MODULE 7

1. MODULE 7 Preparing Cylinders for Filling

2. Introduction You must properly prepare cylinders for service before you fill them with propane. You do this by thoroughly inspecting their overall condition, purging them of air, and repairing or replacing any defective valves. This module introduces you to the different types of cylinders and their parts, and teaches you how to prepare them correctly. After completing this module, you will be able to: • Identify the types and features of DOT/ICC cylinders and their common valves, gauges, and fittings • Understand the process for visually inspecting cylinders to determine if they are safe for continued service • Know why cylinders must be purged of air and how to purge them using either propane vapor or a vacuum pump • Determine if a cylinder valve needs to be repaired or replaced and describe the processes for valve extraction and replacement

3. LESSON 1 Types and Features of Cylinders, Valves, and Gauges

4. Introduction NFPA 58 defines “cylinder” as a container constructed in accordance with U.S. Department of Transportation (DOT) specifications. DOT/ICC cylinders range in size from one lb disposable cylinders to 420 lb propane capacity (or 1,000 lb water capacity) stationary cylinders. As discussed in Basic Principles and Practices of Propane, DOT/ICC cylinders are used for portable, motor fuel, exchange, and stationary propane service. In this lesson, you’ll learn about the construction and features of these cylinders and their service applications. You’ll also learn about common cylinder valves, gauges, and fittings, and how they differ by cylinder type.

5. Cylinder Types All propane cylinders are built to DOT specifications and are often called DOT cylinders. There are three types of DOT cylinders: Small Portable cylinders: Small portable cylinders, up to 40 lb capacity, used for gas grills, small portable heaters, camping trailers, plumbers melting pots, and other small systems. MORE

6. Cylinder Types cont. All propane cylinders are built to DOT specifications and are often called DOT cylinders. There are three types of DOT cylinders: Large portable cylinders:Large portable cylinders are used on large space heaters, tar heaters, some residential sites, ice fishing shacks, and other large equipment. MORE

7. Cylinder Types, cont. All propane cylinders are built to DOT specifications and are often called DOT cylinders. There are three types of DOT cylinders: Stationary cylinders:Stationary cylinders are designed to be installed permanently at customer locations. Stationary cylinders are frequently seen in bulk plants, from which they are delivered to customer sites. Although they can be filled at a bulk plant, they are usually filled at the customer site Their size and weight, when filled, makes loading and unloading difficult without the aid of special lifting machinery. MORE

8. Liquid and Vapor Service Cylinders provide liquid service or vapor service depending on where the product is pulled from in the container. Many cylinders are equipped to handle both liquid and vapor service. Liquid service applications pull propane from the liquid space in the container. Liquid service applications require a high level of energy to fuel applications such as forklift engines or commercial heating applications. Vapor service applications pull propane from the vapor space in the container. Vapor service is more common in the propane industry as the amount of energy created from the vapor space is sufficient for fueling applications such as stoves and dryers. The liquid and vapor connections are marked "liquid" or "vapor."

9. Valve Overview Cylinder valves play a key role in filling and service operations. Valves are designed to regulate the amount of propane that goes in and out of the cylinder. The cylinders you will fill may have several openings for different valves or have only one opening for a multivalve that combines several valve functions in one unit. The number and types of valves will depend upon the cylinder, its construction, and how it is used by your company and its customers. According to NFPA 58, cylinders of 45 lb. propane capacity or less must have a redundant pressure-tight seal (plug or cap) or a listed quick-connect coupling in place whenever the cylinder is not connected for use.

10. Cylinder Valves Review the cylinder valve descriptions to better understand each valve’s purpose and operation. Service valve: Permits the transfer of vapor or liquid propane from the cylinder to gas burning equipment. It controls the flow of product in and out of a container. Some service valves incorporate a fixed maximum liquid level gauge and have an overfilling prevention device (OPD). • Liquid withdrawal tube. The liquid withdrawal tube extends to the bottom of the cylinder so that its opening is always in the liquid section of the cylinder. • Excess flow valve. The excess flow valve is located just below the service valve’s threaded fitting. MORE

11. Cylinder Valves, cont. Review the cylinder valve descriptions to better understand each valve’s purpose and operation. Pressure relief valve: Releases excess pressure from cylinders in the event of overfilling or exposure to extremely high temperatures. Filler Valve: Provides a connection to allow for the transfer of liquid propane from a supply tank into the cylinder. Some cylinders may have a separate filler valve.

12. Cylinder Multivalve Some cylinders have a multivalve that includes a pressure relief valve, service valve, a fixed maximum liquid level gauge, and a filler valve. Multivalves are beneficial because they minimize the potential for leaks as they require only one opening. However, replacement may be costly because one damaged feature (valve) will require a complete unit replacement.

13. Types of Cylinder Gauges There are two types of gauges found on most cylinders: Fixed Maximum Liquid Level Gauge • Purpose: Indicates when the cylinder is filled to its maximum level. • Design: Constructed of a body (with an orifice/hole), plug, and dip tube. • Operation: The dip tube extends far enough into the vapor section of the cylinder so that liquid will just reach its opening when the cylinder is approximately 80% liquid filled. MORE

14. Types of Cylinder Gauges, cont. Float Gauge • Purpose: Continuously indicates the liquid level in a container. • Design: Constructed of a sealed dial, stem, gear housing, float mechanism, and a mounting adapter (normally installed by the container manufacturer). • Operation: When the liquid level in a container changes, the gauge assembly that floats on the top of the liquid moves. As the float assembly moves, the drive assembly turns a "drive" magnet that causes the dial assembly to turn.

15. Overfilling Prevention Devices Service valves on some cylinders have an overfilling prevention device (OPD) which does just what its name suggests. This mechanism helps prevent the cylinder from becoming overfilled by stopping the flow of liquid propane into the cylinder when it is about 80% filled. OPDs are a second way to protect against overfilling cylinders. OPD cylinder valves are distinctively marked and equipped with a unique triangle-shaped handwheel to make identification easier. OPDs need to be appropriately sized to fit each cylinder. The OPD marking is molded into the handwheel and the valve body. MORE

16. Overfilling Prevention Devices cont. OPD Requirements According to NFPA 58, new 4 to 40 lb cylinders must be equipped with an OPD. Exceptions to the OPD requirement are allowed for motor fuel cylinders, horizontal cylinders, and cylinders used for industrial welding and cutting gas. In certain jurisdictions, no cylinder in the 4 to 40 lb vapor cylinder sizes can be filled unless it is equipped with an OPD and a fixed maximum liquid level gauge of the proper length. These requirements may differ in your state or local jurisdiction if the 1998 or a later edition of NFPA 58 has not been adopted, or if the authority having jurisdiction has adopted other requirements for refitting and/or filling cylinders not equipped with OPDs at the time of manufacture.

17. Discovery: Motor Fuel Cylinder Features

18. Discovery: Stationary Cylinder Features

19. LESSON 2 Inspecting Cylinders

20. Introduction You must visually inspect cylinders at several points during the propane delivery process to determine they are in good condition for continued service. • Prior to filling a cylinder with propane: Carefully inspect cylinders before they are filled. Filling a cylinder after inspection assures it has been checked and approved for continued service according to DOT and NFPA 58 regulations. • Prior to loading a cylinder on the delivery vehicle: You must inspect all cylinders before they are loaded on the delivery vehicle or before they leave the bulk plant. • When new cylinders are first received at the bulk plant: After or during unloading at the bulk plant, you must inspect each new cylinder to determine its fitness for continued service. MORE

21. Introduction, cont. This lesson gives you a 4-step process for visually inspecting cylinders. Following this process will help you to make sure that all features and equipment are fully examined. By visually inspecting cylinders, you will be able to determine if they are approved for continued service or need to be removed from service.

22. Steps for Inspecting DOT/ICC Cylinders Always complete these steps every time you inspect a cylinder: • Step 1: Check the Cylinder Requalification Date • Step 2: Determine the Overall Fitness of the Cylinder • Step 3: Identify Required Cylinder Markings • Step 4: Identify Required Cylinder Labels

23. Step 1: Check the Cylinder Requalification Date When inspecting a cylinder, first check the requalification due date. All DOT/ICC cylinders used to transport propane must be requalified 12 years after their manufacture date, and every 5, 7, or 12 years thereafter, depending on the method used for the last requalification. The most recent requalification date is stamped on the cylinder and includes: • The month and year of the last requalification • The requalification identification number (RIN) • A single letter to indicate the requalification method that was used (unless the hydrostatic test is used) When a cylinder is relatively new, the most recent date may be the date when the cylinder was manufactured or tested. MORE

24. Step 1: Check the Cylinder Requalification Date, cont. All cylinders must be requalified before their due date. A DOT/ICC cylinder that does not have a current requalification date must be removed from service and cannot be refilled until it has been retested or requalified. A cylinder may require requalification sooner if it is damaged or subjected to physical abuse, excessive corrosion, or heat. Aluminum cylinders that have been exposed to fire must be immediately removed from service.

25. Requalification Methods There are three ways to requalify a cylinder. The specific method used is indicated on the date stamped on each cylinder: • Hydrostatic Test: A date without a letter indicates the cylinder was subjected to a complete water jacket hydrostatic test. The next requalification must be within 12 years • Proof Pressure Test: A date followed by the letter “S” indicates a proof pressure test has been performed. The next requalification must be within 7 years • External Visual Inspection (CGA Inspection Method): A date followed by the letter “E” indicates a recorded external visual inspection was performed. The next requalification must be within 5 years.

26. Important DOT Requalification Terms Cylinder conditions are clearly defined by DOT regulations. • Condemn: The cylinder is unserviceable for the continued transportation of hazardous materials in commerce, and may not be restored by repair, rebuilding, requalification, or any other procedure. Cylinders with a series of XXXs over the DOT specification number and marked service pressure or stamped with “CONDEMNED” on the shoulder, top head, or neck are condemned cylinders which must not be refilled or continued in service. • Defect: The cylinder has an imperfection requiring its removal from service. • Filled orcharged: The cylinder has had a hazardous material introduced into it. MORE

27. Important DOT Requalification Terms, cont. • Repair: The cylinder has been inspected but cannot be requalified in its current condition.Repair status allows the cylinder to be repaired, or transported for repair, but it can’t be used in continued service. After repair, it can be re-inspected and either requalified or condemned. • Rejected: The cylinder cannot be continued in service without repair, rebuilding, and requalification. • Requalification: The cylinder requires a complete visual inspection and/or the test(s) to determine its suitability for continued service.

28. Step 2: Determine the Overall Fitness of the Cylinder DOT requires a visual inspection of the overall physical fitness of each cylinder before filling and loading for transport, or when it first arrives at the bulk plant. Look for these signs: • Crack or leak • Bulging • Serious denting or gouging • Defective valve(s) • Defective or leaking pressure relief device • Damage to the cylinder valve, valve protection, or cylinder foot rings • Evidence of physical abuse, fire or heat damage, or excessive rusting or corrosion If any of these are found, the cylinder must not be refilled or transported until it has been requalified according to DOT regulations.

29. Inspecting Cylinder Valves Determining cylinder fitness includes visually inspecting the condition of the cylinder valves and fittings. Carefully examine: • Service valve handwheels and stems • Manufacturer date of the relief valve • Pipeaway adapters • Quick-closing couplings on motor fuel cylinder service valves • Filler valves and weather caps • Fixed maximum liquid level gauge • Cylinder valve protective collars or valve caps and threads • Float gauge dial faces and operation of float gauges • Foot rings and welds MORE

30. Inspecting Cylinder Valves cont. Always check out any abnormal condition reported by a customer. If you determine that a valve or fitting must be replaced, mark the cylinder with a tag or suitable marker and move it to a designated area for valve replacement. If requalification is required, mark this as well and move the cylinder to the proper location.

31. Step 3: Identify Required Cylinder Markings In addition to required labels, regardless of their size or application, all DOT cylinders must have permanent cylinder markings stamped on either the shoulder or protective collar. These markings include: A) Tare weight in pounds: The weight of the cylinder when empty (including the weight of the cylinder valves). B) Water capacity in pounds: The weight of water needed to completely fill a cylinder. C) Manufacturer name: The name of the company who built the cylinder. D) Specification design code: Because propane can be transported and stored in more than one type of DOT cylinder there are several approved DOT and ICC cylinder design codes. These design code markings typically consist of a specification design code and the service pressure. MORE

32. Step 3: Identify Required Cylinder Markings cont. E) Serial number: Used to identify the manufacturer’s inspector’s report as to material and required test data which is on file with the Bureau of Explosives. F) DT Symbol: The figure following "DT" is the correct length of the dip tube in inches and decimal fractions, which should be used for volume filling of this size and type cylinder. G) Manufacturer original test date: Indicates the date that the manufacturer inspected the cylinder and determined it suitable for service. H) Requalification date: The month and year of requalification test. I) Requalification identification number (RIN): After 2003, all requalified cylinders must have a unique number stamped on them by those companies holding a RIN.

33. Step 4: Identify Required Cylinder Labels Cylinders must be inspected for proper labels when they are first received at the unloading dock. Labels should be readily visible during transportation, should not obstruct any other required cylinder markings, and must be placed against a background of contrasting color. There are three types of cylinder labels: • Shipping Label: DOT requires shipping labels for all cylinders that contain a hazardous material transported in commerce. These labels must be readable and include the proper shipping name (LP-Gas UN 1075) and its hazard class (2). • Consumer Information/Warning Label: NFPA 58 requires a consumer information label for all portable, refillable propane cylinders of 100 lb or less that are not filled on site. This label includes information on the potential hazards of propane. MORE

34. Step 4: Identify Required Cylinder Labels cont. All three of these labels may be combined into a 3-in1 label. A 4-in-1 label adds propane marketer identification and emergency contact information for company-owned cylinders that are leased to customers. • OSHA Warning Label: To help commercial and industrial customers meet OSHA requirements, many propane marketers attach an OSHA warning label to cylinders that will be handled by customer employees. This label warns employees about the hazardous material stored in the cylinder.

36. LESSON 3 Purging Cylinders of Air

37. Introduction To keep customers safe, new propane cylinders that haven’t been vacuum purged by the manufacturer or have been opened to the atmosphere must be purged of air and moisture before they are placed into service. Cylinders should always be purged in an approved area where with no ignition sources. Two effective methods for purging air from cylinders are: • Using propane vapor to force the air out of the cylinder, or • Using a vacuum pump that removes the air by creating a vacuum. This lesson explains why purging air from cylinders is important and how to purge with propane vapor and a vacuum pump.

38. The Importance of Purging Cylinders It is important to purge air from cylinders. Air in a propane cylinder can cause several problems. The filling operation is slowed down. When a cylinder is filled with liquid propane, any air that is present in the container will be compressed in the top of the cylinder and could reach higher than normal pressures. This scenario may cause the relief valve to open sooner than normally expected. In addition, the compressed air will reduce the filling rate of the container. The cylinder may have unusually high storage pressure. When air is present with propane vapor in a closed cylinder, the total pressure in the cylinder may equal the combined pressure of the air and propane vapor. For example, if propane vapor is stored at 100 psig and the air is at 100 psig, the total pressure in the cylinder will be 200 psig. This excess pressure may cause the relief valve to open or “pop off”, venting flammable propane and air into the atmosphere. MORE

39. The Importance of Purging Cylinders, cont. Moist air may cause regulator freeze-up. If the temperature of the propane in the cylinder drops to the dew point of the air, the moisture in the air may condense and settle in the bottom of the cylinder. Moisture can be the cause of regulator freeze-up and possibly cause it to malfunction. Regulator freeze up can occur when the pressure of the propane is reduced in the regulator. This leads to the “refrigeration effect” which can then cool water vapor in the propane/air mixture, causing it to condense and then freeze, blocking flow through the regulator. Appliances may not operate properly. Both air and propane vapor, or just air, will flow to the burner of the appliance, causing the appliance to burn “lean” (too much air), or not at all. This may result in several service calls for pilot light outages. Air contributes to internal corrosion. Steel cylinders and tanks that have been open to the atmosphere for more than the brief time required for valve or fitting replacement are subject to corrosion on their internal wall surfaces. The by-product of corrosion is iron oxide, which tends to react with ethyl mercaptan, the principle odorant used in LP-gases. A temporary reduction in odorant can result until the iron oxide is no longer capable of reacting with ethyl mercaptan.

40. Steps for Purging Cylinders with Propane Vapor Using propane vapor to force the air out of the cylinder is an effective purging method. The steps for completing this process are as follows. Here’s the proper way to do it: Connect the vapor hose to the cylinder. Ensure that you have the correct fittings installed for connecting the vapor hose to the cylinder service valve. If a service valve that does not have a female POL opening is installed in the cylinder, attach any required cylinder service valve adapter to the POL adapter that is permanently installed in the vapor line hose end valve. Then securely tighten the vapor hose assembly to the cylinder service valve. Pressurize the cylinder with propane vapor to 15 psig. With valve 1 closed, open the service valve on the cylinder. Gradually open the shutoff valve (valve 3) on the end of the vapor hose. If no leakage is detected, open valve 2. Observe the gauge on the purging manifold. When the pressure reaches 15 psig, close valve 2. MORE

41. Steps for Purging Cylinders with Propane Vapor cont. • Bleed off the pressure in the cylinder. Open valve 1 to vent a small volume of propane vapor and air through the purging manifold. When the pressure gauge on the purging manifold reaches 0 psig, close valve 2 and open valve 1. Caution: During this bleed down process, a small amount of propane vapor and air will be vented to the atmosphere. This venting should be done at least 25 feet from any open flame, smoking area, portable electrical tools and extension lights. In addition, the venting should be done at least 35 feet from any metal cutting, grinding, oxygen-fuel gas cutting, brazing, soldering or welding. MORE

42. Steps for Purging Cylinders with Propane Vapor cont. • Repeat the purging process. To ensure that approximately 97% of the air has been purged from the cylinder, repeat Steps 3 and 4 at least four more times. Leave the vapor return hose connected. After the final purging is vented, close valve 1 and re-pressurize the cylinder. Close all valves including the cylinder service valve after the cylinder is pressurized and check the cylinder for leakage. Do not purge with liquid propane. To do so may cause the liquid to flash into vapor, chilling the cylinder and condensing any moisture vapor on the walls. In addition, less than 50% or as little as 25% of the air will be removed.

43. Steps for Purging Cylinders with a Vacuum Pump Another method for purging air from cylinders is by using a vacuum pump to force the air out. To properly purge air from a cylinder using a vacuum pump follow these steps: • Vent any pressure: Vent any positive pressure through a fixed maximum liquid level gauge before connecting the pump inlet hose. Retighten the gauge after the pressure is vented. • Connect the hose: Connect the pump inlet hose to the cylinder valve and tighten securely by hand. MORE

44. Steps for Purging Cylinders with a Vacuum Pump cont. • Turn pump on: Open the cylinder valve and turn the pump on. Allow the pump to pull 2 PSIA. • Turn pump off: Close the cylinder valve and turn the pump off. Disconnect the pump inlet hose from the cylinder valve. The cylinder is now ready to be filled. Always follow manufacturer instructions when using a vacuum pump to purge air from cylinders. Never attach the pump to any cylinder containing propane since the equipment is designed to only purge air.

45. LESSON 4 Replacing Cylinder Valves

46. Introduction You have learned how important it is to protect cylinder valves and fittings during loading, transport, and delivery operations. However, valves and fittings can still become damaged or defective from ongoing use or abuse causing the cylinder to become inoperable or susceptible to a propane leak. At times, you will be required to repair and replace cylinder valves and fittings at the bulk plant or in the field to keep DOT cylinders operating safely and efficiently. You may also be required to replace or install cylinder valves because of new code requirements. In this lesson, you will learn about common valve problems, how to inspect pressure relief valves, service valves, and filler valves, and the procedures for proper valve extraction and installation.

47. Common Problems with Cylinder Valves Inspect cylinder valves and fittings frequently to identify potential problems: Aging Valves: After extended use and/or abuse, springs, valve seats, and gaskets tend to wear out. Two serious valve problems that can develop are pressure relief valves that will not open at a specified pressure and excess-flow valves that will not "slug" shut at the proper flow rate. Check for signs of aging and wear. Leaking Valves: Many valves are made with nonmetallic, soft parts. Nylon, rubber, and Teflon are three materials used in o-rings, packing seals, valve discs, and gaskets to ensure that valves provide a gastight seal. When these materials wear out, propane liquid or vapor can leak out of the valve and create a potentially hazardous situation. With proper inspection and maintenance, leaking valves will be detected and repaired or replaced before causing problems. MORE

48. Common Problems with Cylinder Valves, cont. Missing or Damaged Valve Accessories: Valve accessories, such as relief valve angle adapters and weather caps, may become broken or lost. As a result, dirt, trash, moisture and other impurities can enter the valve. Frequent inspection and replacement of faulty or missing accessories can extend the life of propane valves. Improper Container Maintenance: Improper cylinder maintenance is a common cause of valve damage and malfunctions. For example, when cylinders are repainted, service personnel may fail to use proper trim brushes or applicators around container openings. As a result, gauge faces, "weep" holes in filler valves, and discharge openings of relief valves may become covered with paint.

49. Valve Exposure to Anhydrous Ammonia Exposure to anhydrous ammonia will damage and weaken brass valves used in cylinders. This deterioration will lead to cracking of the valve body or its components, product leakage, and the possibility of the violent unexpected expulsion of the valve from the cylinder, which could cause injury or death. A blue-green stain on the brass portion of the cylinder valve indicates that it has been in contact with anhydrous ammonia. If you find a cylinder that shows evidence of exposure to anhydrous ammonia: • Place the cylinder in an area where hazards from ejection of the valve and product loss would be minimized. • Do not attempt to remove or replace the valve. • Contact local or state law enforcement authorities, and the hazardous materials response agency that serves your location because ammonia contamination is often linked to the illegal manufacture of methamphetamines.

50. Inspecting Pressure Relief Valves When pressure relief valves fail to open at the correct pressure, propane liquid and/or vapor may leak out of the valve or the container may rupture. When the cylinder is filled, inspect pressure relief valves to identify signs of damage and prevent dangerous situations from developing. When inspecting pressure relief valves, be sure to: • Determine the set-to-discharge pressure if so marked. The setting should be 375 psig for all DOT/ICC cylinders and 250 psig for all ASME containers. • Ensure that the flow capacity of the valve is correct if so marked. • Look for missing or damaged rain caps. • Inspect pipe-away adapters for external damage or blockage. MORE