Mechanical Protection of Emergency System

[mshields]

I've got a fire smoke damper with control voltage of 120V (Life Safety Branch - in a hospital) which is controlled via a fire alarm control module in a fail safe manner. i.e. if the power fails, the damper closes. Our spec calls for all Emergency wiring to be mechanically protected in accordance with 517.30©(3) and so the contractor provided the 120V power to the unit in pipe but did not wire the control wiring from the CM module in pipe.

I think this is ok but the owner is questioning it. The reason I think it's ok is that a) the control via the CM is a continuation of the Fire Alarm system which does not need to be in conduit and b) from a practical standpoint, the system is fail safe, if the wiring is damaged for whatever reason, the damper closes. Do you think this reasoning sound? Am I missing something either in my argument for it or forming the foundation for an argument against?

I much appreciate your feedback,

Mike

 

[Gregg Harris]

I've got a fire smoke damper with control voltage of 120V (Life Safety Branch - in a hospital) which is controlled via a fire alarm control module in a fail safe manner. i.e. if the power fails, the damper closes. Our spec calls for all Emergency wiring to be mechanically protected in accordance with 517.30©(3) and so the contractor provided the 120V power to the unit in pipe but did not wire the control wiring from the CM module in pipe.I think this is ok but the owner is questioning it. The reason I think it's ok is that a) the control via the CM is a continuation of the Fire Alarm system which does not need to be in conduit and b) from a practical standpoint, the system is fail safe, if the wiring is damaged for whatever reason, the damper closes. Do you think this reasoning sound? Am I missing something either in my argument for it or forming the foundation for an argument against?

I much appreciate your feedback,

Mike

(3) Mechanical Protection of the Emergency System. The wiring of the emergency systems in hospitals shall be mechanically protected. Where installed as branch circuits in patient care areas, the installation shall comply with the requirements of 517.13(A) and (B). The following wiring methods shall be permitted:

Cables for Class 2 or Class 3 systems permitted by Part VI of this Article, with or without raceways.

VI. Communications, Signaling Systems, Data Systems, Fire Alarm Systems, and Systems Less Than 120 Volts, Nominal

517.80 Patient Care Areas. Equivalent insulation and isolation to that required for the electrical distribution systems in patient care areas shall be provided for communications, signaling systems, data system circuits, fire alarm systems, and systems less than 120 volts, nominal.

 

[AegisFPE]

Some combination fire/smoke dampers, though set to fail closed upon high temperature at the damper, may be required to be open during a fire event when part of a smoke control system. But, this would require the fire alarm wiring to be in conduit, so it appears that you are not dealing with smoke control system equipment.

A potential concern with the absence of mechanical protection for the control wiring is that if the exposed wiring is lost, the damper will close. Because the damper is to be open during normal conditions, the occupants may physically block the damper open, effectively disabling its safety function.

May sound like a stretch, but it's a pitch I've heard.