Produces less smoke (which is toxic) than traditional PVC cables. Type FPLP power-limited fire alarm plenum cable is listed by the NEC as suitable for use in ducts, plenums and other space used for environmental air. All FPLP cables are listed as having adequate fire-resistant and low smoke-producing characteristics and must pass both UL test 1424 and UL tunnel test 910.
Riser (CMR) Rated Cable: Complies with UL-1666. Defined for usage in vertical tray applications, such as cable runs between floors, through cable risers and in elevator shafts; spaces that cannot be used for environmental air. Must self-extinguish and must also prevent the flame from traveling up the cable in a vertical burn test. Plenum rated cables can be used in Riser spaces, whereas Riser rated cables cannot be used in Plenum spaces.
Type FPLR power-limited fire alarm riser cable is listed as suitable for use in a vertical run in a shaft or from floor to floor. All FPLR cables are listed as having fire-resistant characteristics capable of preventing fire from traveling floor to floor. Riser cables must pass both UL test 1424 and the vertical riser flame test UL 1666.
Low Smoke Zero Halogen (LSZH) Rated Cable: Used in shipboard applications and computer networking rooms where toxic or acrid smoke and fumes can injure people and/or harm equipment. Examples of halogens include Fluorine, Chlorine, Bromine and Iodine. These materials, when burned, produce acrid smoke that can cause harm to people and equipment. Does not produce heavy black soot and smoke common with PVC cables. Used mainly outside of the U.S. Self extinguishes. Does not pass UL-910 or UL-1666 for a Plenum or Riser rating.
General Purpose (CM, CMG, CMx) Rated Cable: Complies with UL-1581 testing. Will burn and partially self-extinguish. Not for use between build floors and air plenum spaces. Often used for workstation cable and patch cor.
Stranded Copper Conductor XLPE Insulation LSZH Bedding LSZH Sheath
Conductor Insulation Insulation Screen Copper Tape Screen (CTS) Filler Galvanized Steel Wire Armour (SWA)
CU/XLPE/PVC/SWA/PVC 6.35/11 kV 1/C BS 7835 June 2021 - www.safesecuremagazine.com
Type FPL power-limited fire alarm cable is listed by the NEC as suitable for general purpose fire alarm use. All FPL cables are listed as being resistant to the spread of fire and must pass both UL test 1424 and vertical flame test UL 1581. LPCB approved fire resistant cable standards:BS 7629-1:2008 BS 6387:2013 (Category CWZ) EN 50200:2006 (Class PH30) EN 50200:2006 Annex E (30 mins) BS 5839-1:2013 (Clause 26.2d Standard) 37
