Learning from the OVHcloud data center fire

Overview

This note, published in the Uptime Institute Journal, is an early analysis of the March 2021 fire that destroyed the OVHcloud SBG2 data center in Strasbourg. Because it was written soon after the event, it is not a final root-cause report; it offers first assessments based on the information then available and the design lessons that can be drawn. Copyright belongs to Uptime, so only the summarised facts are restated here in our own words.

On the campus described, SBG2 was a 2 MW facility able to house 30,000 servers, while the newer 4 MW SBG3 was partially damaged. The article reports that firefighters used thermal cameras to identify two UPS units at the heart of the blaze, one of which had been extensively worked on that morning. This suggests the importance of maintenance and post-intervention recommissioning procedures for fire risk, though the article does not claim a definite cause.

The article dwells on batteries in the context of electrical fires. It notes that valve-regulated lead-acid (VRLA) battery cabinets are often installed right next to UPS units, which is not regarded as best practice. The conclusion that can be drawn is that layout decisions directly affect fire load and spread paths, so separating UPS and battery rooms is something to settle at the start of design. Free-air cooled building design is another topic the article raises in connection with fire spread.

Finally, Uptime observes that the Tier system has limited fire system requirements, focused on the impact on critical mechanical and electrical infrastructure. In other words, a Tier-certified facility is not necessarily adequately protected against fire. The article's limit is that it rests on early and partial information; even so, it is a practical case study reminding designers that fire compartmentation, battery placement and the fire protection system must be handled independently of Tier.

Key points

1. SBG2 was a 2 MW facility able to house 30,000 servers; the newer 4 MW SBG3 was partially damaged.
2. Thermal cameras identified two UPSs at the heart of the blaze; one had been extensively worked on that morning.
3. VRLA battery cabinets are often installed next to UPS units, although this is not best practice.
4. Tier requirements for fire systems are limited and focus on the impact on critical mechanical and electrical infrastructure.
5. The article is an early analysis written soon after the event and makes no definitive root-cause claim.
6. Free-air cooled building design was discussed in relation to fire spread.
7. NFPA 75 and NFPA 76 are the related standards.

Using it in design

• Separate UPS and battery rooms with fire-rated barriers.
• Raise a warning in layout checks when batteries share space with UPS modules.
• Consider building compartmentation at the design stage.
• Do not treat Tier certification as a substitute for fire protection; address the fire system separately under NFPA 75 and NFPA 76.

Who should read it

Engineers responsible for data center fire safety, electrical and layout design, and risk managers.

Related standards

• NFPA 75
• NFPA 76

Publication details

Authors

A. Lawrence

Publisher

Uptime Institute Journal (Uptime Institute)

Year

2021

Document language

English

Source type

Industry body

Access

Free to read

Licence

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

Citation