Another authorized reseller that provides the PDF in various formats, including printable versions.

It is not a mandatory law, but rather a "best practice" guideline developed by industry experts from major oil companies, engineering firms, and safety system vendors. However, due to its technical rigor, it is frequently cited by OSHA (Occupational Safety and Health Administration) and insurance underwriters as the standard of care. In a court of law or during an incident investigation, failing to follow API RP 556 can be considered negligence.

A licensed distributor of industry standards. They offer multi-user licenses for engineering teams.

Good for corporate accounts that need simultaneous access for 20+ engineers.

| Feature | First Edition (2011) | Second Edition (2019) | | :--- | :--- | :--- | | Safety Lifecycle | Referenced IEC 61508 vaguely | Aligns strictly with IEC 61511:2016 | | Flame Detection | Standard UV/IR | Includes advanced video imaging | | Startup Verification | Manual checklist required | Automated startup sequence testing | | Cybersecurity | Not covered | Dedicated section on hardening BMS |