5706.5.9 Top loading.

When top loading a cargo tank with Class I and II liquids without vapor control, valves used for the final control of flow shall be of the self-closing type and shall be manually held open except where automatic means are provided for shutting off the flow when the tank is full. When used, automatic shutoff systems shall be provided with a manual shutoff valve located at a safe distance from the loading nozzle to stop the flow if the automatic system fails. When top loading a cargo tank with vapor control, flow control shall be in accordance with FC 5706.5.10. Self-closing valves shall not be tied or locked in the open position.

5706.5.10 Bottom loading.

When bottom loading a cargo tank or tank car with or without vapor control, a positive means shall be provided for loading a predetermined quantity of liquid, together with an automatic secondary shutoff control to prevent overfill. The connecting components between the transfer equipment and the cargo tank or tank car required to operate the secondary control shall be functionally compatible.

5706.5.10.1 Dry disconnect coupling.

When bottom loading a cargo tank, the coupling between the liquid loading hose or pipe and the cargo tank piping shall be a dry disconnect coupling.

5706.5.10.2 Venting.

When bottom loading a cargo tank or tank car that is equipped for vapor control and vapor control is not required or used for the product being loaded, the tank shall be vented to the atmosphere to prevent pressurization of the tank. Such venting shall be at a height equal to or greater than the top of the cargo tank or tank car.

5706.5.10.3 Vapor-tight connection.

Connections to the plant vapor control system shall be designed to prevent the escape of vapor to the atmosphere when not connected to a cargo tank or tank car.

5706.5.10.4 Vapor recovery and processing equipment.

Vapor recovery and processing equipment at bulk plants and terminals shall comply with the requirements of FC 5706.8.

5706.5.11 Switch loading.

Cargo tanks or tank cars which have previously contained flammable liquids shall not be loaded with combustible liquids until such tanks or cars and all piping, pumps, hoses and meters connected thereto have been completely drained and flushed.

5706.5.12 Loading racks.

Where provided, loading racks, stairs or platforms shall be constructed of noncombustible materials. Buildings for pumps or for shelter of loading personnel are allowed to be part of the loading rack. Wiring and electrical equipment located within 25 feet (7620 mm) of any portion of the loading rack shall be in accordance with FC 5703.1.1.