Is the Chilled Water Pipe Sizing Tool free to use?

Yes. The Chilled Water Pipe Sizing Tool is a free browser-based planning calculator from I Love MEP.

Can the Chilled Water Pipe Sizing Tool be used for final engineering design?

No. The result is for planning, tender review, and coordination support. Final design must be checked by a qualified engineer against project specifications, authority requirements, and applicable standards.

Does the PDF report replace approved design calculations?

No. The PDF report records inputs, assumptions, warnings, and planning results. It should be reviewed before any construction, procurement, or authority submission decision.

Chilled Water Pipe Sizing Tool

Chilled water pipe sizing calculator for HVAC planning. Estimate flow rate, pipe velocity, pressure-loss warning, and flow margin from TR and chilled-water delta T.

Last updated: July 27, 2026

Inputs

Forms are empty on load. Use sample data to preview the workflow or enter your own project values.

Learn more

Formula logic, use cases, assumptions, and limits for this tool.

How this tool helps

Use this for early chilled water pipe checks. It is not a replacement for detailed hydraulic balancing, valve authority checks, or manufacturer pressure-loss data.

Assumptions and limits

This tool provides a planning-level result. It does not replace detailed engineering design, approved software, manufacturer data, authority requirements, or project specifications.

Typical use cases

Early estimation and tender support.
BOQ sanity checking and technical review.
Site discussion before final engineering verification.
Comparison of alternatives using consistent assumptions.

Result interpretation

Read the recommendation, warning, and confidence sections together. A result without warnings is still not an approval; it only means the entered values did not trigger built-in planning alerts.

Input definitions and typical values

These notes explain what each input means and which values usually produce a more reliable planning result.

Cooling load TR

Cooling capacity in refrigeration tons. 1 TR equals about 3.517 kW; use calculated load where possible, not only area rule of thumb.

Chilled water DeltaT deg C

Temperature difference across the system. Chilled-water delta T is often around 5-6 C in many conventional systems.

Selected internal pipe diameter mm

Pipe internal diameter. Use actual internal bore from pipe material and schedule for better velocity and pressure checks.

Equivalent pipe length m

Measured length of the route, room, pipe, duct, or cable run. Use the actual equivalent length including bends, fittings, or route offsets where applicable.

Target maximum velocity m/s

Target velocity limit. Comfort ducts often target about 5-7 m/s in mains; water services often stay near 1-2.5 m/s depending system.

Flow margin %

Design safety margin. 5-15% is common for planning; excessive margin can oversize equipment, cables, pumps, or tanks.

Practical verification checklist

Confirm the selected standard profile is suitable for the project location and authority.
Replace sample values with project drawings, schedules, equipment data, or measured site values.
Review warnings, methodology, and PDF report before using the result outside early planning.
Verify final decisions against official standards, manufacturer data, consultant specifications, and local approvals.

Standards references for verification

For final design checks, verify calculator assumptions against the project documents and official standards bodies such as ASHRAE, NFPA, IEC, IET BS 7671, ICC, and CIBSE.

Calculation methodology

Flow is derived from cooling kW and chilled-water delta T. Velocity and friction head are estimated from selected pipe diameter and equivalent length.

Inputs are treated as planning assumptions. The calculator shows warnings when entered values fall outside practical thresholds or selected standard-profile limits.

View full methodology notes

Version history

v1.3.6-prelaunch: Added methodology, standard profile support, version notes, and direct PDF report download.
v1.3.5: Calculator page added with sample data, warnings, and print-ready report layout.

Stage 2 roadmap: optional saved projects, dashboards, and shared calculation history without forcing login for free use.

Trust and verification

Every result includes assumptions, warning logic, and a downloadable report. Final engineering decisions still need qualified review, local authority approval, manufacturer data, and project specifications.

Worked example

Use the sample data button to load a realistic scenario, then download the PDF report to review inputs, results, methodology, warnings, and disclaimers in one place.