DropTubeBuilder
Fuel Tech Assistant
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
Stop guessing drop tube cuts. Exact lengths for OPW, Franklin & EMCO, EPD 3 year inspection PASS/FAIL, tank charts, and Gilbarco, Wayne, Veeder-Root & EVO codes.
DropTubeBuilder: Precision Measurement Made Simple
DropTubeBuilder is the essential tool for fuel system technicians, providing accurate measurements for overfill drop tubes and quick diagnostics for dispenser errors. Ensure compliance with industry regulations while saving time on-site.
Key Features:
• Accurate Drop Tube Calculations: Input simple measurements to get precise drop tube lengths.
• 95% Fill Level Support: Ensures overfill valves sit exactly at the regulatory fill level.
• Tank Chart Builder: Create volume charts with 1/8-inch increments for precise monitoring.
• Dispenser Error Code Reference: Quickly look up error codes for Gilbarco and Wayne dispensers, including possible causes and troubleshooting steps.
• User-Friendly Interface: Designed for efficiency in the field with quick data entry and intuitive navigation.
Perfect for professionals in petroleum equipment management, DropTubeBuilder keeps you compliant, efficient, and confident on the job.
Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Terms of Use: https://christhrasher.wordpress.com/2025/02/16/%f0%9f%93%9c-terms-of-use-for-droptubebuilder/
Privacy Policy: https://christhrasher.wordpress.com/2025/02/02/%f0%9f%93%9c-privacy-policy-for-droptubebuilder/
Support: https://christhrasher.wordpress.com/2025/02/02/droptubebuilder-support/
more Can be used local on device. Has amazing tools for fuel work.
Can be used local on device. Has amazing tools for fuel work.
The biggest update yet, built from real field work.
• EPD 3 Year Inspection: run the Georgia EPD flapper and valve inspection in the app. Enter the form measurements, get an instant PASS or FAIL, and export a signature ready PDF report.
• Pump Controllers: fault codes, DIP switch settings, and calibration steps for the FE Petro MagVFC and the new Guardian single phase controller, all searchable.
• Franklin EVO 550 and 5000 tank gauge alarms: 97 alarms with causes and recommended actions.
• Expanded Gilbarco Encore 500 error codes.
• Tank Chart Builder now shows the 95% and 90% overfill levels and exports a printable PDF chart.
• Drop tube math verified against the official OPW, Franklin, and EMCO worksheets, with Franklin cut lengths corrected to match their calculator.
• Every PDF export now shares as a properly named file for email, text, or Files.
• Improved iPad layouts throughout.
1.2.0 Jul 5
• Corrected the 95% shutoff to use 95% by VOLUME (from the tank chart) — the right method for horizontal tanks.
• New searchable Veeder-Root TLS-300/350/450/450 Plus/4i alarm + troubleshooting library.
• Rebuilt dispenser error-code screen with fast search.
• Cleaner drop tube calculator with two clear shutoff modes.
• Reliability fixes throughout.
1.1.8 Jun 7
Version 1.1.1 - Critical Formula Fixes & Improvements
We've made major improvements based on field technician feedback! This update fixes critical calculation errors and adds highly requested features.
CRITICAL BUG FIXES:
• Fixed OPW ISO Calculator
- Resolved "Invalid input" error that prevented calculations
- Tank height field now appears correctly in all input modes
- Added helpful guidance text for OPW-specific requirements
• Corrected OPW Formula (BACKWARDS ERROR!)
- Fixed critical calculation error in OPW ISO formula
- C value was being calculated from bottom instead of top
- Results are now accurate and match OPW official specifications
- Previous version gave completely wrong results (e.g., 113" instead of 30")
• Updated EMCO Formula
- Implemented official EMCO calculator specifications
- Added +1" adjustment per manufacturer requirements
- Changed bottom clearance to 5" (from 6") per EMCO specs
- Results now match EMCO's online calculator exactly
VERIFIED ACCURACY:
All calculations verified against official manufacturer specifications:
• Franklin Defender - Verified correct (no changes needed)
• EMCO - Now matches official EMCO calculator
• OPW ISO - Corrected to match OPW installation manual
• Georgia EPD - Added compliance validations
ENHANCED VALIDATIONS:
• Added Georgia EPD minimum length requirements
• OPW calculations now validate against EPD standards
• Better error messages for invalid measurements
• Improved validation for edge cases
FORMULA IMPROVEMENTS:
All calculations have been verified against:
- Official manufacturer installation manuals
- Georgia EPD Flapper/Valve Inspection standards
- Field testing by professional fuel technicians
- Industry best practices and compliance requirements
WHAT THIS MEANS FOR YOU:
Before this update, some calculations (especially OPW) were significantly wrong and could lead to failed inspections or incorrect installations. This update ensures:
• Accurate drop tube measurements every time
• Compliance with manufacturer specifications
• Pass Georgia EPD and state inspections
• Confidence in your field calculations
• Time saved with correct results on first try
TECHNICAL DETAILS:
OPW ISO Changes:
- Formula now correctly calculates C from tank top (not bottom)
- Proper handling of 71SO and 71SO-T valve variants
- Minimum 6.5" validation per EPD requirements
- Example fix: 96" tank at 95% now gives correct 30.5" upper tube (was 113.2")
EMCO Changes:
- Upper tube: A - B + 1" (was A - B)
- Total length: A - 5" (was A - 6")
- Matches official EMCO online calculator specifications
- Example: 120" seat at 95% now gives 29.75" upper, 115" total
Franklin Defender:
- Verified correct against official documentation
- No changes needed - calculations were accurate
- Simple geometry approach confirmed mathematically sound
EXISTING FEATURES:
• Professional drop tube calculations
• Support for OPW ISO, EMCO, Franklin Defender valves
• Multiple input modes (percent or inches from bottom)
• Measurement history with 50-calculation storage
• PDF export with professional formatting
• Dispenser error code lookup
• Tank chart builder
• Offline functionality
• Modern iOS design with dark mode support
COMPATIBILITY:
• Requires iOS 16.0 or later
• Optimized for iPhone and iPad
• Full dark mode support
• Works offline - no internet required
IMPORTANT WARNING:
If you've used version 1.1.0 or earlier for OPW calculations, please review those measurements. The formula was incorrect and may have given wrong results. OPW calculations in previous versions calculated the C value from the tank bottom instead of top, resulting in significantly incorrect measurements.
FEEDBACK:
Found an issue or have a suggestion? Contact us through the app settings. We're committed to providing the most accurate calculations for fuel system professionals.
Built by field technicians, for field technicians.
Thank you for using DropTubeBuilder!
1.1.7 Jan 26
What’s new
• Pro plans: Monthly & Yearly.
• Subscription screen redesign; clearer status messages.
• One-tap Manage and Restore.
• More languages: Spanish, French, German, Hindi, and Simplified Chinese.
• Calculator & tank chart refinements for clearer inputs/labels and small accuracy improvements.
• Lots of performance, stability, and UI polish.
Thanks for using DropTubeBuilder!
1.1.5 10/06/2025
What’s New in Version 1.1.4
Major Update: Drop Tube Calculator Overhaul
This version includes a complete rebuild of the Drop Tube Builder feature to align with Georgia EPD Overfill Inspection Worksheet standards. The new logic provides accurate, inspection-ready measurements that reflect real-world conditions in the field.
Updated Measurement Inputs
• Inputs are now clearly labeled using technician-friendly terms:
• Distance from spill bucket base to bottom of tank
• Tank diameter (vertical height)
• Tank chart 95% fill level (inches from tank bottom)
New Calculation Logic
• Automatically calculates riser height based on tank dimensions.
• Computes the correct top and bottom tube segments based on the required shutoff height and 6-inch clearance from the tank bottom.
• Ensures the drop tube meets overfill prevention requirements exactly.
• Includes built-in validation to catch input errors or unsafe drop tube configurations.
Detailed Output
• Top Tube: From grade to the 95% shutoff level
• Bottom Tube: From the shutoff level to 6 inches above the tank bottom
• Total Drop Tube Length: Combined top and bottom tube measurement
Multilingual Support Improvements
• Localized labels and instructions updated across all supported languages, including English, Spanish, French, Simplified Chinese, and Hebrew.
• New instructional strings added for greater clarity and accuracy.
Bug Fixes and Enhancements
• Improved error handling for missing or invalid data
• Better keyboard behavior for a smoother mobile experience
• Layout and spacing adjustments for easier use in the field
Built for Real-World Use
This version reflects actual field-tested workflows and is designed to simplify compliance with overfill prevention standards. Built by a working fuel system technician for others in the industry, this tool saves time, reduces mistakes, and supports fast, confident inspections.
If you find DropTubeBuilder helpful, please consider leaving a rating or review, and share it with other technicians in your network.
1.1.4 07/07/2025
What’s New in DropTubeBuilder
Version 1.0 – Initial Release
DropTubeBuilder is now available as the essential field tool for fuel system technicians.
Highlights:
• Drop Tube Calculator: Accurately calculate top tube, bottom tube, and total drop tube lengths using riser height and the 95% fill level from the tank chart.
• Tank Chart Builder: Generate precise tank volume charts by inputting tank diameter, length, and capacity.
• Dispenser Error Code Lookup: Identify and troubleshoot Gilbarco and Wayne error codes with a comprehensive built-in database.
• Multilingual Support: Available in English, Spanish, Chinese, and German.
• Free 2-Day Trial: Full feature access for 2 days with no commitment required.
Built by professionals for professionals — DropTubeBuilder delivers accuracy and reliability in the field.
1.1.3 05/05/2025
What’s New in DropTubeBuilder 1.1.2
Multi-Language Support
DropTubeBuilder now supports multiple languages. You can use the app in English, Spanish, Chinese (Simplified), Hindi, German, and French. The app automatically follows your device’s language settings, or you can manually select your preferred language in the new Settings menu.
Improved Drop Tube Calculations
We refined the Drop Tube Calculator to improve precision. The updated version now handles riser height, spill bucket depth, and 95% fill levels with better accuracy. You can also now adjust the overfill shutoff percentage as needed, giving you greater flexibility during measurements and installations.
2-Day Free Access Before Subscription
We added a custom 2-day free access period for all new users. You can now try the app’s full features for two days immediately after installing, without needing a subscription. After this period, the app transitions to the optional annual subscription with a 3-day App Store free trial.
New Settings Menu
A new Settings menu has been added where you can change your app language manually. This allows you to switch languages within the app without changing your device’s language settings.
User Agreement and Privacy Policy Access
We have updated the app to make it easier to review our Terms of Use, Privacy Policy, and Support resources directly from the Subscription screen.
Stability Improvements and Bug Fixes
This release improves subscription status handling, speeds up loading of tank charts and error codes, and improves UI behavior across different screen sizes. We also addressed several minor bugs to make your experience even smoother.
Thank you for using DropTubeBuilder. Your support and feedback drive every update we make. If you find the app useful, please consider leaving a review.
1.1.2 04/29/2025
What’s New in DropTubeBuilder
• Added support for custom overfill shut-off percentages
• Improved drop tube calculator to match EPD guidelines
• Now includes riser height input for more accurate tube measurements
• Enhanced validation and error feedback for better usability
• Minor UI polish and performance improvements
1.1.1 04/24/2025
What’s New in Version 1.1.0
• Added subscription support for DropTubeBuilder Pro
• Implemented restore purchases functionality
• UI refinements for a smoother experience
• General performance improvements and bug fixes
Thank you for using DropTubeBuilder. Your feedback helps us improve.
1.1.0 02/26/2025
What’s New in This Version (1.1)
• Introduced Annual Subscription: We’ve added a new auto-renewable subscription plan at $24.99/year with a 3-day free trial, providing unlimited access to all premium features.
• Improved User Experience: Minor performance enhancements and bug fixes to ensure smoother operation and improved stability.
• Subscription Management: Easily manage your subscription directly through the app for hassle-free renewals.
1.1 02/05/2025
The biggest update yet, built from real field work.
• EPD 3 Year Inspection: run the Georgia EPD flapper and valve inspection in the app. Enter the form measurements, get an instant PASS or FAIL, and export a signature ready PDF report.
• Pump Controllers: fault codes, DIP switch settings, and calibration steps for the FE Petro MagVFC and the new Guardian single phase controller, all searchable.
• Franklin EVO 550 and 5000 tank gauge alarms: 97 alarms with causes and recommended actions.
• Expanded Gilbarco Encore 500 error codes.
• Tank Chart Builder now shows the 95% and 90% overfill levels and exports a printable PDF chart.
• Drop tube math verified against the official OPW, Franklin, and EMCO worksheets, with Franklin cut lengths corrected to match their calculator.
• Every PDF export now shares as a properly named file for email, text, or Files.
• Improved iPad layouts throughout.
more Version 1.2.0 Jul 5
Data Not Collected The developer does not collect any data from this app.
Supported Features
VoiceOver
Voice Control
Dark Interface