Employers and engineers / Recruitment field guide
CRAH and fan-wall commissioning: screening air-side experience
Define air-side commissioning scope across CRAH units, fan walls, containment, controls and thermal-performance evidence.
01
Describe equipment and air management together
A computer room air handler, or CRAH, is part of a larger cooling arrangement. Fan walls, containment, room layout and water-side interfaces can all influence the scope. Establish which interfaces the candidate evaluated.
DOE's design guide treats environmental conditions, air management and cooling as linked topics. For hiring, that supports asking about system interaction rather than only the number of units on a resume.
02
Ask what proved the result
Use the project's expected behavior as the starting point. The following are evidence prompts, not field test steps.
- Equipment and control boundary, including vendor responsibilities.
- The approved performance requirement and its source.
- Airflow or thermal evidence the engineer reviewed or captured.
- Alarm, sensor and sequence checks within their remit.
- How deviations affecting the served area were assigned and closed.
03
Make responsibility for testing conditions explicit
Ask who established the test conditions and how limitations were recorded. A result obtained under one load arrangement should not be generalized beyond its documented scope.
For lead roles, check coordination with controls, mechanical and operations teams. For a tester role, check the quality of execution and records. Neither should be inferred solely from having worked in a data hall.
Quick answers
Common questions
- Are CRAH and CRAC the same term?
- No. They describe different equipment arrangements, although terminology can be used loosely. Confirm the actual equipment and heat-transfer arrangement on the project.
- Does testing individual units prove room performance?
- Not by itself. The approved plan must define how equipment results relate to the wider air-management and thermal requirements.
Further reading
Sources
- US Department of Energy — Best Practices Guide for Energy-Efficient Data Center Design
- WBDG — Commissioning Documents: Process, Contents, and Acceptance
- ASHRAE — Commissioning & Performance Validation
Sources provide industry background. Loadbank Talent’s hiring prompts and editorial checklists are not source quotations or operating procedures.