2020 Tech Report Jan-Feb

First page 1 Next page Last page

No download, no waiting. Open and start reading right away!

TECHNICAL REPORT

THE

REFRIGERATING ENGINEERS & TECHNICIANS ASSOCIATION | JANUARY/FEBRUARY 2020

REFRIGERATION SYSTEM STRAINER CLEANING: WITH AND WITHOUT DRAIN VALVES

AUTHORIZED USERS: This procedure is designed for use by Refrigeration Operators / Technicians to clean strainers for the Ammonia Refrigeration System piping and/or control valves. You must consult facility policy and procedures concerning strainer cleaning. You must follow the facility procedure. This procedure is considered minimum requirements. This procedure is to be used in addition to facility procedures. OBJECTIVE: Maintenance Procedures are designed to give general guidance when performing maintenance activities. No procedure is appropriate for every situation. Refrigeration Operators / Technicians should not attempt any repair which is beyond their training. CONCERNS: Careful attention to operating conditions is extremely important during this procedure. The primary incidents we are trying to prevent are injury to personnel. Additionally, our goal is to avoid operator errors or system upsets during maintenance which can lead to an ammonia release, or operator injury. Use by others is not authorized under any circumstances.

REFERENCES: Additional information is available to personnel performing inspections. This information is not required to be reviewed. However, those technicians wishing further information may seek these sources out:

• International Institute of Ammonia Refrigeration (IIAR) 5. Startup and Commissioning of Closed Circuit Ammonia Refrigeration Systems • International Institute of Ammonia Refrigeration (IIAR) Bulletin 107. Suggested Safety and Operating Procedures WhenMaking Ammonia Refrigeration Plant Tie Ins • Hansen Technologies Corporations’ appropriate bulletins for strainers • Refrigerating Specialties appropriate bulletins for strainers

• Danfoss appropriate bulletins for strainers

• Anhydrous Ammonia SDS

• International Institute of Ammonia Refrigeration (IIAR) SRC 2011-1, Interpretation of ANSI/IIAR-2, 2008 AddendumA, Section 10.3.1.2

RETA TECHNICAL REPORT PAGE 1

This includes: • Respirator (Within Arm’s Reach) • Approved Employee Uniform (i.e. Long Sleeve Shirt / Long Pants) • Safety Toe Shoes or Boots • ARC Flash apparel (NFPA Requirement) • Other Personal Protective Equipment as outlined in the PPE Hazard Assessment • Other PPE as outlined by the facility. This may include a wide range of possible equipment, such as confined space entry equipment, retrieval harnesses, dust masks, etc.…

Tools and Materials: • Radio or Cell Phone Communications • StandardMechanic’s Tools • Means of Proper Evacuation and/or Dehydration • Ammonia Rated Gauges • Ammonia Rated Hoses • Ammonia Detector(s) Portable and/or Stationary • RefrigerationWrench • Standard Operating Procedure (SOP) for the operation of the equipment to which the strainer is attached. This is to be used in the event of the necessity of an Emergency Shutdown. • P&ID’s for all equipment to be worked on.

EQUIPMENT / MATERIALS REQUIRED:

Personal protective equipment (PPE) as outlined in the PPE Hazard Assessment for Refrigeration Operators / Technicians.

RETA TECHNICAL REPORT PAGE 2

RETA TECHNICAL REPORT PAGE 3

RETA TECHNICAL REPORT PAGE 4

1. Preparing for Refrigeration System Strainer Cleaning ACTION COMMENT 1. Ensure a Maintenance Work Order has been prepared and authorized.

Work orders are required for all maintenance activities. Consult your supervisor or facility contact if you have questions. NOTE: If performing Task # 2.c. “Cleaning a Strainer without Drain or Gauge Valves: Install- ing Drain Valves” a Management of Change (MOC) form must be prepared if the installed drain valve is to be permanent. The materials must conform to design stan- dards. Consult your supervisor or facility con- tact or review the facility Ammonia Refrigera- tion Compliance Program for this information. NOTE: Verify that all safety equipment and PPE is available and functional. Consult your supervisor or facility contact or review the facility Ammonia Refrigeration Compliance Program for this information. Facility personnel, contractors, and visitors should be trained on the dangers associated with ammonia, including early exposure detec- tion techniques. NOTE: Portable rinse bottles may be neces- sary depending on the location of the strainers. Per the Hazard Assessment for Refrigeration Operators / Technicians. NOTE: If you are using a portable lift, you must have current certification on the type of lift to be used. Perform a ladder inspection after set- up, but prior to use. Do not use facility equip- ment without authorization. If necessary, utilize the appropriate SOP to shutdown individual components of the Am- monia Refrigeration System.

If you are a visiting Refrigeration Opera- tor/Technician, ask your facility contact for all forms and authorization needed for the scope of your work. Verify the locations of the strainer(s) to be inspected. Verify the materials necessary for the work are compatible. (Strainer, screen or filter element, parts replacements, pipe, fittings, equipment, valves, etc.) Gather the appropriate tools and PPE. Gather the appropriate Standard Oper- ating Procedures (SOPs) for the equip- ment you will be working on, and ensure they are readily accessible. Ask your supervisor or facility contact to notify all affected departments and per- sonnel including: Facility personnel, con- tractors, and visitors. Prohibit all vehicular and pedestrian traf- fic in the vicinity of operation. Re-familiarize yourself with the location of escape routes, eyewash, and shower stations.

Don required clothing and PPE.

10.

Place ladder (if required) and tie off per OSHA and facility requirements.

11.

Perform visual inspection of the associ- ated portion of the system to determine the correct isolation procedures.

RETA TECHNICAL REPORT PAGE 5

1. Preparing for Refrigeration System Strainer Cleaning ACTION COMMENT 12. Utilize the “ Control Group Valve Configu- rations Chart” on Page 5 of this Mainte- nance Procedure to assist in choosing the correct procedure.

Based on control group configuration, select the appropriate Task: • Task # 2.a.: Cleaning a Strainer in a Con- figuration “A” Control Group: Drain Valves • Task # 2.b.: Cleaning a Strainer in a Con- figuration “B” Control Group: Gauge Valves • Task # 2.c.: Cleaning a Strainer in an Al- ternate Configuration Control Group: No Drain Valves NOTE: When performing this procedure, the prevention of hydrostatic lock is of extreme importance. The Refrigeration Operator/Tech- nician or facility personnel in charge of this procedure must field verify piping to ensure shutdown will not create safety or operational issues.

13.

Verify the isolation procedures and isola- tion points for affected piping or systems. Write down the valve numbers in the ma- trix below. If a specific letter designator is not utilized in the specific procedure, enter “N/A.”

Diagram

Actual Valve Number

Original Valve Position

Valve “A”

Valve “B”

Valve “C”

Valve “D”

Valve “E”

RETA TECHNICAL REPORT PAGE 6

1. Preparing for Refrigeration System Strainer Cleaning ACTION COMMENT 14. Continue to the proper isolation and pumpout task based on the valve con- figuration of the equipment to be worked on.

See Task # 2.a., 2.b., or 2.c. of this Mainte- nance Procedure.

Task # 2.a.: Cleaning a Strainer in a Configuration “A” Control Group: Drain Valves

ACTION

COMMENT

NOTE: If the possibility exists that the condi- tions may have been altered after prepara- tion of the plan, you must repeat Task # 1 “Preparing for Refrigeration System Strainer Cleaning.” NOTE: Refrigeration Operators / Technicians must follow the facility’s Lockout / Tagout Pro- gram. If you have any questions while perform- ing this procedure, refer to the equipment’s corresponding SOP, consult your supervisor or facility contact, or review the facility’s Am- monia Refrigeration Compliance Program. If the control valve configuration is as shown on Figure #3 and Valve “E” is closed, the rea- son for the closure must be investigated and the valve opened before proceeding. The Master Maintenance Log (or facility equiva- lent) should contain information regarding the proper setting for this valve. If you have any questions, consult your supervisor or facility contact. If for any reason it is necessary to adjust this valve, the number of turns required to close the valve must be recorded in the Master Main- tenance Log (or facility equivalent.) If there is not an established Master Maintenance Log (or facility equivalent), log the information on your work order.

Confirm that Task # 1 “Preparing for Re- frigeration System Strainer Cleaning” has been completed. If not completed, do so now before continuing with this Mainte- nance Procedure. Verify the isolation of other forms of en- ergy to the valves being worked on.

If the control valve configuration is as shown on Figure #3, ensure Valve “E” is not closed.

RETA TECHNICAL REPORT PAGE 7

Task # 2.a.: Cleaning a Strainer in a Configuration “A” Control Group: Drain Valves

ACTION

COMMENT

Slowly close Valve “A.” Apply lock and tag per the facility’s Lockout / Tagout Pro- gram. Change the automatic valve’s manual operating stem to the “MANUAL OPEN” operating position. Valve “B” Solenoid If possible, allow the section of the sys- tem / piping with the control valve to pump down by isolating the liquid feed while maintaining the refrigeration suction. Lower the pressure in the isolated sec- tion of the piping to the lowest pressure available.

NOTE: Any frost on exposed portions of the pipe or valves should disappear with the liquid ammonia in the system. NOTE: If the isolated piping is in a vacuum, take precautions to prevent water from being drawn in when purging the piping. NOTE: If Valve “D” is a hand expansion valve as shown in Figure #2, the number of turns re- quired to close the valve must be recorded in the Master Maintenance Log (or facility equiv- alent). NOTE: Hand expansion valves should never be used as a positive shut-off unless no other option is available, such as in Figure #2. CAUTION: Failure to properly secure the end of the hose in the water bucket can lead to the hose coming free, whipping around, and possibly causing injury to personnel nearby, as well as allowing ammonia vapor to escape to the atmosphere directly. CAUTION: Opening Valve “C” too fast or too far can cause water / ammonia mixture to splatter from bucket.

Slowly close Valve “D.” Apply lock and tag per the facility’s Lockout / Tagout Pro- gram.

Confirm Valve “C” is closed.

10. 11.

Carefully remove the plug from Valve “C.” Attach a suitable hose, approved for am- monia service, to Valve “C.” Terminate and secure the opposite end of the hose (currently attached to Valve “C”) in a bucket of water outside and downwind of the plant if possible.

12.

Slowly throttle open Valve “C.”

RETA TECHNICAL REPORT PAGE 8

Task # 2.a.: Cleaning a Strainer in a Configuration “A” Control Group: Drain Valves

ACTION

COMMENT

13.

When pressure has bled off, close Valve “C.”

14. 15.

Remove hose from Valve “C.”

Check for any remaining pressure by carefully opening Valve “C.” If any pres- sure exists as evidenced by a strong am- monia odor, reattach the hose to Valve “C” and repeat the pumpout procedure (Steps 12 through 15) of this Mainte- nance Procedure. Verify that the strainer and / or strainer and control group has been isolated and pumped out. Ensure that all ammonia refrigerant in the isolated section with the strainer is pumped out to 0 PSIG. Slowly remove the bottom cap of the strainer or filter, either unscrewing the hex bottom or loosening the cover bolts. Slowly remove the screen / filter assem- bly and clean with a good solvent; blow dry and inspect. Lightly oil and place the gasket on the bottom cap. Carefully align the screen assembly in the center body and replace the bottom cover. Tighten cover / bolts in the accept- able prescribed manner.

If pressure continues to exist, it may be neces- sary to repeat this task to ensure all valves are tightly closed. If the problem persists, inform your supervisor or facility contact.

NOTE: The strainer control group should re- main under Refrigeration Operator / Techni- cian control throughout this procedure. If not, the possibility exists that conditions may have been altered after isolation, requiring the rep- etition of this Task.

16.

17.

CAUTION: Be careful to avoid any refrigerant which may still be in the strainer or filter. Refer to the strainer manufacturer’s Operation and Maintenance Manual for instructions.

18.

NOTE: If the screen is damaged or debris / sludge / sediments cannot be removed and cleaned, replace the screen assembly.

19.

20.

21.

Per ANSI/IIAR-2, valve gasket materials shall match valve manufacturer’s specifications, and shall be of the thickness specified.

22.

Fully close Valve “C.”

23.

Reinstall the plug in Valve “C.”

RETA TECHNICAL REPORT PAGE 9

Task # 2.a.: Cleaning a Strainer in a Configuration “A” Control Group: Drain Valves

ACTION

COMMENT

NOTE: Water containing ammonia drained from an Ammonia Refrigeration System may be considered hazardous. If you have any questions, consult your supervisor or facility contact on how to properly dispose of the wa- ter. NOTE: Log entries must contain the name of the person making the entry, as well as the time, date, and pertinent details. Be specific! If there is not an established Master Mainte- nance Log (or facility equivalent), log the infor- mation on your work order. See Task # 1 of this Maintenance Procedure.

24.

Dispose of the water in the bucket.

25.

Log “Isolation, Pumpout, and Strainer Cleaning of Control Valve _____” ( in- sert the appropriate valve number ) in the Master Maintenance Log (or facility equivalent). Repeat this Maintenance Procedure for each strainer to be cleaned, starting with Task # 1 “Preparing for Refrigeration Sys- tem Strainer Cleaning.” If this is the last strainer to be cleaned, cleanup the work area, and secure all equipment. When service / maintenance is complete, return the strainer control group to nor- mal operation by performing Task # 3.a. “Returning a Configuration “A” Control Group to Normal Operation.”

26.

27.

See Task # 3.a. of this Maintenance Proce- dure.

Task # 2.b.: Cleaning a Strainer in a Configuration “B” Control Group: Gauge Valves

ACTION

COMMENT

NOTE: If the possibility exists that the condi- tions may have been altered after prepara- tion of the plan, you must repeat Task # 1 “Preparing for Refrigeration System Strainer Cleaning.”

Confirm that Task # 1 “Preparing for Re- frigeration System Strainer Cleaning” has been completed. If not completed, do so now before continuing with this Mainte- nance Procedure.

RETA TECHNICAL REPORT PAGE 10

Task # 2.b.: Cleaning a Strainer in a Configuration “B” Control Group: Gauge Valves

ACTION

COMMENT

NOTE: Refrigeration Operators / Technicians must follow the facility’s Lockout / Tagout Pro- gram. If you have any questions while perform- ing this procedure, refer to the equipment’s corresponding SOP, consult your supervisor or the facility contact, or review the facility’s Ammonia Refrigeration Compliance Program.

Verify the isolation of other forms of en- ergy to the valves being worked on.

Slowly close Valve “A.” Apply lock and tag per the facility’s Lockout / Tagout Pro- gram. Change the automatic valve’s manual operating stem to the “MANUAL OPEN” operating position. Valve “B” Regulator Allow the section of piping with the control valve to pump down before continuing. Lower the pressure in the isolated sec- tion of the piping to the lowest pressure available.

A lower pressure portion of the system may involve manipulation of compressor set points or utilizing hoses to other portions of the sys- tem. NOTE: Any frost on exposed portions of the pipe or valves should disappear with the liquid ammonia in the system. NOTE: If the isolated piping is in a vacuum, take precautions to prevent water being drawn in when purging the piping.

Slowly close Valve “D.” Apply lock and tag per the facility’s Lockout / Tagout Pro- gram. Slowly close Valve “C” or verify that it is already closed. Carefully remove the gauge or plug from Valve “C.”

If the configuration is per Figure #2, Valve “C” does not have a gauge and should be closed and plugged.

RETA TECHNICAL REPORT PAGE 11

Task # 2.b.: Cleaning a Strainer in a Configuration “B” Control Group: Gauge Valves

ACTION

COMMENT

CAUTION: Failure to properly secure the end of the hose in the water bucket can lead to the hose coming free, whipping around, and possibly causing injury to personnel nearby, as well as allowing ammonia vapor to escape to the atmosphere directly. CAUTION : Opening Valve “C” too fast or too far can cause water/ammonia mixture to splat- ter from bucket.

10.

Attach a suitable hose, approved for am- monia service, to Valve “C.” Terminate and secure the opposite end of the hose (currently attached to Valve “C”) in a bucket of water outside and downwind of the plant if possible.

11.

Slowly throttle open Valve “C.”

12.

When pressure has bled off, close Valve “C.”

13. 14.

Remove hose from Valve “C.”

Check for any remaining pressure by carefully opening Valve “C.” If any pres- sure exists as evidenced by strong am- monia odor, reattach the hose to Valve “C” and repeat pump out procedure (Steps 11 through 14) of this Maintenance Pro- cedure. Verify that the control group has been isolated and pumped out.

If pressure continues to exist, it may be neces- sary to repeat this task to ensure all valves are tightly closed. If the problem persists, inform your supervisor or facility contact.

NOTE: The control group should remain un- der Refrigeration Operator / Technician con- trol throughout this procedure. If not, the pos- sibility exists that conditions may have been altered after isolation, requiring the repetition of this Task.

15.

16.

Ensure that all ammonia refrigerant in the isolated section with the strainer is pumped out to 0 PSIG. Slowly remove the bottom cap of the strainer or filter, either unscrewing the hex bottom or loosening the cover bolts.

CAUTION: Be careful to avoid any refrigerant which may still be in the strainer or filter. See the strainer Manufacturer’s Operation and Maintenance Manual for instructions.

17.

NOTE: If the screen is damaged or debris / sludge / sediments cannot be removed and cleaned, replace the screen assembly.

18.

Slowly remove the screen / filter assem- bly and clean with a good solvent; blow dry and inspect.

RETA TECHNICAL REPORT PAGE 12

Task # 2.b.: Cleaning a Strainer in a Configuration “B” Control Group: Gauge Valves

ACTION

COMMENT

19.

Lightly oil and place the gasket on the bottom cap. Carefully align the screen assembly in the center body and replace the bottom cover. Tighten cover / bolts in the accept- able prescribed manner.

20.

Per ANSI/IIAR-2, valve gasket materials shall match valve manufacturer’s specifications, and shall be of the thickness specified.

21. 22. 23.

Slowly close Valve “C.”

Reinstall the gauge or plug in Valve “C.” Slowly open Valve “C” if it has a gauge.

CAUTION: If Valve “C” contains a plug do NOT open this valve. NOTE: Water containing ammonia drained from an Ammonia Refrigeration System may be considered hazardous. If you have any questions, consult your supervisor or facility contact on how to properly dispose of the wa- ter. NOTE: Log entries must contain the name of the person making the entry, as well as the time, date, and pertinent details. Be specific! If there is not an established Master Mainte- nance Log (or facility equivalent), log the infor- mation on your work order. See Task # 1 of this Maintenance Procedure.

24.

Dispose of the water in the bucket.

25.

Log “Isolation, Pumpout, and Strainer Cleaning of Control Valve _____” ( in- sert the appropriate valve number ) in the Master Maintenance Log (or facility equivalent). Repeat this Maintenance Procedure for each strainer to be cleaned, starting with Task # 1 “Preparing for Refrigeration Sys- tem Strainer Cleaning.” If this is the last strainer to be cleaned, cleanup the work area, and secure all equipment. When service / maintenance is complete, return the strainer control group to nor- mal operation by performing Task # 3.b. “Returning a Configuration “B” Control Group to Normal Operation.”

26.

27.

See Task # 3.b. of this Maintenance Proce- dure.

RETA TECHNICAL REPORT PAGE 13

Task # 2.c.: Cleaning a Strainer in an Alternate Control Group Configuration: No Drain Valves

ACTION

COMMENT

NOTE: If the possibility exists that the condi- tions may have been altered after prepara- tion of the plan, you must repeat Task # 1 “Preparing for Refrigeration System Strainer Cleaning.” Prepare a detailed plan, including written iso- lation and pump out procedures. Review the equipment’s corresponding SOP. Items to include: Valve numbers, Lockout / Ta- gout isolation points, special test pressure re- quirements, order of isolation, etc. Identify and verify locations for purging / vent- ing, attachment of pump down hoses, pres- sure gauges, etc. Check the manufacturer’s Operation and Maintenance Manuals for information or spe- cial instructions to be followed for isolation, testing and evacuation where applicable. NOTE: When performing this procedure, the prevention of hydrostatic lock is of extreme im- portance. The Refrigeration Operator / Tech- nician in charge of this procedure must field verify piping to ensure shutdown will not cre- ate safety or operational issues. NOTE: Refrigeration Operators / Technicians must follow the facility’s Lockout / Tagout Program. If you have any questions while performing this procedure, refer to the equip- ment’s corresponding SOP, consult the facility contact, or review the facility’s Ammonia Re- frigeration Compliance Program. If necessary, expand the area of isolation to include a section of piping that has a purge / drain valve available.

Confirm that Task # 1 “Preparing for Re- frigeration System Strainer Cleaning” has been completed. If not completed, do so now before continuing with this Mainte- nance Procedure. Prepare a proper plan to pump out and shutdown the equipment that requires strainer cleaning.

Field verify the isolation procedures and isolation points for affected piping or sys- tems. Ensure shutdown will not affect other equipment in the system before continuing. Verify the isolation of other forms of en- ergy to the valves and equipment being worked on.

Close or confirm the purge / drain valve identified in the isolation procedure is closed. Carefully remove the plug or gauge from the purge / drain valve identified in the isolation procedure.

RETA TECHNICAL REPORT PAGE 14

Task # 2.c.: Cleaning a Strainer in an Alternate Control Group Configuration: No Drain Valves

ACTION

COMMENT

CAUTION: Failure to properly secure the end of the hose in a water bucket can lead to the hose coming free, whipping around, and pos- sibly causing injury to personnel nearby, as well as allowing ammonia vapor to escape to the atmosphere directly. CAUTION: The system / piping may contain liquid ammonia and may be at a pressure which is much higher than normal suction pressure.

Attach a suitable hose, approved for am- monia service; to the purge / drain valve identified in the isolation procedure. Ter- minate and secure opposite end of hose in a bucket of water outside and down- wind of plant if possible.

Isolate the upstream valve. Look for the flow arrows on the piping. Apply a lock and tag. If automatic valves are located within the section of the Ammonia Refrigeration System being worked on, change the au- tomatic valve(s)’s manual operating stem to the “MANUAL OPEN” operating posi- tion for any automatic valve in the isolat- ed piping. If possible, allow the section of the sys- tem / piping with the control valve to pump down by isolating the liquid feed while maintaining the refrigeration suction. Lower the pressure in the isolated sec- tion of the piping to the lowest pressure available.

NOTE: If the automatic valve is a motorized valve, a special tool is required to change the position of the valve when it is de-energized. Please see the manufacturer’s Operation and Maintenance procedures for specific require- ments.

10.

NOTE: Any frost on exposed portions of the pipe or valves should disappear with the liquid ammonia in the system. NOTE: If the isolated piping is in a vacuum, take precautions to prevent water being drawn in when purging the piping. CAUTION: Do not isolate sections of liquid piping under pressure. This can create a hy- drostatic lock and can result in ruptured piping and a release of ammonia!

11.

12.

Isolate the downstream valve of the sec- tion of theAmmonia Refrigeration System being worked on. Apply Lockout / Tagout per the Lockout / Tagout Program.

RETA TECHNICAL REPORT PAGE 15

Task # 2.c.: Cleaning a Strainer in an Alternate Control Group Configuration: No Drain Valves

ACTION

COMMENT

See the appropriate drawings. CAUTION: Opening the purge / drain valve too fast or too far can cause water / ammonia mixture to splatter from bucket. Refer to the equipment’s SOP and/or refrig- eration system P&ID’s. Refer to the equipment’s SOP and/or refrig- eration system P&ID’s. Refer to the equipment’s SOP and/or refrig- eration system P&ID’s.

13.

Slowly throttle open the purge / drain valve.

14.

When pressure has bled off, close the purge / drain valve. Remove hose from the purge / drain valve. Before opening the system/piping with the control valve, check for any remaining pressure by carefully opening the purge / drain valve. If any pressure exists as evidenced by strong ammonia odor, reat- tach the hose to the purge / drain valve, and repeat pump out procedure (Steps 13 16) of this Maintenance Procedure. If pressure continues to exist, it may be necessary to repeat the isolation pro- cedure to ensure all valves are tightly closed, followed by the pump out proce- dure. If the problem persists, consult your supervisor or facility contact. Slowly remove the bottom cap of the strainer or filter, either unscrewing the hex bottom or loosening the cover bolts. Slowly remove the screen / filter assem- bly and clean with a good solvent; blow dry and inspect. Lightly oil and place the gasket on the bottom cap. Carefully align the screen assembly in the center body and replace the bottom cover. Tighten cover / bolts in the accept- able prescribed manner.

15.

16.

CAUTION: Be careful to avoid any refrigerant which may still be in the strainer or filter. See the strainer Manufacturer’s Operation and Maintenance Manual for instructions.

17.

NOTE: If the screen is damaged or debris / sludge / sediments cannot be removed and cleaned, replace the screen assembly.

18.

19.

20.

Per ANSI/IIAR-2, valve gasket materials shall match valve manufacturer’s specifications, and shall be of the thickness specified.

RETA TECHNICAL REPORT PAGE 16

Task # 2.c.: Cleaning a Strainer in an Alternate Control Group Configuration: No Drain Valves

ACTION

COMMENT

NOTE: If a Management of Change (MOC) form has been initiated to permanently add a purge / drain valve (Valve “B”) to the strainer (Strainer “A”), continue. Otherwise, skip to Step 24. It may be necessary to use a bushing or re- ducer.

21.

Carefully remove the plug from the bot- tom of the strainer.

22.

Install a ¾” nipple into the outlet of the Strainer “A.” Install Valve “B” Drain Valve into the ¾” nipple extending from the outlet of the strainer. Install a ¾” nipple, 90 Deg. elbow and ad- ditional nipple into the outlet of Valve “B.” Slowly close the purge / drain valve iden- tified in the isolation procedure In some instances, the pump down may be required in multiple locations. Dispose of the water in the bucket. Log “Isolation, Pumpout, and Strainer Cleaning of Control Valve _____” ( in- sert the appropriate valve number ) in the Master Maintenance Log (or facility equivalent). Repeat this Maintenance Procedure for each strainer to be cleaned, starting with Task # 1 “Preparing for Refrigeration Sys- tem Strainer Cleaning.” If this is the last strainer to be cleaned, cleanup the work area, and secure all equipment.

23.

24.

25.

Refer to the equipment’s SOP and/or refrig- eration system P&ID’s. Repeat this procedure for each section. NOTE: Water containing ammonia drained from an Ammonia Refrigeration System may be considered hazardous. If you have any questions, consult your supervisor or facility contact on how to properly dispose of the wa- ter. NOTE: Log entries must contain the name of the person making the entry, as well as the time, date, and pertinent details. Be specific! If there is not an established Master Mainte- nance Log (or facility equivalent), log the infor- mation on your work order. See Task # 1 of this Maintenance Procedure.

26.

27.

28.

29.

RETA TECHNICAL REPORT PAGE 17

Task # 2.c.: Cleaning a Strainer in an Alternate Control Group Configuration: No Drain Valves

ACTION

COMMENT

30.

When service / maintenance is complete, return the strainer control group to nor- mal operation by performing Task # 3.c. “Returning an Alternate Configuration Control Group to Normal Operation.”

See Task # 3.c. of this Maintenance Proce- dure.

Task # 3.a.: Returning a Configuration “A” Control Group to Normal Operation

ACTION

COMMENT

Depending upon the conditions which required shutdown, the following permits may require completion before setting up the control group for startup. Pre-Startup Safety Review Form Pre-Charging Checklist Hot Work Permits Management of Change Form

The facility’s Ammonia Refrigeration Compli- ance Program, your supervisor or your facility contact may be able to supply additional infor- mation on these forms and programs. Perform a Pre-Startup Safety Review before removing Lockout / Tagout equipment. In ad- dition, pressure tests may be required if modi- fications have been made requiring tests. If you have any questions, consult your facility contact. Based upon the maintenance that may have been performed while this unit was shut down, portions of this procedure may not be required, provided the unit has remained under the con- trol of the Refrigeration Operator / Technician. Any items which may have been adjusted or modified must be reviewed during setup. If the unit has not remained under the control of the Refrigeration Operator / Technician, the com- plete setup procedure must be utilized. If you have any questions, consult your supervisor or facility contact.

RETA TECHNICAL REPORT PAGE 18

Task # 3.a.: Returning a Configuration “A” Control Group to Normal Operation

ACTION

COMMENT

Ask your supervisor or facility contact to notify all affected departments and per- sonnel including: Facility personnel, con- tractors, and visitors. Confirm that the following valves are closed, locked, and tagged out per the facility Lockout / Tagout Program: Confirm that the following automatic valve’s manual operating stem is in the “MANUAL OPEN” operating position. Valve “B” Solenoid If the control valve configuration is as shown on Figure #3, ensure Valve “E” is throttled open to the correct position. Remove lock and tag and slowly open Valve “A” to introduce pressure to the control group which is isolated. Check for ammonia odor. If a small ammonia leak is observed, the source of the leak should be inves- tigated and the leak repaired. If a large leak occurs, secure the area to prevent unauthorized personnel from entering; notify safety personnel; close, apply lock and tag to Valve “A” then pumpout the valve group. See Task # 2.a. of this Maintenance Pro- cedure. Valve “A” Valve “D”

Facility personnel, contractors, and visitors should be trained on the dangers associated with ammonia, including early exposure de- tection techniques.

If adjusted, the correct position of Valve “E” was noted in the Master Maintenance Log (or facility equivalent) or on your dispatch report during the shutdown procedure. If you have any questions, consult your facility contact. A Pre-Startup Safety Review is required prior to initiating this step.

See Task # 2.a. of this Maintenance Proce- dure.

RETA TECHNICAL REPORT PAGE 19

Task # 3.a.: Returning a Configuration “A” Control Group to Normal Operation

ACTION

COMMENT

CAUTION: Do not stop the procedure at this point. This can create a hydrostatic lock which can result in ruptured piping and a release of ammonia! If the control valve configuration is as shown in Figure #2, the correct position of Valve “D” was noted in the Master Maintenance Log (or facility equivalent) or on your work order dur- ing the shutdown procedure. If you have any questions, consult your supervisor or facility contact. NOTE: Log entries must contain the name of the person making the entry, as well as the time, date, and pertinent details. Be Specific! If there is not an established Master Mainte- nance Log (or facility equivalent), log the infor- mation on your work order. See Task # 4 of this Maintenance Procedure.

Change the following automatic valve’s manual operating stem to the “AUTO- MATIC” operating position. Valve “B” Solenoid Remove lock and tag and slowly open Valve “D.” If the control valve configura- tion is as shown on Figure #2, ensure Valve “D” is throttled open to the correct position. Remove PPE, clean, perform any re- quired preventive maintenance and stow. Secure all tools and equipment utilized. Log “Control group ______ ( insert the appropriate valve number ) has been re- turned to normal operation” in the Mainte- nance Log (or facility equivalent.)

10.

11. 12.

13.

Continue to Task # 4 “Concluding Refrig- eration System Strainer Cleaning.”

RETA TECHNICAL REPORT PAGE 20

Task # 3.b.: Returning a Configuration “B” Control Group to Normal Operation

ACTION

COMMENT

The facility’s Ammonia Refrigeration Compli- ance Program, your supervisor or your facility contact may be able to supply additional infor- mation on these forms and programs. In addition, pressure tests may be required if modifications have been made requiring tests. If you have any questions, consult your super- visor or facility contact. Based upon the maintenance that may have been performed while this unit was shut down, portions of this procedure may not be required, provided the unit has remained under the con- trol of the Refrigeration Operator / Technician. Any items which may have been adjusted or modified must be reviewed during setup. If the unit has not remained under the control of the Refrigeration Operator / Technician, the com- plete setup procedure must be utilized. If you have any questions, consult your supervisor or facility contact. Facility personnel, contractors, and visitors should be trained on the dangers associated with ammonia, including early exposure de- tection techniques.

Valve “A” Valve “D”

Confirm that the following automatic valve’s manual operating stem is in the “MANUAL OPEN” operating position. Valve “B” Regulator Confirm a known good pressure gauge is installed on Valve “C.”

The pressure indicated on the gauge attached to Valve “C” should read 0 PSIG.

RETA TECHNICAL REPORT PAGE 21

Task # 3.b.: Returning a Configuration “B” Control Group to Normal Operation

ACTION

COMMENT

Remove lock and tag and slowly open Valve “A” to introduce pressure to the control group which is isolated. Check for ammonia odor. If a small ammonia leak is observed, the source of the leak should be inves- tigated and the leak repaired. If a large leak occurs, secure the area to prevent unauthorized personnel from entering; notify safety personnel; close, apply lock and tag to Valve “A” then pumpout the valve group. See Task # 2.b. of this Maintenance Pro- cedure. Change the following automatic valve’s manual operating stem to the “AUTO- MATIC” operating position. Valve “B” Regulator Remove lock and tag and slowly open Valve “D.” Remove PPE, clean, perform any re- quired preventive maintenance and stow. Secure all tools and equipment utilized. Log “Control group ______ ( insert the appropriate valve number ) has been re- turned to normal operation” in the Mainte- nance Log (or facility equivalent.)

See Task # 2.b. of this Maintenance Proce- dure.

CAUTION: Do not stop the procedure at this point. This can create a hydrostatic lock which can result in ruptured piping and a release of ammonia!

10.

11. 12.

NOTE: Log entries must contain the name of the person making the entry, as well as the time, date, and pertinent details. Be Specific! If there is not an established Master Mainte- nance Log (or facility equivalent), log the infor- mation on your work order. See Task # 4 of this Maintenance Procedure.

13.

Continue to Task # 4 “Concluding Refrig- eration System Strainer Cleaning.”

RETA TECHNICAL REPORT PAGE 22

Task # 3.c.: Returning an Alternate Control Group Configuration to Service

ACTION

COMMENT

The facility’s Ammonia Refrigeration Compli- ance Program, your supervisor or your facility contact may be able to supply additional infor- mation on these forms and programs. In addition, pressure tests may be required if modifications have been made requiring tests. If you have any questions, consult your super- visor or facility contact. Based upon the maintenance that may have been performed while this unit was shut down, portions of this procedure may not be required, provided the unit has remained under the con- trol of the Refrigeration Operator / Technician. Any items which may have been adjusted or modified must be reviewed during setup. If the unit has not remained under the control of the Refrigeration Operator / Technician, the com- plete setup procedure must be utilized. If you have any questions, consult your supervisor or facility contact. Facility personnel, contractors, and visitors should be trained on the dangers associated with ammonia, including early exposure de- tection techniques.

Ask your supervisor or facility contact to notify all affected departments and per- sonnel including: Facility personnel, con- tractors, and visitors.

RETA TECHNICAL REPORT PAGE 23

Task # 3.c.: Returning an Alternate Control Group Configuration to Service

ACTION

COMMENT

Prepare a proper plan to return the equip- ment to service.

Prepare a detailed plan, including written iso- lation and pump out procedures. Review the equipment’s corresponding SOP. Items to include: Valve numbers, Lockout / Ta- gout isolation points, special test pressure re- quirements, order of isolation, etc. Identify and verify locations for purging / vent- ing, attachment of pump down hoses, pres- sure gauges, etc. Check the manufacturer’s Operation and Maintenance Manuals for information or spe- cial instructions to be followed for isolation, testing and evacuation where applicable. NOTE: When performing this procedure, the prevention of hydrostatic lock is of extreme im- portance. The Refrigeration Operator / Tech- nician in charge of this procedure must field verify piping to ensure shutdown will not cre- ate safety or operational issues.

Field verify the isolation procedures and isolation points for affected piping or sys- tems. Ensure shutdown will not affect other equipment in the system before continuing. Confirm that the following valves are closed, tagged, and locked out: Upstream Hand Valve Downstream Hand Valve If automatic valves are located within the section of the Ammonia Refrigeration System being worked on, change the au- tomatic valve(s)’s manual operating stem to the “MANUAL OPEN” operating posi- tion for any automatic valve in the isolat- ed piping. Close or confirm the purge / drain valve within the section of the Ammonia Refrig- eration System being worked is closed and plugged.

RETA TECHNICAL REPORT PAGE 24

Task # 3.c.: Returning an Alternate Control Group Configuration to Service

ACTION

COMMENT

NOTE: Work quickly and do not stop the procedure as there is a possibility of a hydro- static lock, which can result in ruptured piping and a release of ammonia!

Remove locks and tags and slowly open the Upstream hand valve isolating the section of the Ammonia Refrigeration System. Check for ammonia odor. If a small ammonia leak is observed, the source of the leak should be inves- tigated and the leak repaired. If a large leak occurs, perform emer- gency isolation, secure the area to prevent unauthorized personnel from entering; Close, lock and tag upstream hand valve, notify safety personnel and pumpout the isolated section. See Task # 2.c. If automatic valves are located within the section of the Ammonia Refrigeration System being worked on, change the au- tomatic valve(s)’s manual operating stem to the “AUTOMATIC” operating position for any automatic valve in the isolated piping.

NOTE: Do not stop the procedure at this point. this can create a hydrostatic lock and can result in ruptured piping and a release of ammonia! NOTE: If any of the automatic valves is a mo- torized valve, a special tool may be required to change the position of the valve when it is de-energized. Please see the manufac- turer’s Operation and Maintenance manuals for specific requirements. See the Operation and Maintenance Manuals in the PSM / RMP Program.

10.

11.

Remove locks and tags and slowly open the downstream hand valve isolating the section of the Ammonia Refrigeration System. Remove PPE, clean, perform any re- quired preventive maintenance and stow. Secure all tools and equipment utilized. Complete the work order and return it to the Senior Mechanic.

12.

13. 14.

Note any comments in the “Comments” area.

RETA TECHNICAL REPORT PAGE 25

Task # 3.c.: Returning an Alternate Control Group Configuration to Service

ACTION

COMMENT

NOTE: Log entries must contain the name of the person making the entry, as well as the time, date, and pertinent details. Be Specific!

15.

Log “Control group ______ ( insert the appropriate valve number ) has been re- turned to normal operation” in Master Maintenance Log and Daily Rounds Log.

4. Concluding Refrigeration System Strainer Cleaning STEP ACTION COMMENT 1. Restore allowable vehicular and pe- destrian traffic in your work area. 2. Complete an entry in the facility Mas- ter Maintenance Log (or facility equiv- alent), noting the work performed.

If there is not an established Master Mainte- nance Log (or facility equivalent), log the infor- mation on your work order. This includes the shutting down of equipment or any instance where the system is not left in complete functioning condition.

If a system upset occurred, record the details of the event in the Master Main- tenance Log (or facility equivalent) and on your work order. Note if the system was restored to full functionality, and if it was not, explain why in detail. Complete any permits or paperwork required. Return documents such as Standard Operating Procedures (SOP’s) and P&ID’s. Notify your supervisor or facility con- tact of any issues which may need to be addressed. Remove PPE, clean, perform any re- quired preventive maintenance, and stow. Secure all tools and equipment uti- lized.

Notify your supervisor or facility contact of any issues which may need to be addressed.

RETA TECHNICAL REPORT PAGE 26

THE

TECHNICAL

REPORT

The Technical Report is an official publication of the Refrigerating Engineers & Technicians Association (RETA). RETA is an international not-for-profit association whose mission is to enhance the professional development of industrial refrigeration operating and technical engineers. Don Chason Executive Editor Jim Barron Executive Director

704-455-3551 Sara Louber Senior Director, Office Operations sara@reta.com

jim@reta.com Dan Reisinger Certification Manager dan@reta.com Dan Denton Chapter Relations ddenton@reta.com

Michelle Robinson Conference Manager mi chelle @reta.com Vince Grindel Education Coordinator vince @reta.com

The information in this publication is based on the collective experience of industry engineers and technicians. Although the information is intended to be comprehensive and thorough, it is subject to change based on particular applications, field experience, and technological developments. The Refrigerating Engineers & Technicians Association expressly disclaims any warranty of fitness for a particular application, as well as all claims for compensatory, consequential, or other damages arising out of or related to the uses of this publication.

Get your message to thousands of refrigeration professionals. Advertise in the next

REPORT TECHNICAL

REFRIGERATING ENGINEERS & TECHNICIANS ASSOCIATION 1725 Ferry St. SW, Albany, OR 97322 Telephone: 541.497.2955 | Fax: 541.497.2966 RETA.com

For rates and information, contact Sara Louber at sara@reta.com

RETA TECHNICAL REPORT PAGE 27

Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27

Made with FlippingBook - Online Brochure Maker