Open Rack Wide (ORW) Base Specification, Revision V1.0.1 (effective May 5, 2026)

Overview

The ORW base specification deliberately does not set the frame's external dimensions, depth, height, base geometry or maximum payload. These can vary per end user and are defined in separately contributed ORW Design Specifications; in implementation, payload, packaging, shipping, rack movement and infrastructure constraints can influence overall footprint, height and maximum packaged weight. The version history shows the Meta design specification being removed from the base spec and all drawing views updated with tolerances (0.9.0-rc5, 10 March 2026); version 1.0.0 followed on 28 April 2026 and 1.0.1 on 5 May 2026.

The mechanical core is the critical frame interface dimensions: the dimensions and tolerances in the frame cross-section are critical interfaces for IT equipment, busbars and accessories such as rails. The frame must support both OpenU (OU) and rack-unit (RU) vertical spacing, and because it has cut-outs for each option's support brackets, different IT equipment can be mixed. The frame accepts air-cooled and liquid-cooled 48 V busbars, with mounting interfaces identical to ORV3 HPR. The busbar conductive surface must have a continuous conductive path to the frame that passes ASTM D610 rust grade 6 after 48 hours of ASTM B117 salt spray.

Fastener requirements standardise tooling: 4.5 mm holes take M5 and 5.4 mm holes M6 thread-forming screws (DIN 7500) with a minimum strip-out torque of 6.25 N-m and a nominal torque of 5 N-m; M6 tapped holes in inner verticals need 8 N-m minimum strip-out torque and the upper busbar M5 holes 6.8 N-m. Environmental conditions are 10-60 C operating, -40 to 50 C long-term storage and 5-95% RH. For grounding, M5 x 0.8 threaded features for a telco ground lug, overhead grounding points on the top and underfloor points on the rear base, and a supplemental conductive path from IT equipment to the rack's top grounding lug are required.

On regulatory matters the specification asks for IEC/UL/EN 62368-1 with CB certification, CE marking, RoHS (2015/863/EU), REACH, a declaration on substances of concern under EPA 40 CFR 751 and UL94V-0 or better plastics. Electrical requirements for IT gear are inherited from ORV3: the power shelf delivers nominal 51 VDC and IT gear must operate normally between 46 and 52 V; the connector's power and return paths need 100 A continuous and the PE bond 200 A for 6 minutes with under 2.5 V drop. The document covers base interfaces only; the IT gear design guide and the liquid-cooled busbar specification are listed as in progress.

Key points

1. The base spec prescribes no external frame dimensions (depth, height, base geometry) or maximum payload; these are set by individual ORW design specifications.
2. The ORW frame must support both OpenU (OU) and rack-unit (RU) vertical spacing, allowing mixed IT equipment.
3. The frame accepts air-cooled or liquid-cooled 48 V busbars; busbar mounting interfaces are identical to ORV3 HPR.
4. The busbar ground path must stay continuous to the frame and pass rust grade 6 (ASTM D610) after 48 h salt spray (ASTM B117).
5. Grounding points on the rack top (overhead grounding) and rear base (underfloor grounding), plus a supplemental IT-equipment-to-rack ground path.
6. Regulatory: IEC/UL/EN 62368-1 with CB certification, CE, RoHS (2015/863/EU), REACH and an EPA 40 CFR 751 substances-of-concern declaration; plastics UL94V-0 or better.
7. Fastener holes: 4.5 mm holes for M5 and 5.4 mm holes for M6 thread-forming screws; minimum strip-out torque 6.25 N-m (8 N-m for M6 tapped inner-vertical holes); nominal torque 5 N-m.
8. Environment: operating 10-60 C, long-term storage -40 to 50 C and 5-95% RH, short-term storage -20 to 65 C and 10-80% RH, operating humidity maximum 85% and dew point minimum 5 C.
9. IT gear input: 51 VDC nominal, normal operation across 46-52 V; connector power and return 100 A continuous, PE bond 200 A for 6 minutes with under 2.5 V drop.
10. Critical dimensions in the drawings require CPK >= 1.33, and the drawings were updated in 1.0.1 after the 1.0.0 release.

Using it in design

• Add an ORW rack family whose footprint, height and payload come from the chosen design specification rather than fixed defaults, prompt users for those values, and warn that floor-loading and aisle-pitch checks depend on them.
• Support liquid-cooled busbar options and show overhead or underfloor bonding points in grounding and bonding drawings.
• In IT gear selection check the 46-52 V input range and the connector current ratings (100 A continuous on power and return).
• In mixed OU/RU equipment layouts account for each option having different support bracket pitch and cut-outs.
• In rack procurement require busbar ground path salt-spray evidence and CB, UL/EN 62368-1, RoHS and REACH documentation.
• Reflect the operating temperature and humidity limits (10-60 C, maximum 85% humidity, minimum 5 C dew point) in environmental checks.

Who should read it

Rack and power engineers designing wide AI racks beyond ORV3, rack manufacturers and IT hardware designers.

Document contents

1. License
2. Compliance with OCP Tenets
3. Overview
4. Base Specification for ORW Rack Frame
5. Description
6. Mechanical Requirements
7. Critical Frame Interface Dimensions
8. Vertical OU & RU Spacing
9. Busbar
10. 48V Busbar Geometry
11. Ground Path
12. Busbar Interfaces to the Rack Frame
13. Fastener Requirements
14. Environmental Requirements
15. Color & Markings
16. Electrical Grounding
17. Telco Ground Lug
18. Environmental & Regulatory
19. Electrical Requirements for IT Gear
20. Input Voltage Specification
21. Input Power Delivery Power Sequence Requirements
22. Voltage sense signals (optional)
23. References
24. Appendix A - Full Resolution ORW Base Specification Drawing Images

Related standards

• OCP Open Rack V3 Base Specification
• OCP ORW Meta Design Specification
• IEC 62368-1
• ASTM B117

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Publication details

Authors

Banyard, R.; Daniel, D.

Publisher

Open Compute Project Foundation

Year

2026

Document number

V1.0.1

Document language

English

Source type

Industry body

Access

Open licence — downloadable

Licence

OWFa 0.9 — Open Compute open specification licence; redistribution permitted

Licence evidence

www.opencompute.org

Citation