PART IIIStorage Tanks (continued)
24 (1) All tanks shall be inspected and tested prior to being put into use at the pressure specified by the A.S.M.E. Code by a qualified unfired pressure vessel inspector in accordance with the applicable regulations of the Province concerned.
(2) A copy of the tank test and inspection report shall be filed with the Commission.
25 The tank shall be permanently marked or labelled as required by the A.S.M.E. Code under which the tank was manufactured and the Pressure Vessel Inspection Branch of the provincial government concerned.
26 Each above-ground tank with a water capacity exceeding 1,000 Imperial gallons shall be electrically grounded for protection against lightning with the resistance to ground being as low as possible and preferably not in excess of six ohms.
27 Each tank with a water capacity exceeding 2,000 Imperial gallons shall be equipped with a suitable pressure gauge graduated from 0 to 400 psi.
28 Each tank with a water capacity exceeding 5,000 Imperial gallons should be equipped with a suitable thermometer unless some other provision is made for determining the liquid temperature.
29 The below-ground installation of anhydrous ammonia tanks on the carrier’s right-of-way is prohibited.
30 (1) Except as provided in subsection (7), storage tanks shall be securely installed on solid foundations of steel or reinforced concrete with reinforced concrete footings extending below the frost line or resting on bedrock.
(2) Except as provided in subsection (6), steel foundations shall be fire-proofed with a material having a fire resistance rating of not less than two hours.
(3) Foundations shall be of sufficient width and thickness to adequately support the tank and its contents.
(4) Provision shall be made for the thermal expansion and contraction of a tank.
(5) Only two saddles shall be used for horizontal tanks.
(6) Steel saddles which are welded to a tank need not be fire-proofed if the tank capacity does not exceed 500 Imperial gallons, or if the over-all height of the saddle does not exceed 18 inches.
(7) Footings for tanks with a water capacity less than 500 Imperial gallons need not be installed below frost line if adequate provision is made to protect the piping against the effects of settling.
31 (1) Storage tanks shall not be installed in a building, unless the building is to be used exclusively for the storage of anhydrous ammonia and is ventilated to prevent the accumulation of fumes.
(2) Storage tanks shall not be installed in outdoor locations where the natural dispersal of fumes would be seriously restricted.
32 (1) The filling density of above-ground unrefrigerated tanks shall not exceed 56 per cent for uninsulated tanks and 57 per cent for insulated tanks; for volume filling at various liquid temperatures, refer to chart of figure 23, Pamphlet G-2 of Compressed Gas Association, Inc.
(2) The maximum amount of anhydrous ammonia that may be charged into a refrigerated storage container shall be that which theoretically would make the container liquid-full at a pressure equal to 120 per cent of the design pressure of the container under equilibrium conditions of temperature and pressure.
33 (1) Unless filling is controlled by weighing, tanks shall be equipped with a fixed tube liquid level, a rotary tube, an adjustable slip tube gauge, or other gauging device that will ensure that the maximum permitted filling density is not exceeded. If the gauging device is a float type or pressure differential type, the tank shall also be provided with a fixed tube, rotary tube, or adjustable slip tube gauge.
(2) Gauge glasses of the columnar type shall be equipped with shut-off valves having metallic hand wheels, excess flow valves, extra heavy glass adequately protected by a metal housing applied by the manufacturer and shall be protected from the direct rays of the sun.
PART IVPiping and Transfer Equipment
34 Pumps and compressors used for transferring anhydrous ammonia shall be of a type suitable for anhydrous ammonia service, shall be designed for not less than 250 psig working pressure, and shall be so recommended and permanently marked or labelled by the manufacturer.
35 Piping at pumps and compressors shall be so arranged as to ensure the safe operation of this equipment.
36 Refrigeration load and equipment for refrigerated storage systems shall be in accordance with the current edition of Agricultural Ammonia Institute pamphlet, Standards for the Storage and Handling of Anhydrous Ammonia.
37 (1) Hose and hose connections subject to container pressure shall be designed for a working pressure of not less than 350 psig with a factor of safety of not less than five.
(2) The hose, as assembled for use, shall be tested for leaks at not less than twice the maximum working pressure before being put into service and should be tested at least annually thereafter at not less than 1½ times the maximum working pressure.
(3) The hose shall be permanently and clearly marked or labelled “For Anhydrous Ammonia” or “NH3”, or “A.A.”, together with the maximum working pressure, manufacturer’s name or symbol and year of manufacture.
(4) Hose couplings shall be of steel.
(5) Hose materials shall be resistant to the action of anhydrous ammonia under the service conditions to which they will be subjected.
(6) Hose and hose connections located on the low pressure side of flow control or pressure reducing valves or devices, discharging to atmospheric pressure, shall be designed for a minimum working pressure of 60 psig.
(7) Where hose is to be used for transferring liquid, wet hose is recommended and the hose shall be equipped with a shut-off valve on the discharge end and provision shall be made to prevent excessive hydrostatic pressure on the hose.
(8) The use of hose is prohibited for interconnecting stationary containers.
38 (1) Piping shall be schedule 40 mild steel with welded joints and welding type fittings, or schedule 80 mild steel with either screw type or welded joints and welding type fittings.
(2) Brazed joints are prohibited.
(3) Unless the dryness of the ammonia can be assured, copper; copper, silver or zinc alloys, including brass or bronze; or galvanized pipe, valves or fittings shall not be used.
(4) The use of cast iron pipe, valves or fittings in anhydrous ammonia service is prohibited.
(5) Anhydrous ammonia shall not be allowed to come in contact with mercury in manometers and other equipment.
(6) Joint compounds and pipe dopes shall be suitable for ammonia service.
(7) Welding shall only be done by a qualified welder recognized as such by the Boiler and Pressure Vessel Inspection Branch of the provincial government concerned.
39 All storage tank connections, except those for safety relief valves or gauges, shall be labelled to indicate whether they communicate with the vapour or liquid phase during normal operations.
40 All storage tank connections, except those for gauges, safety relief valves or plugged openings, shall be provided with shut-off valves located as close to the tank as possible.
41 (1) All shut-off valves, throttling valves, gauges, and accessory equipment shall be of a type suitable for anhydrous ammonia service and shall be designed for not less than the maximum working pressure to which they may be subjected, except that the rated working pressure of valves, etc., subject to container pressure shall not be less than 250 psig.
(2) All valves, gauges, fittings, and accessory equipment mentioned in subsection (1) shall be permanently marked or labelled with their maximum working pressure and the letters “A.A.” or “NH3” to indicate their suitability for anhydrous ammonia service; e.g., “250 — A.A.”.
42 (1) Except as provided in subsection (4), all openings in unrefrigerated containers, except those for safety relief valves and those connections protected by an opening not larger than a No. 54 drill size (0.0550 inch), shall be equipped with excess flow valves or other suitable automatic valve or device which will automatically prevent loss of the tank contents in the event of a connection or line failure.
(2) Connections on refrigerated containers shall be protected with excess flow valves or other devices as prescribed in the current edition of Agricultural Ammonia Institute pamphlet, Standards for the Storage and Handling of Anhydrous Ammonia.
(3) Excess flow valves shall be designed with a bypass not to exceed a No. 60 drill size (0.0400 inch) opening to allow equalization of pressures.
(4) An excess flow valve or other automatic device as prescribed in subsection (1) is not required for withdrawal connections of unrefrigerated tanks with a water capacity not exceeding 1,500 Imperial gallons, if the connection is protected by a controlling orifice not exceeding 5/16 inch diameter for vapour withdrawal and 1/8 inch diameter for liquid withdrawal, a manually operated shut-off valve, and a pressure-reducing regulator, all of which shall be assembled to the connection as prescribed in 2.2(d), Division II of the 1958 edition of National Fire Protection Association pamphlet No. 58.
(5) Excess flow valves shall be permanently marked or labelled by the manufacturer with their maximum working pressure, rated capacity and the letters “A.A.” or “NH3” to indicate their suitability for use in anhydrous ammonia service.
(6) Excess flow valves or other automatic devices, as referred to in subsection (1), shall be installed in such a manner that rupture of the line or connection will not adversely affect the protective device.
(7) The connection or line housing an excess flow valve shall have a greater capacity than the rated capacity of the excess flow valve.
43 Portable engines, motors, pumps and compressors are not recommended, but if used, shall be securely mounted on a rigid base and every precaution taken to ensure that the installation is stable and well protected against possible physical damage.
44 Unless the installation is enclosed by a wire mesh fence not less than five feet in height and provided with a locked gate, tank shut-off valves shall be shut tight and locked during the absence of the attendant.
45 (1) Piping shall be carried on permanent steel or concrete supports, and supports for pipelines more than four feet above ground shall rest on footings extending below frost line.
(2) Provision shall be made in the piping for expansion, contraction and settling.
(3) Pipeline shall be protected by metal guard rails against damage from trucks and other traffic.
46 (1) Except as provided in subsections (2) and (3), below-ground ammonia lines shall be laid not less than three feet below ground or be enclosed in a reinforced concrete or steel trench with a recessed removable cover which shall be flush with the ground. The trench shall be of sufficient strength to support all traffic which may pass over it and shall be provided with drainage.
(2) Pipelines under roadways on railway property shall be enclosed in an encasing pipe of sufficient strength to support all traffic which may pass over it and shall be not less than three feet below the surface of the roadway.
(3) Pipelines under railways shall be installed in accordance with Pipe Crossings Under Railways (E-10) Regulations.
47 (1) Except for pipelines between adjacent loading or unloading racks, pipelines on the railway right-of-way within 20 feet of the gauge side of the nearest rail of a track shall be laid not less than three feet below ground, or be enclosed in a reinforced concrete or steel trench as prescribed in subsection 46(1), or be carried on an overhead pipe bridge with a clearance above ground of not less than 13 feet, or be enclosed by a fence.
(2) Pipelines running parallel to a track, except those between adjacent unloading or loading racks, shall not be closer than 10 feet to the gauge side of the nearest rail of that track and shall comply with subsection (1).
48 Provision shall be made in loading or unloading lines for relief of pressure before disconnection.
49 When loading or unloading racks are not employed for loading or unloading tank cars, the filling or discharge terminals shall be protected on all sides by a guard rail of metal or other material of equivalent strength and permanence. The guard rail shall be not less than three feet in height.
50 Tank car loading or unloading lines shall be equipped with shut-off valves located at the tank car end of the loading or unloading line. These valves shall not be used for throttling purposes, but shall be either fully open or fully closed in order not to interfere with the operation of excess flow valves on the tank car.
51 All piping inside buildings where anhydrous ammonia is stored or handled shall be grounded to prevent the build-up of static electricity. The resistance to ground shall be as low as possible and preferably not more than six ohms.
52 (1) All piping, valves and fittings shall be inspected and tested after assembly and prior to commencing operations for the first time and be proven gastight at a pressure not less than the working pressure of the tank, pump or device to which they are connected, or at 150 psig if this is a higher pressure.
(2) The results of the piping inspection and test shall be reported to the Commission.
53 (1) If housed, pumps or compressors driven by internal combustion engines or non-explosion proof motors shall comply with subsections (3) to (6).
(2) The pump or compressor should be separated from the engine or motor by a fireproof and vapour-proof wall.
(3) Except for the frame, the building shall be constructed of noncombustible or fire-resistant materials.
(4) Engine exhausts shall terminate outside the building.
(5) The building shall be cross-ventilated near the ceiling level.
(6) The entire system shall be maintained in good operating condition at all times.
PART VSafety Relief Devices
54 (1) Each unrefrigerated tank shall be equipped with one or more safety relief valves of the spring loaded type or an equivalent type which have been approved for the intended service by the Boiler and Pressure Vessel Committee of A.S.M.E., or the Compressed Gas Association, Inc., or Underwriters’ Laboratories.
(2) The valves referred to in subsection (1) shall be of a size that will ensure a rate of discharge not less than that specified in the current edition of Agricultural Ammonia Institute pamphlet, Standards for the Storage and Handling of Anhydrous Ammonia.
(3) The rate of discharge prescribed in subsection (2) shall be obtained before the pressure is in excess of 120 per cent of the maximum permitted start to discharge pressure setting of the device.
(4) The rate of discharge for relief valves on refrigerated tanks shall be in accordance with the current edition of Agricultural Ammonia Institute pamphlet, Standards for the Storage and Handling of Anhydrous Ammonia.
(5) Safety relief valves on unrefrigerated tanks shall be set to start to discharge at pressures as prescribed in the current edition of Agricultural Ammonia Institute pamphlet, Standards for the Storage and Handling of Anhydrous Ammonia.
(6) Relief valves on refrigerated containers shall be set to discharge at a pressure not in excess of the design working pressure of the container.
(7) Safety relief valves shall be installed in a manner that will ensure that the full relief requirements are always satisfied.
55 (1) All storage tank relief devices shall be located on the storage tank and shall have direct communication with the vapour space of the tank.
(2) If the design of the relief system is such that liquid can collect on the discharge side of the disc, the valve shall be equipped with a suitable drain.
(3) Tank safety relief valves shall be vented vertically to the outside atmosphere at a safe location and at least seven feet above the tank; except that for a tank of 2,000 Imperial gallons capacity or less and not provided with a ladder or other means of access to the top, the top of the vent shall not be less than seven feet above ground level.
(4) The end of the vent pipe shall be fitted with a loose rain cap that will not freeze in place.
(5) Safety relief devices shall be so arranged that the possibility of tampering will be minimized.
(6) Return bends and restrictive piping are not permitted in relief valve piping.
(7) External pressure settings or adjustments shall be sealed.
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