The Lockable Line Valve is suitable for new and existing applications which require a system of secure but easily accessible medical gas isolation valves within a restricted area. The unit is designed to be mounted directly into a medical or laboratory gas pipeline via the copper tail-pieces supplied, and located within wall or ceiling voids or anywhere that general access is restricted. Valves can be provided with a blanking facility as a secondary means of isolation to provide a physical barrier to the gas supply in order to eliminate any risk of contamination during initial installation and upgrade. Valves can be supplied with optional NIST fittings up and/or down stream, incorporating a 100% leak tight seal in the gas specific NIST connector. Other options include pressure switches, pressure gauges and multiple valve boxes.