north star said:
= = =JPohling,
In reading Article 645.4 [ in the `08 NEC ], ...IMO, the requirement
for having rated wall & ceiling assemblies, ...fire/smoke dampers and
a dedicated HVAC system do not have a size [ min. ] threshold, rather,
that all designated ITE rooms must have these fire rated components
and the separation of the HVAC system to be compliant.
Maybe I'm totally wrong, but that is just my take!
= = =
645 is an alternate means to wire this space as apposed to the requirements of article 1 through 4 if all of the requirements are met.
645.4 Special Requirements for Information Technology Equipment Room.
Changed From 2008
645.4: Revised requirement covering applicability of Article 645.
This article shall be permitted to provide alternate wiring methods to the provisions of Chapters 1 through 4 for power wiring, 725.154 for signaling wiring, and 770.113© and Table 770.154(a) for optical fiber cabling when all of the following conditions are met:
(1) Disconnecting means complying with 645.10 are provided. See related UL
(2) A separate heating/ventilating/air-conditioning (HVAC) system is provided that is dedicated for information technology equipment use and is separated from other areas of occupancy. Any HVAC system that serves other occupancies shall be permitted to also serve the information technology equipment room if fire/smoke dampers are provided at the point of penetration of the room boundary. Such dampers shall operate on activation of smoke detectors and by operation of the disconnecting means required by 645.10. See related ROP UL
Informational Note: For further information, see NFPA 75-2009, Standard for the Protection of Information Technology Equipment, Chapter 10, 10.1, 10.1.1, 10.1.2, and 10.1.3.
(3) All information technology and communications equipment installed in the room is listed. See related UL
(4) The room is occupied by, and accessible to, only those personnel needed for the maintenance and functional operation of the installed information technology equipment.
(5) The room is separated from other occupancies by fire-resistant-rated walls, floors, and ceilings with protected openings. See related UL
Informational Note: For further information on room construction requirements, see NFPA 75-2009, Standard for the Protection of Information Technology Equipment, Chapter 5.
(6) Only electrical equipment and wiring associated with the operation of the information technology room is installed in the room.
Changed From 2008
645.4(6): Added new requirement providing an additional condition that has to exist in order for Article 645 to apply to an installation of information technology equipment.
Informational Note: HVAC systems, communications systems, and monitoring systems such as telephone, fire alarm systems, security systems, water detection systems, and other related protective equipment are examples of equipment associated with the operation of the information technology room.
Use of the requirements in Article 645 is based on the assumption that construction of the information technology equipment (ITE) room complies with NFPA 75, Standard for the Protection of Information Technology Equipment. For those ITE rooms constructed in accordance with NFPA 75, Article 645 contains electrical installation requirements that are less stringent than the requirements in the first four chapters of the Code. Application of these provisions is contingent on the ITE room construction and equipment meeting all six provisions specified in 645.4. For example, the provisions for wiring installations in the space beneath the raised floor of an ITE room where that space is also used for environmental air are less stringent than those in Chapters 1 through 4 for that same type of space. The less restrictive provisions in Article 645 cannot be taken advantage of if any one of the conditions specified in 645.4 is absent. Mandatory application of Article 645 is typically determined by the designer or facility manager who wants to use the provisions of this article for the electrical installation in the information technology equipment room instead of the relevant requirements in Chapters 1 through 4.