CM&FD Condition monitoring and fault diagnosis

Unit 50: CM&FD Assignment 2

Task 1: (LO 3: 3.1)

Fault diagnosis and location is branch of control engineering which is concerned with the monitoring of systems, identification of the faults in the system and remedying the faults in the system. Availability of the equipment documentation is very vital for the robust fault finding techniques. The following are the types of documentation that should be made available to help support fault diagnosis and fault location.

Drawings

  1. Pipelines and Instrument Drawings (P&ID)

These types of drawings show the piping of the equipment. They can be used to locate the faults since one is able to understand the general outlook of the equipment. P&ID shows all of piping including the reducers, instrumentation, valves, and physical sequence of branches, equipment and control interlocks.

A P&ID should include: flow directions, all valves and their identifications, process piping, sizes and identification, permanent start-up and flush lines, miscellaneous (like swaggers, reducers, increasers, vents, sampling lines and special fittings), seismic category, interfaces for class changes, interconnection references, control inputs and outputs interlocks, intended physical sequence of the equipment, quality level, identification of components and subsystems delivered by others, annunciation inputs, vendor and contractor interfaces and computer control system input.

P&ID should not include the following; Control relays, primary instrument tubing and valves, Equipment rating or capacity, extensive explanatory notes, instrument root valves, pressure temperature and flow data, elbows and similar standard fittings, manual switches and indicating lights. P&ID is very key in designing and engineering of process designs and piping systems.

  1. Equipment drawings

The drawings of the equipment will give a visual outlook of the equipment. This can be used in the location of the fault. One can be able to pinpoint the location of the fault using the drawings of the equipment. This can also be used to determine the magnitude of the fault in question.

  1. General arrangement drawings

These are the drawings which shows how the equipment is arranged. It depicts the location of each component of the equipment. It can also be used to locate the fault just like the equipment drawing. It shows how the equipment is fixed in into space. It can guide at what point the fault has occurred hence enabling faster diagnosis.

They present the overall composition of the equipment. Depending on the complexity of the equipment, this may be spread across several different drawings. This shows the location of various components and assemblies within the overall design. These types of drawings are prepared at different stages of the equipment development showing the relationship between the several elements and the actual dimensions. As the process advances, the level of complexity of the drawings too increase thus needing more supplementary drawings to show specific elements and assemblies.

General arrangement drawings may have references to additional drawings but should not include information contained in other drawings to avoid duplication of work. It can also include notations and symbols which should be according to the industry standards to make the communication easier. The scale used should reflect the level of detail required for the drawing.

  1. Isometric drawings

This is a two dimension representation of a three dimension object. All the vertical lines are drawn vertically while all the horizontal lines are drawn at 30 degrees to the baseline. An isometric drawing looks like an isometric projection only that all its lines parallel to the three axes are measurable. This is the easy way of drawing 3D diagrams.

Isometric drawings are derived from the perspective view of objects. When one observes objects, the further the elements of an equipment, the smaller they are, the best way to represent this kind of view of objects is through the isometric drawing. This type of drawings can easily be used to identify the fault location. They can as well reveal the level and magnitude of the fault in the equipment. These factors can then be used to rectify the fault. These kind of drawings are widely used since they are regarded as the standard means of communication across all the engineering fields.

They can be used to make many other decisions regarding the equipment of interest. They can also show the areas of weakness in the equipment hence the need to strengthen them. Circles in isometric drawing are represented by ellipses.

  1. Electrical drawings

This are technical drawings which give the information about electrical parameters like power for communication with engineers or architectural projects. Installation of any electrical equipment starts with a good plan. The plan includes a drawing which allows the technicians to install the electrical equipment. This acts as a guide and the success of the installed equipment depends on how well the drawings are done.

A high quality electrical drawing means that the planning was adequately done and subsequently the faults occurring on the electrical component are appropriately mitigated. When an electrical drawing is poorly done, this increases the chances of faults occurring on the said equipment.

These drawings provide certain instructions to the technicians. Standard symbols are used to represent certain types of materials, raceways, conduits, and circuit connections. Therefore, emphasis should be put on the quality of the electrical drawings as a means of mitigating faults in the equipment.

  1. Instrument loop drawings

These type of drawings show a detailed drawing of one connection point to a control system. This diagram shows the symbol of the instrument and the terminals to which it should be connected to, instrument cable number, junction box number, and terminal number assigned for the specified instrument, multi-pair cable and pair number, marshalling cabinet number, terminal number in marshalling cabinet, control system details (rack, slot, I/O channel).

It also indicates the location of each equipment. This helps in locating the fault as well. The first step in fault diagnosis is its location. This kind of drawing helps us located the fault in an equipment. After this, the fault can then be rectified through appropriate means.

Maintenance Documents

  1. Manufacturer’s manuals

This an official document provided by the manufacturer detailing how the equipment should be operated, used and maintained. It gives the user a guidance on the functionality of the equipment. The user is able to get a deeper understanding of the equipment by using the manual. It is mostly used as a reference material. It contains all the uses of the equipment as well as the procedure for its usage.

The maintenance section is of particular interest in the fault detection, location and diagnosis. The manufacturer provides the first hand information particular to the instrument regarding the maintenance. The maintenance section provides crucial information on the fault location. This is achieved after one has understood how the equipment is supposed to function under normal conditions.

The manual also provides avenues through which one can be able to contact the manufacturer in case of a malfunction. These malfunctions might be due to the faults occurring in the equipment or the manufacturer’s faults. This is one of the ways of remedying the fault. Certain procedures have to be followed as laid down in the user manual for the operation, maintenance and fault diagnosis. The manufacturer, in the manual may also provide leads on how and where the user can be able to get the faults rectified.

From the above discussion, it is now clear how useful a manufacturer’s manual is to the user in terms of fault location, detection and diagnosis. It is upon the user to make good use of the manual since it is freely provided by the manufacturer. This is regarded as an after sales service by the manufacturer to the user of the equipment.

  1. Standard Operating Procedures (SOP)

This is a step by step procedure to be followed in the usage of the equipment usually provided by the manufacturer or the industry standards. It is a written document of controlling the operation of the equipment according to the given specifications to achieve a certain target. In this case, our target is to identify, locate and diagnosis a fault in the equipment.

These procedures define good manufacturing practises. It is the duty of the manufacturer to follow these procedures which are determined by the industry of operation. They can be of great use in determining the location and the methods of remedying a fault in the given instrument. They act as a benchmark which means that for a given instrument, regardless of the manufacturer, one only needs to understand the standard operating procedures in order to be able to use and maintain the equipment. This will easily help someone in the identifying, locating and diagnosing a given fault.

Standard operating procedures provide a general similar platform for the operation of different equipment from different manufacturers. This means that the procedure for identifying, locating and mitigating faults in an equipment is not manufacturer dependant but rather industry dependent.

  1. Fault finding tables

This a matrix where the columns represent the faults while the rows represent the test patterns. If the test pattern detects the fault, the output is 1, otherwise the output is 0. Fault finding tables are specifically used to find the faults in a given system. It is a very convenient way of finding faults since it can be easily analysed. It only involves 1 and 0 which makes it simple and straight forward to locate the fault and interpret.

  1. Parts lists

Parts list identifies the components of the equipment and their functions. If a certain functionality of the equipment is not being realised. Then the component responsible for that function has to be checked for the fault. This is the first step in diagnosing the fault in the equipment. This makes the process of fault location easy and faster since the whole equipment is not checked but rather the part responsible for the failing function is the one checked.

Commissioning Documents

  1. Factory acceptance testing (FAT)

This is a laboratory automation where the project integrator system demonstrates how well the equipment meets the Purchase Order requirements or the industry standards. This is created by the project manager generally or the project team. This process is carried out in the presence of the equipment owner and a witness. Once the system meets the required standards, the vendor is paid for this service by the equipment owner.

During the FAT process, in case of any fault in the equipment, both the vendor, owner of the equipment are able to see it and hence it can be diagnosed by the vendor or the manufacturer. The process can be carried out in the presence of those responsible for operating the equipment on a daily basis. Their presence ensures that they are well acquainted with the process of inspecting the equipment for faults as well as gaining a deeper understanding of the equipment.

  1. Site acceptance testing (SAT)

This is a test carried out in accordance to the clients provided standards in order to ensure that the equipment meets the specifications which will enable it be able to function on site. Site acceptance testing also ensures that the equipment is installed properly and can be able to function in line with the existing systems.

In case the equipment does not meet the clients specified conditions, then it means it is faulty in relation to the given specifications. It thus has to be adjusted to conform to the client’s requirements which ensures that it fits into the site existing systems.

  1. Original testing documents

These are the documents which have the records of the equipment testing results. It gives the information and the status of the equipment at the initial testing stage. In case the faults were identified at this point, then the procedure for identifying, locating and remedying should also be documented here. The owner of the equipment can refer to these documents for the subsequent fault diagnosing.

  1. Equipment commissioning documents

Equipment commissioning documents are the records when and how the equipment was officially opened for operation. During that stage, several tests are carried out which are critical in the fault diagnosis process. This documents can be used as reference when a fault analysis is being undertaken. This is because the equipment is commissioned under industry established standards.

The manufacturer in most cases will commission these equipment, which makes the documents more reliable since the manufacturer is in a better position to understand the equipment than other third parties. This makes the documents be of great value in the fault analysis procedure.

Qualification Documents

  1. Design Qualification (DQ)

The design qualification documents are produced during the equipment design process. These are the documents which certify the designs of the equipment. They can provide vital information like the limitations of the equipment as well as the conditions for optimal operation of the equipment. These type of information can be used for the fault diagnosis process.

Before any system it is designed, it has to be approved using industry standards. This implies that these requirements used to approve the designs have to be documented. This type of documentation is necessary for the future operations of the equipment as well as the maintenance which entails fault analysis.

This is done by competent persons to ensure that the design equipment if built, will meet the specified requirements. This is the only document which is ensures that the design will work, hence the need to be done by very competent people. This document is used to determine whether the designed equipment will fully deliver the functionality as detailed. Thus, these documents are very relevant in the fault identification, location and diagnosis.

  1. Installation Qualification (IQ)

These are the records taken during the time the equipment was being installed. The factors on site that could affect the performance of the equipment are usually noted for future reference in regards to the fault analysis. This type of information is readily available to the owner of the equipment. Thus, it can be used to evaluate the effects of the fault depending on the factors listed during the installation.

This verifies the proper installation and configuration of the system. This may include ensuring that the necessary files have been loaded, the equipment has been properly installed, the correct procedures have been followed or the personnel has been properly trained. This process must be performed before the operational qualification and the performance qualification.

  1. Operational Qualification (OQ)

During operation, the performance of the equipment has to be recorded over time. The historical data on the performance of the equipment can be used for the fault analysis process. This type of information will indicate the state of the equipment, the previous faults and the economic life of the equipment remaining.

It is a collection of the test cases carried out to ensure the proper operation of the equipment. This is done before the equipment is released for use. At this stage, the faults, if any, are detected and rectified. Since this process is documented, it means that this document can be used in future to locate and remedy faults in a system.

  1. Process Qualification (PQ)

Before this is done, all the equipment that will come in contact with the system must be tested to ensure they meet the standards. All the production process must be validated, same as the equipment used.

Supporting of the process through activities like cleaning and sterilisation of the equipment must be done according to the standards. This process can be able to locate and identify the faults in the system.

Task 2
(LO 3: 3.2)

Several operational issues have been identified with the cooling water system. For the following problems, identify the type of inspection and test equipment that would be appropriate and how it would be used to detect and locate the following faults:

  1. An increase in current flow to the motor.

  1. Electrical multimeter

An electrical meter to be used for current measurement is an ammeter. An ammeter will read the current flowing to the motor, the ammeter should be connected in series with the motor on the positive terminal side of the motor. This will give the current entering the motor and in case of a fault a large current will be flowing into the motor. Thus the ammeters reading can be used to detect and locate the presence of a fault by indicating the amount of current.

  1. Current tong meter

This is an electrical meter with an ac clump. It is able to measure the current in the conductor without making physical conduct with it. It can also be used to detect and locate the fault by the amount of current measured. The higher the current than normal, the likely presence of a fault it is.

  1. Oscilloscope

An oscilloscope can be used to measure very many electrical parameters like voltage, current, period etc. For the case of current, it can measure both ac and dc currents. Similar to the above instruments, the oscilloscope will detect and locate the fault by measuring the current which is compared to the standard value. Faults usually cause very high currents.

  1. A reduction in the pump’s output flow and pressure.

  1. Pressure gauge

This is an instrument used to measure pressure. If the pressure measured by the gauge is very low, then it means that there is a fault, hence the need to locate and rectify it. A low pressure means that the pump is not performing as per the requirements.

  1. Pressure sensor

This is able to sense the amount of pressure. It is part of the pressure gauge. It senses the pressure and then it allows the pressure gauge to read it. Pressure fluctuations as read by the pressure sensor will be an indication of a fault, especially when the pressure is very low.

  1. Ultrasonic flow meter

This is an instrument which measures the flow of the fluid with an ultrasound in order to calculate the volume flow. If the volume flow falls below the set standard then it is an indication of a fault in the pump.

  1. Doppler flow meter

This is used to measure the fluid flow. If the fluid flow is lower or higher than the set standard then the pump has a fault and must be rectified.

  1. A misalignment between the pump and motor shafts.

  1. Straight edge

This is an equipment with no bends on the edges, i.e. it has straight edges. It is used to measure the straightness of a line. This instrument can be used to check for the alignment between the pump and the motor shafts.

  1. Laser alignment tool

This is a machine used for accurate alignment of the equipment hence increasing the reliability of the equipment. This equipment can be reliably used to check for the misalignment between the pump and the motor shafts.

Task 3
(LO 3: 3.3)

The type of faults that could develop with this system are:

  • high flow

  • Fail closed

  • Fail open

  • Fail mid-range (half open)

Level sensors

  • Fail to switch

Equipment

Loss of water flow from TA102 to TA101

Failed pump PU102

Loss of power

Failed impeller

Failed valve SV102-1

Loss of power

Seized valve

Failed valve CV101

Loss of power

Seized valve

Loss of water flow from TA102 to TA101 via bypass valve SV102-2

Failed pump PU102

Loss of power

Failed impeller

Failed valve SV102-2

Loss of power

Seized valve

Loss of water flow from TA101 to TA102

Failed valve SV101

Loss of power

Seized valve

Failed valve LS101-1

Loss of power

Seized valve

Task 4
(LO 4: 4.1)

For the following component parts of the pumping system, identify the potential causes of failure and how the components could fail.

  1. Pump drive end bearing

The position of the drive end bearing could cause failure. The bearing should be appropriately positioned for optimal performance. Additional stress or temperature could also affect the pump drive and the bearing. The additional stress might alter the position of the bearing or the pump drive hence causing the system to fail. The increase in temperature causes the bearing to expand which may distort its position. A lack of lubrication could also be a key factor in pump drive and bearing failing due to the increased friction that causes wear and tear.

  1. Impellor

If the impeller was damaged through cavitation, dirt or solids are in the water, the impeller will not be able to transfer the energy from the pump which pumps the water since it cannot accelerate the water outwards from the centre of rotation.. This will be same effect if the impeller loses its vane.

  1. Mechanical seal

The parts of the seal would wear out if it started to leak, became hot or was run dry (no lubrication). This because of the friction which wears the parts out.

Task 5
(LO 4: 4.2, M1, D1)

  1. Explain the process of carrying out a failure mode and effect analysis (FMEA) using the cooling water system (figure 1) as an example.

FMEA is a methodology designed to identify the potential failure modes in a system. The procedure followed include:

The level of risk:

  • To human health and safety. The failure of the cooling water system will have adverse effects on the human health and safety: The water by not cooling down due to the failure might be dangerous due to the temperature levels, which affects both the health and safety of human beings.

  • The environment: the hot water not cooled down may kill the fauna and fora in the surroundings hence acting as a pollutant.

  • The quality of the product being manufactured: If water is not properly cooled down, the quality of the product being manufactured will diminish due to high temperatures.

  • Of damage to other equipment (secondary damage): The water which is not properly cooled may damage the equipment not designed to operate at such temperatures.

  • To business profit: The business profits will definitely go down due to the factors discussed above, key among them being the reduced quality of the product being produced which might lead to some consumers switching to the substitutes.

Other areas for consideration are:

  • The time taken to repair the equipment will be long due to the failure.

  • The cost of repair will be more expensive

  • The availability of parts. It will take the parts a short time to wear out. This leads to longer lead times.

  • Mean time between failure and mean time to repair will be longer.

Equipment Description

Equipment Number

Consequences of failure with respect to Safety

Consequences of failure with respect to the polluting the environment

Consequences of failure with respect to loss of manufacturing output

Consequences of failure with respect to equipment downtime

A×B×C×D

Heat Exchanger

Heat Exchanger

Flow Meter

Flow Meter

Flow Meter

Flow Meter

Pressure Sensor

Pressure Sensor

Pressure Sensor

Pressure Sensor

Temperature Sensor

Temperature Sensor

Temperature Sensor

Temperature Sensor

Task 6
(LO 4: 4.3, 4.4)

CM&FD   Condition monitoring and fault diagnosis

Figure 1: Fault tree diagram

CM&FD   Condition monitoring and fault diagnosis  1

Figure 2: The cause effect diagram

Work Cited:

Bedson, Peter, and Mike Sargent. «The development and application of guidance on equipment qualification of analytical instruments.» Accreditation and Quality Assurance 1.6 (1996): 265-274.

Huber, Ludwig. Validation and qualification in analytical laboratories. Buffalo Grove: Interpharm press, 1999.

Mouratidis, Haralambos, and Paolo Giorgini. «Security Attack Testing (SAT)—testing the security of information systems at design time.» Information Systems 32.8 (2007): 1166-1183.

McDermott, Robin, Raymond J. Mikulak, and Michael Beauregard. The basics of FMEA. SteinerBooks, 1996.

Ermer, Joachim, and John H. McB Miller, eds. Method validation in pharmaceutical analysis: A guide to best practice. John Wiley & Sons, 2006.