Detail of GB/T 3216-2016/XG1-2018

Introduction of GB/T 3216-2016/XG1-2018

This standard is drafted in accordance with the rules given in GB/T 1.1-2009. This standard replaces GB/T 3216-2005 Rotodynamic Pumps — Hydraulic Performance Acceptance Tests — Grades 1 and 2. In addition to a number of editorial changes, the following technical deviations have been made with respect to GB/T 3216-2005: — the standard name is modified (see cover hereof; cover of Edition 2005); — the introduction is modified (see introduction; introduction of Edition 2005); — the levels of acceptance are modified (see Clause 1; Clause 1 of Edition 2005); — the normative references are modified (see Clause 2; Clause 2 of Edition 2005); — the terms, definitions, symbols and subscripts are modified (see Clause 3; Clause 3 of Edition 2005); — the instruction for tolerance grades given in Table 8 include manufacturing and measurement tolerance is added (see 4.1); — the guaranteed objects are modified (see 4.2; 4.1 of Edition 2005); — the amplitude of fluctuations of temperature, inlet and outlet head are modified (see Table 3); — the provisions of unstable conditions and the variation limits between repeated measurements of the same quantity have been deleted (see 5.4.2.3.2 and Table 4 of Edition 2005); — the calculation formula of random uncertainty eR and the value of t-distribution are added (see 4.3.3.1 and Table 4); — The measured quantity of systematic uncertainty are modified (see Table 5; Table 7 of Edition 2005); — the grades of overall uncertainties are added (see Table 6); — the tolerances for evaluation of flow, head and efficiency are modified (see 4.4; 6.3 and 6.4 of Edition 2005); — the evaluation of guaranteed efficiency is added (see 4.4.4); — the performance test acceptance grades and corresponding tolerance are modified (see Table 8; Table 10 of Edition 2005); — the default test acceptance grades are added (see 4.5 and Table 9); — the requirements for test points for all performance tests are modified (see 5.7.1; 5.4.1 of Edition 2005); — the test personnel is deleted (see 5.2.4 of Edition 2005); — the feature of "clean cold water” is deleted (see 5.4.5.2 of Edition 2005); — the feature of the test liquid may be replaced by clean cold water is deleted (see 5.4.5.3 of Edition 2005); — the requirements for tolerance factor for NPSHR are modified (see 5.8.2.5; 11.3.3 of Edition 2005); — the determination of reduction of impeller diameter is modified (see 6.2.1; Annex D of Edition 2005); — the measurement of flow rate is modified (see D.3, Annex D; Clause 7 of Edition 2005); — the “Tests performed on the entire equipment set — String test” is added (see Annex E). — the “Special test methods” is added (see Annex G); — the “Witnessed pump test” is added (see Annex H); — the “Measurement uncertainty for NPSH test” is added (see Annex J); — the “Friction losses” is deleted, and the content of the original “Table E.1 Equivalent uniform roughness k for pipes” is moved to “A.4.9 Friction losses at inlet and outlet” (see Annex E of Edition 2005); — the “Costs and repetition of tests” is deleted (see Annex H of Edition 2005); — the “Performance correction chart for viscous liquids” is deleted (see Annex I of Edition 2005); — the “NPSHR reduction for pumps handling hydrocarbon liquids and high temperature water” is deleted (see Annex J of Edition 2005); — the “Statistical evaluation of measurement results” is deleted (see Annex K of Edition 2005); — the “Pump test sheet” is deleted (see Annex M of Edition 2005); This standard is identical with International Standard ISO 9906:2012 Rotodynamic Pumps — Hydraulic Performance Acceptance Tests — Grades 1, 2 and 3. For the purposes of this standard, the following editorial changes have also been made with respect to the ISO 9906:2012: — according to Chinese usage, the rotational speed unit "r/min" is added (see Table 1); — the power and efficiency tolerance curves in Figures 5 and 6 are modified, and the original ISO text is incorrect; — the key in Figure A.1 has been deleted, and the original ISO text is incorrect. This standard was proposed by the China Machinery Industry Federation. This standard is under the jurisdiction of National Technical Committee 211 on Pumps of Standardization Administration of China (SAC/TC 211). The previous editions of this standard are as follows: — GB 3216-1982, GB/T 3216-1989, GB/T 3216-2005.   Introduction The tests in this standard are intended to ascertain the performance of the pump and to compare this with the manufacturer’s guarantee. The nominated guarantee for any quantity is deemed to have been met if, where tested according to this standard, the measured performance falls within the tolerance specified for the particular quantity (see 4.4). Rotodynamic Pumps — Hydraulic Performance Acceptance Tests — Grades 1, 2 and 3 1 Scope This standard specifies hydraulic performance tests for customers’ acceptance of rotodynamic pumps (centrifugal, mixed flow and axial pumps, hereinafter “pumps”). This standard is intended to be used for pump acceptance testing at pump test facilities, such as manufacturers’ pump test facilities or laboratories. It can be applied to pumps of any size and to any pumped liquids which behave as clean, cold water. This standard specifies three levels of acceptance: — grades 1B, 1E and 1U with tighter tolerance; — grades 2B and 2U with broader tolerance; — grade 3B with even broader tolerance. This standard applies either to a pump itself without any fittings or to a combination of a pump associated with all or part of its upstream and/or downstream fittings. 2 Normative References The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 17769-1 Liquid Pumps and Installation — General Terms, Definitions, Quantities, Letter Symbols and Units — Part 1: Liquid Pumps ISO 17769-2 Liquid Pumps and Installation — General Terms, Definitions, Quantities, Letter Symbols and Units — Part 2: Pumping System 3 Terms, Definitions, Symbols and Subscripts 3.1 Terms and definitions For the purposes of this document, the terms, definitions, quantities and symbols given in ISO 17769-1 and 17769-2 and the following apply. Note 1: Table 1 gives an alphabetical list of the symbols used and Table 2 gives a list of subscripts; see 3.3. Note 2: All formulae are given in coherent SI units. For conversion of other units to SI units, see Annex I. 3.1.1 General terms Note: All of the types of test in 3.1.1 apply to guarantee point to fulfil the customer’s specification(s). 3.1.1.1 guarantee point flow/head (Q/H) point, which a tested pump shall meet, within the tolerances of the agreed acceptance class 3.1.1.2 factory performance test pump test performed to verify the initial performance of new pumps as well as checking for repeatability of production units, accuracy of impeller trim calculations, performance with special materials, etc. Note: A typical performance test consists of the measurement of flow, head and power input to the pump or pump test motor. Additional measurements, such as NPSH, may be included as agreed upon. A factory test is understood to mean testing at a dedicated test facility, often at a pump manufacturer’s plant or at an independent pump test facility. 3.1.1.3 non-witnessed pump test 3.1.1.3.1 factory test test performed without the presence of a purchaser’s representative, in which the pump manufacturer is responsible for the data collection and judgement of pump acceptance Note: The advantage of this test is cost savings and accelerated pump delivery to the pump user. In many cases, if the purchaser is familiar with the performance of the pump (e.g. identical pump model order), a factory non-witnessed test may be acceptable. 3.1.1.3.2 signed factory test test performed without the presence of a purchaser’s representative, in which the pump manufacturer is responsible for compliance with the parameters of the agreed acceptance class Note: The pump manufacturer conducts the test, passes judgement of pump acceptance and produces a signed pump test document. The advantage of this test is the same as seen on the non-witnessed test. Compared to a witnessed test, this test is substantially less expensive and often leads to accelerated pump delivery to the end user.   3.1.1.4 witnessed pump test Note: The witnessing of a pump test by a representative of the pump purchaser can serve many useful functions. There are various ways of witnessing a test. 3.1.1.4.1 witnessing by the purchaser’s representative testing physically attended by a representative of the purchaser, who signs off on the raw test data to certify that the test is performed satisfactorily Note: It is possible for final acceptance of the pump performance to be determined by the witness. The benefit of witness testing depends largely on the effectiveness and expertise of the witness. A witness cannot only ensure the test is conducted properly, but also observes operation of the pump during testing prior to pump shipment to the job site. A disadvantage of witness testing can be extended delivery times and excessive cost. With just-in-time manufacturing methods, the scheduling of witness testing requires flexibility on the part of the witness and can lead to additional costs if the schedule of the witness causes delays in manufacturing. 3.1.1.4.2 remote witnessing by the purchaser’s representative pump performance testing witnessed from a distance by the purchaser or his/her representative Note: With a remote camera system, the purchaser can monitor the entire testing remotely in real-time. The raw data, as recorded by the data acquisition system, can be viewed and analysed during the test, and the results can be discussed and submitted for approval. The advantages of this type of testing are savings in travel costs and accelerated pump delivery. 3.2 Terms relating to quantities 3.2.1 angular velocity w number of radians of shaft rotation Note 1: It is given by: w = 2πn (1) Note 2: It is expressed in time, e.g. s-1, where n is given in 60 × min-1. 3.2.2 speed of rotation number of rotations per second 3.2.3 mass flow rate rate of flow discharged into the pipe from the outlet connection of the pump Note 1: The mass flow rate is given in kilograms per second. Note 2: The following losses or limiting effects are inherent to the pump: a) discharge necessary for hydraulic balancing of axial thrust; b) cooling of the pump bearings. Note 3: Leakage from the fittings, internal leakage, etc., are not to be reckoned in the rate of flow. On the contrary, all derived flows for other purposes, such as a) cooling of the motor bearings, and b) cooling of a gear box (bearings, oil cooler) are to be reckoned in the rate of flow. Note 4: Whether and how these flows should be taken into account depends on the location of their derivation and of the section of flow-measurement respectively. 3.2.4 volume rate of flow rate of flow at the outlet of the pump, given by: (2) Note: In this standard, this symbol may also designate the volume rate of flow in any given section. It is the quotient of the mass rate of flow in this section by the density. (The section may be designated by subscripts.) 3.2.5 mean velocity mean value of the axial speed of flow, given by: (3) Note: Attention is drawn to the fact that in this case, Q may vary for different reasons across the circuit. 3.2.6 local velocity speed of flow at any given point 3.2.7 head energy of mass of liquid, divided by acceleration due to gravity, g, given by: (4) See 3.2.16. 3.2.8 reference plane any horizontal plane used as a datum for height measurement Note: For practical reasons, it is preferable not to specify an imaginary reference plane.   3.2.9 height above reference plane height of the considered point above the reference plane See Figure A.1. Note: Its value is: — positive, if the considered point is above the reference plane; — negative, if the considered point is below the reference plane. 3.2.10 gauge pressure pressure relative to atmospheric pressure Note 1: Its value is: — positive, if this pressure is greater than the atmospheric pressure; — negative, if this pressure is less than the atmospheric pressure. Note 2: All pressures in this standard are gauge pressures read from a manometer or similar pressure sensing instrument, except atmospheric pressure and the vapour pressure of the liquid, which are expressed as absolute pressures. 3.2.11 velocity head kinetic energy of the liquid in movement, divided by gravitational acceleration g, given by: (5) 3.2.12 total head overall energy in any section Note 1: The total head is given by: (6) where z is the height of the centre of the cross-section above the reference plane; p is the gauge pressure related to the centre of the cross-section. Note 2: The absolute total head in any section is given by: (7) 3.2.13 inlet total head overall energy at the inlet section of the pump Note: Inlet total head is given by: (8) 3.2.14 outlet total head overall energy at the outlet section of the pump Note: Outlet total head is given by: (9) 3.2.15 pump total head algebraic difference between the outlet total head and the inlet total head Note 1: If compressibility is negligible, H = H2 - H1. If the compressibility of the pumped liquid is significant, the density, ρ, should be replaced by the mean value: (10) and the pump total head should be calculated by Formula (11): (11) Note 2: The correct mathematical symbol is H1-2. 3.2.16 specific energy energy of liquid, given by: y = gH (12) 3.2.17 loss of head at inlet difference between the total head of the liquid at the measuring point and the total head of the liquid in the inlet section of the pump 3.2.18 loss of head at outlet difference between the total head of the liquid in the outlet section of the pump and the total head of the liquid at the measuring point 3.2.19 pipe friction loss coefficient coefficient for the head loss by friction in the pipe 3.2.20 net positive suction head NPSH absolute inlet total head above the head equivalent to the vapour pressure relative to the NPSH datum plane Note 1: NPSH is given by: (13) Note 2: This NPSH relates to the NPSH datum plane, whereas inlet total head relates to the reference plane. Note 3: A derogation has been given to allow the use of the abbreviated term NPSH (upright and not bold) as a symbol in mathematical formulae as a consequence of its well-established, historical use in this manner. 3.2.20.1 NPSH datum plane horizontal plane through the centre of the circle described by the external points of the entrance edges of the impeller blades 3.2.20.2 NPSH datum plane plane through the higher centre See Figure 1. Note: It is the responsibility of the manufacturer to indicate the position of this plane with respect to precise reference points on the pump. Key 1 — NPSH datum plane Figure 1 — NPSH datum plane 3.2.21 available NPSH NPSHA NPSH available as determined by the conditions of the installation for a specified rate of flow Note: A derogation has been given to allow the use of the abbreviated term NPSHA (upright and not bold) as a symbol in mathematical formulae as a consequence of its well-established, historical use in this manner.   3.2.22 required NPSH NPSHR minimum NPSH given by the manufacturer for a pump achieving a specified performance at the specified rate of flow, speed and pumped liquid (occurrence of visible cavitation, increase of noise and vibration due to cavitation, beginning of head or efficiency drop, head or efficiency drop of a given amount, limitation of cavitation erosion) Note: A derogation has been given to allow the use of the abbreviated term NPSHR (upright and not bold) as a symbol in mathematical formulae as a consequence of its well-established, historical use in this manner. 3.2.23 NPSH3 NPSH required for a drop of 3% of the total head of the first stage of the pump as standard basis for use in performance curves Note: A derogation has been given to allow the use of the abbreviated term NPSH (upright and not bold) as a symbol in mathematical formulae as a consequence of its well-established, historical use in this manner. 3.2.24 type number dimensionless quantity calculated at the point of best efficiency Note 1: It is given by: (14) where Q′ is the volume rate of flow per eye; H′ is the head of the first stage; n is given in s-1. Note 2: The type number is to be taken at maximum diameter of the first stage impeller. 3.2.25 pump power input P2 power transmitted to the pump by its driver 3.2.26 pump power output hydraulic power at the pump discharge Note: Pump power output is given by: Ph = ρQgH = ρQy (15)   3.2.27 driver power input Pgr power absorbed by the pump driver 3.2.28 maximum shaft power P2,max maximum pump shaft power, as set by the manufacturer, which is adequate to drive the pump over the specified operating conditions 3.2.29 pump efficiency pump power output divided by the pump power input Note: Pump efficiency is given by: (16) 3.2.30 overall efficiency pump power output divided by the driver power input Note: Overall efficiency is given by: (17) 3.3 Symbols and subscripts   Table 1 Alphabetical list of basic letters used as symbols Symbol Quantity Unit A Area m2 D Diameter m e Overall uncertainty, relative value % f Frequency s-1, Hz g Acceleration due to gravity a m/s2 H Pump total head m HJ Losses in terms of head of liquid m k Equivalent uniform roughness m K Type number Pure number l Length m M Torque Nm n Speed of rotation r/min, s-1, min-1 NPSH Net positive suction head m p Pressure Pa P Power W q Mass flow rate b kg/s Q (Volume) rate of flow c m3/s Re Reynolds number Pure number τ Tolerance factor, relative value % t Students distribution Pure number U Mean velocity m/s v Local velocity m/s V Volume m3 y Specific energy J/kg z Height above reference plane m zD Difference between NPSH datum plane and reference plane (see 3.2.20) m h Efficiency % θ Temperature °C l Pipe friction loss coefficient Pure number u Kinematic viscosity m2/s ρ Density kg/m3 w Angular velocity rad/s a In principle, the local value of g should be used. Nevertheless, for grades 2 and 3, it is sufficient to use a value of g = 9.81 m/s2. For the calculation of the local value g = 9.7803(1+0.0053sin2j)-3×10-6Z, where j is the latitude and Z is the height above sea level. b An optional symbol for mass flow rate is qm. c An optional symbol for volume rate of flow is qv.   Table 2 List of letters and figures used as subscripts Subscript Meaning 1 inlet 1′ inlet measuring section 2 outlet (except for P2) 2′ outlet measuring section abs absolute amb ambient D difference, datum f liquid in measuring pipes G guaranteed H pump total head h hydraulic gr combined motor/pump unit (overall) J losses M manometer n speed of rotation p power Q (volume) rate of flow ref reference plane sp specified T translated, torque v vapour (pressure) h efficiency x at any section 4 Pump Measurements and Acceptance Criteria 4.1 General The specified and contractually agreed upon rated point (duty point), hereinafter “the guarantee point”, shall be evaluated against one acceptance grade and its corresponding tolerance. For a pump performance test, this guarantee point shall always specify the guaranteed flow, QG, and guaranteed head, HG, and may, optionally, specify guaranteed efficiency, guaranteed shaft power or guaranteed net positive suction head required (NPSHR). Where applicable, these optional guarantee parameters need to be specified for those tests, see respective tests in 4.4.3 and 5.8. The acceptance grade tolerance applies to the guarantee point only. Other specified duty points, including their tolerances, shall be by separate agreement between the manufacturer and purchaser. If other specified duty points are agreed upon, but no tolerance is given for these points, the default acceptance level for these points shall be grade 3. A guarantee point may be detailed in a written contract, a customer-specific pump performance curve or similar written and project specific documentation. If not otherwise agreed upon between the manufacturer and the purchaser, the following shall apply. a) The acceptance grade shall be in accordance with the grades given in Table 8. b) Tests shall be carried out on the test stand of the manufacturer’s works with clean, cold water using the methods and test arrangements specified in this standard. c) The pump performance shall be guaranteed between the pump’s inlet connection and outlet connection. d) Pipe and fittings (bends, reducers and valves) outside of the pump are not a part of the guarantee. The combination of manufacturing and measurement tolerances in practice necessitates the usage of tolerances on tested values. The tolerances given in Table 8 take into account both manufacturing and measurement tolerances. The performance of a pump varies substantially with the nature of the liquid being pumped. Although it is not possible to give general rules whereby performance with clean, cold water can be used to predict performance with other liquids, it is desirable for the parties to agree on empirical rules to suit the particular circumstances. For further information, see ISO/TR 17766. If a number of identical pumps are being purchased, the number of pumps to be tested shall be agreed between the purchaser and manufacturer. Both the purchaser and manufacturer shall be entitled to witness the testing. If tests are not carried out at the manufacturer’s test stand, opportunity shall be allowed for verification of the pump installation and instrumentation adjustments by both parties. 4.2 Guarantees The manufacturer guarantees that, for the guarantee point and at the rated speed (or in some cases frequency and voltage), the measured pump curve touches, or passes through a tolerance surrounding the guarantee point, as defined by the applicable acceptance grade (see Table 8 and Figures 2 and 3). A guarantee point shall be defined by a guaranteed flow, QG, and a guaranteed head, HG. In addition, one or more of the following quantities may be guaranteed at the specified conditions and at the rated speed: a) as defined in 4.4.3 and Figures 4, 5 and 6, 1) the minimum pump efficiency, ηG, or the maximum pump input power, PG, or 2) in the case of a combined pump and motor unit, the minimum combined efficiency, ηgrG, or the maximum pump motor unit input power, PgrG. b) the maximum NPSHR at the guarantee flow. The maximum power input may be guaranteed for the guarantee point or for a range of points along the pump curve. This, however, can require larger tolerances to be agreed upon between the purchaser and manufacturer. 4.3 Measurement uncertainty 4.3.1 General Every measurement is inevitably subject to some uncertainty, even if the measuring procedures and the instruments used, as well as the methods of analysis, fully comply with good practice and with the requirements of this standard. The guidance and procedures described in 4.3.2 and 4.3.3 are intended to provide general information to the user, as well as practical procedures allowing the user to estimate measurement uncertainty with reasonable confidence in applying the testing in conformity with this standard. Note: For comprehensive information on measurement uncertainty, see ISO/IEC Guide 99 and associated documents. 4.3.2 Fluctuations Where the design or operation of a pump is such that fluctuations of great amplitude are present, measurements may be carried out by providing a damping device in the measuring instruments or their connecting lines, which is capable of reducing the amplitude of the fluctuations to within the values given in Table 3. A symmetrical and linear damping device shall be used, for example a capillary tube, which shall provide integration over at least one complete cycle of fluctuations.   Table 3 Permissible amplitude of fluctuation as a percentage of mean value of quantity being measured Measured quantity Permissible amplitude of fluctuations Grade 1 % Grade 2 % Grade 3 % Rate of flow ±2 ±3 ±6 Differential head ±3 ±4 ±10 Outlet head ±2 ±3 ±6 Inlet head ±2 ±3 ±6 Input power ±2 ±3 ±6 Speed of rotation ±0.5 ±1 ±2 Torque ±2 ±3 ±6 Temperature 0.3°C 0.3°C 0.3°C 4.3.3 Statistical evaluation of overall measurement uncertainty 4.3.3.1 The estimate of the random component (random uncertainty) The random component due either to the characteristics of the measuring system or to variations of the measured quantity or both appears directly as a scatter of the measurements. Unlike the systematic uncertainty, the random component can be reduced by increasing the number of measurements of the same quantity under the same conditions. A set of readings not less than three (3) shall be taken at each test point. The random component, eR, shall be calculated as follows: The estimate of the random component of measurement uncertainty is calculated from the mean and the standard deviation of the observations. For the uncertainty of the readings, replace x with the actual measurement readings of flow, Q, head, H, and power, P. If n is the number of readings, the arithmetic mean, , of a set of repeated observations xi xi(i = 1…n) is: (18) The standard deviation, s, of these observations is given by: (19) The relative value of the uncertainty, eR, of the mean due to random effects is given by: (20) where t is a function of n as given in Table 4. Note 1: If the value of the overall uncertainty, e, does not meet the criteria given in Table 7, the value of the random component, eR, of the measurement can be reduced by increasing the number of measurements of the same quantity under the same conditions. Note 2: The random component, as defined in this standard, is classified as Type A uncertainty (see ISO/IEC Guide 99). Table 4 Values of Student’s t-distribution (based on 95% confidence level) n t n t 3 4.30 12 2.20 4 3.18 13 2.18 5 2.78 14 2.16 6 2.57 15 2.14 7 2.45 16 2.13 8 2.36 17 2.12 9 2.31 18 2.11 10 2.26 19 2.10 11 2.23 20 2.09 4.3.3.2 The estimate of the instrumental measurement uncertainty (systematic uncertainties) After all known errors have been removed by zero adjustment, calibration, careful measurement of dimensions, proper installation, etc., there remains an uncertainty which never disappears. This uncertainty cannot be reduced by repeating the measurements if the same instrument and the same method of measurement are used. The estimate of the systematic uncertainty of the uncertainty, eS, is in practice based on calibration traceable to international measurement standards. Permissible relative values for the systematic uncertainty in this standard are given in Table 5.   Table 5 Permissible relative values of the instrumental uncertainty, eS Measured quantity Maximum permissible systematic uncertainty (at guarantee point) Grade 1 % Grades 2 and 3 % Rate of flow ±1.5 ±2.5 Differential head ±1.0 ±2.5 Outlet head ±1.0 ±2.5 Inlet head ±1.0 ±2.5 Suction head for NPSH testing ±0.5a ±1.0 Driver power input ±1.0 ±2.0 Speed of rotation ±0.35 ±1.4 Torque ±0.9 ±2.0 a See Annex J for explanation. 4.3.3.3 The overall uncertainty The value for overall uncertainty, e, is given by: (21) Permissible values of overall measurement uncertainties, e, are given in Table 6. Note: The overall uncertainty, as defined in this standard, is equated with expanded measurement uncertainty (see ISO/IEC Guide 99). Table 6 Permissible values of overall uncertainties Quantity Symbol Grade 1 % Grades 2, 3 % Flow rate eQ ±2.0 ±3.5 Speed of rotation en ±0.5 ±2.0 Torque eT ±1.4 ±3.0 Pump total head eH ±1.5 ±3.5 Driver power input ePgr ±1.5 ±3.5 Pump power input (computed from torque and speed of rotation) ep ±1.5 ±3.5 Pump power input (computed from driver power and motor efficiency) eP ±2.0 ±4.0 4.3.3.4 Determination of overall uncertainty of efficiency The overall uncertainty of the overall efficiency and of the pump efficiency is calculated using Formulae (22), (24) and (25): (22) if efficiency is computed from torque and speed of rotation: (23) if efficiency is computed from pump power input: (24) Using the values given in Table 6, the calculations lead to the results given in Table 7. Table 7 Resulting greatest values of the overall uncertainties of efficiency Quantity Symbol Grade 1 % Grades 2 and 3 % Overall efficiency (computed from Q, H, Pgr) eηgr ±2.9 ±6.1 Pump efficiency (computed from Q, H, M, n) eη ±2.9 ±6.1 Pump efficiency (computed from Q, H, Pgr, hmot) eη ±3.2 ±6.4 4.4 Performance test acceptance grades and tolerances 4.4.1 General Six pump performance test acceptance grades, 1B, 1E, 1U, 2B, 2U and 3B are defined in this subclause. Grade 1 is the most stringent grade, with 1U and 2U having a unilateral tolerance and grades 1B, 2B and 3B having a bilateral tolerance. Grade 1E is also bilateral in nature and is important to those concerned with energy efficiency. Note: The grades 1U, 1E and 1B have the same tolerance for flow and head. The purchaser and manufacturer may agree to use any grade to judge whether or not a specific pump meets a guarantee point. If a guarantee point is given, but no acceptance grade is specified, this standard reverts to a default test acceptance grade, as described in 4.5. Guarantee point acceptance grades for pump head, flow, power and efficiency are provided in Table 8. All tolerances are percentages of values guaranteed.   Table 8 Pump test acceptance grades and corresponding tolerance Grade 1 2 3 Guarantee requirement △τQ 10% 16% 18% △τH 6% 10% 14% Acceptance grade 1U 1E 1B 2B 2U 3B τQ +10% ±5% ±8% +16% ±9% Mandatory τH +6% ±3% ±5% +10% ±7% τP +10% +4% +8% +16% +9% Optional τη ≥0% -3% -5% -7% Note: τx(x = Q, H, P, η) stands for the tolerance of the indicated quantity. 4.4.2 Tolerances for pumps with an input power of 10 kW and below For pumps with shaft power input of below 10 kW, the tolerance factors given in Table 8 can be too stringent. If not otherwise agreed upon between the manufacturer and purchaser, the tolerance factors shall be the following: — rate of flow τQ = ±10%; — pump total head τH = ±8%. The tolerance factor on efficiency, τη, if guaranteed, shall be calculated as given by Formula (25): (25) where the pump power input, P2, tallies with the maximum shaft power (input), P2,max, in kilowatts, over the range of operation. A tolerance factor, τP,gr ,is allowed using Formula (26): (26) 4.4.3 Evaluation of flow and head Guarantee point evaluation shall be performed at the rated speed. Test points do not have to be recalculated based on speed in cases where the test speed is identical to the rated speed and for tests with a combined motor and pump (i.e. submersible pumps, close-coupled pumps and all pumps tested with the motor which are installed with the pump). For tests in which the test speed is different from the rated speed, each test point shall be recalculated to the rated speed, using the affinity laws. The tolerances for flow and head shall be applied in the following manner. — The pump flow tolerance shall be applied to the guaranteed flow, QG, at the guaranteed head, HG; — The pump head tolerance shall be applied to the guaranteed head, HG, at the guaranteed flow, QG. Acceptance is achieved if either flow or head, or both, are found to be within the applicable tolerance (see Figures 2 and 3). Key: X — rate of flow, Q; Y — head, H; Curve 1: crosses the head tolerance, P = pass; Curve 2: crosses the flow tolerance, P = pass; Curve 3: crosses both the head and flow tolerance, P = pass; Curve 4: does not cross any tolerance, F = fail; Curve 5: does not cross any tolerance, F = fail; Figure 2 Uni-lateral tolerance acceptance Key: X — rate of flow, Q; Y — head, H; curve 1: crosses the head tolerance, P = pass; curve 2: crosses the flow tolerance, P = pass; curve 3: crosses both the head and flow tolerance, P = pass; curve 4: does not cross any tolerance, F = fail; curve 5: does not cross any tolerance, F = fail; Figure 3 Bi-lateral tolerance acceptance 4.4.4 Evaluation of efficiency or power If efficiency or power has been guaranteed, it shall be evaluated against the applicable acceptance grade tolerance factor, i.e. the same as for Q/H in the following manner. After a best-fit test curve (Q-H-/Q-η/ or Q-P-curves) is drawn and smoothly fitted through the measured test points, an additional straight line shall be drawn between the origin (0 rate of flow, 0 head) and the guarantee point (rate of flow/head). If necessary, this line shall be extended until it crosses the fitted test curve. The intersection between the smoothly fitted test curve and this straight line shall form the new rate of flow/head point, which is used for evaluation of efficiency or power. The measured input power or calculated efficiency at this point shall be compared against the guaranteed value and the applicable power or efficiency tolerance factors (see Figures 4, 5 and 6). Note 1: The reason for using the “line from origin” method when evaluating the guaranteed efficiency or power is that it best retains the pump characteristics if the impeller diameter is changed. Additionally, this method always gives one single point of reference for evaluation. Note 2: The tolerance limits for flow and head can be reduced as a result of adding a power guarantee.

Contents of GB/T 3216-2016/XG1-2018

Foreword II Introduction V 1 Scope 2 Normative References 3 Terms, Definitions, Symbols and Subscripts 3.1 Terms and definitions 3.2 Terms relating to quantities 3.3 Symbols and subscripts 4 Pump Measurements and Acceptance Criteria 4.1 General 4.2 Guarantees 4.3 Measurement uncertainty 4.4 Performance test acceptance grades and tolerances 4.5 Default test acceptance grades for pump application 5 Test Procedures 5.1 General 5.2 Date of testing 5.3 Test programme 5.4 Testing equipment 5.5 Records and report 5.6 Test arrangements 5.7 Test conditions 5.8 NPSH tests 6 Analysis 6.1 Translation of the test results to the guarantee conditions 6.2 Obtaining specified characteristics Annex A (Normative) Test Arrangements Annex B (Informative) NPSH Test Arrangements Annex C (Informative) Calibration Intervals Annex D (Informative) Measurement Equipment Annex E (Informative) Tests Performed on the Entire Equipment Set — String Test Annex F (Informative) Reporting of Test Results Annex G (Informative) Special Test Methods Annex H (Informative) Witnessed Pump Test Annex I (Informative) Conversion to SI Units Annex J (Informative) Measurement Uncertainty for NPSH Test Bibliography