Airflow Management Through the Years - Part 1: The Birth of Aisle Separation
Upsite Technologies blog · Ian Seaton
Ian Seaton's account of how computer-room airflow practice evolved from rows all facing the same way to intentional hot-aisle/cold-aisle layouts.
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Overview
In this 2021 post on the Upsite Technologies blog, Ian Seaton recounts how computer-room airflow practice evolved from rooms with all racks facing the same way to intentional hot-aisle/cold-aisle layouts. He credits Robert 'Dr. Bob' Sullivan with the first deliberate implementation. The post gives context for why current airflow rules exist.
Seaton traces the follow-on best practices: keeping underfloor paths clear, placing cooling units so return air does not cross cold aisles, perforated tiles only in cold aisles, brush grommets and blanking panels. These rules are the historical origin of principles now taken as standard in design guides.
The post notes that blanking panels were used for about a decade for cosmetics before being recognised as an airflow tool. It also critiques rack-top, rear-door and supply fan kits that undermined separation. Rack-top fan kits only worked because per-cabinet loads were typically 2 kW or less; they spread hot air and short-cycled bypass.
As a limitation, this is a vendor blog post based on a personal historical account; it offers neither measurement data nor standard criteria.
Key points
- Robert 'Dr. Bob' Sullivan implemented the first intentional hot-aisle/cold-aisle layout, replacing rooms with all racks facing front.
- Underfloor paths should be kept clear.
- Cooling units should be placed so return air does not cross cold aisles.
- Perforated tiles belong only in cold aisles.
- Brush grommets and blanking panels should be applied.
- Blanking panels were used for about a decade for cosmetics before being recognised as an airflow tool.
- Rack-top fan kits only worked because per-cabinet loads were typically 2 kW or less; they spread hot air and short-cycled bypass.
Using it in design
- In layout rules, allow perforated tiles only in cold aisles.
- Orient cooling units so that returns do not draw across cold aisles.
- Warn about cabinet top-exhaust fan accessories in hot/cold aisle designs.
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Who should read it
Engineers and operators who want to understand the historical rationale for airflow management and layout rules.
Publication details
- Authors
- Ian Seaton
- Publisher
- Upsite Technologies blog
- Year
- 2021
- Document language
- English
- Source type
- Manufacturer
- Access
- Free to read
- Licence
- Copyright retained; citation only — the publisher’s terms apply to the original document
Citation
Ian Seaton (2021). Airflow Management Through the Years - Part 1: The Birth of Aisle Separation. Upsite Technologies blog. https://www.upsite.com/blog/evolution-data-center-airflow-management-birth-aisle-separation/
Events on this subject
- SC26 – International Conference for High Performance Computing, Networking, Storage and Analysis
- ASHRAE Winter Conference
- AHR Expo
All content and rights belong to the respective authors and publishers. SoSo CAD provides only the citation, its own summary and a link to the source, and is not responsible for the sources' content.
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