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3.7.2. Identifying Testing and Inspection Requirements for DOT Intermodal (IM) Tanks . Propane plant personnel should know the requirements for inspecting and periodic testing of IM tank, as part of the verification process, before placing it into service .
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3.7.2 Identifying Testing and Inspection Requirements for DOT Intermodal (IM) Tanks • Propane plant personnel should know the requirements for inspecting and periodic testing of IM tank, as part of the verification process, before placing it into service. • In this module you will learn to identify: • Procedures for inspecting and testing DOT Intermodal (IM) tanks for fitness for continued service • Required markings for DOT Intermodal (IM) tanks
Identifying and Testing DOT Intermodal (IM) Tanks for Fitness for Continued Service. • Called “intermodal containers” because they are designed to be transported by highway and railroads, DOT specification 51 containers are also transported by water vessels under the jurisdiction of the U.S. Coast Guard. • Portable tanks approved for transportation of LP-gas filled to their maximum filling density are known as DOT (specification) 51 tanks • Their water capacities can be as large as 34,500 pounds, or 3,450 gallons propane capacity. Figure 1. DOT 51 IM Portable Tank Picture Courtesy of TTS Containers, Inc., Gainesville, Texas
Identifying and Testing DOT Intermodal (IM) Tanks for Fitness for Continued Service. Tank Openings for Valves • Openings except for pressure-relief devices, inspection openings, and closed bleed holes must be fitted with at least three mutually independent shut-off devices in series: • An internal stop-valve with internal excess flow device • An external stop-valve • A blank flange or threaded cap, plug or equivalent tight liquid closure device (Figure 2) Figure 2. Shut-off Devices in Series
Identifying and Testing DOT Intermodal (IM) Tanks for Fitness for Continued Service. Tank Openings for Valves • For filling and discharge openings located below the liquid level, the internal stop-valve must be a self-closing safety device that fully closes automatically during filling or discharge in the event of fire within 30 seconds of the actuation of the thermal means of closure. Except for tanks having a capacity of less than 264 water gallons, this device must be operable by remote control.
Identifying and Testing DOT Intermodal (IM) Tanks for Fitness for Continued Service. • Mounting and Lifting Hardware • The lugs are welded to support pads which are welded to the tank • Data Plate Information • Water Capacity and Tare Weight • Design Pressure • Note: • Check the skids, lugs and support plates for damage before working with a DOT portable tank. Corrosion or cracked welds are extremely dangerous. If there is any damage, notify your supervisor immediately. Figure 3. DOT/ICC Portable Tank Data Plate • Note: • Check both the DOT and ASME data plates to ensure that both read 250 psig before placing a DOT portable tank into service.
Identifying and Testing DOT Intermodal (IM) Tanks for Fitness for Continued Service. • Design Specific Gravity • The design specific gravity for a DOT 51 portable or IM tank used for propane is 0.510. • Test Dates • The pressure test and inspection must be successfully completed every 5 years, with the month and year of the most recent test and inspection marked on the tank on or near its data plate.
Identifying Required Markup for DOT Intermodal (IM) Tanks. • The shipping name is marked on two opposing sides of the tank located about one-half or two-thirds of the distance between the bottom and the top of the shell. • The name of the owner or lessee of the tank may be clearly painted on the tank or attached to the tank on a label or decal. Figure 4. Accepted Product Shipping Names
Either This: This: or or This: This: Identifying Required Markup for DOT Intermodal (IM) Tanks. Figure 5. Flammable Gas Placards
Identifying Required Markup for DOT Intermodal (IM) Tanks. • IM Tanks with a rated LP-gas capacity greater than 1,000 gallons - four placards, one on each side and each head of the tank (never on the bottom of the tank). • IM Tanks with a rated LP-gas capacity less than 1,000 gallons - two placards or labels, one located on each side of the tank near the shipping name or one on each head of the tank.
Time to See If You Got the Key Points of This Module… • Complete the Review on page 7 & 8. • See if you are ready for the Certification Exam by checking off the performance criteria on page 9.
