Covered Task 007OP Training Guide Operate Valves

Transcription

1 Directions This training guide is to be used by a Subject matter expert (SME) authorized Evaluator/Trainer and Trainee during on-thejob training (OJT) or prior to an evaluation as a resource. (S) Indicates a demonstration or skill task (K) indicates a knowledge task OJT Reminder: OJT is an active hands-on process. Practice should be as similar to the actual job task as possible. However, if the training is being provided on actual job site while a covered task is actually being simulated, the Evaluator either needs to be qualified on that covered task or be assisted by someone that is qualified on the covered task. The Evaluator should closely monitor the Trainee's practices to ensure safe and correct task performance. At no time should a non-qualified individual perform, or train for, a covered task unless directed and observed by a qualified individual. However, if the span of control for that particular covered task is NA (requiring only qualified individuals to perform the covered task), the training must be simulated. Training is simulated by "walking through" the task and simulating all actual manipulations (valves, switches, tools, etc.) an individual would use during the performance of a covered task. Simulating includes the use of safety and administrative requirements as if the task was being performed live. Refer to the Veriforce Evaluator Training Program for more on how to conduct formal OJT. Disclaimer: This training resource is offered in good faith. Anyone choosing to utilize this document is doing so at their own discretion and choice. Although every attempt has been made to ensure the correctness and suitability of this document and to correct any errors brought to our attention, no representation or guarantee is being made regarding correctness or suitability, either directly or indirectly, or regarding correctness or suitability of information referenced or implied. It is intended that this training tool be used exclusively by an Authorized Evaluator, who shall comply with all safety requirements and Company and/or Operator operating procedures, as applicable. In no event shall Boardwalk Pipelines be liable for any special, incidental or consequential damages or any damages whatsoever, including but not limited to, death, personal injury, damage, loss of use, loss of revenues, whether in an action of contract, negligence, or other action, arising out of the use or 1 of 9

2 misuse of this document. All critical information should be independently verified. The subject matter included in this training guide has been compiled from a variety of sources, and is subject to change without notice. Boardwalk Pipelines reserves the right to add, remove and alter information contained in this document without notice. Recommended Student Training or Resources Operator Qualified Criteria N/A To be Operator Qualified you must be able to: Correctly identify the most common types of pipeline valves Open and close a valve Identify the proper type of valve Determine valve position and verify whether a valve is in the correct position Operate a valve (manual or automatic) K: Identify a ball valve Ball Valves: The flow control element of a ball valve is ball-shaped with a round hole bored through the ball to allow for flow of product. The ball rotates within the body of the valve and is therefore always in the product path. When the valve is open, the hole aligns with the product and the product passes through it. When the valve is fully closed, the hole is perpendicular to the direction of flow, therefore flow is stopped. Ball valves are symmetrical, meaning either end can be used as the inlet. Because of this, ball valves allow flow from either direction. Ball valves are best suited for starting or stopping flow, but some designs allow for changing the direction of the flow. There are numerous ball valve manufacturers and many variations of ball valves within the pipeline industry. Ball valves may vary by: Body construction: Differences in body construction are typically a function of the method by which the ball is loaded into the body of the valve. Design examples include (a) split body, (b) end entry, (c) top entry, and (d) 3-piece. Ball design: Differences in ball design usually deal with port size and the manner by which the ball is supported. Port size is the diameter of the hole in 2 of 9

3 the ball that allows product to flow through. Port size dictates the rate of flow through the valve. There are primarily two ways in which the ball is supported within the valve body: (a) the floating ball design, and (b) the trunnionmounted ball design. In the floating ball design, the top of the ball is attached to the shaft, while the bottom is supported solely by the seat rings. For trunnionmounted ball design, both the top and bottom of the ball are attached to shafts at both the top and bottom Figure 1: Ball Valve Seat design: Typically, differences in seat design are related to the materials used to make the seat rings. Soft seats are typically made from non-metallic materials while metal seats are generally made from stainless steel or other base metal. Some of the advantages of ball valves include: Easy to operate Ability to maintain and regulate high volume, high pressure, and high temperature flows, based on design characteristics Durability allows for longer life of service Inspection and repair of seats and seals may be possible without removing the entire valve from the pipeline Possible drawbacks associated with ball valves include: The larger the port, the larger the valve must be from end-to-end, which may take up more space than some other valve types. With soft seats, temperature limitations may be a factor. With metal seats, leak-free seating may sometimes be difficult to achieve. 3 of 9

4 K: Identify Plug Valves Plug Valves The flow control element of the plug valve (the plug) is a cylinder or truncated cone with a hole through it. The plug rotates within the body of the valve to allow, restrict, or stop flow and is therefore always in the flow path. When the plug valve is fully open, the hole aligns with the flow allowing the product to pass directly through the plug. When the valve is fully closed, the hole is perpendicular to the flow path, therefore the flow is stopped. Plug valves are symmetrical, meaning either end can be used as the inlet. Because of this, plug valves allow flow from either direction. Plug valves are best suited for starting or stopping flow, but some designs allow for changing the direction of the flow. Plug valves are sometimes referred to as cock valves or stop-cock valves. Plug valves have a fairly simplistic design. There are three main parts of a plug valve: 1. Body 2. Cover 3. Plug The plug valve is operated by rotation. The plug is the only component that moves. Plug valves may be lubricated or non-lubricated. Lubrication between the plug face and the seat can: Control leakage Reduce wear Make the valve easier to operate Non-lubricated plug valves are typically fitted with a mechanical lifting device that unseats the plug prior to it being turned or is constructed with a special coating that reduces friction to allow for easier operation. Plug valves can have several advantages, including: Simple design makes it relatively to easy to maintain usually plug valves can be serviced without removing them from the pipeline Offers little resistance to flow when fully open Easy to operate Versatility High capacity Can be used for directional flow control (with multi-port plug valves) Ability to handle a wide range of pipeline products Possible drawbacks associated with plug valves include: 4 of 9

5 Relatively larger end-to-end size (as compared to some other types of valves), which may take up more space. Temperature limitations may be a factor, depending upon design characteristics. For lubricated plug valves, if sealant not renewed periodically, product may dissolve the sealant, causing seizing when the plug is turned. Figure 2: Plug Valve K: Identify a Gate Valve Gate Valves The flow control element of a gate valve (known as a gate, wedge, or slide) actually enters the product flow and cuts through the flow until the flow is completely closed off, or stopped. When the gate valve is fully open, the gate is entirely out of the flow path causing little to no restriction of flow through the valve. When the gate is fully closed, flow is stopped completely. For this reason, gate valves are a type of stop valves or block valves. Gate valves are symmetrical, meaning either end of the valve can be used as the inlet thereby allowing flow from either direction. Gate valve designs vary according to manufacturer and how a gate valve is to be used. The design differences that exist deal with particular design features, including: Body-Bonnet Joint: Differences in body-bonnet joint design relate to the method by which the bonnet is attached to the body of the valve. Variations include: (a) screwed joint, (b) union joint, (c) bolted-bonnet joint, (d) pressureseal joint, and (e) welded bonnet joint. Stem Design: Typically, there are three types of stem designs: (a) inside screw rising stem (ISRS), non-rising stem (NRS), and outside screw and yoke (OS&Y). 5 of 9

6 Gate Design: The most common gate designs are called wedge gates. The wedge that is formed when the valve is closed pushes the gate tightly against the seats, stopping flow in either direction. There are three primary types of wedge gates, including (a) the one-piece solid gate (also known as a solid wedge), (b) the one-piece flexible gate (also known as a flex wedge), and (c) the two-piece split wedge. Some of the advantages associated with the use of gate valves include: Little to no resistance of flow when the valve is fully open. Excellent where a shutoff valve is needed Manufactured in a wide range of sizes, pressure classes, materials, etc. Can be used to throttle flow, although they are not ideal for this purpose because vibration may lead to excessive wear on the seats and discs. There may be pressure limitations associated with gate valves. Inexpensive relative to most other valve types. Possible drawbacks associated with gate valves may be: Usually larger and heavier than other types of stop valves. Because of the potentially long distance the gate must travel from the open to the closed position, it can take longer and be more difficult to operate when frequent operation is required. Solids may build up between the seat rings preventing proper seating of the gate. Figure 3: Gate Valve 6 of 9

7 S: Demonstrate how to open and close a valve 1. Identify the proper valve (by tag, sign, or other means); 2. Unlock the valve if required; 3. Determine valve position 4. Operate valve (include in operation There are many different types of valves in use throughout the pipeline industry and many different valve manufacturers. Manufacturer specific procedures should always be followed while operating valves. Before beginning any valve inspection or operation, you should always refer to company operating procedures and manufacturer guidelines to ensure that company requirements are followed and that the inspection accounts for the operating characteristics of the valve being inspected. Verify that the valve is properly identified In order to verify proper valve identification: Company records, maps, alignment sheets, schematics, as-built drawings, etc. should be used to help identify the location of the valve. Verify the valve type and number (should be on the nameplate); Verify that valve type and manufacturer are correctly identified Proper Operation To ensure the valve will operate properly, the valve must be operated (partially operate when full operation is not possible). Include manually operating the valve and operating it with the use of an operator (mechanical assistance). Perform valve testing/operation, especially the opening and closing of mainline and station valves, only with the coordination and consent of the Operator s Gas Control Department and following all associated Operator procedures. During the valve test/operation: Unlock the valve (if required) Determine valve position (document if appropriate) Be prepared to take over manually incase of operator failure or malfunction Operate the valve (partially operate when full operation is not possible) Include in operation both manual valve and valve with operator Verify valve travel indication and alarms are functioning properly Note any difficulty encountered opening and closing the valve. Investigate and correct any binding, dragging, or excessive force required to operate the valve. Take prompt remedial action to correct any valve designated as an emergency valve which is found inoperable or designate an alternate valve as the 7 of 9

8 emergency valve. Once valve test is completed: Return valve to desired position Verify the valve is in the position Lock in desired position Notify affected parties of test completion Document accordingly Abnormal Operating Conditions K: Describe the proper actions to take in case of corrosion on pipeline component that has impaired or is likely to impair the serviceability of the pipeline. Response: Follow appropriate procedures for notification, documentation, and K: Describe the proper actions to take in case of a failure or malfunction of pipeline component(s). Response: Protect the public, property, and the environment. Follow appropriate procedures for notification, documentation, and 8 of 9

9 K: Describe the proper actions to take incase of an unintended fire and/or explosion near the pipeline. Response: Leave the area immediately. Protect the public, property, and the environment. Follow appropriate procedures for notification, documentation, and K: Describe the proper actions to take incase of a failure or malfunction of pipeline component(s). Response: Protect the public, property, and the environment. Follow appropriate procedures for notification, documentation, and K: Describe the proper actions to take incase of corrosion on pipeline component that has impaired or is likely to impair the serviceability of the pipeline. Response: Follow appropriate procedures for notification, documentation, and K: Describe the proper actions to take incase of loss of communication. Response: Find alternate means of communication, if not possible, suspend activities and follow appropriate procedures for notification, documentation, and K: Describe the proper actions to take in case of unexplained high pressure deviation exceeding design limits. Response: Follow appropriate procedures for notification, documentation, and 9 of 9