Optimistic Outlook on CMR Communication Riser Cables Usage

Where are Type CMR communication riser cables permitted to be used?

a. In-wall
b. Plenum
c. Riser
Final answer: CMR communication riser cables are permitted to be used in the in-wall and riser applications.

Answer:

CMR communication riser cables are permitted to be used in the in-wall and riser applications. CMR cables are suitable for riser and in-wall applications but not for plenums. They are designed to prevent the spread of fire between floors through vertical shafts and are tested for vertical flame spread. The correct answer is A.

CMR (Communication Riser) cables are designed to prevent the spread of fire between floors through risers or vertical shafts. These cables are specifically tested for vertical flame spread, making them suitable for use in multi-story buildings. The 'R' in CMR stands for 'riser,' which indicates the intended use for these cables.

CMR cables are permitted for use in riser applications, where they are run between floors. They are not rated for plenum spaces; plenum-rated cables are identified as CMP and are required in spaces used for air circulation for heating, ventilation, and air conditioning systems, where fire resistance is paramount. CMR cables are also suitable for use in-wall installations, provided that the wall is not a plenum space.