The Maxton OSV STD is an elevator safety shut off valve designed to protect against elevator car overspeed in the down direction due to supply line failure and car overload situations. The OSV STD is used in high flow system applications (300 gpm max,1136 l/min max). Use the Maxton valve calculator for valve sizing to the job specifications. The Maxton OSV STD can be adjusted to stop the elevator in the event of an overspeed condition resulting in an abnormally high rate of flow between the OSV STD valve and the power unit. Can be installed in a horizontal or vertical position. The Maxton OSV STD complies with ASME A17.1/CSA B44 and meets (UFGS Division 14 Conveying Equip Section 14 24 00 Part 22.214.171.124) requiring a valve equipped with manufacturer's manual shut off feature. The use of this valve is required in areas of high level seismic activity IE: California. Check your local codes for compliance.