Demystifying IT room protection requirements

Overview

This 2017 article in Consulting-Specifying Engineer is a practical companion to NFPA 75, which sits behind registration. Its order follows how a room is built: construction type and location (fully sprinklered building or Type I/II construction, away from hazardous processes), noncombustible raised floors, rated separation and firestopping, sprinkler design and hazard classification, gaseous agent use, interaction with aisle containment, and power disconnect with warning signs.

The checkable rules are these: raised-floor structure must be noncombustible, with decking either noncombustible or fire-retardant wood with a flame spread index of 25 or less. Penetrations through rated barriers must be firestopped to the barrier's rating. An IT room in a sprinklered building must be sprinklered, and designers commonly classify IT rooms as Ordinary Hazard. As good practice it suggests placing sprinkler branch lines over aisles rather than over equipment.

The interaction that causes most trouble is containment: containment collars or roofs must not obstruct sprinklers (modified per NFPA 13) or the distribution of gaseous agent. Gaseous systems must be actuated automatically by NFPA 72-compliant detection. Where power stays on after suppression or disconnect, warning signs are required at each perimeter entrance. The article is a trade-press view, not the standard text.

Key points

1. Raised-floor structure must be noncombustible; decking noncombustible or fire-retardant wood with flame spread index <= 25.
2. Penetrations through rated barriers are firestopped to the barrier's rating.
3. An IT room in a sprinklered building must be sprinklered; designers commonly classify it Ordinary Hazard.
4. Containment collars/roofs must not obstruct sprinklers (modified per NFPA 13) or gaseous agent distribution.
5. Gaseous systems must be automatically actuated by NFPA 72-compliant detection.
6. Where power stays on after suppression, warning signs are required at each perimeter entrance.
7. Good practice: sprinkler branch lines over aisles rather than equipment.

Using it in design

• If containment roofs or chimneys are placed, require sprinkler heads below or inside the containment, or fusible-link drop-away panels.
• If clean agent is chosen, add a rule requiring agent distribution into contained aisles.
• Default sprinkler hazard class for white space to Ordinary Hazard Group 1 (editable).
• As a layout hint, route sprinkler branch lines over aisles.

Who should read it

Designers applying NFPA 75 to a hall with aisle containment.

Related standards

• NFPA 75
• NFPA 13
• NFPA 72
• NFPA 80
• NFPA 2001

Publication details

Authors

Merton Bunker

Publisher

Consulting-Specifying Engineer

Year

2017

Document language

English

Source type

Expert / community

Access

Free to read

Licence

Copyright retained; citation only — the publisher’s terms apply to the original document

Citation