Last reviewed: July 22, 2026
Systems Guides explains general concepts. It does not evaluate a specific facility, asset, utility, transport service, building, industrial site or maintenance program.
No professional advice
Content is not engineering, legal, financial, regulatory, environmental, insurance, safety, operating or emergency advice. It does not replace site-specific records, drawings, standards, inspections, calculations, manufacturer instructions or professional judgement.
Safety and emergencies
Do not rely on this site during an emergency or to operate, isolate, repair, test or maintain equipment. Follow local emergency services, responsible operators and approved procedures.
Accuracy and change
Systems, technologies, rules and terminology change. Although pages are reviewed for clarity and internal consistency, errors or omissions may remain.
External links
External links are provided for context. Systems Guides does not control external content, availability, privacy practices or later changes.