Specification of Inst for Revamps

1. Purpose

This procedure provides guidelines for the preparation of instrument specifications for revamp projects.

2. General

This procedure describes the options available for Revamp Schedule A Instrument Specifications. Generally, instruments are not included in the Inflection Point Engineering scope of work for Revamp Feasibility Studies and Process Revamp Studies. Therefore, this procedure is limited to Revamp Schedule A Instrument Specifications.

3. History

For many years, the normal procedure for specifying instrumentation for revamps was to specify all instruments as new, regardless of whether or not the existing instruments were affected by the revamp operating conditions. While this method provides the Contractor with information for all of the instrumentation required for the revamp, this method is time consuming for Inflection Point Engineering and does not provide any added value for the existing instruments not affected by the revamp. One benefit of this technique (Option 3) is that it has the minimum impact on Inflection Point Engineering’s work process.

4. Defining the Scope of Work

Discuss the Inflection Point Engineering options for revamp instrument specifications with the client BEFORE THE DESIGN BASIS MEETING.

Clearly explain Inflection Point Engineering design intent, scope of work, approximate cost, and engineering time for EACH option to the client, before option selection.

Discuss and mutually agree to Special Client requirements and requests such that engineering fees and schedules may be established for the scope of work required. Client requests, however, must not conflict with Inflection Point Engineering design requirements for safety, process guarantees, and process control.

Consult the Process Control Coordinator during the design basis phase to verify that any special revamp requirements will be accurately reflected in the schedule.

5. Instrument Specification Options

Four basic options are available for specifying instruments for a Revamp Schedule A. Communicate the option selected to the Process Control Coordinator and Instrument Engineer via the Design Basis Meeting notes, or through the Team Leader or Project Manager.

In all cases, inform the customer if their existing instrumentation violates safety or current engineering philosophy, and specify these instruments as new, using Inflection Point Engineering current practices.

5.1 Option 1

This option provides the minimum essential instrument specifications for a revamp, and has the lowest cost and schedule time.

• Specifications are prepared for ONLY those instruments affected by the revamp operating conditions, and any new instruments required.

• The instrument specifications for those instruments affected by the revamp operating conditions are written as NEW.

• For example, a revamp for capacity increase will change flow rates and system hydraulics which will generally affect only control valves, flow metering devices, and control center scale ranges. The instrument specifications for this option will be prepared ONLY for the affected instruments, which will be specified as new. The instruments unaffected by the revamp, such as pressure gauges, most thermocouples, analyzers, etc., will not be specified or listed in any specification.

• The responsibility for determining which instruments are affected by the revamp is shared between the Design Engineer and the Process Control Coordinator.
• Use Option 1 as the default for cost estimating purposes in the initial stages of a project. If the Client chooses another option conduct a reevaluation of the engineering cost and schedule.

5.2 Option 2

• This option provides the same equipment specifications as Option 1, and also provides a listing of those instruments that are unaffected by the revamp. The unaffected instruments will be listed in their appropriate specification, by tag number and service description only, and noted as "Existing - Unaffected by the Revamp".

• Explain the differences between Option 1 and Option 2 to the Client. Option 2 provides the same technical content as Option 1. The Client must evaluate, on the basis of additional cost and longer schedule time, the benefit of the additional documentation for equipment lists.

5.3 Option 3

• This option provides specifications for all instruments deemed necessary by Inflection Point Engineering.

• Specifications are prepared for all instruments deemed necessary by Inflection Point Engineering, whether they are affected by the revamp or not.

• All instruments are specified as if they are NEW.

• If Option 3 is to be used by the Client or Contractor for equipment cost estimating purposes, then the client or Contractor must evaluate whether any of the existing instruments may be satisfactory for use as is and need not be replaced.

5.4 Option 4

• This is the most comprehensive option, which provides a review and evaluation of existing instruments, similar to what is done for other equipment such as vessels, exchangers, pumps, etc. (This review does not include an inspection of the actual instruments’ condition in the field.)

• A review of existing instrument data sheets is made to determine the suitability of existing equipment for use with the revamp operating conditions. The Client must furnish to Inflection Point Engineering data sheets that accurately define the existing instruments. Per Client request, the review of existing instruments may include only certain types of instruments, such as control valves and orifice plates. The types of instruments to be reviewed must be defined in the design basis meeting.

• Specifications will be written for those instruments that are affected by the revamp, and that require either modification or replacement. New instruments will be specified in the usual manner. For instruments requiring modification, the specification will show the new conditions for the revamp operation, and will indicate how the existing instrument is to be modified.

• As a Client option, existing instruments that do not require modification or replacement may be listed in their appropriate specification, by tag number and service description only, and noted as "Existing - Unaffected by the Revamp".

6. PFD Representation of Instruments for Revamps

The instruments shown on the PFD for revamp projects follow the guidelines set forth in Procedure .

7. P&ID Representation of Instrument for Revamps

Inflection Point Engineering may use existing MFD's or P&ID's, or produce new P&ID's depending upon the Client or Contractor preference. If new Inflection Point Engineering P&ID's are produced, the instrumentation shown will only be that which is required for normal process control and safety. Additional instrumentation, beyond that required for process control and safety, will generally not be shown, and therefore will not be specified by Inflection Point Engineering, unless specifically requested by the Client and agreed to by Inflection Point Engineering in the Design Basis stage of the project.

If the Client/Contractor requests Inflection Point Engineering to work from existing MFD's or P&ID's, good quality prints (or preferably electronic CADD files) which are suitable for marking with the required changes, must be provided. Instruments shown which are not required by Inflection Point Engineering for process control or safety, will not be reviewed or specified (unless specifically requested by the Customer and agreed to by Inflection Point Engineering). Note: All instruments to be reviewed by Inflection Point Engineering, are expected to be clearly identified on the marked up drawing.

The guidelines for the representation of instruments on P&ID's, for revamp projects, are covered in Procedure .