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1.0 Scope of Work

RAM CONSULTANT shall carry out RAM study to establish / predict the level of theReliability / Availability / Maintainability of the components for the 100 MBD DAS FACILITIES UPGRADE PROJECT. RAM CONSULTANT will submit an assumption report prior to start of work and get it approved from COMPANY through CONSULTANT. RAM study report shall include, but not limited to, the following:1. Identify the potential bottlenecks.2. Estimate the on-stream availability of the units3. Outline the planned and unplanned maintenance demands.4. Predict the impact of equipment redundancy and sparing.5. Develop optimum shutdown strategies.6. Develop mitigation strategies for expected failure modes.7. Perform preliminary equipment criticality analysis.8. Optimise reliability by analysing wide range of scenarios that are critical from

1. reliability point of view.

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2.0 Approach and Methodology

2.1 Data Gathering

Consultant will collate and review available data relevant to build a database for the project.Likely data required includes:

o P&IDs

o PFDs

o Layout Drawings

o Cause and Effects Drawings

Output: Assumption and Methodology Report

2.2 Site visit

No site visit is required

2.3 Workshop

No workshop has been identified as being required for the project. The list of equipment that shall be within the RAM scope shall be provided to COMPANY for review and approval.Output: List of equipment that will taken forward into RAM study


3.0 Reliability Availability Maintainability Study

3.1 Failure model

Random failures can be caused by a number of factors, for example, the result of poor design, construction, wear, inadequate maintenance, etc. This potentially affects all equipment to a greater or lesser extent. Reliability models normally make use of generic reliability data which is representative of a particular equipment type unless specific failure data is available and deemed more appropriate. For this study, the failure rate will be taken mainly from OREDA, but also from EXIDA, or historical performance data from industry sources. The majority of the equipment covered by OREDA is subject to regular maintenance and replacement policy which ensures that it is operating in the useful life phase, as depicted in the figure below.

time

failu

re r

ate

useful life phase wear out phaseburn in phase

The failure rates reported in OREDA are based on the assumption that the failure rate function is constant and independent of time (sometimes referred to as an exponential distribution). This is appropriate as equipment is subject to regular inspection and preventive maintenance which restores equipment to its original state.

3.2 Failure rates

Failure rate data comes generally from OREDA 2002. Where OREDA does not supply data, other databases will be used. The databases are sometimes presenting failure rates based on a number of service parameters. Oreda 2002 presents the data both on ‘operational time’ and ‘calendar time’. Whenever this differentiation is made in the databases, the data presented for ‘calendar time’ will be used. This data covers also stand-by time in which components are not operating and non operational time due to maintenance or other operational modes. Whenever no differentiation is made, it is assumed that the data presented is for the ‘calendar time’.In those cases where no applicable data is available, a MTBF of 1 year (8760) is placed into the model with a MTTR of 0 hours.The failure rates in OREDA include instrument failures, for “normal” instrumented equipment.

3.3 Repair time data

In the event of a failure, the Mean Time To Repair (MTTR) for a piece of equipment comprises several activity phases:a) Logistic delays associated with planning the task, obtaining permits to work,

waiting for personnel, tools or parts, etc.


b) Access time includes time for isolation, depressurisation and inerting as appropriate.

c) Repair time spent diagnosing the problem and repairing or replacing the failed item.

d) Testing the repaired equipment to confirm correct operation.e) Restoration time required to bring the equipment back into service and

return to normal production levels.OREDA 2002 contains repair time information in the form of an Active Repair Time, which covers diagnosing, repair or replacement of the affected part, and testing after assembly.To this, additional time is added for preparation and finalisation, i.e., planning, work permits, mobilisation of personnel, isolation, depressurisation, inerting and bringing the equipment back in service. The average times have been estimated using the following assumptions:

o An effective Permit To Work (PTW) system is in place

o Resources including manpower, tools, test equipment and spares are assumed to be available when required and do not contribute to the logistic delay

A full list of repair times for different equipment types will be presented.


4.0 Avsim Computer ProgramFor the modelling and Monte Carlo simulation, Consultant suggest to use the Availability Workbench 1.0.0.29, which includes AvSim 10.Modelling featuresThere are no buffers incorporated in the model, therefore the exact value of the standard deviation is theoretically not important to the result. If a number of systems have redundant components installed, these redundant components are modelled as ‘hot stand by’. In this mode the failure characteristics do not change when the component is non-operational. This approach for the model is consistent with the ‘calendar time’ data used for the MTBF. If multiple components of a group of parallel components fail, the capacity of the installation is reduced according to the nominal capacity of the component. The capacity of each of the components is for that purpose put into the model. However, the efficiency effects on the capacity due to changes in the flows can not be modelled. Examples; the output of 1 centrifugal pump is higher then 50% of the combined output of 2 pumps placed parallel in the same system. Also, the heat transfer in heat exchangers is influenced by changes of the velocities of the flows through these heat exchangers.The simulation of a system is done by generating and calculating the effects of simulated ‘events’ that occur according to the element data in the model. An ‘event’ is anything that can change the state of a model or a group. The possible states for an element are as follows:

o State 1Undergoing preventive maintenance

o State 2Being repaired following a failure

o State 3Failed but not detected (a dormant failure)

o State 4 ‘Up’ and passive (available, but not being currently used)

o State 5 ‘Up’ and active (being used)

The possible transitions between these states is shown in the figure below.


Figure 5.1 – Element State Transition Diagram

STATE 4'Up' but passive

STATE 5'Up' and active

STATE 1Undergoing PM

STATE 2Down for repair

STATE 3Dormant failure

The time spent by each element in these states and the resultant capacity propagates through the groups which interact according to their rules and configuration and allows the overall system availability and reliability to be calculated.When the data has been specified for, the model is run and simulates the process running for a period of time. It averages the capacity of the process taking into account random and common cause failures. This cycle is repeated many times to give an average capacity and hence the availability.The availability of an individual element depends on both the reliability and the maintainability and can be expressed as the ratio of ‘up time’ over total time:

Where the MTBF is the Mean Time Between Failures, and MTTR is the Mean Time To Repair, including the mean logistic delay.Output: RAM Report


5.0 Cost Time Resources

5.1 Cost

No. TaskOverall Cost

1 RAM Study $21,460

Project-related travel and accommodation have not been included in this proposal, they will be back charged at cost.

5.2 Deliverables

RAM Consultant will deliver the following:o Data manual including assumptions, data sources, block diagrams

o Draft RAM Report

o Final RAM Report

Resources

Task Name

RAM Study Mr. Kakade (Principal Consultant – RAM)

CVs for the above personnel are presented in Appendix A.

Payment Terms

70% upon submission of draft report.30% on submission of final report.

Validity

This proposal is valid for 120 days.


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