Part 1 of changes in API 610 11th Edition. First part will cover all the new clauses.
NEW CLAUSES:
1: (NOTE added): For sealless pumps, reference can be made to API Std 685. For heavy duty pump applications in industries other than petroleum, petrochemical and gas processing, reference can be made to ISO 9905.
3.2: Allowable Operating Region (Definition added) - Portion of a pump's hydraulic coverage over which the pump is allowed to operate, based on vibration within the upper limit of this International Standard or temperature rise or other limitation, specified by the manufacturer.
3.8: Classically Stiff (Definition added) - Characterized by the first dry critical speed being above the pump's maximum continuous speed by the following:
- 20 % for rotors designed for wet running only.
- 30 % for rotors designed to be able to run dry.
3.11: Design
- Manufacturer's Calculated Parameter
NOTE: “Design” is a term that may be used by the equipment manufacturer to describe various parameters, such as design power, design pressure, design temperature, or design speed. This term should be used only by the equipment manufacturer and not in the purchaser's specifications.
3.18: Identical Pump (Definition added) - Pump of the same size, hydraulic design, number of stages, rotational speed, clearances, type of shaft seal (axial face or breakdown bushing), type of bearings, coupling mass, coupling overhang, and pumping the same liquid.
3.24: Maximum Operating Temperature (Definition added) –Highest temperature of the pumped liquid, including upset conditions, to which the pump is exposed.
NOTE: This temperature is specified to the seal vendor. See ISO 21049 or ANSI/API Std 682/ISO 21049.
3.31: Multistage Pump (Definition added) - Pump with three or more stages See 4.2.
3.51: Similar Pump (Definition added) - Pump that is accepted, by agreement between purchaser and manufacturer as sufficiently similar to not require a lateral analysis, taking into account the factors listed for an identical pump (3.18).
3.53: Stage (Definition added) - One impeller and associated diffuser or volute and return channel, if required.
3.58: Trip Speed (Definition added) <variable-speed driver> variable-speed driver -speed at which the independent emergency over-speed device operates to shut down the driver.
4.1: Unit Responsibility - Unless otherwise specified, the pump vendor shall have unit responsibility. The pump vendor shall ensure that all sub-vendors comply with the requirements of this International Standard and all reference documents.
4.1: Statutory Requirements - The purchaser and the vendor shall mutually determine the measures necessary to comply with any governmental codes, regulations, ordinances, or rules that are applicable to the equipment, its packaging and preservation.
5.3.1: (Requirements) - In case of conflict between this International Standard and the inquiry, the inquiry shall govern. At the time of the order, the order shall govern.
6.1.12: (General Design) - (Note added) “Best efficiency flowrate of the pump as furnished” refers to the pump with the impeller diameter properly selected to meet head-flowrate performance requirements as stated on the data sheet.
It is recognized that very low-specific-speed pumps might not be able to reach flowrates beyond 105 % to 110 % of BEP. In such cases, the expected flow limitations shall be indicated on the proposal curves (see 10.2.4).
6.1.29.1: (General Design) This is a bulleted clause now - The details of threading shall conform to ISO 261, ISO 262, ISO 724 and ISO 965 (all parts), or to ANSI/ASME B1.1. The vendor shall advise the type of bolting used on the pump.
6.1.29.2: (General Design) - When ANSI/ASME B1.1 threads have been specified, the thread series shall be the variable-pitch series UNC. The threads shall be Class 2 for bolting, studs and nuts. For other threads and nuts, they shall be Class 2 or 3.
[Above 1" dia. 8 series UN threads are used in accordance with ASME VIII]
6.1.29.3: (General Design) - When ISO 261 and ISO 262 have been specified; the thread series shall be coarse. Threads shall be Class 6g for bolting and studs, and Class 6H for nuts.
6.1.30: (General Design) - Commercial fasteners shall be manufactured in accordance with the requirements of ANSI/ASME B18.18.2M or shall be procured from distributors having quality plans in accordance with ANSI/ASME B18.18.2M.
6.3.16: (Pressure Casings) - If the manufacture of cast pressure-casing parts requires the use of openings for core support, core removal or waterway inspection and cleaning, these openings shall be designed so they can be closed by welding, using an appropriate, qualified weld procedure, during the completion of casting manufacture.
6.4.2.6: (Suction and Discharge Nozzles) - To minimize nozzle loading and facilitate installation of piping, machined faces of pump flanges shall be parallel to the plane as shown on the general arrangement drawing within 0.5°. Bolt holes or studs shall straddle centrelines parallel to the main axes of the pump.
6.4.3.2: (Auxiliary Connections) -If specified, for pumps in pipeline service with a maximum operating temperature of 55 °C (130 °F) or less, auxiliary connections may be threaded.
6.4.3.3: (Auxiliary Connections) -If specified, special threaded fittings for transitioning from the casing to tubing for seal flush piping may be used provided that a secondary sealing feature, such as O-rings, are used and that the joint does not depend on the thread contact alone to seal the fluid. The connection boss shall have a machined face suitable for sealing contact.
6.4.3.10: (Auxiliary Connections) Bulleted clause - If specified, piping shall be gusseted in two orthogonal planes to increase the rigidity of the piped connection, in accordance with the following stipulations.
a) Gussets shall be of a material compatible with the pressure casing and the piping and shall be made of either flat bar with a minimum cross section of 25 mm by 3 mm (1 in by 0,12 in) or round bar with a minimum diameter of 9 mm (0,38 in).
b) Gusset design shall be as shown in Figure 20.
c) Gussets shall be located at or near the connection end of the piping and fitted to the closest convenient location on the casing to provide maximum rigidity. The long width of gussets made with bar shall be perpendicular to the pipe and shall be located to avoid interference with the flange bolting or any maintenance areas on the pump.
d) Gusset welding shall meet the fabrication requirements (see 6.12.3), including PWHT when required, and the inspection requirements (see 8.2.2) of this International Standard.
e) Gussets may also be bolted to the casing if drilling and tapping is done prior to hydrotest.
f) Proposals to use clamped or bolted gusset designs shall be submitted to the purchaser for approval.
[If specified, piping shall be gusseted in two orthogonal planes]
6.6.14: (Rotors) - If the vendor can demonstrate that electrical or mechanical runout is present, the demonstrated amount of runout can be vectorially subtracted from the measured vibration during the factory test as long as it does not exceed 25 % of the allowed peak-to-peak vibration amplitude or 6.5 µm (0.25 mil), whichever is less.
6.8.9: (Mechanical Shaft Seals) - Seal chambers shall be designed to provide for an additional flush port to approximately the centre of the chamber and extending vertically upward. If specified, this port shall be drilled and machined for a piping connection. Tapered pipe thread connections are not allowed.
[Seal chambers shall be designed to provide for an additional flush port to approximately the centre of the chamber and extending vertically upward.]
6.8.13: (Mechanical Shaft Seals) - The vendor and purchaser shall agree on the maximum static and dynamic sealing pressures that can be anticipated to occur in the seal chamber and the vendor shall state these values on the data sheet [see 6.3.5 c)].
6.9.2.1: (Dynamics-Torsional Analysis) - There are three general types of torsional analyses that are normally performed on pumps:
a) Undamped natural frequency analysis: determination of the unit's torsional natural frequencies and associated mode shapes and generation of a Campbell diagram to determine potential resonance points;
b) Steady-state damped response analysis: evaluation of the resonance points uncovered in the undamped analysis via a forced response analysis that utilizes representative values for excitation magnitudes and damping; the results are cyclic torques and stresses in all shaft elements in the model, which can then be used to evaluate the structural adequacy of the machine;
c) Transient torsional analysis: similar to a steady-state damped response analysis, except that it is done for the transient condition and its results are cyclic torques and stresses as functions of time; by far, the most common application for this analysis type is the start-up of a synchronous motor.
A flow chart for the torsional analysis is shown in Figure 29.
6.9.2.3: (Dynamics-Torsional Analysis) Bulleted clause - If specified, for variable-frequency ASD's, a steady-state, damped-response analysis shall be performed. The analysis shall consider all resonant frequencies through 12 times line frequency.
Most modern variable-frequency ASD's, when performing properly, produce insignificant torsional vibration and shaft stress. Variable-frequency ASD malfunctions can produce significant excitation. Certain designs still exist that produce significant torsional pulsations.
6.9.2.4: (Dynamics-Torsional Analysis) Bulleted clause - If specified, or if the driver is a synchronous motor rated 500 kW (670 hp) or higher, a transient torsional analysis shall be performed. If performed, the time-transient analysis shall meet the requirements of 6.9.2.8 through 6.9.2.11.
NOTE: Some purchasers choose to perform transient analysis if generator phase-to-phase or phase-to-ground faults are considered a significant risk or if rapid bus switching occurs on loss of power.
6.9.2.5: (Dynamics-Torsional Analysis) - Excitation of torsional natural frequencies can come from many sources, which might or might not be a function of running speed and should be considered in the analysis. These sources can include but are not limited to the following:
a) Impeller vane and cutwater pass frequencies;
b) Gear mesh frequency;
c) All trains including those with gear(s): 1 and 2 times the rotor speed, expressed in revolutions per minute, of either shaft;
d) 2-cycle engine drive: n times the rotor speed, expressed in revolutions per minute;
e) 4-cycle engine drive: n and 0.5 times the rotor speed, expressed in revolutions per minute;
f) Synchronous motor: n times the slip frequency (transient phenomena only), 1 and 2 times line frequency;
g) Induction motors: 1 and 2 times line frequency;
h) Variable-frequency drive: n times the rotor speed, expressed in revolutions per minute, for relevant multiples through 12 times the line frequency where n is an integer determined by the drive manufacturer as follows:
-for engines: derived from the number of power strokes per revolution.
-for motors: derived from the number of poles.
6.9.2.7: (Dynamics-Torsional Analysis) - Torsional natural frequencies at two or more times running speeds shall preferably be avoided in systems in which corresponding excitation frequencies occur or, if the natural frequency cannot be moved, shall be shown to have no adverse effect.
6.9.2.11: (Dynamics-Torsional Analysis) - In addition to the parameters used to perform the steady-state, undamped torsional analysis specified in 6.9.2.2, the following shall be included in the transient torsional analysis:
a) Motor average torque, as well as pulsating torque (direct and quadrature axis) vs. speed characteristics;
b) Load torque vs. speed characteristics.
c) Electrical-system characteristics affecting the motor terminal voltage or the assumptions made concerning the terminal voltage, including the method of starting, such as across the line or some method of reduced voltage starting.
6.9.2.12: (Dynamics-Torsional Analysis) - The analysis shall generate the maximum torque as well as a torque vs. time history for each of the shafts in the train.
The maximum torques shall be used to evaluate the peak torque capability of coupling components, gearing and interference fits of components, such as coupling hubs. The torque vs. time history shall be used to develop a cumulative damage-fatigue analysis of shafting, keys and coupling components.
6.9.2.13: (Dynamics-Torsional Analysis) - Appropriate fatigue properties and stress concentrations shall be used.
6.9.2.14: (Dynamics-Torsional Analysis) - An appropriate cumulative fatigue algorithm shall be used to develop a value for the safe number of starts. The purchaser and vendor shall mutually agree as to the safe number of starts.
NOTE: Values used depend on the analytical model used and the vendor's experience. Values of 1000 to 1500 starts are common. ANSI/API Std 541 requires 5000 starts. This is a reasonable assumption for a motor since it does not add significant cost to the design. The driven equipment, however, would be over-designed to meet this requirement.
EXAMPLE: A 20-year life with 1 start per week equals 1040 starts. Equipment of this type normally starts once every few years rather than once per week. It is necessary, therefore, to specify a reasonable number of starts.
6.10.1.5: (Bearing) - Rolling-element bearing life (basic rating life, L10h, for each bearing or bearing pair) shall be calculated in accordance with ISO 281 and be equivalent to at least 25000 h with continuous operation at rated conditions, and at least 16000 h at maximum radial and axial loads and rated speed.
NOTE 1: ISO 281 defines basic rating life, L10, in units of millions of revolutions. Industry practice is to convert this to hours and to refer to it as L10h.
NOTE 2: For the purpose of this provision, ANSI/ABMA 9 is equivalent to ISO 281.
6.10.1.6: (Bearing) - Bearing system life (the calculated life of the combined system of bearings in the pump) shall be equivalent to at least 25000 h with continuous operation at rated conditions, and at least 16000 h at maximum radial and axial loads and rated speed. The system life shall be calculated as given in Equation
If specified, the bearing system life calculations shall be furnished. See Clause K.2 for a discussion of bearing system life.
NOTE: A bearing system L10h life of 25000 h and 16000 h requires that the L10h life of each individual bearing be significantly higher.
6.10.2.7.2: (Bearing Housings) - For purge oil-mist lubrication, bearings and bearing housings shall meet the following requirements in a) to d) below.
a) A threaded 6 mm or 12 mm (NPS 1/4 or 1/2) oil-mist connection shall be located in the top half of the bearing housing to act also as a vent-and-fill connection.
b) Constant-level oilers shall be provided, and a mark indicating the oil level is required on the bearing housing. Bearing lubrication is by a conventional oil bath, flinger or oil ring system.
c) Constant-level sight feed oilers shall be equipped with overflow control to allow excess coalesced oil from the mist system to drain from the bearing housing so that oil level in the sump is maintained at proper level. The oil shall be contained to prevent it from draining onto the baseplate.
d) Constant-level sight feed oilers shall be piped so that they operate at the internal pressure of the bearing housing, do not vent excess mist at the bearing housing, or allow oil to drip to the baseplate.
6.10.2.7.3: (Bearing Housings) - For both pure and purge mist applications, a drain connection shall be located on the bottom of the bearing housing to provide complete oil drainage (see 6.10.2.7.5).
6.10.2.7.4: (Bearing Housings) - Shielded or sealed bearings shall not be used in conjunction with either pure or purge oil-mist systems.
6.10.2.7.4: (Bearing Housings) - The oil-mist supply, reclassifier(s) and drain fitting shall be provided by the purchaser. Unless otherwise specified, directional reclassifiers, if required, shall be provided by the machine manufacturer.
6.10.2.12: (Bearing Housings) - The purchaser shall specify whether synthetic oil shall be used. If specified, the purchaser shall specify the oil type. The vendor shall ensure that bearing-housing internal paint, if used, is compatible with the specified oil.
6.12.1.12.2: (Materials) - If reduced-hardness materials are specified in 6.12.1.12.1, they shall be supplied in accordance with NACE MR0103.
NOTE: NACE MR0103 applied to oil refineries, LNG plants and chemical plants. NACE MR0103 applies to materials potentially subject to sulfide stress-corrosion cracking.
6.12.1.12.3: (Materials) - If specified, reduced-hardness materials shall be supplied in accordance with ISO 15156-1.
NOTE 1: For the purposes of this provision, ANSI/NACE MR0175 is equivalent to ISO 15156-1.
NOTE 2: ISO 15156 (all parts), which is the equivalent of ANSI/NACE MR0175, applies to material potentially subject to sulfide and chloride stress-corrosion cracking in oil and gas production facilities and natural gas sweetening plants.
6.12.1.15: (Materials) - Bearing housings, load-carrying bearing housing covers and brackets between the pump casing or head and the bearing housings shall be steel except for pumps constructed in accordance with Table H.1, Classes I-1 or I-2. Driver supports for vertical pumps that utilize thrust bearings in the driver to support the shaft shall be steel.
6.13.5: (Nameplates and Rotation Arrows) - Nameplates and rotation arrows (if attached) shall be of austenitic stainless steel or of nickel-copper alloy (Monel15) or its equivalent). Attachment pins shall be of the same material as the nameplate or rotation arrow. Welding is not permitted as an attachment method.
7.2.14: (Couplings and Guards) Bulleted clause - If specified, coupling guards shall be constructed of an agreed spark-resistant material (see 6.10.2.6, note).
7.2.15: (Couplings and Guards) Bulleted clause - If specified for coupling guards with potentially explosive atmospheres, an “ignition hazard assessment” (risk analysis) in accordance with EN 13463-1 shall be conducted and a suitable report provided.
7.2.14: (Baseplates) Bulleted clause - If specified, the baseplate shall be supplied without a deck plate, i.e. open deck design.
7.5.2.5: (Auxiliary process liquid piping) - Drain valves and a drain manifold shall be supplied, for pumps that require more than one drain connection. The drain manifold shall be inside the drain pan limits.
Drain valves are not required for pumps that can be drained with one drain connection. The vendor shall provide space on the baseplate for a purchaser-supplied drain valve inside the pump drain pan or drain rim.
7.5.2.9: (Auxiliary process liquid piping) - Threaded piping joints may be used only on seal glands, instrumentation connections and for pumps of cast iron construction (Class I-1 or I-2 in Table H.1).
7.5.2.9: (Auxiliary process liquid piping) - Transmitters and pressure gauges shall have block-and-bleed valves.
8.2.2.1: (Pressure casing materials inspection) - Unless otherwise specified, pressure-casing materials shall be inspected in accordance with the requirements of Table 14.
NOTE: Although the pump is designed to meet specific pressure and temperature requirements and the casing is hydrostatically tested in accordance with the requirements of this International Standard, this alone does not guarantee that the material is of a suitable quality for the service. Casting quality can be affected by considerable variations in material processing. Material standards, such as ASTM, provide minimum requirements for the material itself, but castings can be subject to areas of shrinkage, gas porosity, hot tears, sand inclusions, improper weld repairs, etc. In addition, some materials are prone to grain boundary tears or cracks that can propagate under in-service stresses caused by temperature, pressure, vibration and pipe strain.
8.2.2.2: (Pressure casing materials inspection) - For double-casing pumps, the outer casing pressure/temperature should be used to determine the inspection class of the outer casting (see 8.2.2.1). The inner casing should be inspected to Class I (Table 14).
8.2.2.3: (Pressure casing materials inspection) - The timing of the inspections required by Table 14 shall be as follows.
a) VI/MT/PT shall be performed after final heat treatment in the proof (rough) machined condition. In the proof (rough) machined condition, an additional amount of material remains on areas where machining to critical dimensions and tolerances is required. The additional amount of material removed shall not exceed 1 mm (0.040 in) material stock or 5% of minimum allowable wall thickness, whichever is less.
b) RT/UT of castings shall be performed after final heat treatment.
c) RT of welds and UT of wrought material and welds shall be performed after final heat treatment. UT of wrought material shall be performed prior to any machining operations that can interfere with the UT examination.
8.2.2.4: (Pressure casing materials inspection) - Where the configuration of a casting makes radiography impossible, radiographic examination may be replaced by ultrasonic testing.
8.2.2.8: (Pressure casing materials inspection) - If specified, pressure boundary parts of alloy materials shall be subject to positive material identification (PMI) using recognized testing methods, instrumentation and standards. The purchaser and vendor shall agree on the specific parts tested, procedures used and acceptance criteria. Only techniques providing quantitative results shall be used. Mill test reports, material composition certificates, visual stamps or markings shall not be considered substitutes for PMI testing.
8.3.2.1: (Hydrostatic test) - The intent of a hydrostatic test of a centrifugal pump casing is to ensure that the design and construction of the pump pressure containing components and joints are leak-free from ambient conditions to the maximum operation conditions defined on the data sheet.
8.3.2.3: (Hydrostatic test) - The test set-up and/or apparatus shall not provide stiffening that improves the integrity of any joint.
8.3.2.13: (Hydrostatic test) - Piping systems fabricated by welding shall be hydrostatically tested in accordance with ISO 15649. For piping, the stress shall conform to ISO 15649.
NOTE 1 For the purpose of this provision, ANSI/ASME B31.3 is equivalent to ISO 15649.
NOTE 2 It is not necessary to hydrostatically test piping systems assembled with tubing or threaded connections after assembly.
8.3.3.4: (Performance test) - For higher-power pumps (> 1 MW), performance tolerances other than those in Table 16 can be appropriate. If specified, pump efficiency at rated flow shall be quoted to the tolerance given by the purchaser and shall be included in the pump's rated performance. If a tolerance is specified for rated efficiency, an additional test point as close to rated flow as practical shall be taken. The rated efficiency and tolerance shall be consistent with the test code being used, with particular attention to the uncertainty of efficiency determined by test to that code.
The purchaser should expect that adding efficiency with a specific tolerance to the pump's rated performance usually affects pump cost and delivery.
8.3.3.6: (Performance test) - If specified, the performance test shall be conducted with test stand NPSHA controlled to no more than 110 % of the actual NPSHA specified on the data sheet.
NOTE: It is the purpose of this test to evaluate pump performance with the specified NPSHA at pump suction.
8.3.3.8: (Performance test) - Unless otherwise specified, pumps shall not be disassembled after final performance testing. The pump, including the seal chamber, shall be drained to the extent practical, filled with a water-displacing inhibitor within 4 h of testing and redrained.
8.3.4.3.3: (Optional Tests) - The NPSH required test shall determine the actual NPSH required at a 3 % head drop. Unless otherwise specified or agreed, curves shall be developed at constant flow by reducing the NPSHA to a point where the head curves break away from that developed with sufficient NPSHA (8.3.4.3.2) by at least 3 %. The NPSH required test shall start with at least the same NPSHA as the performance test and at least twice the NPSH3 shown on the proposal curve. The first two test points shall not differ by more than the uncertainty of the head measurement. If the second test point at the same flowrate shows a decrease in differential head then the NPSHA shall be increased to a value sufficient to establish two consecutive points of equal head. The first two points shall be separated by a minimum of 1 m (3 ft) of NPSHA. These NPSH3 curves shall be developed and submitted in accordance with Hydraulic Institute Standards (ANSI/HI 1.6) or ISO 9906, as specified. The test shall not proceed beyond a 20 % head breakdown (20 % of first-stage head for multistage pumps).
NOTE: If 8.3.3.6 is specified, it is possible that the head has already been affected by insufficient NPSHA, so starting at a higher NPSHA is desirable.
8.3.4.4.2: (Complete Unit Tests) - The acceptable vibration limits of each component of the train shall be as per its applicable standards and specifications, except for reciprocating engines (in this case, limits shall be mutually agreed upon by purchaser, pump vendor and engine supplier).
8.4.1: (Preparation for Shipment) - Unless otherwise specified, equipment shall be prepared for domestic shipment. Domestic shipment preparation shall make the equipment suitable for outdoor storage for a period of at least six months with no disassembly required before operation except possibly inspection of bearings and seals. Preparation for longer storage or export shipment is more rigorous and, if specified, shall be provided by the vendor following agreed procedures.
8.4.8: (Preparation for Shipment) - Horizontal pumps, and all furnished drivers and auxiliaries, shall be shipped fully assembled on their baseplates, except as noted below. Coupling spacers with bolts and other items, such as minimum flow orifices that are not part of the assembled pumping unit, shall be separately boxed, tagged and securely attached to the baseplate.
8.4.9: (Preparation for Shipment) - Drivers for vertical pumps and horizontal drivers with a mass over 200 kg (450 lb) may be removed after shop mounting and alignment and shipped separately but alongside pump. Vertical pumps with suction cans shall be shipped with the suction cans (barrels) removed.
8.4.10: (Preparation for Shipment) - If it is necessary to ship other major components separately, prior purchaser approval is required.
8.4.11: (Preparation for Shipment) - reinstalled prior to shipment. Non-metallic filter elements shall be shipped and installed in an unused condition.
8.4.12: (Preparation for Shipment) - Suitable rust preventatives shall be oil-soluble and compatible with all pumped liquids.
9.1.1.2: (Horizontal (Type OH2) pumps) - The distance between the pump and driver shaft ends (distance between shaft ends, or DBSE) shall permit removal of the coupling spacer and back pullout assembly without disturbing the driver, coupling hubs or casing.
9.1.1.3: (Horizontal (Type OH2) pumps) Bulleted clause - If specified, the shaft flexibility index shall be calculated by the vendor in accordance with K.1 and stated on the data sheet.
The design and operation requirements for overhung pump rotors are detailed in several areas of this standard. K.1 lists these requirements and establishes a standardized process of calculating a shaft flexibility index that may be used to evaluate these latter parameters and to establish a baseline for the comparison of shaft flexibility.
9.2.1.5: (Horizontal (Type OH2) pumps) - For pumps with machined and studded suction and discharge nozzles, the vendor shall provide the minimum acceptable length for break-out spool pieces to facilitate maintenance activity. Spool pieces should be provided by the purchaser.
NOTE: Break-out spool pieces eliminate the requirement to remove large sections of piping in order to take the pump casing out during major overhauls.
9.3.2.3: (Vertically suspended pumps) - Assemblies designed for O-ring seals only do not require flanges and bolting designed to seat a spiral-wound gasket (see 6.3.10).
9.3.8.1.2: (Vertically suspended pumps) - Unless otherwise specified, motors for vertical pumps shall have solid shafts. If the pump thrust bearings are in the motor, the motors shall meet the shaft and base tolerances shown in Figure 36.
9.3.8.3.4: (Vertically suspended pumps) - The outside corners of the sole plate or mounting plate imbedded in the grout shall have at least 50 mm (2 in) radii in the plan view (see Figure D.1).
10.3.2.3: (Contract Data) - If specified, a generic casing drawing defining casing retirement thickness (es) in critical areas shall be provided. The retirement thickness (es) shall be based on failure to comply with any of the criteria in 6.3.3. and 6.3.4.
