Review a high-altitude proposal in four parts: local moisture conditions, airflow basis, delivered performance and complete-equipment suitability. Keeping these separate prevents a sea-level airflow rating from becoming an unsupported claim about the whole installation.
Use the correct moisture basis
ASHRAE's psychrometric definitions distinguish relative humidity from humidity ratio: water-vapor mass per dry-air mass. Pressure is part of the moist-air calculation. Use local coincident temperature, humidity and pressure, and compare dew point with relevant cold surfaces. Elevation alone does not establish condensation risk.
For moisture-load calculations, dry-air mass flow and humidity-ratio difference belong together. State whether a quoted m³/h represents actual conditions or a defined reference. Changing only one part of the calculation cannot establish the resulting moisture load.
Read the fan curve with its conditions
AMCA's fan-curve explanation identifies air density and rotational speed among the information needed to interpret a curve. Obtain the applicable curve and system operating point; do not assume that a nameplate volume flow is the installed air service at the site.
An airflow assessment also has a limited purpose. It does not supply the missing water-removal performance of the dehumidifier, or establish the permitted altitude of the complete electrical assembly.
Compare a proposal against four separate questions
| Question | Evidence needed |
| What conditions can cause condensation here? | Coincident local air data and relevant surface temperatures |
| What airflow will the installation deliver? | Defined flow units, density basis, curve and operating point |
| What duty can the equipment meet? | Cooling and water-removal evidence at the intended conditions |
| Is the complete configuration suitable? | Documentation for the supplied equipment and installation environment |
For example, a proposal containing only sea-level airflow and the phrase “high-altitude suitable” leaves the duty and configuration questions unanswered. The missing information is a request for evidence, not proof that the equipment is unsuitable.
Use the sizing-input checklist to assemble the review. These checks organize equipment selection; they do not grant engineering approval. Discuss your application.
Related project questions
Carry the same site conditions into the assessment of cabinet-cooling air and heat paths and delivery of dehumidification to each protected zone. For the wider project context, return to energy-storage humidity control.
