8 Process Equipment Integrity 8.1. OVERVIEW Management systems are essential to a process safety program to ensure that all process equipment is fabricated and installed in accordance with design specifications. A documented file should be maintained for all equipment, including initial equipment and any new or replaced equipment. A significant number of losses in the chemical industry are partially attributable to im- properly maintained or replaced equipment or to newly installed equipment that does not meet required codes or standards. The management system should include measures that train line managers to fully understand the equipment design specifications so that they can be sure it is properly oper- ated and maintained. For example, line managers should be aware of areas that are electrically classified, the location of underground piping, and interlock systems; and, most importantly, they should know where in the plant to find this information. 8.1.1. Scope This chapter provides examples of plant management systems designed to make certain that plant employees who have direct responsibility take the necessary precautions so that design criteria and specifications are not compromised. The examples in these guidelines cover maintenance, testing, fabrication, and instrumentation pertaining to piping, vessels, and equipment in the handling of toxic, reactive, and combustible flammable materials.
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Process Equipment Integrity
8.1. OVERVIEW
Management systems are essential to a process safety program to ensure thatall process equipment is fabricated and installed in accordance with designspecifications. A documented file should be maintained for all equipment,including initial equipment and any new or replaced equipment. A significantnumber of losses in the chemical industry are partially attributable to im-properly maintained or replaced equipment or to newly installed equipmentthat does not meet required codes or standards. The management systemshould include measures that train line managers to fully understand theequipment design specifications so that they can be sure it is properly oper-ated and maintained. For example, line managers should be aware ofareas that are electrically classified, the location of underground piping, andinterlock systems; and, most importantly, they should know where in theplant to find this information.
8.1.1. Scope
This chapter provides examples of plant management systems designed tomake certain that plant employees who have direct responsibility take thenecessary precautions so that design criteria and specifications are notcompromised. The examples in these guidelines cover maintenance, testing,fabrication, and instrumentation pertaining to piping, vessels, and equipmentin the handling of toxic, reactive, and combustible flammable materials.
Control of plant design modifications is important to prevent the acci-dental use of improper materials or equipment. Even with the intent to"replace in kind," replacement with something different may occur. Thisprobably occurs most commonly with substitutions in material of constructionin which the different material has essentially the same appearance as theoriginal. Examples are bolts of different materials; some gaskets; O-rings;and instrumentation, such as a differential pressure transmitter, which musthave specific materials within it. As a minimum, an effective system shouldidentify those who must be involved, from the person who plans a mainten-ance job and orders materials through the warehouse where the materialsare stored, to the maintenance personnel who request and install equipment.(See Chapter 7, "Management of Change," for other examples relating tocontrol of equipment or facility changes.)
8.1.2. Staffing or Resources
Process and equipment integrity requires the commitment of management toensure that individuals with the proper expertise are given the responsibility,authority, and time to prevent premature malfunction of equipment thatcould release hazardous materials. Specific resources and staffing needs willbe covered in the following subsections of this chapter.
8.2. RELIABILITY ENGINEERING
The objective of a reliability engineering program is to prevent occurrenceof a safety incident by identifying equipment that is critical to process safetyand to establish a management system that is capable of predicting failureor malfunction. Reliability engineering is essentially proactive managementin its truest sense. Resources should include individuals with knowledge ofoperations, maintenance engineering, process safety, and plant stores.
8.3. MATERIALS OF CONSTRUCTION
This section covers the choice of materials for new installations and for repairof existing equipment. A management system to track the materials frompurchasing request through installation and testing is essential and is depictedin the flowchart below.
Construction Request
Job Design
Design Review
Project/MCN
Design Package
Procurement ofEquipment and Materials
Work Orders
Fabrication
Purchasing
Receiving
Installation
Field Hazards Review
Storage
Job Closing
Job Flowchart for tracking material. ("Positive Material Identification" or "PMI")
(1) Initiator of work designates PMI in the title and/ordescription of the job.
(2) Specify proper materials of construction and in-spection requirements (verification). Document ex-ceptions approved by area supervisor and metal-lurgist. The person responsible for each job mustgive vendors, fabricators, etc., all the appropriateinformation and specifications required at the startof the job. Special tests/procedures and tests re-ports, if needed, must be requested, and respons-ibility for each phase must be assigned. Specialtests may include chemical composition with millcertifications, tensile and Charpy impact tests,radiographic tests, etc. A materials consultantshould be contacted when needed.
(3) Purchase orders designated PMI and state "no sub-stitutes for specified material of construction1':specify proper material of construction: and detailcertifications, markings, color coding analyticalverifications, special handling at receiving, etc., re-quired.
(4) Documentation checked. Analysis done as definedby area, and documented and tagged.
For proper control of materials of construction, it is necessary to employa management system that guarantees that critical equipment is subjected toproper selection and that documented inspections are maintained. Specialistsmay be needed, such as metallurgists, civil engineers, electrical engineers,etc. Appendix 8A is an example of a management system that reduces thepossibility of using improper materials.
8.4. FABRICATION AND INSPECTION PROCEDURES
Fabrication and installation of critical equipment handling hazardous ma-terials can be accomplished by plant personnel or often by outside vendorsor contractors. In either case, a management system should be implementedthat includes a mechanism to verify that the work being performed meetsthe required specifications. Specifications may include dimensions, materialsof construction, welding techniques, etc.
8.5. INSTALLATION PROCEDURES
A management system should have a program to verify that the installationof critical equipment meets all the specifications. Qualified personnel mustbe assigned during installation stages to perform visual inspections to besure that design criteria and specifications are not being compromised. Aprocedure should be established for the testing of installed equipment, verify-ing that it is ready for safe operation. A documented file should be perma-nently maintained with appropriate sign-offs.
8.6. PREVENTIVE MAINTENANCE
Planned tests and inspections of critical equipment are essential to a soundprocess safety program. The primary objective of a preventive maintenanceprogram is to minimize or avoid premature failure. Therefore, a managementsystem should include a listing of critical equipment, frequency of inspectionor testing, detailed maintenance procedures, and a documented file to assurethe procedures are being implemented. See Appendix 8B for an example ofone plant's procedures for testing and inspection of equipment.
8.7. PROCESS HARDWARE AND SYSTEMS INSPECTIONSAND TESTING
A management system such as the plant example depicted in Appendix 8Cis needed to verify by field inspection and/or testing that all items previouslyidentified in hazard and design reviews are in operable condition. Theseverifications should be conducted prior to start-up and before hazardousmaterials are introduced into the process. They should also be conducted atperiodic intervals to ensure proper functioning of critical items, such asinterlocks, purges, etc. Resources to conduct these verifications should in-clude personnel with expertise or knowledge of the following areas: thedesign criteria, operations or process emergency procedures, maintenance,construction, and other disciplines or resources as may be needed. (SeeAppendix 8G which is a table of contents of the Fixed Equipment InspectionGuide published by the Chemical Manufacturers Association.
8.8. MAINTENANCE PROCEDURES
Written maintenance procedures as well as a training program (includingskills training and knowledge of process) are needed for maintenance ofequipment piping or vessels in which hazardous materials are being pro-cessed. These procedures must address two potentially serious conditions:
• Creation of a hazardous condition after start-up as a result of animproper repair or preventive maintenance procedure.
• Creation of a hazardous condition during the course of repair orpreventive maintenance.
In both cases, work permits that require special procedures to be followedare needed to be certain that all the hazards have been identified and properprecautions are taken to avoid them, as shown in Appendix 8D. A mainten-ance procedure or program requires that a management system be im-plemented, including accountability, documentation, and feedback mechan-isms. An example of a management system pertaining to the testing andinspection of safety relief devices is shown in Appendix 8E. The same man-agement principles covered in this program are applicable to all hazardousmaintenance procedures.
8.9. ALARM AND INSTRUMENT MANAGEMENT
Critical operating parameters are usually controlled through alarms and shut-off devices and systems. It is therefore essential that a management system
be in place to assure that catastrophic events are avoided. A well-definedset of definitions and rules must be established and communicated to allemployees. Adequate training programs should be provided so that there isno confusion concerning maintenance of the integrity of alarms, interlocks,and shutdown systems. Appendix 8F is an example of a plant's managementsystem for critical and unique safety features.
8.10. DECOMMISSIONING AND DEMOLITION PROCEDURES
A management system is needed when equipment is "mothballed" in placefor extended periods of time or is razed. In either event, procedures arenecessary to ensure that all the hazardous materials have been safely re-moved. In some cases, decontamination procedures may be needed to restoresafe operation of mothballed equipment or to decommission equipment. Inall cases, a documented sign-off by knowledgeable individuals should berequired to establish adequate accountability and to avoid any unsafe con-ditions.
Appendix 8AExample of Plant Management System for Materials ofConstruction (MOC)
The purpose of this procedure is to prevent equipment failures resulting from the use ofimproper materials. The guidelines herein apply to all process systems in this plant wherethe materials of construction (MOC) are deemed critical to safe operation.
L POLICIES
A. Only specified materials shall be used in the fabrication and repair of criticalMOC systems.
B. The alloy and/or composition of material(s) (gaskets, o-rings, etc.) of all criticalMOC shall be tested and/or visually inspected to verify composition prior toinstallation.
C. Personnel performing tests and/or inspections to verify the composition of ma-terials of construction shall be qualified to perform the work.
D. Departments with primary responsibility for specifying, inspecting, and installingmaterials in critical MOC systems shall provide and maintain departmental proce-dures/guidelines in accordance with standards defined in Section II.
II. STANDARDS
A. Production Department1. Critical MOC for all piping and equipment within the department are iden-
tified, documented, and the information made accessible to department person-nel and service groups.
2. Procedures for verification testing and inspection of materials for all criticalMOC within the department are accessible to personnel.
3. Components of critical MOC systems installed by production personnel aretested and/or visually checked to verify the proper alloy or composition ofmaterial prior to installation.
4. Work requests for repairs, revisions, and engineering projects identify criticalMOC.
5. Instructions for testing are prepared for each requisition involving the purchaseof critical MOC.
B. Maintenance Department1. Procedures for the verification testing and inspection of materials for all critical
MOC are accessible to personnel.2. Components of critical MOC systems are tested and/or visually checked to
verify the proper alloy or composition of material prior to installation.3. Critical MOC and testing procedures are provided for all repair work and
fabricated items.
C. Engineering Department1. Verification test procedures for all plant critical MOC alloys are provided and
accessible to functional groups.2. Critical MOC and verification test procedures are specified and documented
on all engineering projects and are reviewed as part of the engineering designsafety review.
3. Services for the testing of exotic metals are provided on request.D. Materials Department —Stainless steel and special alloy pipe, pipe fittings, tubing,
shapes, plates and valve trim are randomly checked and tagged for correct MOCwhen shipments are received.
E. Construction Department—Components of critical MOC systems are testedand/or visually checked to verify the proper alloy or composition of material priorto installation.
Appendix 8BExample of Test and Inspection of Equipment andProcedures
The purpose of these procedures is to ensure the operational safety, protection of theenvironment, and integrity of plant equipment. These procedures are applicable to allclassified equipment including rental equipment specified by the department manager.Classified equipment is defined as all equipment for which periodic test, inspection, andrecordkeeping is mandatory. Classified equipment is identified within the plant's reliabilitymaintenance listing of equipment, designated as RM-I and RM-2. (These lists are notreproduced in this book.) Priority field A consists of equipment identified in operationalsafety standards. (See Appendix A.) Priority field B consists of equipment in governmentalregulations, plant policies, plant management directives and by the department manager.
I. POLICIES
A. Each item of classified equipment shall be permanently labeled with its engineer-ing item number of otherwise identified if an engineering item number is notapplicable, with the following exceptions:1. Equipment such as hoses, ladders, etc., may be grouped by unit or area and
identified only in the reliability maintenance list.2. Individual components of instruments loops may be grouped under a single
instrument loop identification.B. Each item (or grouping) of classified equipment shall be identified within the
reliability maintenance list as either priority A, B, or C.C. Procedure guidelines for the testing and inspection of each type of classified
equipment shall be maintained.D. All classified equipment shall be tested and inspected by qualified personnel in
accordance with the minimum schedules listed in Appendices A and B.E. Records of testing and inspection performed and deficiencies noted shall be
entered into the RM-2 system by the group performing the testing and inspection,with the following exception: For items that receive testing and inspection atintervals more frequent than 6 months, records may be retained for a minimumof one year on written logs or checksheets.
F. Visual verification of testing and inspection performed shall be provided forequipment listed in Appendix C.
G. Status and forward forecast reporting shall be provided according to the standardslisted in Section II.
IL STANDARDS
A. Forward forecast reporting.1. Issued monthly to the department manager.
2. Lists equipment due for preventive maintenance in the following month andequipment overdue for preventive maintenance.
B. Status reporting.1. Issued quarterly to the department manager and assistant plant manager.2. Lists summary of items overdue for testing by more than 20% of scheduled
interval.
III. ACCOUNTABILITIES
A. Owning Department—identified under "minimum schedules" in Appendices Aand B.1. Permanent labeling of classified equipment.2. Identification of classified equipment within the reliability maintenance lists.3. Scheduling of equipment preventive maintenance and adjustment of preventive
maintenance frequency within the reliability maintenance system.4. Reporting to appropriate government agencies.
B. Testing Department—identified under "minimum testing and inspection required"in Appendices A and B.1. Detailed procedures/guidelines are developed and maintained for testing and
inspection of classified equipment.2. Provides qualified personnel to perform testing and inspection.3. Enters records of testing and inspections performed and deficiencies noted
into RM-2 system for classified equipment tested.4. Provides test and inspection reports identifying deficiencies noted to the appro-
priate department manager and maintenance or engineering group.C. Maintenance Department
1. Maintains RM-I and RM-2 systems.2. Issues status and forward forecasting reporting.
APPENDIX APriority A Minimum Testing and Inspection Requirements Identified in Unit OperationalSafety Standards
Equipment
1. Critical Instrumentsand Alarms
2. Critical Safety ReliefDevices
3. Critical Vessels,Corrosive Service
4. Critical Vessels,
Minimum testing and inspection required(Accountability)
Functional Check of Each Loop(Maintenance)
Standard Relief Device Inspection(Maintenance)
External Visual Inspection(Maintenance)
Internal Visual Inspection(Maintenance)
External Visual Inspection
Minimum schedule(Accountability)
1 year(Operations)
History or asspecified in OSS(Operations)
5 years or 1/4remaining life(Operations)10 years or 1/2remaining life(Operations)
5 years or 1/4
APPENDIX A. Continued.
Equipment
Noncorrosive Service
5. Critical Pumpsor Motors
6. Critical ElectricalDistribution Systems
7. Other CriticalEquipment
Minimum testing and inspection required(Accountability)
(Maintenance)
Standard Pump or Motor Inspection(Maintenance)
Standard Electrical Inspection(Maintenance)
As Specified in OSS(Maintenance)
Minimum schedule(Accountability)
remaining life(Operations)History or asspecified in OSS(Operations)History or asspecified in OSS(Operations)History or asspecified in OSS(Operations)
APPENDIX BPriority B Minimum Testing and Inspection Requirements Identified in GovernmentRegulations or Company Policies
Equipment
1. Portable O2/FlammableGas Meters
2. Fixed Flammable andToxic Gas Monitors
3. Safety Relief Devices
4. Serious Instrumentsand Alarms
5. Overspeed Trip Device
6. Vessels, Pipes, Tanks,Thermowells,Corrosive Service
7. Vessels, Pipes, Tanks,Thermowells,Noncorrosive Service
8. Portable Ladders
9. Testing and InspectionTest Equipment
10. Chain Operated Valves
Minimum Testing andInspection Required
(Accountability)
Test and Calibration(Maintenance)
Test and Calibration(Maintenance)
Standard ReliefDevice Inspection(Maintenance)
Functional Check ofEach Loop(Maintenance)
Standard(Maintenance)
External Visual Inspection(Maintenance)
Internal Visual Inspection(Maintenance)
External Visual Inspection(Maintenance)
Standard(Maintenance)
Standard(Maintenance)
Standard(Maintenance)
Minimum Schedule(Accountability)
Quarterly(Operations)
Quarterly(Operations)
History, not toexceed 5 years(Operations)Two years(Operations)
14 months(Operations)
5 years or1/4 remaining life(Operations)10 years or1/2 remaining life(Operations)
5 years or1/4 remaining life(Operations)
1 year(Operations)
1 year(Maintenance)
History, not toexceed 5 years(Operations)
APPENDIX B. Continued.
Equipment
11. Utility, Fire,Marine Chemical Hoses
12. Temporary ServiceChemical Hoses*
13. In Line Flex Hosesand Expansion Joints
14. Tank Vents andVacuum Breakers
15. Chainfalls, Hoistsand Slings
16. Monorails and OHCranes
17. Impact Tool Accessories
18. Air Movers
19. Extension Cords,12 Volts Lights, FloodLights, Power Packs,Gang Plugs
20. Fall ProtectionEquipment
21. Fire and Safety EquipmentInside Process Units
22. Fire and Safety EquipmentOutside Process Units
Safety and HealthTesting and Inspection Manual(Safety and Health Dept.)Safety and HealthTesting and Inspection Manual(Shift)Safety and HealthTesting and Inspection Manual(Owning Dept.)Safety and HealthTesting and Inspection Manual(Safety and Health Dept.)Industrial Hygiene Manual(Safety and Health Dept.)
Per Procedure(Safety and HealthDept.)Per Procedure(Safety and HealthDept.)1 year(Operations)Varies withEquipment(Owning Dept.)Varies by Type(Owning Dept.)
"Hoses used in open dome loading are exempt if no connection exists on the open end.**Leased cylinders are hydrotested by the vendor. The using dept. has the responsibility to return the cylinder
through the Material Dept. to the vendor prior to required hydrotest date.
APPENDIX CPriority C Testing and Inspection Requirements
A. Visual verification, using the color code in B. below, is required on the following equipment:
B. Color codes used to visually confirm test/inspection:
Color YearGreen 1987Purple 1988White 1989Black 1990Blue 1991Brown 1992Orange 1993
C. Where six months testing is required, one tie wrap indicates first six months of the year, two tiewraps indicate second six months.
Appendix 8CExample of Field Inspection and Testing of ProcessSafety Systems
SUBJECT: Prooftesting
TO: Operators
FROM:
It is necessary to routinely prooftest critical instruments to be sure they will actin the manner required to prevent an unsafe condition in the department.
These prooftests are set up for the operator to check these instruments, with theoperations foreman being responsible for repairing any discrepancies andkeeping records of the prooftests and repairs. The frequency of the prooftest isdependent on the frequency that the loop is called on to act and the failure rateof the device.
The forms will be distributed as the prooftests are due, with the MaintenanceDepartment being responsible for seeing that the prooftesting due dates are sentto the operations foreman.
As these forms are given to the operators, they will do the prooftests accordingto the testing instructions in the operating manual, and return the forms to theoperations foreman. The operations foreman will note any discrepancies andwrite appropriate work orders to repair and then date the form when thediscrepancies are corrected. The form will then be filed in the operationsforeman's office.
These prooftests are set up to be simple and easily done during a normal shift,such as the equipment checksheets. No equipment should be shut down to runthese tests. Should a prooftest be required on a piece of equipment that isrunning, and the test cannot be performed without shutting that equipmentdown, the test will be delayed until it is down. If any equipment requiring aprooftest is down for more than 24 hours, the test will be completed anddiscrepancies corrected before it is started up.
PROOFTESTING STORAGE WATER RELATED SAFETY DEVICES
DATE:
OPERATOR:
The purpose of this prooftest is to check the operation of the safety devices on the 110storage tank used to prevent air from entering the tank. This test will check the operationof the safety valves, pump shutdown, pneumatic valve operation, N2 valve operation,and all water related alarms.
1. There cannot be any loading or transferring of material from any storage tank.
2. Lift each cover on the two safety valves to assure free operation. They should liftsmoothly and fall freely.
3. Put the air switch on the loading pneumatic valves in the open position.
4. Start the 110 storage tank circulating.
5. Close the H2O block valve at the H2O level control valve. This will shut off the H2Oflow to the tank and trigger the shutdown switches.
Did the: YES NO
A. N2 valve open?B. Pump shut down?C. Pump off alarm come on?D. Low H2O overflow alarm come on?E. Low H2O level alarm come on?F. Pneumatic valves close?G. Safety valves lift?
6. Open the H2O block valve slowly until the H2O controller starts controlling the levelagain, then open it wide.
7. Restart the loading pump to circulate 110 storage.Did the: YES NO
A. Loading pump restart?B. Load pump on alarm come on?
8. Return this form to the operations foreman.
PROOFTESTING 106A AND 106B STORAGE TANK HIGH LEVEL ALARMS
DATE:
OPERATOR:
TANK BEING PROOFTESTED:
The purpose of this prooftest is to check the operation of the high level alarm on 106Aor 106B storage tanks.
1. The level should be about 5 feet.
2. No product can be going into the tank and no transfers can be made from the tankduring this test, except as noted.
3. Using gasoline indicator and a tank measuring tape, measure the level in the tankthrough the safety valve cover.
TAPE MEASUREMENT FLOAT READING COMPUTER READING
A. Is the measurement within 6 inches of the float indicator?B. Is the measurement within 6 inches of the computer indication?
4. Pull the level indicator down about 1 foot and release it. It should return to the previouslevel indication within about 2 inches.
5. Pull the level indicator down to where the alarm switch is activated, then release it.Did the: YES NO
A. High level alarm sound?B. High level alarm clear when the indicator was released?C. Indicator return to the previous measurement?
6. Reset the high level alarm on the computer to 1 foot above the actual level in thetank. Start product going into the tank. When the level increases 1 foot, did thecomputer alarm sound?
7. Reset the high level alarm on the computer to the original value. Normal alarm pointsare 3' for low level and 13' for high level.
8. Return this form to the operations foreman.
PROOFTESTING THE TANK CAR HIGH LEVEL ALARM ANDSHUTOFF VALVE
This prooftest will check the operation of the safety devices at tank car loading.
1. There can be no loading or transferring operations being performed.
2. Open the drain on the collection tank and drain it completely empty.
3. Determine the pressure on the supply water being used for the test.
4. Install a pressure gauge on the float chamber inlet line.
5. Have the CS2 purification operator start 110 storage tank circulation.
6. Hook up the H2O supply to the vent line and open slowly to fill the float chamberwith H2O.
7. Note the pressure on the gauge.
8. While leaving the H2O supply on, check the following:A. Did the high level alarm sound?B. What was the H2O supply pressure?C. What was the pressure on the float chamber after 5 minutes?D. Did any H2O come out the drain at the collection tank?
9. Push the loading rack loading pump stop button.Did the: YES NO
A. Loading pump shut down?B. Loading pump off alarm come on?C. Pneumatic valves close?
10. Disconnect the H2O supply and drain the lines and float chamber.
11. Hook up N2 to the line and purge through the system and out the collection tank toclear out all H2O.
12. Close the drain line on the collection tank.
13. Notify the purification operator that the prooftest is complete.
This prooftest is designed to test the operation of the high and low methane pressureswitches and the double block and bleed valves.
1. The furnace must be down with the fuel gas block valve shut at the header.2. Bleed all pressure off the manifold and piping downstream of the header block valve
by opening the bleed at each of the pressure switches. When completed close thetwo bleeds.
3. Hook up a N2 supply hose from the plant N2 Header to the 1" Durco cock just upstreamof the Maxon valve and pressure the fuel gas line to 45 psig. Could you open theMaxon valve?
4. Slowly bleed the N2 pressure off the fuel gas line at the low pressure switch bleed onthe downstream side of the Maxon valve, until the Maxon valve closes. At whatpressure did the Maxon valve trip?
5. Pressure up the fuel gas line again with N2 to 45 psig. Open the Maxon valve. Increasethe pressure until the Maxon valve closes. This will check the pressure switch on theupstream side of the Maxon valve. At what pressure did the Maxon valve trip?
6. Disconnect the N2 supply hose, close and plug all three bleeds.7. Open the fuel gas header block valve to repressurize the fuel gas line and put the fuel
system back in service.8. Return this form to the operations foreman.
Appendix 8DExample of a Hot Work Permit
I. POLICY
Hot work will be done only after evaluation and the issuing of a hot work permit. Thispermit is valid for only one shift and must be renewed at shift change if work extendsbeyond one shift,
II. SCOPE
This standard covers the responsibilities for planning, issuing a permit, and maintainingsafe working conditions for jobs requiring hot work.
III. DEFINITIONS
Hot work is any work that may generate a source of ignition in areas where flammable orcombustible materials may be present. Welding, flame cutting, use of pneumatic hammers,and spark-producing equipment are examples of this type of work.
IV. RESPONSIBILITY
A. The owner or designee in charge of the facility where hot work is to be done isresponsible for:1. Preparing the area for hot work.2. Performing or requesting an explosimeter check if necessary. Operator of explosi-
meter must be certain that the meter is calibrated, that it functions properly, andmust have a current certificate of training (3-year validation).
3. Issuing the hot work permit in duplicate.4. Cosigning the hot work permit for work to be done along a plant right-of-way for
reasons stated in Section V.5. Notifying the supervisor or representative responsible for the performance of hot
work of the nature of the hazards involved and precautions to follow for the safeexecution of the work.
6. Maintaining the safe conditions on which the permit is based.7. Suspending the permit if these conditions cannot be maintained.8. Reissuing a permit when safe conditions are established following a suspended
permit.9. Establishing a fire watch if necessary.
B. The person in charge of doing the work is responsible for:1. Conferring with the owner or designee to be sure the area is prepared for the safe
performance of hot work. Considerations should be given to hazardous operationsin the surrounding area.
2. Determining that a permit will be issued immediately before work begins.3. Ensuring that the employee(s) who will do hot work has the protective equipment
required and is aware of the possible hazards of the area.4. Notifying the owner or designee when hot work is completed.
C. Each person actually doing hot work is responsible for:1. Reviewing the hazards of the work area with the owner or designee and/or the
supervisor.2. Cosigning the hot work permit.3. Reporting any changes in conditions that affect the safety of the area.4. Suspending all hot work during an "alert" signal.5. Requesting that a hot work permit be reissued following work suspension due to an
"alert" or changing conditions.6. Notifying his or her representative when the hot work has been completed.
V. ADMINISTRATIVE PROCEDURES
1. Plant Right-of-Ways
The owner and/or designee shall survey the area of work prior to issuing each hot workpermit. They should consider all overhead lines and sewers in the work area for potentialhazards. They should also give consideration to hazardous operations in the surroundingarea. They shall get the hot work permit cosigned by the "owner" of adjacent property.This cosigning (a) acknowledges the presence of the contractor or service unit in thecosigner's yard, and (b) certifies that the cosigner will not do anything to adversely affectthe contractor or service unit and vice versa. The owner or designee shall notify all cosignerswhen the job has been completed or delayed so that production operations can proceednormally.
2. Permit Form
Hot work permit books are available from stock. See the example hot work form printedon page 168.
3. Exceptions
Supervision may authorize hot work in established shops without a hot work permit.However, previously used equipment brought into shops must be checked for flammablematerials.
Combustion engines may be operated on established plant roads and parking lotsunder normal working conditions without a hot work permit.
HOT WORK PERMIT TAG
HOT WORK PERMIT
REQUIRED FOR WELDING, CUTTING, BURNING OR OTHER HOT WORKIN ANY LOCATION OTHER THAN ESTABLISHED SHOPS.
THIS PERMIT TO BE ISSUED ONLY AFTER WORK SITE HAS BEEN INSPECTED.THIS PERMIT IS SUSPENDED IN THE EVENT OF PLANT ALERT OR EVACUATION.
DATE I FROM A.M. I TO AJIVl I WORK AREAP.M. P.M.
JOB DESCRIPTION
SITE PREPARATION
1. Equipment PreparationSteamed [ ] Washed [ ] Purged with
2. Has equipment been checked for linings, deposits, orpockets that could be flammable, corrosive, or toxic? [ ] Yes [ ] No
3. Explosimeter check performed?If yes:
Time area was checkedName of person who made check
4. Have hazards of nearby areas been checked?Other Floor Levels [ ] Yes [ ] No Sewers [ ] Yes [ ] NoNeighboring Bldgs. [ ] Yes [ ] No Other Equipment [ ] Yes [ ] No
6. Will an operating representative or fire watch be present? [ ] Yes [ ] No
7. Is a Vessel Entry Permit required? [ ] Yes [ ] No
8. Special procedures
ADDITIONAL SPACE ON BACK
SIGNATURE OF PERSONAUTHORIZING PERMIT
DEPARTMENT OR GROUPASSIGNED JOB
SIGNATURE OF EMPLOYEESASSIGNED TO JOB
Space for additionalsignatures on back
SAFETY
STANDARD
Appendix 8EExample of Criteria for Test and Inspection of SafetyRelief Devices
The following criteria were developed to provide a minimum standard for a test andinspection program, to assure that safety relief devices are maintained,in a reliable con-dition, in compliance with company standards and other applicable regulatory agencies.
The criteria are intended to provide location personnel with procedural and guidelineinformation sufficient for the development of local procedures and/or regulations andsufficient to do the work intended.
The following safety relief devices are included in this criteria:
Safety Valve —Direct Spring LoadedSafety Valve—Pilot OperatedRupture DisksControl Loop/Manual Actuated Emergency Vent DevicesWeight Loaded Conservation and Emergency VentsExplosion Vents
SAFETY VALVES-DIRECT SPRING LOADED
I. Accountability
The location test and inspection program identifies the ownership of the relief devices,specifies responsibilities for test and inspection, and provides for auditing of the program.
IL Inspections
A. InstallationAt installation or later rearrangement, an inspection is made to assure that the correctsafety valve is installed and oriented properly.
B. Monthly for Block ValvesApproximately monthly, block valves isolating safety relief valves are inspected to assurethat they are sealed in the open position.
C. Six Weeks for Leak MonitoringSafety valves having pressure gauges or remote pressure indication systems (installed tomonitor for leakage through the bellows, or to detect pressure buildup between the safetyvalve and a rupture disk at either its inlet or outlet) are inspected to ensure operability ofthe leakage detection system.
Installations employing purge gas or liquid to protect the safety valve (or safety valvewith rupture disk) from corrosion or pluggage are inspected to ensure integrity of the purgesystem.
D. Quarterly for Safety Valve LeakageInspections are recommended to determine if installed safety valves give indication ofleakage. Particular attention is paid to installations where the relief capacity could bedisabled by leakage (such as plugging), and where vibration or pulsating loads create ahigh potential for leakage.
III. Testing
A. Reliability MaintenanceTesting of the relief point of safety valves is to be performed using a test system which hasbeen certified, and periodically rechecked, to be of satisfactory accuracy.
B. Test Interval SelectionTypical test frequencies are as follows:
1. Liquids:a. Significant exposure consequences 1 year or lessb. Residue—fouling 1 year or lessc. Corrosive (depending on material of construction) 1-2 yearsd. Nonresidue—clean 2 yearse. Relief valve protected by rupture disk1
With knife blade 1-2 yearsWithout knife blade 3-5 years
2. Gases:a. Dirty or corrosive 1 yearb. Moderately clean 2 yearsc. Clean, dry, and noncorrosive 3 years
3. Water and Steam (except as regulated by law—2 years)
Initial test intervals will be chosen based on previous experience, or best judgment, consider-ing safety valve type and service characteristics, but should not exceed 2 years.
Safety valves that operate frequently may be subjected to mechanical damage andrequire short test intervals to reduce fluid loss. Safety valves with elastomeric seals shouldhave a maximum interval of 2 years between seal replacement.
Safety valves which are found to be plugged, frozen shut, corroded, or having drifted±10% away from set pressure should have the interval between tests reduced. Conversely,valves which are found free of fouling and other functional problems can have the intervalbetween tests extended, not to exceed 5 years.
C. IdentificationAll safety valves shall be stamped or tagged with a legible identifying code number,individual to each valve, to minimize the potential for error during handling and testing.Bellows type valves should be coded additionally to make them readily identifiable.
1AIsO test when rupture disk is serviced.
D. Servicing Criteria
1. Bench Testing and Repair. Bench testing and repair servicing of safety valves shallinclude:
a. Determine "as received" opening pressure (by bench test). Note: Slowdownsettings must be changed to accommodate small volumes of test stands.
b. Disassemble and clean as necessary.c. Inspect parts for wear, cracks, or other damage.d. Relap seat and disk as required.e. Reassemble with parts replacement as necessasry.f. "Lifting lever" operational check (at 75% of set pressure) for safety valves in
air, steam, or hot water service. (Lifting lever stem packing required in hotwater service.)
g. Set pressure resetting and verification. Tolerance not to exceed ±2psi up to70 psig setting and 3% above 70 psig.
h. Reposition blowdown rings, when changed to accommodate bench testing, permanufacturers' specifications.
i. "Bubble tight" leak test, dependent on criticality of service,j. Leak test the valve body and bellows on bellows equipped safety valves by
applying pneumatic pressure via the discharge port. Valve body and bellowsmust be leak tight.
k. Restamp nameplate, when capacity/set pressure change involving spring re-placement is made.
1. Provide supplemental identification on bellows type valves,m. Color code serviced valves to indicate last service date,n. Apply seals to spring setting and blowdown mechanisms,o. Document "as received" condition of the valve and the service work done,p. Revise as necessary, with U/A of owning department, test and inspection
frequency based on "as received" condition,q. Verify service, location, and process as shown on safety valve records. Note:
Problem valve should be reported to the accountable operating departmentfor investigation and corrective action.
2. Testing in Place. Safety valves may be tested in place (field tested) only everyother time. They must be bench tested at least every other occasion on the test andinspection frequency cycle. Note: The elastometric and/or plastic parts are to be replacedat least every 2 years.
When pilot operated valves are tested in place, the test arrangement should allowthe relief valve to be blocked in during the test and the pilot and main vaive assemblies tobe tested as an integral operating unit.
E. Servicing PersonnelOnly qualified (trained) personnel shall be allowed to service safety valves when repair orresetting is deemed necessary following testing. Spring changes, or other actions that wouldchange the performance of a valve, shall be performed or supervised by an individualcertified by the manufacturer of the valve to repair and reset the model safety valve. Note:"Qualified" means trained to a level that satisfies standards established by individual
locations. ''Certified" means trained by the valve manufacturer and given a certificate forwork on specific types of safety valves, per the ASME Boiler and Pressure Vessel Code.
IV. Records
A. InstallationRecords of safety valve installations shall be maintained, and may be part of the Test andServicing Records. They shall include:
1. installation schematics or flow diagrams,2. sizing basis and data (calculations),3. dates of installation and/or rearrangements.
B. InspectionRecords verifying inspections should be maintained for a period of at least the two previousinspections (or a minimum of 6 months).
C. Test and ServicingSafety valve service/test records shall be maintained for the life of the valve in completeand updated form. They shall include:
1. Process ID or other identifying number.2. Service/equipment description.3. Location description (or provide installation schematic).4. Contacting fluid identify.5. Manufacturer's name and shop no. or serial no.6. Spring number and orifice size.7. Size/model no./style/type/connection sizes, and service class.8. Materials of construction.9. Operating temperature and pressure.
10. Set pressure and considerations for back pressure and temperature compensation.11. Data of installation in current service.12. Service history:
a. "As received" condition of safety valve.b. Work done on valve.c. Testing frequency changes recommended to owning department.
13. Last test and next test dates.14. Testing frequency.
D. ReportsPeriodic status reports of the safety valve testing program shall be provided to appropriatefacility managers.
Periodic exceptions reports shall be provided to appropriate facility and locationmanagers. The reports will indicate the safety valves that are past due the scheduled testdates by time period, such as 6 months overdue; by frequency, such as past due twoconsecutive test dates; or by percent of normal test interval overdue.
SAFETY VALVES-PILOT OPERATED
I. Accountability
The location test and inspection program identifies the ownership of pilot operated reliefdevices, specifies responsibilities for test and inspection, and provides for auditing of theprogram.
II. Inspections
A. InstallationAt the initial installation, or later rearrangement, an inspection is made to assure that thecorrect pilot operated safety valve is installed and oriented properly.
B. Monthly for Block ValvesApproximately monthly, block valves isolating pilot operated safety valves are inspectedto assure that they are sealed in the open position.
C. Monthly for Safety Valve LeakageAt the same time that isolating valves at pilot operated relief devices are inspected toensure that they are sealed open, the safety valve is to be visually inspected for indicationsof leakage to the atmosphere. Particular attention should be paid to installations wherevibration, pulsating loads, or other circumstances might subject the relief valve to a highpotential for leakage.
The pilot valve vent port is inspected to ensure that it is open to the atmosphere andprotected by a vent screen from plugging. Also, the strainer or filter in the pressure sensingline, if used, is checked to ensure that it it not plugged.
Installations employing purge gas or liquid to protect the pilot operated safety valvefrom corrosion or pluggage are inspected to ensure integrity of the purge system.
III. Testing
A. Reliability MaintenanceTesting of the relief point of pilot operated safety valves is to be performed using a testsystem which has been certified, and periodically rechecked, to be of satisfactory accuracy.
B. Test Interval SelectionTypical test frequencies are as follows:
1. Chemicals:a. Significant exposure consequences 1 year or lessb. Nonresidue—clean 2 years
2. Gases:a. Moderately clean 1 yearb. Clean, dry and noncorrosive 2 years
Initial test intervals will be chosen based on previous experience, or best judgment,considering safety valve type and service characteristics, but should not exceed 2 years.Since pilot operated valves are limited to use in clean vapor or gas service, an initial testfrequency interval of !5 to 2 years is typically selected.
Pilot operated valves that operate frequently may be subjected to mechanical damageand require short test intervals to reduce fluid loss. Pilot operated valves have elastomericseats and seals, and should have a maximum interval of 2 years between parts replacement.
Safety valves which are found to be plugged, frozen shut, corroded, or having drifted±5% away from set pressure should have the interval between tests reduced. Conversely,valves which are found free of fouling and other functional problems can have the intervalbetween tests extended, not to exceed 2 years.
C. IdentificationAll pilot operated safety valves shall be stamped or tagged with a legible identifying codenumber, individual to each valve, to minimize the potential for error during handling andtesting.
D. Servicing Criteria
1. Bench Testing and Repair. Bench testing and repair servicing of pilot operatedsafety valves shall include:a. Determine "as received" opening pressure (by bench test). Note: Slowdown
adjustment must be changed to accommodate small volumes of test stands.b. Disassemble and clean as necessary.c. Inspect parts for wear, cracks, or other damage.d. Relap seat and disk as required.e. Reassemble with parts replacement as necessary.f. Set pressure resetting and verification. Tolerance not to exceed ±2 psi up to
70 psig setting and 3% above 70 psig.g. Reposition blowdown adjustments, when changed to accommodate bench or
field testing, per manufacturers' specifications.h. "Bubble tight" leak test, dependent on criticality of service,i. Restamp nameplate, when capacity/set pressure change involving spring re-
placement is made.j. Color code serviced valves to indicate last service date.k. Apply seals to spring setting and blowdown mechanisms.1. Document "as received" condition of the valve, including condition of elasto-
meric and/or plastic parts, and the service work done.m. Revise as necessary, with U/A of owning department, test and inspection
frequency based on "as received" condition.n. Verify service, location, and process as shown on safety valve records. Note:
Problem valves should be reported to the accountable operating departmentfor investigation and corrective action.
2. Testing in Place. Pilot operated safety valves may be tested in place (field tested)only every other time. They must be bench tested at least every other occasionon the test and inspection frequency cycle. Note: The elastomeric and/or plasticparts are to be replaced at least every 2 years.
E. Servicing PersonnelOnly qualified (trained) personnel shall be allowed to service pilot operated safety valveswhen repair or resetting is deemed necessary following testing. Spring changes, or otheractions that would change the performance of a valve, shall be performed or supervised by
an individual certified by the manufacturer of the valve to repair and reset that modelsafety valve. Note: "Qualified" means trained to a level which satisfies standards establishedby individual locations. "Certified" means trained by the valve manufacturer and given acertificate for work on specific types of safety valves per the ASME Boiler and PressureVessel Code.
IV. Records
A. InstallationRecords of pilot operated safety valve installations shall be maintained, and may be partof the Test and Servicing Records. They shall include:
1. installation schematics or flow diagrams,2. sizing basis and data (calculations),3. dates of installation and/or rearrangements.
B. InspectionRecords verifying inspections should be maintained for a period of at least the two previousinspections (or a minimum of 6 months).
C. Test and ServicingPilot operated safety valve service/test records shall be maintained for the life of the valvein complete and updated form. They shall include:
1. Process LD. or other identifying number.2. Service/equipment description.3. Location description (or provide installation schematic).4. Contacting fluid identity.5. Manufacturer's name and shop no. or serial no.6. Spring number, orifice size, main valve and pilot valve information.7. Size/model no./style/type/connection sizes, and service class,8. Materials of construction, including elastomeric or plastic parts.9. Operating temperature and pressure.
10. Set pressure and considerations for back pressure and temperature compensation.11. Date of installation in current service.12. Service history:
a. "As received" condition of valve, including condition of elastomeric and/orplastic parts.
b. Work done on valve.c. Testing frequency changes recommended to owning department.
13. Last test and next test dates.14. Testing frequency.
D. ReportsPeriodic status reports of the safety valve testing program shall be provided to appropriatefacility managers.
Periodic exceptions reports shall be provided to appropriate facility and locationmanagers. The reports will indicate the pilot operated safety valves that are past due the
scheduled test dates by time period, such as 6 months overdue; by frequency, such as pastdue two consecutive test dates; or by percent of normal test interval overdue.
RUPTURE DISKS
I. Accountability
The location test and inspection program identifies the ownership of the relief devices,specifies responsibilities for test and inspection, and provides for auditing of the program.
II. Inspections
A. InstallationAt installation or later rearrangement, an inspection is made to assure that the correctrupture disk is installed and oriented properly.
B. Monthly for Block ValvesApproximately monthly, block valves isolating rupture disks are inspected to assure thatthey are sealed in the open position.
C. Six Weeks for Leak MonitoringInstallations having pressure gauges or remote pressure indication systems (installed todetect pressure buildup between the rupture disk and a safety valve at either its inlet oroutlet) are inspected to ensure operability of the leakage detection system.
Installations employing purge gas or liquid to protect the rupture disk from corrosionor pluggage are inspected to ensure integrity of the purge system.
III. Servicing
A. Reliability MaintenanceRupture disks do not have an infinite life. Even though the materials may not be attackedby the process fluid or by the atmosphere, they are affected by pressure and/or vacuumcycles. Disks that can release toxic or explosive vapors to the atmosphere should be replacedon a regular schedule to prevent opening at less than the specified bursting pressure.
B. Servicing Interval SelectionTypical servicing frequencies are as follows:
1. Residue—fouling service 1 year or less2. Pulsating service near 70% rating 1 year or less3. Toxic—explosive materials 1-2 years4. Flammable vapor cloud release 1-2 years5. Corrosive service 1-2 years6. Critical service operation 1-2 years7. Nonresidue—Clean 2 years8. RB-90 (reverse buckling w/knife edge) 2 years9. Nonhazardous service 3 years
10. Noncritical service —reliability not a major concern 5 years
Initial servicing intervals will be chosen based on previous experience, or best judgment,considering rupture disk type and service characteristics, but should not exceed 3 years(note 2-year limit for RB-90).
Rupture disks which are found to be plugged or corroded should have the intervalbetween servicing reduced. Conversely, disks which are found free of fouling and otherfunctional problems can have the interval between servicing extended, not to exceed 5years.
C. IdentificationAll rupture disk assemblies shall be stamped or tagged with a legible identifying codenumber, individual to each assembly, to minimize the potential for error during servicing.Reverse buckling disks with knife edges should be coded additionally to make them readilyidentifiable.
D. Servicing CriteriaRupture disk servicing shall include:
1. Inspectiona. Remove safety head assembly with disk (or other rupture disk holder) from
mounting.b. Inspect upstream and downstream piping at mounting location for product
buildup, corrosion, or physical damage. Correct as necessary.c. Inspect rupture disk in safety head or holder for:
(1) Solidified product under the disk. (Could increase burst pressure.)(2) Signs of pitting or corrosion on metal disk or the penetration of product
past the plastic liner.(3) Heat discoloration. (Especially evident on plastic liners.)(4) Physical damage—on occasion, dimpling of reverse buckling disks occurs
(for example, by being hit with a water stream during vessel cleaning; bypressure excursions close to disk bursting pressure).
(5) If knife blades are required to assist in opening of the RB-90 type disk,these should be in place and sharp.
d. Reinstall only BS&B "STA-SAFE" pretorqued disk and head assembly wheninspection reveals no problem. In all other cases, install a new disk.
2. Disk Replacementa. After physical inspection, install a new, exact replacement disk. The reason is
that the seat of the inspected disk has been weakened by the release of theload on it. The disk burst performance will be changed by reapplying the torquea second time.
b. Proper handling and installation of rupture disks are critical to their perfor-mance. Improper handling and installation can drastically affect the burst pointand/or service life of rupture disks.
(1) Do not open shipping container until you are ready to ,install the rupturedisk.
(2) After opening, read installation instructions before touching rupture disk.(3) Handle rupture disk by edges only. Never touch domed area. (Perspiration
could begin corrosion.)(4) Examine rupture disks for damage. Never install reverse buckling disks
with any visible damage to dome or sweating area.
c. Inspect safety heads. Mating surfaces must be clean and free of product buildup,dirt, corrosion, etc. Clean and polish surfaces with fine emery paper.
d. Do not clean the base flange with emery cloth or other abrasives in such afashion that will damage the surface. The use of a solvent to clean deposits isrecommended. Be sure to thoroughly wash the solvent off the flange. Certainchlorinated solvents may cause corrosion problems.
e. Inspect the knife blades in the hold-down flange in BS&B RB-90 assemblies.They must be clean and sharp. Sharpen with a mill file or stone if required.Inspect the welds at the end of the blades. (Disk ruptures have been knownto crack the blade welds.)
f. Place the disk between the safety head flanges squarely and evenly. Make upthe disk in the safety head flanges with the tabs or Allen screws provided. Useno gasket or sealant compound above or below the rupture disk. The disk maybe received with top and bottom protective shipping covers. These are not partof the disk assembly—do not install them with the disk. (Reverse bucklingdisks are never supplied with vacuum supports.)
g. Reverse-buckling type disks furnished by one manufacturer must not be usedin safety head (holder) furnished by another manufacturer. Such interchangingcan severely alter the operating characteristics of the disk.
h. Prebulged (conventional) type disks furnished by one manufacturer may beused in a conventional-type safety head (holder) furnished by another manufac-turer only until a convenient time when the correct disk can be installed.
3. Reinstallationa. Install safety head in companion flanges carefully, and inspect safety head flow
arrows to assure "right side up" installation.b. Reverse-buckling type disk holders shall be installed with a spiral wound gas-
ket(s) (Flexitallic or equal) between the base flange of the holder and thepiping flange. Free-venting disks do not require a gasket on the top side of theassembly.
(1) Prebulged (conventional) type disk holders must not be installed with spiralwound gaskets.
(2) Graphite rupture disks must be installed with either elastomeric or Teflonencapsulated elastomeric gaskets.
c. The condition of the bolt and nut threads is critical to the bolting operation.The values obtained with the torque wrench are to relate to bolting force—notto friction on rusty, dirty, or scarred threads. Use a thread die to clean thethreads of each bolt. Inspect the thread condition; discard damaged bolts ornuts. Lubricate threads with a good thread dope.
d. Install bolts and tighten evenly, hand tight.
(1) Release the top bolt on the assembly holder tab (if any). Let the tab fall
free, held by the bottom bolt, and leave the top bolt in the hold-downflange.
(2) Tighten the flange bolts with a dial indicating torque wrench. Proper loadis critical to performance. Installation instructions state load requirementsin foot-pounds.
(3) Use correct bolting procedures. Tighten opposite bolts, using at least fourcycles to achieve recommended load, i.e., 25%, 50%, 75%, then 100% onload.
e. Companion flange gasketing must be of a type which does not cold flow. Coldflowing relaxes load on all except pretorqued assemblies.
f. Make final inspection of installation to assure:(1) Flow direction on disk tab and flow arrows on safety head assembly match
product flow direction in case of burst.(2) Flanges of mating pipes holding safety head appear even and parallel.
(Uneven flanges product stress on safety head, with improper loading todisk and unreliable burst point.)
g. Provide a loose fitting, lightweight cover to protect the downstream side of thedisk from atmospheric corrosion (for free venting to air installations).
h. Document "as found" condition of rupture disk and the service work done.i. Revise as necessary, with U/A of owning department, servicing frequency
based on "as found" condition.j. Verify service, location, and process as shown on rupture disk records. Note:
Problem rupture disk installations should be reported to the responsible op-erating department for investigation and corrective action.
E. Servicing PersonnelOnly qualified (trained) personnel shall be allowed to handle rupture disk assemblies, whenremoval, inspection and/or replacement, and reinstallation are necessary. Note: "Qualified"means trained to a level which satisfies standards established by individual locations.
IV. Records
A. InstallationRecords of rupture disk installations shall be maintained, and may be part of the servicingrecords. They shall include:
1. installation schematics or flow diagrams with discharge point (atmospheric, flare,header, knock-out pot);
2. sizing basis and data (calculations);3. dates of installation and/or rearrangements.
B. InspectionRecords verifying inspections should be maintained for a period of at least the two previousinspections (or a minimum of 6 months).
C. ServicingRupture disk service records shall be maintained in complete and updated form. They shallinclude:
1. Process LD. or other identifying number.2. Service/equipment description.3. Location description (or provide installation schematic).4. Contacting fluid identity.5. Manufacturer's name and serial number.6. Size/model no./style/type/companion flange size.7. Materials of construction.8. Operating temperature and pressure.9. Set pressure and back pressure considerations.
10. Date of installation in current service.11. Service history:
a. "As received" condition of rupture disk.b. Work done.c. Servicing frequency changes recommended to owning dept.
12. Last inspection and next inspection dates.13. Servicing frequency.
D. ReportsPeriodic status reports of the rupture disk servicing program shall be provided to appropriatefacility managers.
Periodic exceptions reports shall be provided to appropriate facility and locationmanagers. The reports will indicate the rupture disks that are past due the scheduledinspection dates by time period, such as 6 months overdue; by frequency, such as past duetwo consecutive test dates; or by percent of normal test interval overdue.
CONTROL LOOP/MANUAL ACTUATED EMERGENCY VENT DEVICES
I. Accountability
The location test and inspection program provides mechanisms for identifying controlloop/manual actuated emergency vent devices and their ownership, specifies responsibilitiesfor test and inspection, and provides for auditing of the program.
II. Definition
Control loop/manual actuated emergency vent devices vent the pressure and/or dischargehazardous materials from process equipment when harmful or dangerous conditions occur.Activation may be automatic or manual.
III. Inspections
A. OrientationControl loop/manual actuated emergency vent device orientation should be visually in-spected at installation and, therefore, during other regularly scheduled inspections. Theinspection is made to assure that the vent device is installed and oriented consistent withgood installation practices for the device type. Close attention should be given to dischargeconfiguration, particularly when a discharge header is involved (for vapor delivery to a
flare, liquid delivery to a dump pit, etc.). The impact on personnel and equipment from arelease should be considered.
D. Weekly for Backup Drive Mechanism IntegrityParticular attention should be given to the integrity of the drive mechanisms. Systems(cylinder air banks, inverter battery banks, etc.) provided as a backup to primary ventdevice drive mechanisms (instrument air, electrical) are inspected weekly as a minimum,to ensure that they will be functional, if needed.
C. Monthly for Block ValuesApproximately monthly, the following categories of block valves isolating vent devices areinspected to assure that they are sealed in the open position:
1. Shutoff valves at the inlet and/or outlet of a relief device.2. Isolation shutoff valves in vent device collection headers.3. Shutoff valves isolating separate pieces of equipment sharing a vent device.
D. Quarterly for Vent Device LeakageQuarterly, as a minimum, inspections are recommended to determine if installed ventdevices are leaking to the atmosphere or give indication of leakage. Particular attention isgiven to installations where the relief capacity could be disabled by effects of leakage (suchas plugging or corrosion) and where vibration, pulsating loads or other circumstancessubject the vent device to a high potential for leakage.
IV. Testing
A. Test Interval SelectionTesting shall be performed on a schedule consistent with the desired level of vent deviceintegrity and the satisfactory service history of the device. Test interval shall not exceedone year.
B. Test MethodsEach installation will have to be evaluated as to the test method to be used. The objectiveis to obtain as good a test of the functionality of the relief system as is practical.
1. Manual Switch Actuated Vent Device. Actual operation of the vent device isthe preferred method of testing. Should actual operation of the vent device beundesirable, a method of testing individual components for integrity should bedeveloped. The devices which link these individual components must also betested.
2. Control Loop Actuated Vent Devices. Automatic systems can be tested by any ofthe three methods listed below, the first two being preferred:
a. If possible to do so without undue risk or difficulty, take the process activatingvariable to the activation point and activate the vent device.
b. Simulate the process activating variable reaching the activation point and acti-vate the vent device.
c. Test individual components of the vent device activation control loop. Also
test devices linking individual components of the loop together. Test sensorswhich detect abnormal conditions.
C. Malfunction ResolutionAny malfunctioning element of the relief system should be repaired or replaced and asatisfactory retest of the system obtained.
Repeated functional problems identified during testing should be reported to account-able unit management and problem resolution pursued until a satisfactory correction isattained.
V. Records
A. InstallationA record of the original vent device and activation system installation along with recordsof any subsequent rearrangements shall be maintained. This documentation may be main-tained in the test and inspection/service records as well as in the operating department. Itshall include as a minimum:
1. installation schematics and loop sketches.2. sizing basis and data (calculations).3. dates of installation and/or rearrangements.
B. InspectionRecords verifying inspections should be maintained for a period of at least the two previousinspections (or a minimum of six months).
C. Testing/ServiceVent device testing/service records shall be maintained in complete and updated form,which include but are not limited to:
1. Process LD. or other identifying number.2. Service/equipment description.3. Location description (or provide installation schematic).4. Contacting fluid identity.5. Manufacturer's name and serial number for components.6. Size/model no./style/type/connection flange size, etc., for components.7. Materials of construction for components, where exposure to process or environ-
ment is a consideration.8. Operating temperature and pressure.9. Set pressure and back pressure considerations.
10. Date of installation in current service.11. Testing/service history:
a. Document "as found" condition of vent device components.b. Document work done.c. Recommended testing/servicing frequency changes.
12. Last inspection and next inspection dates.13. Testing/servicing frequency.
D. Reports
1. Periodic status reports of the vent device servicing program shall be provided toappropriate facility managers.
2. Where appropriate, periodic exceptions reports shall be provided to appropriatefacility and location managers. The reports will identify vent devices that are pastdue the scheduled testing/servicing dates. The reports will indicate the individualvent devices that are past due the scheduled test dates by time period, such as 6months overdue; or by frequency, such as past due two consecutive test dates; orby percent of normal test interval overdue.
E. UpdatingMechanisms exist to assure the timely updating of records and include information on statusor changes for existing vent devices, along with any additions or deletions.
WEIGHT LOADED CONSERVATION AND EMERGENCY VENTS
I. Accountability
The location test and inspection program identifies the ownership of weight loaded conser-vation and emergency vents, specifies responsibilities for test and inspection, and providesfor auditing of the program.
II. Inspections
A. Inspection I Servicing CriteriaWeight loaded conservation and emergency vents should be inspected at installation andserviced, thereafter, at regular intervals, not to exceed 5 years. The work shall involvechecks:
1. To ensure that the vent areas are open and separation is not restricted by frozenchemical deposits, packing materials, bird's nests, bee hives, deposits by muddaubers or other insects, etc.
2. To ensure that vent and vacuum breaker pallets and seating surfaces are cleanand free of nicks and abrasions.
3. To identify and correct situations where corrosion of vent assembly parts is occur-ring and where elastomeric or plastic parts need to be replaced.
4. To ensure that the vent unit is functionally active.5. To ensure that moving parts of the vent unit are properly lubricated.6. To ensure that flame arresters, where provided, are not restricted and are in good
repair.
B. Inspection Interval SelectionTypical inspection frequencies are as follows:
1. Residue—fouling—freezing potential 1 year or less2. Corrosive service 1 year or less3. History of obstructions 1 year or less4. Nonresidue, noncorrosive 2 years
III. Testing
Testing of weight loaded conservation and emergency vents is limited to those units con-sidered to be problem vents. Testing normally involves:
1. Manometer checks on vessel pressure characteristics to determine if the ventproblem resides in the vent unit or in the pressure regulation/control system forthe vessel.
2. Removing the weight pallets from the vent unit and weighing them after cleaning.The weighing can be done under shop conditions or in the field using portablescales.
IV. Records
A. Service History RecordsService history records for weight loaded conservation and emergency vents shall be main-tained in complete and updated form, which include but are not limited to:
1. Process LD. or other identifying number2. Service/equipment description3. Location description4. Contacting fluid identity5. Manufacturer and model no.6. Inlet size and flange rating/type7. Pressure setting: standard/maximum8. Vacuum setting: standard/maximum9. Sizing basis and data (calculations)
10. Materials of construction11. Operating temperature and pressure12. Service history:
a. Documents test dates and frequency changesb. Documents "as found" conditions of vent unitc. Documents work done on vent unit
13. Next inspection date
B. ReportsPeriodic status reports of the weight loaded conservation and emergency vents testingprogram shall be provided to appropriate facility managers.
Where appropriate, periodic exceptions reports shall be provided to appropriatefacility and location managers. The reports will identify the vent units that are past duethe scheduled test dates by time period, such as 6 months overdue; by frequency, such aspast due two consecutive test dates; or by percent of normal test interval overdue.
C. UpdatingMechanisms exist to assume the timely updating of records, and include information onstatus or changes for existing vent units, along with any additions and deletions.
EXPLOSION VENTS
I. AccountabilityThe location test and inspection program identifies the ownership of explosion vents,specifies responsibilities for test and inspection, and provides for auditing of the program.
II. Definition and Scope
Explosion vents are relief devices designed to vent gases from deflagrations of dusts, gases,vapors or mists in equipment or buildings, to protect personnel and minimize propertydamage.
Explosion vents are of two types: (1) rupture disks or large thin panels or (2)mechanical devices such as pivoted doors or spring-loaded inserts that deflect to vent.
III. Inspections
A. Installation I ReplacementVisual inspection of explosion vents and vent panels shall be made at installation and atthe time of panel replacement.
1. Verify that the explosion panel is the same as or meets the specifications of theoriginal design. A change in panel material, thickness, or tensile strength mayhave a detrimental effect on the venting capability.
2. Verify that the design method of securement of the explosion vent has not beenchanged. Nylon bolts, intended to fail in tension, may have been replaced withsteel bolts; or, panels designed to "pop out" may have been fastened in place.
3. Check for proper installation and position of vacuum support, when vent panel isso equipped.
4. Check the condition of gaskets, where applicable. Deteriorated gaskets can actlike glue, impeding the opening of the panel.
5. Check the condition of spring fasteners and latches with adjustable tension, whereapplicable. Clean and lubricate, then check and adjust as necessary for properoperation.
6. Check the items listed for Annual inspection in Section III.B below.
B. AnnualVisual inspection of explosion vents and vent panels shall be made at least annually toassure that they will perform as designed. Replace vent panels found to be deteriorated orabnormal.
1. Make sure that no piping, wiring, or other equipment has been installed whichwould keep the explosion vent from opening fully.
2. Check to see that the discharge of the explosion vent is not pointed at nearbyoperations or at vent panels of adjacent equipment, to negate the potential for achain reaction of explosions.
3. Check to see that the discharge of the explosion vent is positioned, or restrictiveguard rails are provided, to minimize exposure of personnel to flame, gases, orflying material during a venting episode.
4. Look for possible obstruction of the explosion vent such as a buildup of process
materials or accumulation of ice and snow in winter, which might interfere withthe designed operation.
5. Inspect the condition of explosion vent panels for mechanical damage, corrosion,erosion, stress hardening, and oxidation (a problem with lightweight aluminumpanels).
6. Inspect large area thin aluminum panels for signs of fatigue failure from normalpressure fluctuations.
7. Check the condition of tethers (flexible restraints) on vent panels so equipped,and the condition of vent panel opening sensors where used.
8. Check hinged explosion relief doors for proper operation. Keep clean and lu-bricated, as they are susceptible to malfunction from rust, excessive paint, and iceor snow in winter.
IV. Records
A. InspectionRecords verifying the inspections of explosion vents should be maintained per the acceptedlocation practice. Records should include:
1. Process LD. or other identification.2. Location and department.3. Service and fluids contacted.4. Pressure and temperature ratings.5. Special features, such as nylon bolts.6. Installation date.7. Inspection date and frequency.8. Inspection results and name of inspector.
V. Reports
Periodic status reports on the explosion vent inspection program shall be provided toappropriate facility managers.
Where appropriate, periodic exception reports shall be provided to appropriate fa-cility and location managers. The reports will indicate the explosion vents that are past duethe scheduled inspection dates by time period, such as 6 months overdue; by frequency,such as past due two consecutive inspection dates; or by percent of normal inspectioninterval overdue.
Appendix 8FExample of Management System for Critical and UniqueSafety Features
UNIQUE SAFETY FEATURES
This guide describes the concept of the unique safety feature (USF) program and offers areference list to assist in setting up a formal system within the plant whereby the criticaland more unusual safety design premises built into a project at the start-up and implemen-tation stage are carried forward for the life of the facility.
DEFINITIONS
The unique safety feature of a project is a concept, a control, a system which if it failed tobe maintained as originally provided would increase either the likelihood or severity of anunacceptable event.
FOREWORD
During the development of a project, many safety concerns are brought to the attention ofthe design team—who in turn design features into the project to safely cope with each ofthe hazards.
Some period of time after the project installation and start-up, the environment startschanging; people turnover begins; and the reasons for some of the more unusual or uniqueloss prevention concepts and controls for the project become obscure. Since the currentmanagement team may not be sensitive to or aware of the original need or purpose, anincreasing number of loss prevention controls are no longer maintained; are forgottenabout; are eliminated; until the unacceptable event occurs and the safety wheel must bereinvented.
For example, the nitrogen inerting system on a maleic storage tank was turned off(someone in charge at the time felt that inerting was not necessary). When tank inventorybecame low enough that the electric induction heated coils were exposed to flammablevapors, rather than a flammable liquid, ignition occurred, and the tank ruptured. Of course,there were other problems, such as the coils had shifted and were arcing to the tank sidewalls and apertures. But if the unique safety feature (the critical safety devices) had beenfunctioning—if the system were properly inerted—the explosion would not have occurred.
In the manufacture of a chemical which was unstable from the initial reaction throughthe finished goods, the degree of stability was governed by the preciseness of and complianceto the process controls. A number generated by the Analytical Lab, called Rearrangement,determined whether or not the intermediate was stable enough to process to completion.
In time, supervision would begin accepting material with lower and lower Rearrange-ment numbers (below that determined to be safe—with 100% confidence) until an uncon-trolled decomposition occurred. Among the many things that would come out of an accident
investigation is a rededication to the fact that if the Rearrangement is below x,y% thebatch must be disposed of.
Other "unique (to this project) safety features" might be:
• Redundant instrumentation on critical reactions• Interlocks which stop or change flow directions of process streams• A thermocouple installed in the relief line off the rupture disk to detect weepage• Weep holes in the dip pipes to the flammable storage tank to prevent siphoning• A tank with a weak seam roof• Minimum controller mode settings for fast reactions or operations• The building with a precisely calculated emergency ventilation system or overpres-
sure protection• High tensile strength bolts used on large piping systems which operate at very high
temperatures• Mushroom buttons for emergency shutdown of equipment
These are very specific design features which are geared to preventing or limiting theconsequences of an accident. Each process has a set of specific safety features which areimportant to its successful performance. For purposes of this document, these safety featuresare called unique.
DISCUSSION
Responsibility
The manufacturing representative for each project has the charge to develop the originalunique safety feature as part of the operation manual. Manufacturing line supervision isresponsible to keep the unique safety feature visible and current via the standard manufac-turing procedure.
On existing processes manufacturing supervision is responsible for both the develop-ment and maintainance of the USF program.
Relationship between the USF and CSD Program
The Critical Safety Device is a back-up that comes into play when the process controls fail;that is, the temperature is much too low, the level dangerously high, an unsafe action isabout to be taken. Special alarms, shutdowns, interlocks fall into this "back-up" categoryand identified as critical safety devices.
Other important process safety devices that are normally included as CSDs are flamearresters, conservation vents, excess flow and check valves, a few other items, and possiblyinerting systems.
The unique safety feature goes a step further—it includes all the CSDs plus additionalitems.
Definition: The Unique Safety Feature of a project is a concept, a control, a system whichif it failed to be maintained as originally provided would increase either the likelihoodor severity of an unacceptable event.
This definition can include the basic critical safety devices and systems common to
most processes like rupture disks or interlocks, but it would also include some special designinnovation which makes the safety device more reliable such as
• monitoring the heating system on a conservation vent to ensure against sublinationand blockage;
• utilizing plastic tubing in an air line at the valve so that the remote operated valvewill automatically close under fire conditions:
• introducing process liquid under rupture disk on a tank nozzle to help ensure nobuildup of material between the disk and the batch.
Furthermore, the unique safety feature can include such periphery process items as:
• Blowdown tanks• Explosion relief panels on buildings• Flares and incinerators• Flammable gas analyzers• Emergency systems which become available on power outages• Housekeeping• Redundant instrumentation• Special gasketing (Refer to Appendix for a partial listing of unique safety features.)
For example, with respect to the previous list, as an original design team evaluateda project, they were sensitive to the following design and operational requirements.
Blowdown TankA 4000-gallon steel tank located in a curbed area 25 feet from ignition sources to receivean unstable batch from one of four 2000-gallon reactors. When the automatic dump valveis remotely opened by the operator, the water deluge system on the blowdown tank isconcurrently activated to cool the tank and scrub the flammable vapors discharging fromthe tank. The area within the curb is sloped to one end and connected to plant storm sewer.
An installed spare blowdown tank is provided so that production can continue whilethe first tank is isolated from the process and decontaminated.
Building Pressure ReliefThe process contains a number of low flashpoint materials which would normally requireopen-air construction. Because of unfavorable climate conditions the 100,000ft buildinghousing the solvent recovery area has been equipped with 2500 ft of explosion relief panel-ing; each panel weighing 1.81b/ft is fastened with eight 1/8-inch-thick aluminum, clips andrestrained with 1 foot flexible steel cable. It is important that each panel is identified as anexplosion relief panel; the panels are not used to mount or support equipment, and noobstacles are built outside to impede its emergency function. Suggested inspection frequencyis once per year and should include such items as: condition of panels, obstructions,corrosion, cable condition, etc.
HousekeepingThe dried product is extremely dusty and a serious fire-explosion hazard. The project teamhas provided a building vacuum system with three stations on each floor tied to a collector
on the roof of the building. In addition, the equipment and building are designed so thatfrequent wet washdowns of the area can occur to prevent accumulation of dust and sec-ondary explosion hazard.
The Program
Now that we are aware of what types of safety features on a project are considered uniqueand important to preserve and to circumvent the people changeover and changing priorityproblems, the following mechanism is offered to accomplish the objectives of developingand maintaining a USF program.
Just as key items in the fire protection and personnel safety systems must be peri-odically tested and inspected, so must all unique safety features be addressed. The projectsafety inspection program is a bit more difficult to accomplish in that there is not as muchstandardization within the process system as compared to the fire and people protectionsystems. In addition, unique safety features many times are very subtle items which arenot readily visible (and difficult to highlight) during a field inspection.
To achieve an ongoing USF program in the plants, the following six steps should betaken:
1. Develop a list of the unique safety features.2. Describe concisely the purpose or function or premise for each item on the list.3. Determine how each unit is to be tested or inspected and with a suggested
frequency.
There are many loss prevention discussions held during the project design phase, butthe important safety controls are the ones that have withstood the detailed process-safetyeconomic evaluation and are included in the final design. The start-up team is very muchattuned to the design premises of the project as installed, and in the best position toinitiate the vehicle needed to preserve this information for future managers of the project(installation).
Therefore, with regard to 1, 2, and 3 above, it is felt that the manufacturing repre-sentative and his start-up team are the ideal group to develop the unique safety featurelist; describe the purpose of each system, together with some tips on inspection frequencyand procedure. (On an existing installation a knowledgeable department supervisor or aprocess engineer might be assigned this responsibility.)
Manufacturing supervision would be responsible for:
4. Having the information readily available for quick reference—either as a sectionof the operating manual or a,special safety book.
5. Tailoring the inspection frequency and procedure to ongoing plant programs, likemonthly checklists, daily batch sheets, preventive or safety maintenance programs.
6. Periodically reviewing and updating the USF list at least triennially during the in-depth auditing of the process.
Obsolescence, process changes, accident recommendations, S&PP and insurance rec-ommendations, and company experience with the process all become reasons for peri-odically reviewing and updating the list.
APPENDICES
In the following "evergreen" list are examples of the type of safety design concerns whichmight be carried forward through the life of the facility. Some are very obviously unique;others are merely critical safety devices or good safety design practices which are new,different, unusual, rare (i.e., unique for the location or uniquely applied). Note that thereare national consensus standards and/or S&PP publications concerning many of these items.
Layout and Maintenance
• Maintain critical area around/over/under equipment for maintenance or replace-ment purposes.
• Insulate outdoor equipment to 30-50 feet height so that surface temperature ofequipment is well below autoignition temperature, thereby minimizing chances ofvapor cloud explosion.
• Maintain critical space separation of extremely hazardous from other operations,i.e., flare isolation, catalyst storage, incinerator location.
• Elevate inlet air source to fireboxes 50 feet off grade to minimize chance of vaporcloud ignition.
• Fintube equipment, sprinkler heads, inspection glass or post indicator valves arenot painted.
Storage Tanks
• Weak seam roof design—no additional weight on roof or obstructions should beadded that might prevent full opening of relief vent.
• Flow or pressure monitoring devices available to the operator to ensure that systemsare properly inerted.
• Key alarms/shutdown—high level, high temp, high pressure.• Backflow prevention devices from dip-piped tanks—such as check valves and siphon
breaks.• Isolating (insulating) internal electric heaters from storage tanks containing flam-
mables to prevent arcing and subsequent ignition.• Extended storage of chemical at elevated temperatures. Excessive time at elevated
temperatures less than that predicted by lab scale thermal stability data can resultin uncontrolled decompositions.
• Exceptions to normal design: (a) pump located inside dike walls for environmentconcerns, (b) dike drain valve normally left open rather than closed, (c) dikestorage tank equipped with deluge sprinkler protection . . . must then design fordike overflow during spill-fire.
• Coded vessels—i.e., bullet type —no field welding without 100% x-ray.
Building Construction
• Building explosion panels—maintain integrity of clips, fasteners and attachments.• Emergency ventilation system—two speed fans, method of activation by either
remote/manual or vapor detection.• Prevent pooling of flammables in processed areas—contain via curbing on three
sides only and rapid preferential drain to sewer.
• Catalyst storage —remote for large inventory; very special precautions for 24 hourdepartmental storage.
• Building explosion relief area—design relief integrity maintained by ensuring noobstruction outside to prevent panel operation; no shunting out of relief area frominside by new equipment installations.
• Sewers—provide liquid seal to prevent flammable vapor back-up.• Open air—list design premises as to why open, partially opened, closed. Also
specify building management seasonal practices (e.g., open 9 months/year).• Fire walls to localize the incident; stair towers to provide safe building egress.
Rupture Disks/Relief Valves
• Temperature alarm downstream of relief device to indicate weepage.• Introduction of nitrogen or charging liquid to underside of rupture disk or relief
valve to ensure the nozzle to the relief device is not blocked.• Vent discharge line does not impinge on the enclosure (tank or building) releasing
the flammables.• Slowdown tank is ready to receive an out-of-control batch, that is, empty or
charged with a proper heel.• Continuous nitrogen purges to exclude air from operating and relief vents off
pressurized systems containing hydrogen.• Manifolded relief vents should be internally inspected after an overpressurization.• Valve under and over relief valve/rupture disk should be painted yellow and locked
or car sealed open.• Pressure relief and inerting relief on vessels have independent vent lines to the
atmosphere to prevent liquid, solids blockage of pressure relief line.• No restrictions such as flame arresters, check valves, etc., should be in rupture
disk or relief valve lines.• Slip fit plastic baggies used to cover vertical vent pipe discharge.• Rupture disk plus relief valve combination accepted provided that annular space
is monitored, with pressure gauge and excess flow valve in annular space, etc.• Water cooled rupture disk concern as in polymer type operations. Improper design
of overflow can result in flammables venting in operating area; whereas, a blockageof overflow line can result in water column on top of disk negating pressure reliefsetting.
• Planned elimination of specified bolts on reactor heads or flanges to provide systemweak spot.
• Depressurization or controlled shutdown systems.
Flame Arresters
• Make certain procedures are clear so that grid assembly on flame arrestor isreinstalled precisely as designed after repair/inspection to maintain integrity.
• Conventional flame arrestor location is less than 10 pipe diameters from the endof pipe.
• Flame arrestors should be located as close to the fire box (furnace) as possible, butnot in a straight line (eye sight) with the radiant heat within the closed system.
• Monitoring of the flame arrestor temperature or the steam supply to the tracing toprevent sublimation or blockage.
• In-line arresting unit is of special design to contain detonation.• Temperature monitoring of flame arrestor screen (en route to incinerator) to indi-
cate that flashback occurred.
Conservation Vents
• Monitoring temperature of the traced, insulated conservation vents to preventblockage and overpressurization or tank suck in on pump out.
• Liquid seal type and monitoring to prevent tank damage.
Piping Systems
• Identification of lethal piping systems—hydrogen cyanide, nitrogen, etc.• (a) System has been designed to contain a deflagration; therefore inerting may not
be required, (b) System designed to contain a detonation', therefore pressure reliefnot required.
• Overflow lines which have tendency to block (caustic) require special monitoring.• Special material of construction concerns: ammonia—no copper, brass; benzyl
chloride —no copper, iron.• High temperature shutdown of deadheaded pumps on heat sensitive material.• Frangible flange systems (bolt design) to control break point.• Surge vessels (as opposed to pressure relief) on expanding liquid piping like chlor-
ine.• Special insulation on Therminol or high temp systems to prevent cracking of
high molecular weight organics to a lower flash point material with subsequentautoignition.
• Discourage use of bellows type expansion joints in flammable or pressure reliefsystems. If used must be aligned correctly during installation.
• Dip-pipes for emergency gas agitation rather than for flammable addition.• Exception to normal design such as dip-pipes with weep holes.• Remote "stop" for pump transporting flammables into the operating area from
outside the battery limits.• "Deadman" start-stop station to prevent overflows of flammable or very hazardous
materials.• Uninsulated (bare) sections of pipe for planned heat loss—for example, feed water
regulator on boiler.• Documentation of spring hanger settings during installation in high temp/high
pressure piping systems.• Services requiring special gasketing materials—lethal systems need spiral wound.
Valves
• Provide plastic air tubing at remote operated valve to activate in event of fire.• Remote operation to close or open valve in emergency.• Cap off valves, nipples (open ended) in pressurized flammable, lethal gas or oxygen
systems.• Degrease valves, piping before start-up (after repair) of chloride or oxygen systems.• Excess flow valves in pressurized hazardous gas systems—ammonia, chlorine, hy-
drogen.
• Provide hole in butterfly valve to act as a thermal overpressure relief.• "Deadman" (spring-to-close) sampling valve in high pressure, flammable or lethal
systems.• Manually activated water flush or quench system to stop reaction or provide internal
fire fighting capability.• Defuse (lock-out) air-activated valves in field, while maintenance is in progress.• Fail safe valve analysis in event of a specific or total utility outage.• Valve in tank car, truck unloading line which closes on disconnecting or must be
closed to disconnect.• Special valve position indicator on 3-way valves.
Inerting Systems
• Pressure indication on equipment being inerted.• Check valves to prevent back-flow and contamination.• Flow indication to verify inerting is adequate during pump out.• Capability to test system on some frequency.• Nitrogen vacuum break and block valve in line to vacuum source on systems.• Inert purge (or steam) to flare systems to prevent flashback.• Furnace purge timer set for 4-6 changes of furnace volume.
Sight Glasses
• Pressure type glasses require periodic adjustment to minimize weepage.• "Push-to-activate" light behind sight glass.
Key Process Interlocks
• Ensure agitation before reactant is added to prevent overpressurization.• A minimum temperature must be achieved before next chemical added to prevent
a buildup of reactants and delayed exothermic reaction.• High temp/high pressure which might alarm, stops flow, activates cooling on coils,
etc., to effect safe shutdown.• Dryer fans must be operating to remove residual flammable vapors generated in
process.
Shutdowns
• Vibration switches on cooling tower fans.• Interlocked gates to prevent accessibility to rotary and double cone dryers.• Access hatches on centrifuges interlocked to power or motion.• Interlocked covers and openings on hazardous machinery such as blenders, mills,
switches to provide emergency shutdown of machinery.• High temp shutdown on oil lubricated air compressors (more than 100 pounds) to
prevent fires/explosions.• Chemical short-stop addition system to immediately stop reaction.• Vibration monitoring, alarms shutdowns on high speed machinery.
Monitoring
• Key manual temperature or pressure gauges to indicate batch condition on poweroutage.
• Alternate power source (battery or generator) for sensitive equipment during poweroutage.
• Battery pack to provide power to critical instruments during power outage.• Redundant instrumentation on very critical parameters—temperature, pH, pres-
sure, oxygen content.• Alignment (cold settings) on machinery.• Logging of key settings (pressure switches, timers, expansion joints, etc.) after
start-up.
Analyzers
• Oxygen analyzers to ensure inert stream to flare/furnace.• Oxygen (percent) analyzer to monitor nitrogen generating station for quality of
inerting gas.• Oxygen analyzer to ensure adequate oxygen to prevent polymerization or sufficient
oxygen to prevent by-product formation (instability).• Flammable gas analyzer to trigger alarms for spills in departments or sewers or to
activate ventilation system.• Check the monitoring units with calibrated gas similar to environment being moni-
tored.
Dust Systems
• Explosion relief panels are lightweight, equipped with frangible latches or clips andrestraining chains.
• Carbon dioxide extinguisher system and blower shutdown activated on high tempfor fire fighting.
• Periodic contract maintenance and regular check on Fenwal system.• Weak seam ducting or relief panels every 10 pipe diameters.• High temp monitoring of hot spots—bearing, mills.• Pressure relieve (or locate) outdoors.• Maintain excellent housekeeping level via wet wash, vacuuming to prevent sec-
ondary explosion.• Eliminate cloth transition socks in free-board area (source of overpressure relief
indoors).• Bonding straps over flanges and condensers to provide continuous path to ground.• Plastic baggies for sprinkler head protection in dryers, paint spray booths.
Scrubber Systems
• Siphon breaks to prevent water backflow to vessel storing material reactive withwater—phosphorus oxychloride, oleum, chlorosulfonic acid.
Electrical in Hazardous Areas
• Pressurized system—low-pressure, time-delayed alarm.• Continuous air flow or low pressure alarm on control cabinets in classified areas.• Sealing of conduit lines from hazardous to non-hazardous areas to prevent transmis-
sion of flammable vapors through conduit to ignition sources.
Back-up Systems
• Emergency blower to maintain positive flow to flare.• Self-contained nitrogen or air systems to open dump valves during emergency.• Inert gas to provide agitation on power loss.
Computers and Programmable Controllers
• Back-up power to prevent memory loss.• "Key" control to prevent unauthorized program changes.• Approval hierarchy and procedure for process (program) changes.• Safe storage of back-up programs.• Documentation procedure to monitor portion of computer program bypassed dur-
ing trouble-shooting.• Display and trend recording of key safety related variables.• Emergency conversion from computer to normal instrument control mode.
EXAMPLE OF SAFETY STANDARD FOR CRITICAL INSTRUMENTS
I. Policy
Each plant or location shall have procedures for the regular testing of critical instrumentsthat are required for the continued safe operation of the plant.
II. Scope
This safety standard pertains to the identification, testing, and maintenance of "criticalinstruments."
III. Definition
A critical instrument is a device whose failure or malfunction requires immediate action upto and including shutdown of a plant or system due to potential for serious injury, significantproperty loss, or environmental insult.
IV. Owner Responsibilities
A. The plant superintendent or owner is responsible for definition and identificationof "critical instruments" in his plant.
B. The plant superintendent is responsible for establishing appropriate test frequencyand procedures. The preferred method of testing is to actually "insult" the systemand determine if the entire system responds correctly.
C. Each plant is responsible for maintaining the following:
1. List of all "critical instruments" including methods and frequency of testingand persons responsible for the testing.
2. Record of each test of "critical instrument" with actions taken if the instrumentor system failed to operate properly.
D. Each plant must have its "critical instrument" program audited annually. Morefrequent internal self-audits should be made to ensure the program is continuouslyin operation.
E. Design: Critical instrument systems should be designed and/or modified, if pos-sible, to make actual "insult" testing practical.
Appendix 8GTable of Contents from Chemical ManufacturersAssociation Fixed Equipment Inspection Guide
TABLE OF CONTENTS
1.0 Introduction2.0 Management Responsibilities3.0 Plant Inspection Approach4.0 Plant Inspection Procedures5.0 Inspection System Approval6.0 Personnel Qualifications7.0 Audits8.0 Glossary9.0 Developing Site Manual
