This specification covers the application, design, and materials for valve locking devices. According to the method of locking, these devices are classified into three types: Type I using a wire rope assembly, Type II using a handwheel latch, and Type III using a locking shield. These devices are also grouped into three grades depending on material composition: Grade A is made of stainless steel, Grade B is made of anodized aluminum, and Grade C is made of carbon steel. Locking devices Types I and II described in this specification are designed to secure the valve in a fully opened or completely closed position. Materials to be used in the manufacture of Type I valve locking device shall consist of pipe clamp, ring link, common wire strand, tiller rope clamp, rigid eye spring hook, and sleeve. As for Type II valve locking device, the materials shall consist of modified pipe clamp, flat head rivet, single-acting quick release pin, lanyard, sleeve, lanyard clip, and lever arm. Type III devices shall consist of plate, single-acting quick release pin, lanyard, sleeve, lanyard clip, and lockbar. The locking device must be able to lock the valve in both the fully opened and completely closed positions.