Terms of Use
StandbyCalc — Last updated: 29 March 2026
These Terms of Use govern your use of the StandbyCalc mobile application ("the App") published by D4N LTD ("we", "us", "our"). By downloading or using the App, you agree to these terms.
Use of the App
StandbyCalc is a tool for calculating standby battery requirements for fire alarm, intruder alarm, and standalone PSU systems in accordance with UK standards. The App is provided for professional reference and convenience.
Professional Responsibility
StandbyCalc is a calculation aid. It does not replace professional judgement, site assessment, or compliance with applicable regulations. You are responsible for verifying that calculations are appropriate for your specific installation and that all inputs are correct.
Battery sizing should always be confirmed against the relevant standard (BS EN 50131, BS 5839-1:2025, or other applicable standards) and any site-specific requirements from the system manufacturer, the Authority Having Jurisdiction, or your certifying body.
Accuracy
We have made every effort to ensure the calculations in StandbyCalc are accurate and reflect current British Standards. However, we do not warrant that the App is error-free. Standards may be updated or amended, and local requirements may differ.
D4N LTD is not liable for any loss, damage, or claim arising from reliance on calculations produced by the App.
In-App Purchases
StandbyCalc offers a one-time, non-consumable Pro upgrade. All purchases are processed by Apple through the App Store and are subject to Apple's terms and conditions. We do not process payments directly.
- Pro is a one-time purchase with no subscription or recurring charges
- Refunds are handled by Apple per their refund policy
- You can restore purchases on any device signed in with the same Apple ID
Intellectual Property
The App, its design, code, and content are the property of D4N LTD. You may not copy, modify, distribute, or reverse-engineer any part of the App.
PDF reports generated by the App are yours to use, distribute, and include in your professional documentation.
Third-Party Services
The App uses the following third-party services:
- Google AdMob for advertising (free tier only), subject to Google's Terms of Service
- Apple CloudKit for iCloud sync (Pro only), subject to Apple's iCloud Terms
Termination
We reserve the right to discontinue the App at any time. You may stop using the App at any time by uninstalling it from your device.
Limitation of Liability
To the maximum extent permitted by law, D4N LTD shall not be liable for any indirect, incidental, special, consequential, or punitive damages arising from your use of the App. Our total liability shall not exceed the amount you paid for the Pro upgrade.
Governing Law
These terms are governed by the laws of England and Wales. Any disputes shall be subject to the exclusive jurisdiction of the courts of England and Wales.
Changes to These Terms
We may update these terms from time to time. Changes will be posted on this page with an updated date. Continued use of the App constitutes acceptance of the updated terms.
Contact
D4N LTD
Email: [email protected]
Web: d4n.io