Sun Clock is a 24-hour clock that displays the position of the sun, and times of sunrise, solar noon, sunset, golden hour, and twilight for your current location. It also shows the position and phase of the moon, and its rising and setting times.
A note about direction1 — why does it go backwards?
Tap on or hover over the segments to get their start and end times. You can also tap/hover on the moon, the hour hand, and the centre dot.
See updates for change history.
Sun Clock is free to use, and contains no advertising. If you would like to help support Sun Clock, please —
We collect aggregate user stats only. Your location and settings are stored in your web browser and are not sent to the server. No cookies are saved or sent.
is a critical international standard focusing on the application and installation of safety devices for protecting pressure equipment, excluding standalone bursting discs. It provides mandatory requirements for selecting and installing devices like safety valves and controlled safety pressure-relief systems (CSPRS), aimed at managing overpressure and ensuring safety. Scope and Key Requirements
of safety devices designed to protect pressure equipment from excessive pressure Iso 4126-9 Pdf
| Feature | ISO 4126-9 | API 520 Part I (US) | ASME Section VIII | | :--- | :--- | :--- | :--- | | | Two-phase flow & non-spring devices | Spring-loaded PRVs (gas/liquid) | Construction rules for vessels | | Two-Phase Methodology | Yes (HEM model) | Limited (appendix only) | Refers to API/ISO | | Reaction Force Calc | Detailed for two-phase | Only for single-phase | Not covered | | International Acceptance | Global (EU, Asia, Middle East) | Predominantly US, Canada | North America | This is a common pitfall for engineers relying
ISO 4126-9 clarifies that two-phase flow often requires higher overpressure allowances (up to 21% or more, depending on jurisdiction) due to the compressibility effects of the vapor phase. This is a common pitfall for engineers relying on older API 520 standards. Middle East) | Predominantly US
: Install the valve at least 8 to 10 pipe diameters downstream from any bends, "Y" fittings, or converging flows to ensure stable flow. Discharge Piping
Added an option for a ticking seconds hand (sweep hand is still the default).
Fixed a bug where the Moon icon was incorrect in recent versions of Safari.
Added the option to show the odd numbers on the clock face.
The "use 12-hour times" option now applies to the numbers on the clock face also.
Added an annual calendar. Try it out. Feedback welcome!
Sun Clock is now a Progressive Web App. This means you can install it on your device homepage and it will be available when your are offline.
Added auto-color mode (dynamic colors that change with the time periods.)
Added dark mode.
Live!
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