Technical specifications for centrifugal pumps - Class II (ISO 5199:1986)

Requirements for centrifugal pumps of back pull-out construction as used in the chemical and petrochemical industries. ISO 2858 pumps are typical of those conforming to this standard.

Kreiselpumpen, technische Anforderungen - Klasse II (ISO 5199:1986)

Spécifications techniques pour pompes centrifuges - Classe II (ISO 5199:1986)

Technical specifications for centrifugal pumps - Class II (ISO 5199:1986)

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Technical specifications for centrifugal pumps - Class II (ISO 5199:1986)Kreiselpumpen, technische Anforderungen - Klasse II (ISO 5199:1986)Spécifications techniques pour pompes centrifuges - Classe II (ISO 5199:1986)Technical specifications for centrifugal pumps - Class II (ISO 5199:1986)23.080ýUSDONHPumpsICS:Ta slovenski standard je istoveten z:EN 25199:1992SIST EN 25199:2000en01-december-2000SIST EN 25199:2000SLOVENSKI

SIST EN 25199:2000

SIST EN 25199:2000

SIST EN 25199:2000

w - International Standard INTERNATIONAL ORGANIZATION FOR STANDARDIZATION*MEX,lIYHAPOflHAR OPI-AHM3Al-W fl0 CTAHAAPTM3Al4’lWORGANISATION INTERNATIONALE DE NORMALISATION Technical specifications for centrifugal Pumps - Class II Spkifica tions techniques pour pompes ten trifuges - Classe ll First edition - 1986-04-15 UDC 621.671 Ref. No. ISO 51994986 (E) Descriptors : Pumps, rotary Pumps, centrifugal Pumps, specifications. üi 0 cn - Price based on 37 pages SIST EN 25199:2000

Foreword ISO (the International Organization for Standardization) is a worldwide federation of national Standards bodies (ISO member bedies). The work of preparing International Standards is normally carried out through ISO technical committees. Esch member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with ISO, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISO Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 5199 was prepared by Technical Committee lSO/TC 4 15, Pumps. Users should note that all International Standards undergo revision from time to time and that any reference made herein to any other International Standard implies its latest edition, unless otherwise stated. 0 International Organkation for Standardkation, 1986 Printed in Switzerland ii SIST EN 25199:2000

Contents Page 0 Introduction . 1 1 Scope and field sf application . 1 2 References . 1 3 Definitions . 2 4 Design . 3 5 Materials . 10 6 Shop inspection and tests . 10 7 Preparation for despatch . 11 Annexes Centrifugal pump - Data sheet . 13 Peakdisplacement . 18 Externat forces and moments on flanges . 19 Typical seal arrangements . 23 Piping arrangements for Seals . 25 Enquiry, proposal, purchase Order . 34 Documentation after purchase Order . 35 Checklist . 36 . . . Ill SIST EN 25199:2000

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INTERNATIONAL STANDARD ISO 51994986 (EI. Technical specifications for centrifugal Pumps - Class II 0 Introduction This International Standard is the first of a series dealing with technical specifications for centrifugal Pumps; they correspond to three classes of technical specifications, 1, II and Ill, of which class I has the most severe, and class Ill the least severe re- quirements. Where a decision may be required by the purchaser, or agree- ment is required between purchaser and manufacturer, the relevant text is printed in bold typeface and listed in annex H. 1 Scope and field of application 1.1 This International Standard covers class II requirements for centrifugal Pumps of back pull-out construction as used primarily in the Chemical and petrochemical industries. However the Standard, or individual clauses of it, tan be ap- plied in other industries, for general industrial use or to pump designs other than of back pull-out construction. 1.2 Pumpaasspecifiedl in ISO 2858 are typicafof those con- forming to. this International Standard. 1'3 This Internatiönal Standard includes design features con- cerned with installation, maintenance and safety for these Pumps, including baseplate couplings and auxiliary piping but excluding the driver. 1.4 Where application of this International Standard has been called for a) and a specific design feature is required, alternative designs which meet the intent of the Standard may be offered, provided that the alternative is described in detail; b) Pumps not complying with all requirements of the Stan- dard may be offered for consideration provided that all deviations are stated. 1.5 Whenever the documents include contradicting technical requirements, they shall apply in the following sequence: a) purchase Order (or enquiry if no Order is placed) (sec annexes F and G); c) this International Standard; d) other Standards to which reference is made in the Order or enquiry. 2 References To the extent specified in the text, the following International Standards are used in the application of this Standard. ISO 76, Rolling bearings - Sta tic load ratings. ISO 28111, Rolling bearings - D ynamic load ra tings and ra ting life - Part 7 : Calculation methods. ISO 1940, Balance quality of rotating rigid bodies. I S 0 2084, Pipeline flanges for general use - Metric series - Ma ting dimensions. ISO 2229, Equipment for the Petroleum and natura1 gas in- dustries - S teel pipe flanges, nominal sizes 112 to 24 in - Metric dimensions. ISO 2372, Mechanical Vibration of machines with operating Speeds from 10 to 200 revls - Basis for specifying evaluation Standards. ISO 2373, Mechanical vibra tion of certain rotating electrical machinery with shaft heights between 80 and 400 mm - Measurement and evaluation of the Vibration severity. ISO 2548, Centrifugal mixed flow and axialpumps - Code for acceptance tests - Class C. ISO 2858, End-suction centrifugal Pumps (rating 16 bar) - Designa tion, nominal duty poin t and dimensions. ISO 3069, End-suction centrifugal Pumps - Dimensions of cavities for mechanical Seals and for soft packing. ISO 3274, Instruments for the measurement of surface roughness by the Profile method - Contact fstylusl in- s trumen ts 0 f consecutive Profile transforma tion - Con tat t Profile meters, System M. ISO 3555, Centrifugal mixed flow and axialpumps - Code for acceptance tests - Class B. b) data sheets (sec annex A); ISO 3661, End-suction centrifugal Pumps - Baseplate and installa tion dimensions. SIST EN 25199:2000

ISO 51994986 (El ISO 3744, Acoustics - Determination of Sound power levels of noise sources - Engineering methods for free- field conditions over a reflec ting plane. 3.3 rated conditions: Conditions Idriver excluded) that define the (guarantee) Point necessary to meet all defined operating conditions, taking into account any necessary margins. ISO 3746, Acoustics - Determination of Sound power levels of noise sources - Survey method. 3.4 rated driver output: The maximum permissible driver output under site operating conditions. 3 Definitions 3.5 basic design pressure: This is derived from the per- mitted Stresses at 20 OC of the material used for the pressure- containing Parts. Terms in this International Standard which are not self- explanatory are defined as follows. 36 . rated pressure: The pressure limit at the most severe operating conditions in a given application. 3.1 operating conditions: All Parameters (for example, operating temperature, operating pressure) determined by a given application and pumped liquid. These Parameters will in- fluence the type of construction and construction materials. 3.7 rated inlet pressure: The inlet pressure which, with the rated head (converted to pressure) at rated flow, results in the rated outlet pressure. 3.8 rated sutlet pressure: Outlet pressure of the pump at 3.2 allowable operating range: The flow range at the specified operating conditions with the impeller supplied as limited by cavitation, heating, Vibration, noise, shaft deflection and other similar criteria. This range shall be defined by the manufacturer. below). Basic design pressu re Operating pressure rated flow, rated head (converted to pressure) rated inlet pressure. 39 * pressure - temperature rating : Welationship between pressure and temperature given in the form of a graph (sec Operating temperature Temperature 2 SIST EN 25199:2000

ISO 5199-1986 EI 3.10 corrosion allowance: That Portion of the wall thickness of the Parts wetted by the pumped liquid in excess of the theoretical thickness required to withstand the pressure limits given in 4.4.1. 3.11 maximum allowable continuous Speed : The highest Speed at which the manufacturer permits the pump to operate continuously. 3.12 trip Speed: The Speed of rotation emergency stop mechanism operates. at which the turbi ne 3.13 first critical Speed: The Speed of rotation of a machine at which the first (lowest) lateral natura1 frequency of Vibration of the rotating Parts corresponds to the frequency of rotation. 3.14 design load: The maximum hydraulic radial forces on the largest impeller (diameter and width) operating within the manufacturer’s specified range on its maximum Speed curve with a liquid density of 1000 kg/m? 3.15 maximum load: The maximum hydraulic radial forces on the largest impeller (diameter and width) operating at any Point on its maximum Speed curve with a liquid density of 1000 kg/m? 3.16 shaft runout: The total radial deviation indicated by a device measuring shaft Position in relation to the bearing housing as the shaft is rotated manually in its bearings with the shaft in the horizontal Position. 3.17 face runout: The total axial deviation indicated at the outer radial face of the stuffing box by a device attached to and rotated with the shaft when the shaft is rotated manually in its bearings in the horizontal Position. The radial face is that which determines the alignment of a seal component. 3.18 shaft deflection: The term as used in this International Standard describes the displacement of a shaft from its geometric centre in response to the radial hydraulic forces acting on the impeller. lt does not include shaft movement caused by tilting within the bearing clearances, bending caused by impeller imbalance or shaft runout. 3.19 circulation (flush): Return of pumped liquid from high pressure area to seal cavity tan be by external piping or internal passage and is used to remove heat generated at the seal or to maintain positive pressure in the seal cavity or treated to im- prove the working environment for the Seal. In some cases it may be desirable to circulate from the seal cavity to a lower pressure area (for example, the inlet). 3.20 injection (flush) : lntroduction of an appropriate (clean, compatible, etc.) liquid into the seal cavity from an extemal Source and then into the pumped liquid. Used for the same purpose as circulation but also used to provide an im- proved working environment for the Seal. 3.21 quenching : Continuous or intermittent introduction of an appropriate (clean, compatible, etc.) fluid on the atmospheric side of the main shaft Seal. Used to exclude air or moisture, to prevent or clear deposits (including ice), lubricate an auxiliary Seal, snuff out fire, dilute, heat or cool leakage. 3.22 barrier liquid (buffer) : An appropriate (clean, com- patible, etc.) liquid inserted between two Seals (mechanical seal and/or soft packing). The barrier liquid pressure depends on the seal arrangement. The barrier liquid may be used to prevent air entering the pump. The barrier is normally easier to seal than the pumped liquid and/or creates less of a hazard on leaking. 4 Design 4.1 General 4.1.1 Characteristic curve The characteristic curve shall indicate the permitted operating range of the pump. Pumps with a stable characteristic curve are preferred. The characteristic curves of the smallest and largest impeller diameter of the pump shall be plotted on the perfor- mance Chart as a function of flow. 4.12 Net positive suction head (NPSH) The NPSH required, (NPSH),, shall be based on cold water as specified in ISO 2548 or ISO 3555 unless other- wise agreed. A (NPSH), flow. curve shall be provided for water as a function of Should the pump manufacturer consider that, because of the construction material and liquid pumped, more NPSH is required, this should be stated in the proposal and the ap- propriate curve provided. The NPSH available (NPSH), shall exceed (NPSH), by a margin of at least 0,5 m. Correction factors for hydrocarbons are not allowed. For NPSH tests, refer to 6.323. 4.1.3 Outdoor installation The pu mps shall be suitable normal ambient cond itions. for outdoor installation under Extraordinary local ambient conditions, such as high or low temperatures, corrosive environment, sand storms, etc. for which the pump must be suitable shall be specified by the pur- chaser. 4.2 Prime movers The following have to be considered rated Performance of th Ie drive: when determining the a) application and method of Operation of the pump. For instance in the case of parallel Operation, the possible per- formante range with only one pump in Operation taking into account the System characteristic shall be considered; b) Position of teristic curve; the operating Point on the Pump charac- 3 SIST EN 25199:2000

ISO 51994986 (El c) shaft seal friction loss; 4.3.2 Balance and Vibration d) circulation flow for the mechanical seal (especially for Pumps with low rate of flow); e) properties of pumped liquid (viscosity, solids content, density); fl power and Slip loss through transmission; g) atmospheric conditions at pump site. Prime movers required as drivers for any Pumps covered by this International Standard shall have power output ratings at least equal to the percentage of rated pump power input given in figure 1, this value being never less than 1 kW. Where it appears that this will lead to unnecessary oversizing of the driver, an alternative proposal shall be submitted for the purchaser’s approval. 4.3 Critical Speed, balance and Vibration 4.3.1 Critical Speed Under operating conditions, the actual first lateral critical speed of the rotor when coupled to the drive agreed upon shall be at least 10 % above the maximum permitted continuous Speed including the trip Speed of a turbine driven pump. Balancing of the pump rotating Parts shall be carried out. Vibra- tion shall not exceed the Vibration severity limits as given in table 1 when measured on the manufacturer’s test facilities. These values are measured radially at the bearing housing at a Single operating Point at rated Speed ( + 5 %) and rated flow ( + 5 %) when operating without cavitation. For information, this tan normally be achieved by balancing in accordance with grade G 6,3 of ISO 1940. Table - Limits of Vibration severity for horizontal Pumps with multivane impellers” l min-1 I mmls I mmls I I n < 1800 1 23 4,5 I 1800 < n < 4500 4,5 7,l * The table is based on ISO 2372 and ISO 2373. Pumps with a special impeller, for example a Single channel impeller, may exceed the limits given in the table. In such a case the pump manufacturer should indicate this in his offer. See also annex B. 01 I 05 J 1 . 5 10 50 100 kW Pump power input at rated conditions Figure 1 - Prime mover output, percentage of pump power input at rated conditions SIST EN 25199:2000

4.4 Pressure-containing Parts ISO5199-1986 (EI Casing gaskets 4.4.1 Pressure-temperature rating The pressure limit (rated pressure) of the pump at the most severe operating conditions shall be clearly defined by the manufacturer. In no case may the rated pressure of’the pump (casing and cover including shaft seal housing and gland follower/end plate) exceed that of the pump flanges. The basic design pressure of the pump shall be at least a gauge pressure of 16 bar’) at 20 OC when made of cast iron, ductile iron, carbon steel or stainless steel. For materials the tensile requirements of which do not permit the 16 bar rating, the pressure-temperature rating shall be ad- justed according to the stress-temperature rating for the material and shall be clearly stated by the manufacturer. 4.4.2 Wall thickness Pressure casings including the shaft seal housing and gland end plate shall be of such thickness as will be suitable for containing pressure and limiting distortion under the rated pressure at operating temperature. The casing shall also be suitable for the pressure (see 6.3. 1) at ambient temperature. hydrostatic test Casing gaskets shall be of a design suitable for the rated operating conditions and for hydrostatic test conditions at am- bient temperature. The casing-cover gaskets shall be confined on the atmospheric side to prevent blow-out. Vapour venting A pump handling a liquid at a pressure near its vapour pressure or with a gas content shall be designed so that the vapours tan be properly vented. External bolting Bolts or studs that connect Patts of the pressure casing, including shaft seal housing, shall be at least 12 mm diameter (ISO metric thread). NOTE - If, due to space limitations, the use of 12 impractical, smaller bolts or studs may be used. mm bolts or The bolting selected (property class) shall be adequate for the rated pump pressure and for normal tightening procedures. If at some Point it is necessary to use a fastener of special quality, interchangeable fasteners for other joints shall be of the same quality. Hollow-head screws should be avoided if possible. Casing support for high temperature a corrosion For applications above 175 OC for example, due consideration should be given to supporting the centreline pump casing. The pressure-c ontaining Parts shall have allowance of 3 mm unless othe lrwise agreed 4.4.3 Materials 4.5 Branches connections (nozzles) and miscellaneous 4.4.4 Mechanical features Dismantling The pump shall preferably be designed in back pull-out con- struction in Order to permit removal of the impeller, shaft, shaft seal and bearing assembly without disturbing the inlet and outlet flange connections. Provision shall be made for easy Separation of components, for example jackscrews. Jackscrews When jackscrews are supplied as a means of separating contacting faces, the mating face shall be counterbored to receive the jackscrews where marring offers a possibility of a leaky joint or poor fit. Hollow-head screws should be avoided if possible. Jackets NOTE nozzle - are For the purposes synonymous. 4.5.1 Extent This section is concerned with all fluid connecti whether for Operation or maintenance. of this Standard the terms branch ons to the Pump 4.5.2 Inlet and outlet branches Inlet and outlet branches shall be flanged and designed for the same pressure unless the pump manufacturer states this is not so and emphasizes the requirement for pressure relief. 4.5.3 Vent, pressure-gauge and drain Venting of all areas of casing and seal chamber shall be pro- vided unless the pump is made self-venting by arrangement of branches. The connection of pressure gauges at the inlet and outlet branches shall be possible. The connections are not drilled. The enquiry and/or Order should state if such connections are re- quired to be drilled. 1) 1 bar = 0,l MPa 5 SIST EN 25199:2000

Provision shall be made Bor draining at the lowest Point, or Points, of the pump. The enquiry and/or Order should state if such connections are required to be drilled and to be fitted with a plug or other closures. 4.5.4 Closures The material for the closures (plugs, blank/blind flanges, etc.) shall be appropriate to the pumped liquid. Attention shall be paid to the suitability of material combinations for corrosion resistance and to minimize the risk of seizure or galling of screw threads. All openings exposed to the pumped liquid under pressure, including all shaft seal openings, shall be fitted with removable closures adequate to contain pressure. 4.5.5 Auxiliary pipe connections All auxiliary pipe connections shall be of adequate material, and thickness fo r the intended du tY (see also 4.1 3.5). size The inside pipe diameter shall always be at least 8 mm and the wall thickness 1 mm. Greater diameters and wall thicknesses are preferred. Auxiliary piping shall be provided with detachable joints to permit easy dismantling. The type of con- nections shall be subject to agreement. 4.5.6 Connection identification All connections shall be identified in the installation drawing in accordance with their duty and function. lt is recommended that this identification also be applied on the pump. 4.6 Externa and outlet) I f orces and moments on flanges ( inlet The method given in annex C shall be used for cast steel Pumps unless another method is agreed upon between the purchaser and the manufacturer. The pu rchaser shall calculate by the piping on the pump. the forces and momen ts exerted The manufacturer shall verify that these loads are permissible for the pump under consideration. If the loads are higher than permissible, the Solution of the Problem shall be agreed upon between purchaser and manufacturer. 4.7 Branch (nozzle) flanges The flange envelope shall be of a size to enable flanges to ISO 2684 and/or ISO 2228 to be provided. If the pump manu- facturer’s Standard Pattern entails a flange thickness and a diameter greater than that of the rating specified, the heavier flange may be supplied, but it shall be faced and drilled as specified. Good seating of the bolt head and/or nut on the back face of cast flanges shall be ensured. Bolt holes shall straddle the centreline. Cast or welded wear rings. impellers shall consist of one piece, excluding Impellers fabricated by other means are permissible in special cases, i.e. for small impeller outlet widths or of special materials. This, however, requires agreement with the purchaser. 4.8.2 Securing of impellers Impellers shall be secured against circu mferential movement when rotating in the intended direction. and axial 4.8.3 Axial adjustment If field adjustment of impeller axial clearance is required, ex- ternal means of adjustment shall be provided. If adjustment is achieved by axial movement sf the rotor, attention shall be paid to the possibly dangerous effect on the mechanical Seal(s) (see also 4.11.6). 4.9 Wear rings or equivalent components Wear rings should be fitted where appropriate. When wear rings are fitted they shall be renewable and securely locked to prevent rotation. 4.10 Running clearance When establishing running clearances between stationary and moving Parts, consideration shall be given to operating condi- tions and properties of the material used (used as hardness and gall resistance) for these Parts. Clearances shall be sized to pre- vent contact, and material combinations selected to minimize the risk of seizure and erosion. 4.11 Shafts and shaft sleeves 4.11.1 General Shafts shall be of ample size and stiffness to a) transmit the Prime mover rated power; b) minimize unsatisfactory packing or seal Performance; c) minimize wear and the risk of seizure; d) take due consideration of the static and dynamic radial loads, the critical Speed (sec 4.3.1) and the methods of starting and inertia loading involved. 4.11.2 Surface roughness The roughness of the shaft or sleeve at the stuffing box, mechanical seal and oil seal shall be not greater than 0,8 pm unless otherwise required for the Seal. Measurement of surface roughness shall be in accordance with ISO 3274. 4.8 Impellers 4.11.3 Shaft deflection 4.8.1 Impeller design Impellers of closed, semi-open according to the application. or open designs may be selected The calculated shaft deflection at the radial plane through the outer face of the stuffing box caused by radial loads exerted during Operation of the pump shall be consistent with the SIST EN 25199:2000

ISO51994986 EI proper functioning of mechanical Seals. In the case of ISO 2858 Pumps, this value shall not exceed 50 Pm as verified by pro- totype testing . 4.12 Bearings 4.12.1 General The following condition a) always applies; in addition condi- tion b) and/or condition c) may be required by agree- ment : Rolling bearings of Standard design are Other types of bearings may be used. normally employed. 4.12.2 Rolling bearing life a) within the allowable operating range of the pump; Rolling bearings shall be selected and rated in accordance with ISO 76 and ISO 281/1; the “basic rating life (BlO)” shall be at least 17 500 h when operating within the allowable operating range. The manufacturer shall specify the limits of the inlet pressure as a function of the pump head at maximum load to achieve a calculated bearing life of at least 17 500 h. b) at design load; Cl at maximum load. Support by pack s haft def lection. ing shall not be considered when d etermining 4.12.3 Bearing temperature 4.11.4 Diameter The pump manufacturer shall specify if cooling or heating is necessary to maintain bearing temperatures within the limits given by the bearing manufacturer. The diameter of the portions of the shaft or shaft sleeves in contact with shaft Seals shall be in accordance with ISO 3069 where practicable. 4.11.5 Shaft runout 4.12.4 Lubrication Manufacture and assembly of the shaft and sleeve, if fitted, should ensure that the runout (sec 3.16) at a radial plane through the outer face of the stuffing box is not greater than 50 Pm for nominal outside diameters smaller than 50 mm, not greater than 80 Pm for nominal outside diameters 50 to 100 mm, and not greater than 100 Pm for nominal outside diameters greater than 100 mm. The Operation instructions shall include information on the sf lubricant to be used and the frequency of application. tYPe 4.125 Bearing housing design In Order to prevent loss or contamination, gasketed or threaded connections shall not be used to separate cooling or heating fluids from lubricants. 4.11.6 Axial movement All openings in the bearing housing shall be designed to pre- vent the ingress of contaminants and the escape of the lubri- cant under normal operating conditions. Axial movement of the rotor permitted by the bearings shall adversely aff ect the pe rformance of the met hanical Seal. not In hazardous areas any device for sealing the beari shall be desig ned not to be a Source of ignition. ng housing 4.11.7 Securing and sealing of shaft sleeve When a shaft sleeve is fitted it shall be positively secured against circumferential and axial movement. The shaft sleeve shall be sealed against the impeller hub so that the shaft is not wetted. In case vided. of oil lubrication a plugged oil drain hole shall be pro- If the bearing housing also serves as an oil chamber, an oil level indicator or constant level oiler shall be used. The mark for the recommended oil level or the setting of the constant level oiler shall be permanent and visible and shall state whether the level is stationary or running. 4.11.8 Arrangment of shaft sleeve, if fitted On a pump arranged for packing, the end of the shaft sleeve assembly, if fitted, shall extend beyond the outer face of the packing gland follower. On a pump arranged for mechanical Seals, the shaft sleeve shall extend beyond the seal end plate. On Pumps employing an auxiliary seal or a throttle bushing, the shaft sleeve shall extend beyond the seal end plate. Leakage between the shaft and sleeve thus cannot be confused with leakage through box packing or mechanical seal faces. Where regreasable bearings are used, grease relief shall be pro- vided. 4.13 Shaft sealing 4.13.1 General For certain mechanical seal arrangements (for example, external mechanical Seals, double mechanical Seals) deviations may be offered. The pump natives : design shall permit the use of all the following alter- - soft packing (P), 4.11.9 Securing of thrust bearing - Single mechanical seal (SA 1 01, Snap rings in direct contact with the bearings shall not be used for transmitting the thrust from the shaft to the inner rate of the thrust bearing. Locknuts and lockwashers are preferred. double mechanical sea as shown in annex D. SIST EN 25199:2000

ISO 51994986 (El Quench arrangements (Q), which in certain necessary, are also shown in annex D. cases tan become Materials Appropriate material for the seal components shall be Chosen to withstand corrosion, erosion, temperature, thermal and mechanical stress, etc. For mechanical Seals, metallic Parts wetted by the pumped liquid shall have at least the same material quality as the pump casing (sec clause 5) as far as mechanical properties and corrosion resistance are concerned. The seal cavity dimensions shall be in accordance with ISO 3069 except where the operating conditions dictate other- wise. Arrangements shall be available for con tainin draining all liquid leakage from the seal area. collecting and Construction features 4.13.2 Stuffing box Provision shall be made for centring the seal end plate in rela- tion to the seal chamber bore. An inside or outside diameter register fit is an acceptable method of achieving this. Provision shall be made to allow fitting of a lantern ring. Outlet connections where required shall be specified by the pur- chaser or manufacturer. Ample space shall be provided for repacking without removing or dismantling any part other than gland components or guards. The gland component

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