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MODULE 5

MODULE 5. Unloading Bobtails. Introduction. This module reviews the features and installation requirements of ASME tanks at customer locations. It also presents detailed procedures for unloading a bobtail at a customer location and risks associated with unloading a bobtail at the bulk plant.

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MODULE 5

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  1. MODULE 5 Unloading Bobtails

  2. Introduction This module reviews the features and installation requirements of ASME tanks at customer locations. It also presents detailed procedures for unloading a bobtail at a customer location and risks associated with unloading a bobtail at the bulk plant. Objectives After completing this module, you will be able to: • Identify features of ASME tanks including tank size, design information, and valves and gauges • Identify procedures for examining customer containers and installations to ensure a safe unloading operation • Identify procedures for filling propane storage containers from a bobtail • Identify risks associated with unloading a bobtail at a bulk plant

  3. LESSON 1 ASME Tank Requirements

  4. U.S. DOT and ASME Containers Although cylinders and tanks are both pressure vessels, they must comply with different codes and specifications, are often used in different settings, and are filled by different methods. U.S. Department of Transportation (DOT) cylinders are designed for transportation while most ASME tanks are not designed for shipping at their maximum permitted filling capacity. Cylinders may be filled at the bulk plant and transported to the customer while stationary cylinders and tanks may be filled at the customer site. Understanding the features and functions of ASME tanks will prepare you for safely and efficiently filling customer tanks with your bobtail.

  5. ASME Tank Size ASME tanks are manufactured according to design specifications developed by the American Society of Mechanical Engineers. The tanks are then categorized by the maximum amount of water they will hold. • A 1,000 gallon tank has a maximum water capacity of 1,000 gallons. However the tank can be filled with a maximum propane capacity of 800 gallons to allow for 20% liquid expansion. • ASME tanks range in size from 15 gallons water capacity (w.c.) for temporary motor fuel service to 120,000 gallons w.c. for permanent storage at terminals and large industrial installations. • Typically, residential and commercial customers use tanks ranging in size from 120 to 1,000-gallon w.c. • ASME tanks used to supply motor fuel range in size from 15 to 110 gallons. Some lift trucks use ASME tanks ranging in capacity from 4 to 24 gallons. MORE

  6. ASME Tank Size cont. ASME tanks used to supply motor fuel range in size from 15–110 gallons w.c. Residential and commercial customers use tanks ranging in size from 120–1,000 gallon w.c.

  7. ASME Tank Design Information All ASME tanks must have an attached data plate containing the following design information: • Service for which the container is designed. For example, underground, aboveground, or both. • Year of manufacture. • Water capacity of container in pounds or gallons. • Manufacturer's serial number. • Maximum allowable working pressure (MAWP) in psig. • The wording “This container shall not contain a product that has a vapor pressure in excess of 215 psig at 100° F.” MORE

  8. ASME Tank Design Information cont. • Name and address of container manufacturer or trade name of container. • Outside surface area in square feet. • Shell thickness and head thickness. • Overall Length (OL), Outside Diameter (OD), and Head Dish Radius (HD). • ASME code symbol. If the tank is buried, mounded, or insulated in a way that covers the data plate, the above information must be displayed on adjacent piping or on a structure in a clearly visible location.

  9. Valves and Gauges on ASME Stationary Tanks Valve and gauges on ASME stationary tanks vary in number, size, and location. Each specific type of tank is manufactured with the number of openings required for the type of intended service. Stationary installations can have tanks that are either: • Aboveground, or • Underground

  10. Aboveground ASME Tanks ASME tanks used in aboveground installations have valves and gauges that may include: • Service valve • Filler valve • Liquid withdrawal valve • Vapor equalization valve • Liquid level gauges • Fixed maximum liquid level gauge • Float gauge • Separate pressure relief valve • Pressure gauge (optional) Fittings on aboveground ASME tank installations are usually threaded, and commonly ¼″ to 2 ½″ female National Piping Thread (NPT). Openings may be on both the top and bottom of the tank. ASME tanks typically used for residential and commercial vapor service are often fitted with a single multivalve that combines the vapor service valve, vapor equalizing valve, fixed maximum liquid level gauge, and plugged ¼″ threaded opening for an optional pressure gauge. MORE

  11. Aboveground ASME Tanks cont. Typical gauges on an aboveground tank. Pressure relief and liquid withdrawal valves not shown. Multivalve example. Separate pressure relief valve not shown.

  12. Underground ASME Tanks Most ASME underground tanks with less than 2,000 gallons w.c. have one opening in the top of the tank with a pipe attached to it called a riser. The top of the riser is threaded to a 2 ½″ male NPT connection. Usually, a large combination valve is then installed on the top of the riser and includes a: • Pressure relief valve • Service valve • Filler valve • Vapor equalization valve • Float gauge • Fixed maximum liquid level gauge • Plugged vapor pressure gauge opening (installation of a pressure gauge is optional) MORE

  13. Underground ASME Tanks cont. A separate liquid withdrawal valve typically installed in a tank opening on the top of the tank shell, inside the dome near the riser, or about halfway toward one of the tank heads.

  14. Parts, Valves, and Gauges on ASME Vehicle-Mounted Tanks ASME vehicle-mounted tanks may include: • Heavy metal guards for valve protection • Container openings • Data plate • Barrel or shell • Head • Mounting bracket • Float gauge The number, size, and location of valves and gauges on ASME vehicle-mounted tanks also vary. However, two general rules apply only to mobile tanks: • Vehicle-mounted ASME tanks have a maximum of five threaded openings. • Valve fittings in a vehicle-mounted tank are threaded, and limited in size to ¼", ¾", and 1" female NPT.

  15. LESSON 2 Examining Propane Container Installations

  16. Introduction Before transferring propane to a customer’s container, you need to ensure that the container is safe for filling, and the surrounding area is free of hazards. If you determine conditions are unsafe for filling, you must notify your supervisor. You may be required to inspect the following types of containers at customer locations before unloading your bobtail: • ASME aboveground tanks • ASME underground tanks • ASME vehicle-mounted tanks • DOT stationary cylinders • DOT portable cylinders This lesson presents information on how to inspect each of these types of containers.

  17. Inspect the Supporting Foundation When inspecting the supporting foundation on ASME aboveground tanks and DOT stationary cylinders, make sure that: • All containers are properly supported and level. • Aboveground containers are installed on firm, non-combustible foundations that prevent contact of the container body with soil or standing water. • Masonry foundation is not significantly cracked or compromised. • There is no erosion that is undermining the tank’s foundation.

  18. Inspect Container Location: Aboveground ASME Tanks Aboveground ASME tanks must be positioned so that the filling connection, the relief valve discharge and the fixed maximum liquid level gauge are at least 10 ft from any external source of ignition (e.g., open flame, window A/C, compressor), intake to direct-vented gas appliances, or intake to a mechanical ventilation system. In addition, the relief valve discharge must be at least 5 ft horizontally from any opening in the building below the level of the discharge. This requirement is typically for ASME containers that are placed next to a structure. Tank Size Minimum Distance Requirements • 125–500 gallons w.c.—Must be located no closer than 10 ft from any important building, or property line that can be built on. • 501–2000 gallons w.c.—Must be located no closer than 25 ft from important buildings or property lines. An exception to this rule is that a single container of 1,200 gallons w.c. or less can be located 10 ft or more from an important building or property line when it is at least 25 ft from any other propane container greater than 125 gallons w.c. • 251–2000 gallons w.c.—Must be located at least 3 ft from each other. MORE

  19. Inspect Container Location: Aboveground ASME Tanks cont.

  20. Inspect Container Location: DOT Stationary Cylinders NFPA 58 sets the following minimum separation distance requirements for DOT stationary cylinders: • For cylinders filled on site, the relief valve, fixed maximum liquid level gauge vent discharge and filling connection must be at least 10 ft from any exterior source of ignition, openings into direct-vent appliances, or mechanical ventilation air intakes. • In addition, all cylinder relief valve discharges must be at least 3 ft horizontally from any opening into the building located below the discharge.

  21. Inspect Container Location: Underground ASME Tanks NFPA 58 puts the following minimum distances on the location of underground ASME tanks: • The relief valve, fixed maximum liquid level gauge vent discharge, and filling connection must be at least 10 ft from any exterior source of ignition, opening into direct-vent appliances, or mechanical ventilation air intakes. • All relief valve discharges must be at least 5 ft horizontally from any opening into the building located below the discharge. • All parts of the underground container must be at least 10 ft from an important building or line of adjoining property that may be built upon.

  22. Inspect Container Information When examining the container information, be sure to check the following on ASME tanks and DOT cylinders: ASME Tanks • Serial number on the delivery ticket against the serial number on the data plate, if the information is available. • Design pressure of the tank. ASME aboveground tanks must have a minimum design pressure of at least 250 psi. Tanks marked 200 psi manufactured under Paragraph U-68 and U-69 of 1949 or earlier additions of ASME code are acceptable for LP-gas. MORE

  23. Inspect Container Information cont. DOT Stationary and Portable Cylinders • Serial number on the delivery ticket against the serial number on the cylinder, if the information is available. • Requalification date and the Requalification Identification Number (RIN), as applicable.

  24. Inspect Overall Fitness Check customer containers for signs of damage such as: • Fire. • Deep dents or cuts. • Gouges, bulges, or digs. • Extensive corrosion. • Leaks. • General distortion. • Cylinder protective collar defects on ASME aboveground and stationary tanks and portable cylinders. • Leg/foot ring defects on ASME aboveground and stationary tanks and portable cylinders. • Mounting bracket defects on ASME vehicle-mounted tanks. MORE

  25. Inspect Overall Fitness cont. If any of these conditions are found, contact your supervisor.  Note: Because ASME underground tanks are buried, they can only be checked for extensive corrosion, leaks, and general distortion within the dome.

  26. Inspect Valves Always inspect the condition of the filler, pressure relief, and service valves on the customer’s container prior to filling. Be sure that: • All protective/rain caps are in place. • There is no evidence of leaking. • There is no debris blocking the valve. • There are no signs of corrosion. • The gasket is in place on the filler valve. • The weep hole is open on the pressure relief valve. • The handwheel is functioning on the service valve. Never look directly into, or place your face over the pressure relief valve especially during or right after filling.

  27. Inspect Pressure Regulator(s) Check to ensure the pressure regulator on the container meets these requirements: • It is the proper service type such as high pressure, first stage, or integral two-stage. • Has a tightly closed adjusting closure cap. • It is protected from rain, sleet, or snow by a protective dome or cover, or by a secure installation with the regulator vent pointing down; and if applicable on ASME underground tanks, a snorkel tube is installed to protect the vent from being under water. • It is fitted with an insect screen to protect the vent opening. • Has no indication of vapor leakage at the connection, vent, any closure, or body seam. • Shows no evidence of tampering.

  28. Inspect the Gas Meter If there is a gas meter at the customer location, be sure that it is: • Located to allow for examination, reading, replacement, or necessary maintenance. • Properly supported so there is no unnecessary strain from the meter on the piping system. • Free of any leaks or tampering.

  29. Inspect the Transfer Site Inspecting the propane transfer site is the first step in ensuring a safe transfer. Before beginning any propane transfer operation, make sure the following conditions are met: • All internal combustion engines within 15 ft of the transfer are shutdown, unless the engine is being used to drive the transfer pump or compressor. • There is no source of ignition such as smoking, open flame or portable electrical tools within 25 ft of the point of transfer. • There is no metal cutting, grinding, welding, brazing or soldering within 35 ft of the point of transfer while filling operations are in progress. Note: Using a residential customer installation checklist will help you ensure a consistent and thorough examination of customer containers and installations.

  30. Hazards at Residential Customer Sites Make every attempt to ensure a safe path to the customer’s container before driving your bobtail on the property. If possible, choose a path that: • Is free of any obstructions such as lawn equipment and other vehicles. • Is free of problem areas such as gardens, septic tanks, or fences. • Does not require “zigzag” driving or backing out of the site after completing the delivery. • Does not include soft or water-soaked ground that might cause the truck to become stuck. • Does not require the hose to be stretched across a roadway or railroad track. • Is away from areas where children are playing, or where animals roam freely.

  31. Hazards at Commercial and Industrial Sites • When making deliveries at commercial and industrial sites, conduct the site survey and take special care to ensure that transfer hoses are protected from damage or cutting due to: • Vehicles, including industrial lift trucks. • Railcars and siding tracks. • Sharp objects or process machinery. • Routing the hose in or through any building. • Other hazards.

  32. LESSON 3 Filling Propane Storage Containers at Customer Locations

  33. Introduction This lesson presents a suggested 8-step procedure for filling a customer’s container from a bobtail. This procedure is the same regardless of the type of container you are filling at the customer site. • Step 1: Position the Bobtail • Step 2: Perform the Site Inspection and Check the Liquid Level in the Container • Step 3: Set the Meter, Open Valves, and Engage the PTO • Step 4: Prepare Hoses and Filler Valve • Step 5: Connect Hoses and Check for Leaks • Step 6: Fill the Customer’s Container • Step 7: Disconnect Hoses • Step 8: Prepare the Bobtail for the Next Delivery

  34. Unloading Safety Precautions During filling, always remember: • You should never leave the transfer area. If you must leave the area, stop the unloading operation. • DOT regulations require that you remain within 150 ft of the truck and 25 ft of the delivery hose during unloading. On deliveries that take longer than 5 minutes to complete, you must observe the vehicle and the customer’s tank once every 5 minutes while the liquid internal valve is open. • If a leak or fire develops, if safe to do so, shut off the liquid delivery hose-end valve and liquid internal valve and stop the pump by using your remote device or the emergency remote shutoff switch located on the truck. • Follow other emergency procedures, as appropriate. If filling a container on an RV, be sure to turn off all appliance pilot lights and electronic ignition systems.

  35. Step 1: Position the Bobtail When positioning your bobtail at the customer location, be sure to: • Drive your bobtail in a low gear on the property. • Park it in a proper position to make the delivery and at least 10 ft from the customer’s container. • Set the parking brake. • Place chock blocks in front of and behind a rear wheel to help prevent the vehicle from rolling forward or backward.

  36. Step 2: Perform the Site Inspection and Check the Liquid Level in the Container • Overall Site Inspection: Check the container’s foundation, location, valves, regulators, and container information to ensure a safe filling operation. • Check the Fixed Maximum Liquid Level Gauge: In order to prevent overfilling, check the fixed maximum liquid level gauge on the customer’s container to verify it is not already full. Do not rely on the float gauge. The fixed maximum liquid level gauge should also be checked to ensure that there is pressure in the container before starting to fill it. If no pressure is indicated, follow your company’s policy to determine if the fixed maximum liquid level gauge is functioning properly. If the gauge is functioning properly and there is no pressure in the container, follow your company’s policy regarding interruption of service. Proceed to the next step once you have confirmed that the container is safe to fill.

  37. Step 3: Set the Meter, Open Valves, and Engage the PTO Once you have completed the site inspection, do the following: • Depending on the type of meter on the truck, you may need to insert a delivery ticket into the meter register or the electronic printer in the cab. • Open any manual shutoff valves upstream or downstream from the automatic by-pass valve. If the bobtail is so equipped, ensure that the manual by-pass valve is closed. • Open the liquid internal valve and engage the PTO. • Set the engine RPM to the proper speed.

  38. Step 4: Check Hoses and Filler Valve Before connecting the liquid fill hose, be sure to: • Ensure the liquid delivery hose-end valve is fully closed and the liquid delivery hose-end safety adapter is in place. • Extend the bobtail’s liquid delivery hose to the customer’s container. Make sure that the valve outlet is pointed away from your body. Never carry the hose-end valve by the valve lever or hand wheel and never drag the hose-end valve on the ground.  • Remove the dust cap from the filler valve on the customer’s container. If the dust cap is missing, replace it from the supply in your truck. If the filler valve begins to leak substantially when the dust cap is loosened, retighten the cap. Do not fill the container and contact your supervisor for instructions. • Inspect the filler valve and, if necessary, replace the O-ring or gasket. Remove any dirt and debris from the filler valve with a clean dry cloth. MORE

  39. Step 4: Check Hoses and Filler Valve cont. Ensure the liquid delivery hose-end valve is fully closed and the liquid delivery hose-end safety adapter is in place. Never carry the hose-end valve by the valve lever or handwheel and never drag the hose-end valve on the ground. If the filler valve begins to leak substantially when the dust cap is loosened, retighten the cap. Do not fill the container and contact your supervisor for instructions.

  40. Step 5: Connect Hoses and Check for Leaks • Connect the liquid delivery hose to the filler valve on the storage container, gently moving the hose-end valve back and forth while it is tightened in the ACME connector. Hand-tighten only. • Open the bobtail’s liquid delivery hose-end valve and check the connection for leaks If the connection is leak free, proceed with the filling operation. • If the connection leaks, try to retighten it. If the connection continues to leak, bleed down and disconnect the liquid delivery hose. • Recheck the gasket or O-ring and, if necessary, reseat or replace it. • Reconnect the liquid delivery hose and retest the connection. If the connection still leaks, do not fill the container and report it to your supervisor. MORE

  41. Step 5: Connect Hoses and Check for Leaks cont. Hand-tighten the liquid delivery hose to the filler valve. Open the bobtail’s liquid delivery hose-end valve and check the connection for leaks.

  42. Step 6: Fill the Customer’s Container To fill the customer’s container: Open the vent valve on the fixed maximum liquid level gauge installed in the storage container. Open the liquid delivery hose-end valve to start the flow of propane. When a white mist sprays out of the fixed maximum liquid level gauge, immediately close the liquid delivery hose-end valve and the vent valve on the fixed maximum liquid level gauge.

  43. Step 7: Disconnect Hoses When the unloading operation is complete: • Open the bleeder valve on the liquid delivery hose-end valve. When propane stops venting from the connection, disconnect the hose-end valve from the filler valve on the container. • Retract and lock the liquid delivery hose in the travel position. • Replace the dust cap on the filler valve on the container. • Return the engine speed to the normal idle and disengage the PTO. • Close the liquid internal valve and all applicable valves on the back of the bobtail. MORE

  44. Step 7: Disconnect Hoses cont. Disconnect the hose-end valve from the filler valve on the container. Disengage the PTO and close the liquid internal valve and all applicable valves on the back of the bobtail.

  45. Step 8: Complete the Delivery To prepare the bobtail for next delivery: • Reset the meter register so the delivery ticket is stamped or print the ticket in the electronic printer. Remove and separate any customer copies of the ticket and leave them with the customer. • Complete any additional paperwork such as the route book, delivery vehicle manifest. • Walk around the truck to ensure that all transfer equipment is stored and the pathway out of the customer site is clear. Always try to avoid backing into traffic. • Remove the chock blocks and store them on the bobtail.

  46. Unloading the Bobtail at the Bulk Plant There maybe times when you will need to unload your bobtail at the bulk plant such as when: • Your cargo tank has been overfilled. • Your cargo tank needs to be serviced or repaired. • You need to drive or park your vehicle in a high security area. Note: All bulk plants are different. Contact your supervisor for specific bulk plant procedures.

  47. Summary Some important points to remember from this module are: • You should understand the design, features, and functions of ASME tanks for safely and efficiently filling customer tanks with your bobtail. • Valves and gauges on ASME stationary tanks vary in number, size, and location. Each specific type of tank is manufactured with the number of fittings required for the type of intended service. • Before unloading at a customer location, you are responsible for ensuring customer storage containers and installations are in good condition and properly located. • If you determine that the container or surrounding area is unsafe for filling, NFPA requires that the user and owner of the container must be notified in writing that the container does not comply with NFPA codes. You should follow your company policy and suspend all unloading operations if you find an unsafe condition. • This module presented an 8-step unloading process as a guide. Remember that bobtail design and operation differ between companies and manufacturers, so unloading sequences may vary. Be sure to ask your supervisor for your company’s unloading procedure.

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