CSST Sizing

Online Sizing Calculator

Our FlashShield™ Online Sizing Calculator has been developed for you to easily create a customized sizing table to help design a FlashShield fuel gas piping system layout. The calculator can be used for a natural gas or propane system and you can include custom gas supply pressures, pressure drops and lengths of CSST. Click HERE to get started.


Mobile Sizing App - iPhone & Android

We've updated our mobile sizing app for Flashshield™ and it is available for FREE download in iTunes and Android. Based on the project’s gas type, length of tubing run, supply pressure, pressure drop, and flow capacity – the scrollwheel design will calculate the appropriate size FlashShield CSST for your application.


  • Includes a location selector for US and CA *NEW*
  • Scroll wheel automatically adjusts depending on values selected
  • Find your certification card to link a digital version to your device *NEW*
  • View the latest Design and Installation Guide in the app *NEW*
  • Search for Gastite and FlashShield products *NEW*
  • Contact Page submits questions and requests directly to Gastite  
  • FAQs
  • Minimum iOS version 8
  • Minimum Android version 5.0



Design the layout of your gas supply system using Gastite's Size-It software. Based on the design you create, the appropriate pipe sizes will be calculated automatically.

Advanced Sizing Services

Gastite offers advanced sizing services on all commercial projects at no charge. Years of experience and collaboration with industry's finest are applied to deliver designs that render the most efficient gas piping installations. Submit your next project to Gastite! Contact the Gastite Technical Support Team at 800.662.0208 to submit your drawings and begin your project today.
    •    Available for all commercial projects
    •    Cost-effective designs that incorporate all approved gas piping materials
    •    Receive a complete set of CAD drawings ready for plan check review
    •    Electronic AutoCAD files
    •    "D" size hard copies (22" x 30")
    •    Engineering relationships (ASPE)
    •    Code knowledge
    •    Gas company relationships
    •    Quick turnaround

Sizing Charts

The following sizing tables are utilized to determine the proper size and maximum capacity of Gastite/FlashShield Flexible Gas Piping in cubic feet per hour based on total appliance load and total length of runs.

Natural Gas Sizing Charts
Propane Gas Sizing Charts


Pressure Drop Tables

Table 7-21
Pressure Drop of Natural Gas in Gastite/FlashShield CSST

Based on gas pressure of 0.5 PSI or less and a 0.60 specific gravity.

Table 7-22
Pressure Drop of Propane Gas in Gastite/
FlashShield CSST
Based on gas pressure of 0.5 PSI or less and a 0.60 specific gravity.

Table 7-24
Steel IPS Pipe Pressure Drop Table

Pressure Drop Per Foot - Inches of Water Column for Iron Pipe. Based on a gas of 0.60 specific gravity.

Tables include losses for four 90° bends and two end fittings. Tubing runs with a larger number of bends and/or fittings shall be increased by an equivalent length of tubing to the following equation: L=1.3n where L is additional length of tubing and n is the number of additional fittings and/or bends. Conversion factor for use with propane: Divide BTUs of LPG by 1535 to obtain equivalent CFH of Natural Gas.

Sum of Pressure Loss Worksheet

With Gastite’s Excel-based workbook, it’s easy to calculate the pressure at the start and end of a run. Use this resource to enter the details for your gas system and determine the sum of pressure loss. There’s even a worksheet with a reserved area to enter a drawing of your project.


Have questions? Our technical support team is ready to help.
Call (800) 662-0208 or e-mail gastite@gastite.com