Equipment Technology and Maintenance (1) Lecture 3 PDF

Equipment Technology and Maintenance(1) LECTURE 3  CALIBRATION DOCUMENTATION  Several generic documents will be required for the calibration program. These will include:  A master list or inventory of all instrumentation within the Laboratory; specifications relating to the p...

Equipment Technology and Maintenance(1) LECTURE 3  CALIBRATION DOCUMENTATION  Several generic documents will be required for the calibration program. These will include:  A master list or inventory of all instrumentation within the Laboratory; specifications relating to the performance of each instrument. Standard operating procedures for the calibration of each type of instrument.  A planning program listing the individual calibrations to be carried out (preferably as part of the formal planned preventative maintenance program).  Records of calibrations carried out internally within the lab.; calibration certificates issued internally or by external bodies carrying out calibration; and training plans and records for the calibration technicians.  All calibration records and certificates should be completed, stored, and archived by documentation procedures. INSTRUMENT CALIBRATION INDEX( CALIBRATION MASTER LIST) The purpose of the master list to catalogue all instruments on a calibration regime and to trigger the execution of the calibrations at predetermined times. It should contain a record for each instrument requiring periodic calibration. Each record should include: the last due date, the last calibration date, the expiry date, the (next) due date, and the calibration period. SPECIFICATIONS The specification for calibration of an individual instrument is very important and requires appropriate authorization and control. In particular, there are a number of key factors: The category of the instrument critical instrument will be treated significantly differently from a major or a reference instrument.  Accuracy and range: these should be set to meet the minimum needs of the parameter being measured.  Calibration period: this should be arrived at to give a reasonable balance between over frequent calibration and ‘as-found’ failures. It may include consideration of, for example: the durability and stability of the instrument; the required accuracy; the nature of the environment CALIBRATION STANDARD OPERATING PROCEDURE 8 The calibration standard operating procedure (SOP), which states how to calibrate an instrument should contain all the instructions necessary to ensure that a competent craftsperson following the instructions will correctly calibrate the instrument.  Each calibration SOP should have a unique identity and the appropriate one for each instrument should be included on the instrument calibration index.  The calibration SOP should be signed by the appropriate functions within the Lab. to indicate acceptance of the calibration instructions, the category rating, the accuracy and range. These would include the instrument specialist, a process specialist and a representative of quality assurance.  Any changes to the format of the calibration SOP should be authorized by the same signatories.  The revisions should be recorded on a revision-tracking sheet, which should list all the  CALIBRATION RECORD This is a record of every calibration report produced and should indicate the date it was created, the due date, calibrated by whom and passed /failed results  Calibration certificates (report) Calibrations certificates (report) should only be issued (or adopted if externally generated) for calibrations that meet the accuracy requirements laid down in the appropriate specification.  Calibration certificates (report) should have a unique certificate number and give a clear indication of the tag number and plant number or manufacturer’s serial number of the instrument.  They should contain the date that calibration was carried out, together with the next due date and date of expiry of the calibration.  There should also be an indication of the person who carried out the calibration and that person’s signature to indicate responsibility for the accuracy of the information on the certificate.  CALIBRATION LABEL  An instrument Calibration label is the unique identifier that applies to each instrument location within the Lab..  Each instrument should be labeled with such a label carrying a summary of the calibration history of that instrument.  The tag should carry such information as the identification number of the instrument; the date of the previous calibration; the due date for the next calibration; and the signature of the calibration technician.  CARRYING OUT CALIBRATION The calibration should be carried out following the instructions in the appropriate calibration SOPs and the required responses on the worksheet completed. First of all, the ‘as-found’ condition is determined. The as-found’ condition is defined as the accuracy of the instrument over the required range before any calibrating adjustment or repairs are made. If this is outside the limits specified on the calibration certificate, it may indicate that faulty product, readings, or results have been delivered since the instrument was last known to have been correct. To address this possibility, a deviation should be raised in accordance with procedure. It may also be necessary to place on hold any product batches that may consequentially have suspect quality, depending on the nature of the instrument in question.  CARRYING OUT CALIBRATION The instrument is then calibrated and a final ‘as-left’ condition is determined. This is defined as the accuracy of the instrument over the required range after calibration.  If the ‘as-left’ condition meets the accuracy requirements, the calibration certificate is completed, and a calibration sticker indicating the calibration date affixed in a prominent position.  If the ‘as-left’ condition does not meet the accuracy requirements, the technician raises a deviation and the actions to repair or replace it. 3 When the calibration is carried out and the Report is completed, the master list is updated to show the completion date and the instrument calibration Master list is updated to the new  CARRYING OUT CALIBRATION  All instruments covered by the calibration programme should be calibrated prior to the expiry date.  External parties (individuals or organizations) may be used for calibrating or repairing instruments. Where they are used, they should be monitored by internal personnel in order to ensure that the facility’s procedure for the control of external parties is being met. "The ultimate standards against which all reference equipment is calibrated." This equipment is the primary reference used to calibrate the rest of the instruments. It is either maintained at the national testing laboratory or kept at the company, and is used as the reference standard against which the company's secondary standards are calibrated. It is generally four times more accurate than the secondary standard (4:1 5 accuracy ratio).  This is the calibration standard maintained within the company, which is used to carry out routine calibrations. It is generally four times more accurate than the measuring standard. This is the instrument used for routine measurement and control within the company.  It is important that calibration equipment is stored and handled in an appropriate manner.  As a minimum, the temperature and the humidity of the calibration laboratory should be controlled.  The influence of other environmental conditions such as 6 vibrations should also be considered.  The frequency of calibrating individual instruments will vary depending on circumstances such as:  the pattern of usage;  the sensitivity of the process being controlled and/or monitored;  the recommendations within the manufacturer’s operation and maintenance manual;  the history of previous calibration performance. For example, an instrument that has been shown to maintain its previous calibration state over a period of more than six months would not necessarily need to be calibrated on a quarterly basis. The frequency of calibration should be determined based on the process being controlled and/or monitored, as well as the level of accuracy required. There are three categories of instrumentation: 7  These are instruments whose performance will affect both the process and the product. An example of such an instrument would be a temperature control on an autoclave. These instruments would generally be calibrated at least six monthly. These are instruments whose performance will affect either the process or the product. An example of such an instrument would be a balance in the dispensary. These instruments (and, in the context of calibration, a balance may be considered as an instrument) would generally be calibrated at least annually. These are instruments that are installed as reference points only and whose performance does not affect either the process or the product. An example of such an instrument would be a thermometer in an ambient condition warehouse where temperature is monitored but not 8 controlled. These instruments would generally be calibrated on installation but not afterwards. When a new instrument is purchased, there are a number of steps that should be taken.. 1. The instrument should be identified and the instrument group informed so that they can issue a tag number. 2. must be categorized as either critical, major or reference. 3. This categorization and the rationale behind it is recorded and authorized. 4. All critical instruments should be purchased with current calibration certificates that cover appropriate accuracy and range, and state a specific expiry date. 5. These certificates must be traceable to national standards 9 a If certificates cannot be supplied with the instrument, there will be need to carry out initial calibration.  On an annual basis, it is a good idea to review the calibration programme to ensure that it is still appropriate and effective. There are two key elements that should be reviewed. 1. the frequency of calibration of individual instruments needs to be determined. As mentioned above, the history of previous calibrations should be taken into account when determining the most appropriate frequency of calibration. There may be some instruments for which a re- categorization is appropriate. 2. this would be the time to review standard operating procedures to determine whether they need to be amended. For example, the procedure is generally written such that the instrument is tested across the whole of its operational range. However, if an instrument is normally used to measure around one focal point in the range, it may be more appropriate to concentrate the taking of readings around this point. 10 It is important to have a training program in place that not only covers the individuals conducting the calibration, but also includes those responsible for reviewing the data to ensure full understanding. Similar to other parts of the training program, there should be a written training plan and comprehensive records of all completed training. This allows for monitoring the available skills pool and the ongoing plans to maintain that pool.Training should be conducted when a person starts a role and regularly thereafter. It is recommended to have refresher training at least annually to ensure that standard operating procedures are being followed correctly and to prevent the development of any bad habits over time. When a new piece of instrumentation is purchased and installed, it is important to ensure that all relevant personnel are trained in the new methodology relating to calibration. 11 WHATS IS MAINTENACE Definition Any activity—tests, measurements, replacements, adjustments, and repairs—intended to retain or restore a unit to a specified state where it can perform its required functions or services.  Combination of all technical and management actions intended to retain an item in, or restore it to, a state in which it can perform as required.  Fixing any sort of mechanical or electrical device that has become out of order or broken.  Performing routine actions that keep the system in working order or prevent trouble from arising.  Burdens relevant to Maintenance  Operators less able to do repairs themselves  Machine and product failure can have an effect on a company’s operation and profitability  Idle workers, facility  Losses due to breakdown. 1Toachieve product quality and customer satisfaction through adjusted and serviced equipment 2. Maximize the useful life of equipment 3. Keep equipment safe and prevent safety hazards 4. Minimize the frequency and severity of interruptions 5. Maximize production capacity–through high utilization of the facility 6. Prevent breakdown or failures 7. Minimize production loss from failures 3 8. Increase the reliability of the operating systems  RELIABILITY This means that the system can run continuously without failure. AVAILABILITY the system is ready to be used immediately. MAINTAINABILITY when a system fails, it can be repaired easily and quickly (and, sometimes, without its users noticing the failure). SAFETY if a system fails, nothing catastrophic will happen.  WHAT IS “FAILURE’’  A system is said to “fail” when it cannot meet its promises or its inability to perform the its functions or services in appropriate manner.  A failure is brought about by the existence of “errors” in the system.  The cause of an error is called a “fault”. TYPES OF FAULT 1. Transient Fault – appears once, then disappears. 2. Intermittent Fault – occurs, vanishes, reappears; but: follows no real pattern (worst kind). 3. Permanent Fault – once it occurs, only the replacement/repair of a faulty component will allow the desired system to function normally.  TYPES OF MAINTENANCES Maintenance may be classified into four categories: Corrective or Breakdown maintenance Preventive maintenance Scheduled maintenance Predictive ( condition- based)maintenance Some prefer three categories- scheduled and preventive maintenance are merged.  CORRECTIVE OR BREAKDOWN MAINTENANCE Corrective or Breakdown maintenance implies that repairs are made after the equipment is failed and can not perform its normal function anymore. DISADVANTAGES OF CORRECTIVE MAINTENANCE  Breakdown generally occurs inappropriate times leading to poor and hurried maintenance causing excessive delay.  Increases chances of accidents and less safety for both workers and machines.  Sometimes may result in spoilt materials.  Direct loss of profit.  Can not be employed for equipments regulated by statutory provisions e.g. cranes, lift and hoists ….etc.  Scheduled maintenance Scheduled maintenance is a stitch-in-time procedure and incorporates:  inspection,  lubrication,  Repair, and  overhaul of equipment If neglected, it can result in a breakdown . Generally followed for: overhauling of machines changing of heavy equipment oils cleaning of water and other tanks etc ‘Preventive MAINTENANCE (PM) PRINCIPE ‘Prevention is better than cure’  Procedure - Stitch-in-time, It: locates weak spots of machinery and equipments. provides them periodic/scheduled inspections and minor repairs, enabling the maintenance crews to take timely actions, such as machine adjustment, repair or overhaul to reduce the danger of unanticipated breakdowns. makes use of human sense, the equipment operation log (record) and other sensitive instruments, such as audio gauge, pressure, temperature and resistance strain gauges etc.  An excessively hot electric cable predicts a trouble.  Simple hand touch can point out many unusual equipment conditions and thus predicts a trouble. ADVANTAGES OF PREVENTIVE MAINTENANCE Reduces breakdown and thereby down time. Greater safety of workers. Lower maintenance and repair costs. Less stand-by equipments and spare parts. Better product quality and fewer reworks and scraps. Increases equipment life. Increases chances to get production incentive bonus. Predictive Maintenance  Performed after one or more indicators show that equipment is going to fail or that equipment performance is deteriorating.  Introduced to try to maintain the correct equipment at the right time.  PM is based on using real-time data to prioritize and optimize maintenance resources.  It may help achieve improvements in fields such as the establishment of safe minimum levels of maintenance, changes to operating procedures strategies and the establishment of capital maintenance regimes and plans.  Techniques help to determine the condition of in-service equipment in order to predict when maintenance should be performed. This approach offers cost savings over routine or time –based predictive maintenance, because tasks are performed only when warranted. 13  Corrective Maintenance Corrective maintenance actions in case of a fault in order to return to normal condition Run to failure: inspections aren’t performed. Replacement is done when component fails. Age replacement. Periodic inspections. Sequential inspections 14