Piping Checklist for 60% 3D Model Review

60% model review is one of the reviews planned in all the EPC projects execution at different stages- 30%, 60% and 90% of design completion.

60% 3D model review is an intermediate review which take place when the final structural steel, final equipment and the majority of the major piping runs, duct-work, instrument and electrical trays have been MODELLED. The primary purpose of these reviews is to review the routings to insure that process integrity has not been compromised, that the pipe, duct-work and tray runs are in accordance with the minimum criteria established for the project and to observe any potential interference in the operability or maintainability, created by the routing of these items.

Below is the piping check point which shall be reviewed prior to 60% 3D model review:


Check List for 60% Model Review



1 All underground piping systems are modeled and checked.
2 Piping having size 2” and above is modeled and checked.
3 Pipe supports locations & types are correct. Supports for stress critical systems shall be based on stress analysis calculations.
4 Utility stations locations are shown by volume box and the locations are checked.
5 Foam powder & Water Spray Systems are modeled and checked.
6 Eye wash and Safety Shower locations modeled and checked.
7 Access and egress, operation and maintenance of valve and instruments are checked.
8 The model is updated as per the vendor drawings of the packages.
9 All equipment are modeled as per latest vendor drawings & checked.
10 All mechanical handling equipment’s like cranes, monorails, davits, eye pads, EOT’s etc… are modeled and checked.
11 All structural steel, e.g. pipe racks, technological structures, shelters, platforms, stair cases /ladders, pipe supports designed by civil etc… are modeled as Civil design and checked.
12 All Paving and curbing is modeled and checked.
13 All foundations are modeled and checked.
14 All buildings are modeled and checked.
15 All Instrument items like junction boxes, panels, cabinets, SIV vessels Inclusive of supports) are modeled and checked.
16 All Electrical items like junction boxes, panels, cabinets, lighting poles, flood lights, masts etc… (Inclusive of supports) are modeled and checked.
17 All Telecom items like junction boxes, panels, cabinets, CCTVs, PAGA speakers, telecom tower, etc… are modeled and checked.
18 All above ground cable tray routing is modeled and checked. Outline of drops to equipment/all users is shown in the model.
19 All underground cable trenches are modeled and checked.
20 Analyzer shelters modeled and checked.
21 Where applicable passive fire proofing is incorporated in the model.
22 Construction access is checked.
23 Review tags of 30% model review are closed.
24 Interdisciplinary model review is conducted and all the comments are resolved.

Process related:

25 All line numbers, line size, pipe class & flow direction are checked as per P&IDs.
26 All tags for equipment, valve, SP item and Instrument are checked as per P&IDs.
27 All in-line & on-line components are located and sequence of branch connections are as per P&IDs.
28 The special requirements such as slope, no pocket, removable spool etc. and design related P&ID notes are taken care.
29 Ensure the hydro test vents and drains are provided where necessary (for all lines that will be hydro tested).
30 The insulation type & limit/extent are correctly specified.
31 The electrical tracing and limit/ extent are shown, if applicable.
32 The requirement of symmetrical piping and minimum piping are properly taken care as per process requirement, if applicable.(esp. for air cooler piping)
33 The requirement of straight length for inlet pipes at column inlets, knock out drums/vessels and cyclones etc. are taken care as per Process/Mechanical requirement.
34 The straight length requirement for suction & discharge of pumps/ Compressors, if any is checked.
35 The suction line for compressor is routed with a slope towards the knock out drum.
36 The length / no. of elbows on suction line between tank/vessel and pump should be minimum. Pockets may be avoided if possible. High points shall be below the LL level in the tank (i.e. Fully flooded line).
37 All the vapor lines branch off from the top of the main line.
38 All valves required for emergency operations are operable from grade.
39 Lines are provided with drain connection between two valves, especially when the second valve is a check valve.
40 The hot lines which are near to the operating platform or near the reach of the person are insulated for personnel protection. The limits of insulation modeled are checked.
41 The routing of flare header is free of any pocket and kept continuously sloping towards knock-out drum as per process requirement.

Layout related:

42 Ensure all vertical lines rising or dropping from rack to unit are maintained same back of pipe from rack.
43 Arrangement of piping entering and leaving the plant are logically grouped together at the battery limit.
44 The PSV outlet lines are self draining to flare header and ensure no pocket in PSV inlet lines.
45 The personnel access/ingress paths are free from hazards posed by blow out panels, rupture discs and relief valve discharge stacks.
46 Removable spool shall be of minimum length and shall not have any instruments, vents, drains and other tapping/connected piping.
47 The area for large filters, strainers etc. are located within curbed areas to contain the spillage during cartridge/element replacement operations.
48 The handling & removal of all valves, blinds etc. for maintenance are reviewed with respect to arrangement and access space.
49 Ensure that the design has been done effectively to reduce the number of flanges required for internally lined pipes and Galvanized pipes greater than 2”.
50 Operation and maintenance access for all valves, Instrumentation, spec. blinds/spacer & spade are provided.
51 Platforms requirement for accessibility, operation, maintenance are taken care. Also ensure proper access is provided by proper selection of ladders or stairways.
52 Proper size cut outs are provided on platform/floor openings for piping.
53 All ladders are checked for side entry on vertical Vessels/Columns.
54 Ensure there is no interference with adjacent lines/structure due to expansion of piping in hot condition.
55 Open sewer pit is avoided near the hot oil/fluid pumps.
56 The flat side up (FSU) eccentric reducer is used in pump suction line to avoid pocket formation which may cause the cavitations of the pump.
57 In general, on straight pipe run the eccentric reducer is used with its flat side down (FSD).
58 Placement of valves in pipe racks has been avoided. If unavoidable they are to be provided with access.
59 For routing of jacketed sulphur piping, cross is used where the direction change is envisaged. Also ensure proper space for rodding from two directions.
60 Ensure that the valves and instruments located on sulphur pits are safely accessible in case of fire for shutdown.
61 Provision of tundish where drain is to be collected from the open drain system is checked.
62 Ensure the discharge of process and hydrocarbon lines should not be let to open at grade; This should be connected to closed drain system.
63 Ensure the Relief valve piping should be as short as possible when discharging into a closed system.
64 The valve pits, sumps, catch basins and trenches, culverts and any other pits etc. are properly located and checked.
65 The dyke, curb walls, bund walls and fire separation walls etc. are properly located and checked.
66 The underground oily/sewer piping is properly shown and checked.
67 The piping for Pumps in parallel and Fin fan coolers is checked for symmetry to have same performance.
68 The elevation of equipment with relation to NPSH requirement of pumps is checked.
69 Location of suction air filters is checked so that the air quality is clean and free from obstacle.
70 Hand wheel/lever location/orientation to be checked for plug/ball valves for interference with operating access, platforms, structures etc.
71 Check the distance of snuffing steam isolation valve for fired heaters, it is to be located 15m away from heater.
72 Elevation of U/G drain drum and pit depth shall be reviewed.

Layout and Mechanical Handling Related:

73 Requirements for equipment removal hatches and construction opening in floors, walls and roofs have been identified and shown and checked.
74 The adequate clearance availability for the maintenance and removal of rotors/shafts/internals etc (including the installation of temporary rigging beams, hoists, chain falls, etc.) should be checked.
75 The bottom of monorails/ hoists/EOT/HOT hook elevation should not be lower than the usable openings of roll-up doors, forklift access aisles etc.
76 The Crane/Hoist hook limits have been considered when setting crane/monorail elevations. (The compressor/blower/pump shelter sizes to checked w.r.to available operation & maintenance space.)
77 Projection of monorails should be minimum 1 meter outside the shelter/buildings for loading/unloading/dropout area if the same is outside the shelter.
78 Adequate lay down areas are identified and located for use with cranes, gantries and monorails.
79 The requirement of breakup flanges should be checked for piping running over equipments (esp. compressors, chemical injection package, blowers).
80 Fire proofing requirement to be checked as per HSE. Fire proofing if required, shall be modeled and checked for clearances and interferences.
81 The pumps with a vertical suction line and the elevated strainer are properly located and ensured the opening of such strainer does not result in spilling the flammable liquid.
82 Access around the pumps is to be checked for obstruction due to hook up around the pumps like seal oil lines, casing drains to closed drain network etc.
83 All Cryogenic service valves stem are to be checked for the stem in Vertical position or at less than 45 degree angle to vertical.
84 The stem of gate valves in flare service should be horizontal.

Instrument/Mechanical and Vendor related:

85 The equipment/package items are checked with Vendor drawings.(for nozzle no, size, rating, elevation & orientation)
86 The Control valves, ESDV, & PSV are modeled and checked as per vendor drawings along with correct size and orientation of actuators. Maintenance access is checked for Control valves, ESDV, PSV & actuators of valves.
87 All inline/online Instrument connections are checked as per the Inst. Hook-up drawings.
88 The instrument orifice tapping orientations are checked as per Instrument Standards as per type of fluid (e.g. gas & liquid).
89 The upstream/downstream straight length requirement for orifice is checked as per instruments/vendor requirement.
90 The suction of the air blower of buildings and the inlet for HVAC is taken from a non-hazardous area.
91 Check that tracing around the suction and discharge lines can be dismantled to allow pump removal.
92 The clearance for removal of strainer basket is checked. Also checked for requirement of breakup flanges, if any for strainer drain lines.
93 Instrument and electrical push buttons on poles are checked so as they are not obstructing the accessibility of the pump.
94 The piping with instrument connections is properly positioned for easy accessibility. If needed for access, the necessary platform and walkways are provided.
95 In case ultrasonic flow meter is used, then adequacy of space available around the flow meter is checked for installation of the flow meter sensor so that it does not touch adjacent line.
96 Electrical, Instrumentation and Telecommunication JB are locations are checked so that they are not causing obstruction in the walkway.
97 Sample cabinet and coolers are properly located and checked, wherever applicable.
98 Cathodic protection (CP) rectifier is properly located as a Block, wherever applicable.
99 The electrical power generation package is shown as a Block, wherever applicable.
100 The electrical main cable trays are properly shown and checked.
101 The underground electrical/instrumentation cable trenches etc. are properly shown and checked.
102 The underground electrical conduits are properly shown and checked (esp. where crossing is expected).
103 Electrical transformers as a block are shown. Bus duct between Generator and the Switchboard are shown.
104 Electrical Panel, Junction Boxes, Push Button stations are shown and checked.
105 Instrument main & branch cable trays of 150 mm and above along with, trenches, junction boxes, transmitter boxes etc. are located and shown and checked.

Stress and supporting related:

106 The appropriate secondary supports are provided and span is checked as per the support specification.
107 Stress group comments for stress critical lines are incorporated and checked.
108 The routings of two-phase lines are to be without pocket to the maximum extent possible. Also ensure proper supporting of these lines.
109 Ensure civil foundation is modeled for standard secondary supports.
110 Ensure civil structural & foundation is modeled for non standard secondary supports (by civil)
111 Ensure that correct types of primary supports are selected like clamp type shoes shall be used for Stainless steel, Alloy steel and galvanized pipes. Clamp type shoes shall be used for Carbon steel pipes requiring PWHT.
112 All foundation including footing/ piling wherever applicable is located and shown (for equipments, pipe support and platforms, etc).
113 Adequate supporting provided for all control valve stations.
114 Spring supports are modeled and checked.
115 Small bore branches with long runs are checked for proper supporting and requirement of stiffeners at branch–off locations.

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