Norwell EDGE - * FULL OPENING SAFETY VALVE* The Full Opening Safety Vale, also known as a TIW (Texas Iron Works) Valve, is a fully opening, ball-type value used on drilling rigs.
WNCO Valve | Safety Valve
Safety valves | RNGI
Products - M&M International
Full Opening Safety Valve
What is a Full Opening Safety Valve (TIW valve)?
Debunking the Terminologies of IBOPs and FOSVs
What are differences between Full Opening Safety Valve (TIW valve) and Inside BOP valve (Gray Valve)?