'Immediately Dangerous' , 'At Risk', 'Not to current standards'. Find Out Exactly What The Problem Is  
  Landlord Gas Safety Certificates : Unsafe Definitions  
Tutorial : Interpreting an Unsafe Situation Following A Gas Safety Check
Glossary Of Terms Used
The Gas Industry Unsafe Situations Procedure
Earth Bonding
Insufficient Ventilation
Unsafe Definitions and Not To Current Standard Situations - Codes and Explanations