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Subchapter 1. Unfired Pressure Vessel Safety Orders
Article 6. Anhydrous Ammonia

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§506. Installation of Tanks Mounted on Farm Machinery.

(a) Tanks or cylinders used to furnish anhydrous ammonia to agricultural applicator tanks and tanks used on applicators, etc., shall be so installed that the bottom of the container and/or any outlet connection, including hose, shall not be lower than the lowest horizontal edge of the vehicle axle when fully loaded. These tanks shall be secured to prevent jarring loose, slipping, or rotating of the tanks while in service. Such supports and fastenings shall be designed to withstand a loading in any direction equal to the loaded weight of the tank when filled to the maximum permissible level with a factor of safety of at least 8.

Field welding where necessary, shall be made only on nonpressure parts that were installed by the manufacturer of the tank.

(b) The connections between the applicator tank and pressure-reducing valve shall be extra heavy fittings and Schedule-80 pipe, high-pressure anhydrous ammonia hose (1750 psi minimum bursting pressure), or equivalent, and where exposed, shall be protected against physical damage. All main shutoff valves shall be readily accessible while the unit is in normal operation. All shutoff valves shall be suitably protected against physical damage.

(c) While in use on farm machinery, each skid tank, applicator tank, or combination thereof shall have securely attached a container holding not less than 5 gallons of fresh water. This container shall have a suitable opening to permit the application of water to flush the eyes.

The container of fresh water required by this subsection may be attached to the tractor or other source or power used to tow the vehicle or device on which the tank is used.

(d) All trailers shall be securely attached to the vehicle drawing them by means of drawbars supplemented by suitable safety chains.

(e) A trailer shall be constructed so that is will follow substantially in the path of the towing vehicle and will not ship or swerve dangerously from side to side.


1. Amendment of subsection (a) and new subsections (d) and (e) filed 3-28-75; effective thirtieth day thereafter (Register 75, No. 13).

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