Table of Contents
1. Scope
2. General
3. Materials
4. Accessibility
5. Conditions
6. Installation Requirements
7. Mechanical Completion
1. Scope
1.1 This specification will provide the general technical rules to be followed in performing the instrument installation work.
Design drawings, requisitions and local regulations will have priority above this specification.
2. General
2.1 For definitions references is made to the requisition for the installation of instrumentation.
2.2 The various requirements apply to the mounting of instruments, the installation of instrument process piping, instrument air piping, heat tracing and instrument electrical installation work.
2.3 The installation work shall comply with all requisition, drawings, applicable regulations (codes), site conditions, vendor documentation and prescriptions given by the engineer.
2.4 Installation comprises all instruments, instrument components as well as the assembly of components which come separately with analyzer sampling systems, etc.
2.5 The contractor is responsible for the take-off and the ordering of materials in his scope of supply.
It is the contractor’s responsibility to transport the material to the place of work.
2.6 The contractor shall only work to the latest issue of drawings released for construction.
Any rework resulting from the use of obsolete drawing issues shall be executed on contractor’s account.
Contractor shall arrange for his own document filling system.
3. Materials
3.1 Handling of Materials
3.1.1 Instrument equipment shall be properly unloaded, transported and stored to prevent deterioration.
Instruments, transmiters, analyzers, gauges and inline metering equipment (positive displacement, turbine meters etc.) shall be stored in an enclosed, weatherproof and dry store room away from heavy materials handling. Other instrument equipment such as (heavy) control valves, relief valves, level gauges, etc.. may be stored as detailed for piping bulk components, providing they are kept away from sand and debris. Manufacturers instructions for storage shall be followed.
All covers on instrument connections shall be left in place. Machined surfaces such as flange facing shall be left protected with flange covers as long as possible.
3.1.2 Instrument equipment shall be protected against general construction site hazards and in particular against the elements during construction.
3.1.3 Field mounted instruments with the exception of advanced instrumentation (analyzers, pre-tested systems, etc.) shall be checked as detailed under chapter warehouse inspection of specification BN-SP-K10.
3.1.4 Instruments and/or components shall not be modified or altered without instructions from the engineer.
3.1.5 After installation instruments shall be cleaned, lubricated, shipping stops removed, floats installed and made operational.
3.1.6 Scrap materials shall be collected and be deposited at approved places.
3.1.7 At the end project the installation contractor shall, on request, prove the allocation of materials received free of charge.
Unexplained differences may be incured at contractors cost.
3.2 Free Issue Materials
3.2.1 Free issue materials are materials which will be made available by the engineer.
These materials are purchased against requisitions and will be issued to the contractor from the engineer’s warehouse area. It is contractor’s responsibility to transport the material to the place of work.
3.2.2 On receipt, the contractor shall inspect the equipment for compliance with the specifications.
Any discrepancy between the equipment specified and the equipment provided or any defects, shall be brought to the notice of the engineer within two (2) working days after receipt.
3.2.3 “Free issue” materials which are left over after completion of instrument installation work will remain the property of company, and must be transported by contractor to the engineers compound or any other place within site designated by the engineer.
Some installation material will be supplied together which instrument equipment as specified in the relevant requisition.
3.3 Installation Materials
3.3.1 Contractor shall furnish all materials required for the instrument erection which are not referred to in the requisition as supplied by others.
All materials purchased by the installation contractor shall be approved by the engineer before installation.
3.4 Tools
3.4.1 The contractor shall have available and maintain all needed tools.
This will include but is not limited to welding equipment, pipe bending machines, test equipment, small ladder sections, etc.
4. Accessibility
4.1 Instrument components shall be located in convenient positions to facilitate maintenance and inspection. Accessibility shall be in agreement with specification BN-SP-K2 “general design specification for the accessibility of instruments and instrument connections”.
4.2 When the instrument installation can not be made permanenly accessible the installation contractor shall advise purchaser in writing.
4.3 When available, the instrument installation accessibility shall be in agreement with the plant model.
4.4 The instrument installation shall not obstruct access to process equipment and walkways.
5. Conditions
5.1 Procedures
5.1.1 For procedures, reference is made to the terms and conditions applicable to orders for field labour.
5.2 Scheduling of the Work
5.2.1 All phases of instrumentation work shall be planned in harmony with the overall project schedule.
Priorities will be determined by the engineer.
5.2.2 The engineer will execute a detailed progress/forecast control system.
The installation contractor shall report his progress on a weekly basis in accordance with the site procedures. Measurements of work accomplished in the field shall be based on the agreed method.
5.3 Field Changes
5.3.1 The purchase order documents are not covering every possible needed activity to achieve installation completion.
During the installation it may become necessary to deviate from the engineering documents.
Omissions and additional activities not covered by the scope documents shall be completed as a field change, the project design criteria, however, shall still apply.
5.3.2 Field changes may only be commenced on the basis of an approved extra work authorization.
Additional charges without authorizatio will not be accepted.
5.4 As Built Drawings
5.4.1 Field modifications shall be recovered on the drawings.
At the end of the installation activity, the installation contractor shall hand over the following drawings and related vendor drawings “as built”:
- Local panel layouts
- Air piping details
- Wiring diagrams
- Schematic logic and loop details
- Cable list
6. Installation Requirements
6.1 Instrument and Instrument Components
6.1.1 Instruments are to be located in accordance with the applicable field layout drawings, as noted on the instrument schedule.
These field layouts are established as a guide. The exact location is to be determined in the field under observance of this specification.
6.1.2 Instrument equipment shall be located such that it is protected against direct drainage of condensate, water and process fluids from adjacent plant equipment that can make the instrument, instrument component, junction box, etc., dirty, wet or inoperable.
6.1.3 Care shall be taken that no passageways are obstructed or access to other plant equipment, electrical lighting panels, other instruments, etc., is impossible. All equipment shall remain easily operable.
6.1.4 Mounting shall be in accordance with the applicable mounting details and vendor documentation. Instrument mounting details may be modified to suit field conditions after written approval from the engineer.
6.1.5 Transmiters or transducers shall not be located too close to hot lines, vessels or other equipment.
6.1.6 Most instruments are susceptible to damage, abnormal wear, or malfunction if mounted in locations where they are subject to vibration.
If no part of the equipment is non-vibrating the instrument shall be mounted on a vibration free remote support.
6.1.7 Special attention is to be paid to the mounting of vulnerable components (also refer 6.2).
These instruments shall not be installed before painting, insulation and flushing activities have been completed.
Capillarary tubing shall be adequately supported and protected against mechanical damage. Extra length of capillary shall be neatly coiled up with a minimum diameter of 30 cm.
6.1.8 Instruments shall be properly tagged when taken into the field for installation. When required, the installation contractor to fit temporary labels.
After installation, field instrument shall be identified by nameplates supplied by the engineer.
6.1.9 Where required by the requisition the contractor shall provide for the fabrication and installation of small local panels gauge boards.
The instrument cut-out shall be done by using appropriate tools.
6.2 In Line and Vessel Mounted Instruments.
6.2.1 In line and direct vessel mounted instruments are installed by others. The instrument installation contractor, however, shall provide assistance to the piping erection contractor and the engineer for the correct implementation of instrumentation and operability requirements.
The instrument installation contractor shall prepare the instruments for installation by others i.e. remove delicate parts, collect thermowells from the warehouse and secure these (by straps) at the field location, etc.
6.2.2 When installing in line instruments care shall be taken to ensure the correct direction of flow i.e. arrow on the body pointing in the direction of flow.
6.2.3 Control valve hand wheels, valve positioners and the control head of external displacer type level instruments shall face the access side of the work area. If required, the orientation shall be modified.
When reorientating the control head of displacer assemblies new gaskets shall be installed.
It is advisable to remove the control head when installing displacer chambers.
6.2.4 Orifice plates, turbine/positive displacement meters, ceramic probes, vane type flow switches and other delicate inline instruments shall not be installed before completion of insulation and flushing activities.
Where required for the completion of piping installation work the piping instalation contractor shall install spool pieces.
Spool pieces shall be fabricated locally and be available in good time.
6.2.5 Connections and interconnecting piping for level instruments shall be installed in such a manner that no pockets or traps can occur.
Connections between vessels and heavy level gauges, controllers or transmitters shall be relieved of strain by proper supporting. The installation of supports and drain valves shall be supervised by the engineer.
6.2.6 For the installation of orifice meter runs reference is made to BN-SP-K9.
6.3 Supporting
6.3.1 Instruments, piping, tubing, tray, etc. shall be properly supported.
All brackets and supports shall be in accordance with the relevant typical drawings and details. It is the contractors responsibility to select the appropriate supporting depending upon application.
Supports and fixing devices shall be free from rough edges and be finished smoothly. Close drilling tolerances are to be observed.
Supports, framework, etc. not supplied in prefabricated from shall be fabricated locally.
6.3.2 The main fixing method shall be by brackets welded to structures.
Where brackets, mounting pads, yokes, etc. are welded to structural steelwork (supplied and erected by others) the surfaces of same shall be cleaned before welding. The instrument installation contractor is not allowed to weld supports, etc. to process equipment and lines.
The welding and/or connecting of supporting elements to structural steel may only be done after authorization of the construction supervisor.
Supports and brackets shall be either galvanized or made free of rust cleaned and painted with a layer of primer. (Refer specification of field painting BN-SP-R1).
Mounting materials clamped around piping shall be isolated or selected to avoid electrolysis.
6.3.3 Care shall be taken not to damage equipment (vessels, process lines) which is lined.
The installation of instrument equipment around glass or plastic pipe shall be performed with extreme care.
No acid resistant tiled surface shall be drilled for fixing. If any such fixing should be required, it will be made by others.
6.3.4 Instruments should be supported independent of the process connection.
Pipe stand at grade and on platform structures are recommended.
Instruments should not be supported from platform grids or handrailing or any other vibrating structure.
A pressure gauge may be supported by its piping if it is close coupled to the connection.
6.3.5 Bolts and nuts for fixing of mounting materials shall be cadmium plated.
6.3.6 Nameplates shall be attached to prefabricated brackets, supported from structural members, instrument mounting stands, conduits, etc.
6.4 Instrument Cable Way, Conduit and Routing
6.4.1 Cable way and conduit installations shall provide the necessary support to and protection of signal transmission/power distribution systems. Materials and construction shall resist corrosion and reduce the posibility of damage from mechanical abuse.
6.4.2 Routing must be arranged to protect the transmission cable from physical damage and fire. Routing close to hot pumps, heat exchanger and heaters shall be avoided.
Routing shall result in a minimum of bends and minimal danger from mobile equipment, falling objects, debris, spils and construction hazards.
A minimum distance of 30 cm shall be observed between “hot” points and instrument cable routing.
Following minimum clearances shall be provided:
- Headroom within unit areas and inside buildings 2.10 m
- Secondary access way 3.10 m
- Main access roads (mobil lift access) 4.30 m
- Railroads (op of rail) 6.00 m
Care shall be taken that no passageways or access to equipment are obstructed.
6.4.3 Location of all instrument components as well as the routing of trays, conduit and cable are shown on the applicable drawings.
These drawings are to be regarded as a guide.
The exact routing is to be determined in the field.
6.4.4 Main routing of cable will be:
0 Underground up to the proximity of a junction box
0 Accomplished by overhead cableways or trunking.
Secondary runs will be overhead by cable ways or trunking with open conduit branches to the instruments.
Cable ways shall be sized so that not more than 60% is filled.
Sufficient drain holes shall be provided to ensure that no water can collect in the ducting system.
Cables shall be pulled from one location to assure identical sequence in core identification.
6.4.5 Overhead cable ways shall be designed for a support distance of 3 meters and a maximum deflection of 1/500 “1” under load.
Rigid conduit shall be supported at a minimum distance of 2.5 meters for horizontal runs and 3.5 meters for vertical runs. All sharp edges shall be removed so that damage of cable/tubing cannot occur. Elbows or tees are not required in open conduit runs to make a change in direction. Openings are to be protected by plastic sleeves.
Cable way sections shall be joined by mushroom head screws with the head always at the inside.
6.4.6 Where indicated, overhead cable runs in process areas shall be fireproofed by others. The instrument installation contractor shall allow for the required provisions (clearance, supporting, etc.).
6.4.7 The following shall apply to closed conduit installations (non standard practice, only valid when specified).
- Ducts, conduits, or entry plates extending from hazardous areas into nonclassified locations should be sealed in accordance with the applicable electrical codes to prevent the entrance of vapors in instrument enclosures, panels, and control rooms.
- The execution of the conduit system shall be weatherproof
Special precautions shall be taken to avoid that rain water enters the conduits at junction boxes or thermocouples and runs back to the control room or into electronic components.
- Branch conduits shall be supported as much as possible by existing platform, ladders and rails.
All conduits shall be swabbed clean before wire or cable is installed.
- All rigid metal conduit joints and connections shall be made up using a suitable sealing compound or thread lubricant.
All joints and connections shall be made up watertight
Rigid metal conduit joints and connections shall be screwed up tight using wrenches
- For aluminium parts a zinc or graphite base thread lubricant shall be used for all joints and connections
- Minimum radius for bending conduits shall be 15 times the diameter
- At the end of each branch conduit, a weatherproof flexible conduit shall be run to the instrument
Sufficient stack in this flexible conduit to be provided
- Sufficient pull and junction boxes shall be provided to pull the wire through the conduits without damage
Material of boxes to be malleable iron or equal, zinc plated. The boxes shall be threaded (thickwall), the covers shall be provided with gaskets.
6.5 Process Piping
6.5.1 Instruments are to be hooked-up in accordance with the applicable process piping details as noted on the instrument schedule. The materials to be used are listed in the material summary sheets.
Primary connections up to the first block valve will be provided by others.
The use of substitute material is subject to the approval of the engineer.
6.5.2 Process piping is to be installed by skilled labour only. Welding procedures and certification shall be in agreement with the piping specification BN-SP-C3.
6.5.3 When API threadings are made by a thread cutting machine dies shall be oiled and threads product shall be fully acceptable to the engineer.
Dopes or teflon tape shall be used for the installation of all API or NPT threaded fittings. For temperatures in excess of 200ºC a suitable dope shall be used. Teflon tapes nor dopes shall be applied in case of seal welding.
6.5.4 When installing steel or stainless steel tubing with compression type fittings, all the fitting manufacturer’s instructions, shall be exactly followed, which will include, but are not limited to:
- Proper cutting of tube
- Proper installation of the ferrules
- Taking care that all tubes have the required roundness.
When storing tubes, care is to be taken that no mechanicel damage can occur, which makes the tubes unround.
In order to avoid unroundness of the tubes at the places where the ferrule is to be applied, it is absolutely necessary to cut the tube at least 5 cm from the end of a bend. Mounting closer to the bend will not be accepted.
To avoid galling of stainless steel ferrules into the tapered end of the stainless steel fitting, the stainless steel ferrules are to be greased slightly at the outside before installation.
The number of joints in tubing runs shall be minimized. Whenever practical, bends shall be used instead of fittings.
6.5.5 Process piping should be installed and supported so that forces that develop from the expansion and vibration cannot result in piping failure or strain on the instrument.
The first anchor point shall be at least 2 m away from the take-off point to allow for pipe movement.
6.5.6 Process piping shall be installed free draining (slope approximately 10%) toward the instrument or connection without pockets or traps.
Where pockets are unavoidable drain valves shall be provided and oriented in safe position.
6.6 Air Piping
6.6.1 The installation of instrument air piping comprises the branch air headers, multicore air tubing and single core air tubing systems for pneumatic operated instruments and components.
The air supply piping and fittings to the air filter set, tubing from air set to the instruments, air signal tubing from field instruments to components in control panel or visa versa and other air piping shall be installed in conformance with the applicable drawings. The branch air header shall be routed to the individual air consumer to within a distance of 0.5 m.
6.6.2 The location and routing of instrument branch air headers shall be determined in the field in accordance with drawing indications. Unless otherwise stated in the requisition the main header does not form part of the instrument piping system (piping will install first block valve).
All threaded connections in the branch air supply piping shall be sealed with liquid compound. The first there threads are to be free of compound. As an alternative, Teflon tape may be used.
All NPT or API threaded connections on fittings, instruments and instrument components are to be sealed with Teflon tape.
6.6.3 Long continuous tubing runs should be used to minimize the number of joints.
Where air tubing is extended by a union connector, the joint shall be accessible for leak testing.
Sufficient slack or free movement shall be provided in all air tubing to avoid strain on the instrument connections and to facilitate dismantling of the instruments.
6.6.4 Branching of individual tubes from multicore cables shall be by means of properly constructed bulkhead strips or junction boxes.
At all joints and terminations an ample length of “tail” shall be left.
Elbow connectors should be used for attaching the tubing to transmitters, controllers, etc., to avoid that plastic tubing is bent with a small radius.
Tubing shall be identified and tagged at each end adjacent to their termination point with suitable plastic cable markers.
Joints shall be made with compression fittings with metal inserts to support the tubing.
6.6.5 When routing air tubing, care to be taken that the tubing is well away of any pipe or equipment, which will be installed to avoid that the tubing is insulated together with the pipe or equipment.
A clearance of not less than 30 cm is required between any hot service equipment or line and air tubing.
6.6.6 Individual air tubes in the field shall be braced to existing structural steel, where practical. In all cases, conduit, perforated trays or angle iron shall be used for support. Attachment to air headers is permitted, but attachment to other piping only after approval from the construction supervisor.
6.7 Heat tracing, Seals, Purges
6.7.1 The installation of instrument heattracing includes the routing, bending and clipping of the heattracer complete with connectors, fittings, unions and spacers.
The length of electrical traces shall be measured after installation of the instrument.
Steamtracing shall be in accordance with the “specification for design and installation of steamtracing” (BN-SP-C6).
6.7.2 Heattracing shall be installed after testing of process leadlines for leakage and shall allow for instrument removal and maintenance.
Instruments are to be heattraced separately from the main process tracing an exception is allowed for in line instruments and pressure gauges which may be protected by the pipeline/equipment tracer.
6.7.3 Heattracing for special instrumentation i.e. analyzer systems shall be tailored to the service involved. Housing shall be rainproof, dustproof and corrosion resistant. Instruments are not to be heated above manufacturer’s recommendations.
6.7.4 Instrument protection shall be installed complete with sealing fluids, condensate post, purge hook-ups, insulation etc.
Selfsealing instrument installations shall have the meter piping arranged in a way to facilitate condensation so that the seal will be formed by the condensate.
6.8 Electrical
6.8.1 The electrical installation of instruments comprises the installation of electric power supply, the alarm system, thermocouple/resistance element wiring, electronic signal, analyzer wiring, etc.
6.8.2 To avoid signal distorsion, main low voltage instrument cable routings shall be kept away from power cables, transformers and electric motors whenever possible.
The distance of main instrument cable routings relative to power cables will be 0.6 meters minimum when run in parallel. Segregation of instrument cables in trenches or on cable tray shall be in accordance with the drawings.
6.8.3 The installation contractor shall cut the cable, which is supplied by the purchaser on reels, to the required lenghts.
He shall measure carefully the required length of the cable before cutting and select the best reel assignment to minimize cable cutting losses. When cutting off cables at the required length, the cable tag attached to the cable shall not be lost. After cutting cables shall be sealed against ingress of moisture by a suitable cap.
6.8.4 The ends of underground cables coiled and buried in the trench local to junction boxes by others shall be dug-up and connected by contractor to these boxes.
The contractor will be responsible for proper location and mounting of junction boxes. From these boxes overhead cables for alarm, shut-down or power supply will be routed to the instrument components.
Instrument overhead cable shall be installed in conduit or on cable trays.
If it appears that the future addition of cables will be difficult the drawing may indicate the installation of spare cabling.
6.8.5 Cables shall be pulled in one piece between termination points, splices are not acceptable.
All incoming cables in the control room shall be identified by tagging with plastic ferrules or equal.
6.8.6 If cable with standed core is used, insulated crimp connectors (wire tips and spade lugs) shall be used to connect the wires to instruments and terminals.
Signal leads shall be installed with sufficient slack. Where shielded cable is used the electrical continuity of the shields shall be warranted.
To facilitate identification, each wire shall be tagged in accordance with the numbering system.
Tags shall be of such construction that they cannot be lost.
6.8.7 Field instrumentation devices with metal enclosures operated above 48 volts shall be earthed for personnel protection via the ground wire or leads provided with the cabling. Where the instrument component is not provided with an earth connection the installation contractor shall make this connection, wherever possible, to the instrument housing.
Flame proof constructions shall not be invalidated. Signal cable armoring/lead sheating for all signal levels in flammable atmospheres shall be earthed via an armor grip in the cable gland or by clamping to an earth rail.
6.8.8 Covers on instruments, on connection boxes, pull and junction boxes shall be put in place immediately after use. Covers should not be left open after working hours.
6.8.9 The installation contractor shall assure the proper installation of components certified for installation in flammable atmospheres.
Particular attention shall be paid to cable entries in flame proof enclosures and the segregation of intrinsically safe cabling. Where required by local codes the installation contractor to supply installation certificates to confirm compliance with the regulations.
6.8.10 Cable screens applied for the reduction of electrical noise interference shall be installed, insulated and terminated as current conducting wiring.
7. Mechanical Completion
7.1 Contractor shall make sure that all systems are completed and installed as per document requirements.
It will be contractors responsibility to prove the completion of work to the satisfaction of the engineer.
7.2 Contractor to rectify all faults discovered during testing operations.
7.3 The mounting is considered mechanically complete when:
- The instrument is instalated in accordance with the process piping, purge piping, instrument air piping, electrical conduit and wiring, and mounting details
- The location is accessible as per design requirements
- Steam tracing and condensate disposal, where required, are installed but not lagged
- Electrical tracers, where required, are installed but not lagged
- Field nameplates are attached.