The library
Air dryer sizing: the inputs to collect
Start with compressor delivered flow, pressure at the dryer inlet, inlet and room temperatures, and the pressure dew point your tools or process require.
On this page
Collect one operating record
Keep these items together in the sizing worksheet:
- Compressor model and source document revision.
- Delivered flow, original units, reference conditions and the pressure at which it is stated.
- Pressure and hottest expected temperature at the dryer inlet.
- Room temperature around the dryer.
- Required pressure dew point and application specification.
- Supply voltage, phase and frequency.
- Pipe connections and the adapter package.
Use the conditions the dryer will face during operation. Leave unconfirmed items unanswered; a nominal flow headline cannot fill them in.
Read the dryer rating conditions
Parker's SPE selection table states its nominal conditions as 100 psig, 100°F inlet and 100°F ambient. Its SPE procedure multiplies system flow by the applicable temperature and pressure factors to find the required nominal capacity. The neighbouring DRD table uses different factors. Keep the model family with the table.
Do not transfer those factors to another manufacturer's dryer. In our model references, California Air Tools has published operating limits, but the captured product pages do not supply a model correction table.
Read a conditional table calculation
At 50 SCFM, 100 psig, 110°F inlet and 100°F room temperature, the dated SPE table gives multipliers of 1, 1.33 and 1. The required nominal rating is 50 × 1 × 1.33 × 1 = 66.5 SCFM. This arithmetic explains the table convention. It leaves flow-reference compatibility, current SKU and dew-point applicability to be confirmed. It does not establish a 75 SCFM model as a fit.
Prepare the supplier questions
Ask the supplier to confirm the exact SKU, capacity at your conditions, the resulting pressure dew point, power and connection package. Ask which document and revision support the answer. Include any input you have not measured.
You can also print the supplier question sheet and keep it with a quotation.
Use the sizing worksheet to keep those values together. Read the flow reference guide before treating two CFM figures as directly comparable.
Sources and limitations
Catalog 0700P: Refrigeration Dryers Checked 2026-11-07
Parker Hannifin · Source document
Published: Date unavailable · M4, Product Selection and Correction Factors
Minimum Drying Capacity = System flow x CFIT x CFATx CFMIP
Dated web extraction; fresh raw PDF request returned 403 on November 12, 2026. Numeric PDP, standard reference state and package admission unresolved.
RD-91502 product specifications Checked 2026-11-12
California Air Tools · Source document
Published: Date unavailable · FEATURES; model/SKU fields above the description
Max Inlet Temperature: 176F
No correction table in captured product page. Headline52CFM differs from feature52.97CFM; retain both. Numeric PDP range does not promise its lower endpoint at all conditions.
RD-91503 product specifications Checked 2026-11-12
California Air Tools · Source document
Published: Date unavailable · FEATURES; model/SKU fields above the description
Max Inlet Temperature: 176F
No correction table in captured product page. Headline52CFM differs from feature52.97CFM; retain both. Numeric PDP range does not promise its lower endpoint at all conditions.
Compressed Air and Gas Drying Checked 2026-11-12
Compressed Air & Gas Institute · Source document
Published: Date unavailable · Printed pages 3–4, 7–9; selecting, specifying and drying system sections
Naming a pressure dew point is how to state the degree of dryness wanted.
General technology guidance; does not establish any listed model’s performance.