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INSTRUCALC - Instrument Engineering Calculations

Control Valves, Flow Elements, Relief Devices, Fluid Properties, Pipe Pressure Loss, Liquid Waterhammer

Size more than 50 different instruments with this easy-to-use and accurate sizing program.

InstruCalc 9.0 calculates the sizes of control valves, flow elements, and relief devices; produces data sheets for calculated items; and prepares instrument summaries and uses data sheets as a database for generating reports. The Control valve and Flow element modules calculate, display and print graphs of your calculations.  InstruCalc 9.0 allows you to select any set of engineering units, including your own customized set. Units can be mixed, matched and changed in the middle of a calculation.  InstruCalc 9.0 calculates process data at flow conditions for 54 fluids in either mixtures or single components and 66 gases in either mixtures or single components. Files can be updated with additional users' fluids and gases.

InstruCalc 9.0 consists of more than 74 routines divided into five main sections


  • Control Valve sizing:   Gas, liquid and two-phase flow. Noise prediction and cavitation. Graphs available for Control Valves are: valve Cv and flow; valve pressure drop and flow; linear trim; and, equal percent trim.  Uses ANSI/ISA 75.01.01 Standard
  • Relief Valve sizing:  Valves, rupture disks, tank vents.  Program uses API RP 520 7th Edition.  Tank venting is to API 2000 5th Edition April 1998.
  • Flow Element sizing:  ISO and AGA orifice plates, nozzles, venturis; annubars; integral flow orifice meters; restriction orifices; vortex, target, rotameter and elbow meters.  Program calculates the orifice size, flowrate or differential range, which enables the user to select the flowrate with optimum accuracy. It provides the recommended size and corrects the orifice size accordingly.  Flow Element graphs include: flow and differential.  Uses Miller's Handbook, 3rd edition, 1996 , and ISO 5167, 2003.
  • Pressure drop in liquid and gas pipes - Calculations use Darcy Formula, Colebrook equation and Crane Technical Paper No.410
  • Waterhammer calculations:  Waterhammer Closing Time, Pressure Rise and Support Force.  Uses Joukowski formula


1.Engineering Standard upgrades

  • Latest CV ISO Standard ANSI/ISA 75.01.01-2007
  • Pressure Relief Devices Program follows API 520 2009

2. Engineering Improvements

  • Technique for showing cavitation in restriction orifices and venturi meters  (Flow Elements)
  • Expanded vortex meter sizes available – up to size 36 (Flow Elements)
  • Incorporation of Z-factor in gas-flow for sizing Flow Elements
  • AGA8 option for Natural Gas in Flow Elements
  • Added option to specify outlet pressure of orifice Flow Element.
  • Added Text box at the bottom of the calculation for comments such as exit angle of venture meters
  • PRV Program provide option to calculate flow rate for a known size RV.
  • Clarify status to show more clearly flashing, cavitation and choking of control valves.
  • Outlet of control valves - flow velocity at outlet flange
  • Allow for Density input instead of Specific Gravity in all Programs
  • Allow  absolute and gauge units for all pressure inputs

 3. Operational Improvements

  • Compatibility with Windows 7 and Windows 10 (both 32 bit and 64 bit)
  • Rearrange appearance of program – basic form set-up  and day to day options – removed them and clarified there use.
  • Excel Import/Export for process data
  • Database Print manager with options to print all the database stored data and all the calculations or any combination of them.

 4. Ability to Transfer Data between Files

  • Data files are now Microsoft Access.
  • Data files can be imported from earlier versions
  • Version 9.0 now saves all calculated data. There are separate tables for calculation data, units' data, data sheets, pressure drop calculations, chemical properties composition data and water hammer data. This allows for data to be available for manipulation.

Purchase ISA Standards for Control Valves, On-Off Valves and Actuators Here

Purchase ISA Standards for Measurement Devices and Transducers Here

If you have any further queries concerning this software, please drop us a note and we will get back to you as soon as possible.

Purchase Online

We have a number of purchase options available in our store. Our goal is to ensure that you feel comfortable in buying our software. We therefore employ the highest level of security for online transactions and accept all major credit cards as well as various options to purchase such as electronic fund transfer (EFT) or bank draft. Should you prefer not to provide your details online, we understand and ask that you send us an email requesting a pro-forma invoice for the software in question. Please include relevant company details should you decide on this option.

We have been selling software via the internet for many years, and have a list of satisfied customers from across the globe. Should you require references from some of these companies and individuals please let us know.


Purchase Online
Product License Type Price Purchase
INS1_INS1InstruCalc v9 Single User StandalonePurchase (incl 12 months MUS)$ 2,800.00
INS4_INS1Instrucalc v9 Single User StandaloneAnnual Maintenance$ 700.00
INS3_INS1Instrucalc v9 Single User StandaloneUpgrade from 8.x (incl 12 months MUS)$ 2,250.00
INS5_INS1Instrucalc v9 1-User NetworkPurchase (incl 12 months MUS)$ 3,200.00
INS9_INS1Instrucalc v9 1-User NetworkAnnual Maintenance$ 800.00
INS6_INS1Instrucalc v9 2-User NetworkPurchase (incl 12 months MUS)$ 5,900.00
INS2_INS1Instrucalc v9 2-User NetworkAnnual Maintenance$ 1,475.00
INS7_INS1Instrucalc v9 3-User NetworkPurchase (incl 12 months MUS)$ 8,000.00
INS8_INS1Instrucalc v9 3-User NetworkAnnual Maintenance$ 2,000.00

Should you like to download a demo of this software, it is available by clicking the link below.

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