PSEMIC ENGINEERING RESOURCE CENTRE

Water Treatment, Flushing & Chemical Dosing Calculators for HVAC & Chilled Water Systems

Practical engineering tools for chilled-water flushing, system water volume, circulation, inhibitors, chemical cleaning, glycol mixing, dilution, dosing pumps, conductivity/TDS and water-treatment planning.

Engineering & safety note: Final chemical selection, dosage, compatibility, exposure time, discharge, handling and PPE must follow the chemical manufacturer's current TDS/SDS, approved method statement and project specification. Never mix chemicals unless compatibility has been explicitly confirmed.

01 · SYSTEM CAPACITY

Chilled Water System Volume Calculator

Estimate water volume contained in pipework and add known equipment or tank volumes.

Pipe internal diameter (mm)

Total pipe length (m)

Number of identical lines

Additional equipment/tank volume (m³)

Pipe Volume—

Total System Volume—

Total Litres—

US Gallons—

Pipe volume = π × ID² ÷ 4 × length.

02 · FLUSHING

Flushing Flow Rate & Velocity Calculator

Calculate required water flow for a target flushing velocity or check achieved velocity from available flow.

Required flow from target velocity

Pipe internal diameter (mm)

Target velocity (m/s)

Required Flow—

Litres / Second—

USGPM—

Achieved velocity from available flow

Available flow (m³/h)

Pipe internal diameter (mm)

Achieved Velocity—

Use the flushing velocity required by the approved commissioning procedure or project specification.

03 · CIRCULATION

System Turnover & Flushing Water Calculator

Estimate time per turnover and total circulation time.

Total system volume (m³)

Circulation flow (m³/h)

Required turnovers

Time / Turnover—

Total Circulation Time—

Water Equivalent—

04 · CHEMICAL DOSING

Chemical Dose by ppm Calculator

Calculate indicative commercial product quantity from system volume, target active concentration and product strength.

System water volume (m³)

Target active concentration (ppm)

Product active content (%)

Product density (kg/L)

Active Chemical Required—

Commercial Product Mass—

Commercial Product Volume—

This calculator does not determine the correct treatment concentration. Use only supplier/project-approved dosage.

05 · SUPPLIER DOSING

Manufacturer Recommended Dose Calculator

Scale an approved dosage such as 2 L per 1,000 L to the actual system capacity.

System volume (L)

Corrosion Inhibitor Top-Up Calculator

Estimate additional active inhibitor required to move from a measured level to an approved target.

System volume (m³)

Measured level (ppm)

Approved target (ppm)

Product active content (%)

Product density (kg/L)

Concentration Increase—

Active Chemical—

Commercial Product—

07 · SOLUTION PREPARATION

Chemical Dilution Calculator — C₁V₁ = C₂V₂

Calculate stock solution and dilution water needed for a lower-concentration solution.

Stock concentration C₁ (%)

Required concentration C₂ (%)

Final solution volume V₂ (L)

Stock Solution Required—

Dilution Water—

Do not use this tool to determine mixing sequence. Follow SDS/TDS instructions exactly.

08 · HVAC GLYCOL

Glycol Concentration & Top-Up Calculator

Estimate glycol and water quantities for a new mix or concentration increase.

Total system volume (L)

Required glycol concentration (%)

Glycol Volume—

Water Volume—

Increase existing concentration

System volume (L)

Current concentration (%)

Target concentration (%)

Top-up glycol strength (%)

Approx. Glycol to Add—

Verify freeze protection and maximum concentration using the approved glycol manufacturer's data.

09 · DOSING EQUIPMENT

Chemical Dosing Pump Rate Calculator

Estimate product feed rate from water flow and an approved active dosage.

Water flow (m³/h)

Required active dose (mg/L)

Product active content (%)

Product density (kg/L)

Dosing pump max capacity (L/h)

Product Feed Rate—

Daily Product Use—

Approx. Pump Setting—

10 · GENERAL WATER CHEMISTRY

General Water Treatment Calculators

Supporting calculations for conductivity/TDS, ppm, storage, treatment cost, batch concentration and project limit checks.

Conductivity → Approx. TDS

Conductivity (µS/cm)Conversion factor

Approx. TDS—

ppm ↔ mg/L

Concentration (ppm)

Dilute Water Approximation—

Chemical Storage Days

Available stock (L)Daily consumption (L/day)

Stock Autonomy—

Treatment Cost per m³

Chemical used (L)Chemical price / LWater treated (m³)

Chemical Cost / m³—

Batch Tank Chemical Quantity

Tank volume (L)Required solution concentration (%)

Indicative Product Volume—

Water Quality Limit Check

Measured valueProject maximum limit

Status—

Need a CHW Flushing, Cleaning or Water-Treatment Plan?

For chilled-water flushing, pressure testing, chemical cleaning, system circulation and commissioning, contact the PSEMIC engineering team for project-specific support.

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