ISO/TC 131 - Fluid power systems

This document specifies the mounting dimensions required for interchangeability of accessories for 16 MPa (160 bar) compact cylinders conforming to ISO 6020‑2. The accessories have been designed specifically for use with cylinders manufactured in accordance with ISO 6020‑2, but this does not limit their application[1]. This document covers the following accessories, identified in accordance with ISO 6099: — AP6 — rod eye spherical, female thread (see Figure 1 and Table 1); — AB5 — clevis bracket, spherical eye, in angle (see Figure 2 and Table 2); — AA6-L — pivot pin, spherical bearing, locking plate (see Figure 3 and Table 3); — AL6 — locking plate for pivot pin (see Figure 4 and Table 4); — AP2 — rod clevis, female thread (see Figure 5 and Table 5); — AP4 — rod eye plain, female thread (see Figure 6 and Table 6); — AB2 — eye bracket (see Figure 7 and Table 7); — AB4 — clevis bracket, straight (see Figure 8 and Table 8); — AA4-S — pivot pin, plain (split pins) (see Figure 9 and Table 9); — AA4-R — pivot pin, plain (rings) (see Figure 10 and Table 10); — AT4 — trunnion bracket (see Figure 11 and Table 11). These accessories are used on hydraulic cylinders for mechanically transmitting the cylinder force. The design of these accessories is based on the maximum forces resulting from the specified internal diameters of the cylinders and pressures according to ISO 3320 and ISO 2944. This document only applies to the dimensional criteria of products manufactured in conformity with this document; it does not apply to their functional characteristics. [1] 1 bar = 0,1 MPa = 105 Pa; 1 MPa = 1 N/mm2

This document specifies the mounting dimensions required for the interchangeability of accessories for 16 MPa (160 bar) medium series cylinders in accordance with ISO 6020‑1 and for 25 MPa (250 bar) series cylinders in accordance with ISO 6022. The accessories have been designed specifically for use with cylinders manufactured in accordance with ISO 6020‑1 and ISO 6022, but this does not limit their application[1]. This document covers the following accessories, identified in accordance with ISO 6099: — AP2 — rod clevis, female thread (see Figure 1 and Table 1); — AF3 — rod flange, circular (see Figure 2 and Table 2); — AB4 — clevis bracket, straight (see Figure 3 and Table 3); — AB3 — clevis bracket, in angle (see Figure 4 and Table 4); — AT4 — trunnion bracket (see Figure 5 and Table 5); — AA4-R — pivot pin, plain bearing (snap ring type) (see Figure 6 and Table 6); — AA4-S — pivot pin, plain bearing (split pin type) (see Figure 7 and Table 7); — AA6-R — pivot pin, spherical bearing (snap ring type) (see Figure 6 and Table 6); — AA6-S — pivot pin, spherical bearing (split pin type) (see Figure 7 and Table 7); — AP6 — rod eye spherical, female thread (see Figure 8 and Table 8); — AP4 — rod eye plain, female thread (see Figure 9 and Table 9). These accessories are used on hydraulic cylinders for mechanically transmitting the cylinder force. The design of these accessories is based on the maximum forces resulting from the specified internal diameters of the cylinders and pressures according to ISO 3320 and ISO 2944. This document applies only to the dimensional criteria of products manufactured in conformity with this document; it does not apply to their functional characteristics. [1] 1 bar = 0,1 MPa = 105 Pa; 1 MPa = 1 N/mm2.

This document specifies procedures for the following: a) primary particle-sizing calibration for particle sizes 1 µm(c) and larger, sensor resolution and counting performance of liquid automatic particle counters that are capable of analysing bottle samples; b) secondary particle-sizing calibration using suspensions verified with a primary calibrated APC; c) establishing acceptable operation and performance limits; d) verifying particle sensor performance using a test dust; e) determining coincidence and flow rate limits. This document is applicable for use with hydraulic fluids, aviation and diesel fuels, engine oil and other petroleum-based fluids. This document is not applicable to particle-sizing calibration using NIST SRM 2806b primary calibration suspensions.

This document describes the following: — a multi-pass filtration performance test with continuous contaminant injection for hydraulic fluid power filter elements; NOTE 1 For the background interlaboratory study used to verify the test methodology, see Annex D. — a procedure for determining the contaminant capacity, particulate removal and differential pressure characteristics; — a test currently applicable to hydraulic fluid power filter elements that exhibit an average filtration ratio greater than or equal to 75 for particle sizes ≥ 25 µm(c), and a final reservoir gravimetric level of less than 200 mg/L; NOTE 2 It is necessary to determine by validation the range of flow rates and the lower particle size limit that can be used in test facilities. — a test using ISO medium test dust (ISO MTD) contaminant and a test fluid in accordance with Annex A. This document is intended to provide a test procedure that yields reproducible test data for appraising the filtration performance of a hydraulic fluid power filter element without influence of electrostatic charge. This document applies to three test conditions: — test condition 1, with a base upstream gravimetric level of 3 mg/L; — test condition 2, with a base upstream gravimetric level of 10 mg/L; — test condition 3, with a base upstream gravimetric level of 15 mg/L.

This document specifies which characteristics of electro-pneumatic continuous pressure control valves are to be included in the supplier's literature. In accordance with ISO 5598, these control valves include: — electrically modulated pneumatic proportional pressure valves, — proportional pressure control valves without electronic pressure feedback, and — proportional pressure control valves with electronic pressure feedback. This document is limited to the characterization of components with an exhaust port to the atmosphere. NOTE 1 The characteristics of non-electrically modulated pneumatic pressure control valves are specified in ISO 6953‑1. NOTE 2 The characteristics of electro-pneumatic continuous flow control valves are specified in ISO 10041‑1.

This document specifies the test procedures and a method of presenting results concerning the parameters which define the main characteristics to be included in the supplier's literature of the electro-pneumatic continuous pressure control valves, conforming to ISO 10094-1. The purpose of this document is: — to facilitate comparison by standardizing the test methods and the presentation of the test results, and — to assist in the proper application of these components in compressed air systems. The specified tests are intended to allow comparison between the different types of continuous pressure control valves; these are not production tests to be carried out on each manufactured product. The tests described in this document are for components with an exhaust port vented to the atmosphere. NOTE 1 The tests related to non-electrically modulated pneumatic continuous pressure control valves are specified in ISO 6953-2. NOTE 2 The tests related to electro-pneumatic continuous flow control valves are specified in ISO 10041-2. NOTE 3 ISO 6953-3 provides an alternate dynamic test method for flow-rate characteristics using an isothermal tank instead of a flow meter. However, this method measures only the decreasing flow rate part of the hysteresis curve of the forward flow and relief flow characteristics.

This document specifies methods for determining the performance and the efficiency of water-hydraulic positive displacement pumps having continuously rotating shafts. This document provides test equipment, a test procedure under steady-state conditions and the presentation of test results.

This document specifies the general and dimensional requirements for the design and performance of flange hose fittings, made of carbon steel, for nominal hose inside diameters of 12,5 mm to 76 mm inclusive, in accordance with ISO 4397, for use with ports and clamps in accordance with ISO 6162‑1 and ISO 6162‑2. Note 1 Materials other than carbon steel can be supplied as agreed between the manufacturer and user. Note 2 For hose fittings used in hydraulic and pneumatic braking systems on road vehicles (as defined in the scope of ISO/TC 22/SC 2, Road vehicles), see ISO 4038, ISO 4039‑1 and ISO 4039‑2. These hose fittings are for use in hydraulic fluid power systems with a hose that meets the requirements of the respective hose standards and in general applications with suitable hoses.

This document specifies a method for the evaluation of the buckling load which: a) takes into account a geometric model of the hydraulic cylinder, meaning it does not treat the hydraulic cylinder as an equivalent column, b) can be used for all types of cylinder mounting and rod end connection specified in Table 2, c) includes a factor of safety, k, to be set by the person performing the calculations and reported with the results of the calculations, d) takes into account possible off-axis loading, e) takes into account the weight of the hydraulic cylinder, meaning it does not neglect all transverse loads applied on the hydraulic cylinder, f) can be implemented as a simple computer program, and g) considers the cylinder fully extended. The method specified is based on the elastic buckling theory and is applicable to single and double acting cylinders that conform to ISO 6020 (all parts), ISO 6022 and ISO 10762. If necessary, finite element analyses can be used to verify as well as to determine the buckling load. The method is not developed for thin-walled cylinders, double-rods or plunger cylinders. The method is not developed for internal (rod) buckling. The friction of spherical bearings is not taken into account. NOTE This method is based mainly on original work by Fred Hoblit[2]. This method has been established in reference to the standard NFPA/T3.6.37[1].

This document specifies dimensions and tolerances of housings for wiper-rings used in reciprocating rod applications for fluid power cylinders. The range of rod diameters is from 4 mm to 450 mm.

This document specifies: a) A multi-pass filtration performance test under cyclic flow conditions with continuous contaminant injection for hydraulic fluid power filter elements. b) A procedure for determining the contaminant capacity, particulate removal and differential pressure characteristics. c) A test currently applicable to hydraulic fluid power filter elements that exhibit an average filtration ratio greater than or equal to 75 for particle sizes ≤25 µm(c), and a final test system reservoir gravimetric level of less than 200 mg/L. It is necessary to determine by validation the range of flow rates and the lower particle size limit that can be used in test facilities. d) A test using ISO12103-1 A3 medium test dust contaminant and a test fluid. This document provides a test procedure that yields reproducible test data for appraising the filtration performance of a hydraulic fluid power filter element without influence of electrostatic charge. This document is applicable to three test conditions: 1) Base upstream gravimetric level of 3 mg/L. 2) Base upstream gravimetric level of 10 mg/L. 3) Base upstream gravimetric level of 15 mg/L.

This document establishes methods for: — validating equipment used to prepare secondary calibration suspensions for automatic particle counters; — performing online secondary calibration of automatic particle counters; — matching two or more online particle counters, i.e. to count the same number of particles at a given size by two APCs associated online; — validating online particle counting systems with and without online dilution as used, for example, to measure the filtration efficiency of a hydraulic filter as described in the multi-pass filter test in ISO 16889.

This document specifies uniform methods for the testing and performance evaluation of metallic tube connections, stud ends for ports and flange connections for use in hydraulic fluid power applications. This document does not apply to the testing of hydraulic quick-action couplings, which is covered by ISO 18869. Tests outlined in this document are independent of each other and document the method to follow for each test. See the appropriate component International Standard for indications of which tests to conduct and for performance criteria. For qualification of the connector, the minimum number of samples specified in this document is tested, unless otherwise specified in the relevant connector standard or as agreed upon by the manufacturer and the user.

This document specifies the dimensions and associated tolerances for a series of hydraulic cylinder piston seal housings to accommodate elastomer-energized, plastic-faced seals used in reciprocating applications. This document does not stipulate details of seal design, since the manner of construction of seals varies with each manufacturer. The design and material of the seals, and any associated anti-extrusion components, are determined by conditions such as temperature and pressure. This document only applies to the dimensional characteristics of products manufactured in accordance with this document. It does not apply to their functional characteristics.

This document specifies the dimensions and associated tolerances for a series of hydraulic cylinder rod seal housings to accommodate elastomer-energized, plastic-faced seals used in reciprocating applications. This document does not stipulate details of seal design, since the manner of construction of seals varies with each manufacturer. The design and material of the seals, and any incorporated anti-extrusion components, are determined by conditions such as temperature and pressure. This document only applies to the dimensional characteristics of products manufactured in accordance with this document. It does not apply to their functional characteristics.

This document describes a recommended method for the interpolation of particle concentration and filter Beta Ratio data when results are not otherwise available at the desired particle sizes. It is applicable for assessing conformance with existing fluid cleanliness and filter Beta Ratio specifications whereby the specification and actual test results are provided in different units of particle size, for example, the specification is in µm(c), but the particle counts or Beta Ratio data are in units of µm(b). This document is also applicable when particle sizes in specifications and available data use the same units of particle size, but do not correspond to exactly the same sizes, for example, when particle counts at 20 µm(c) are specified, but data was collected at 21 µm(c). This method allows interpolation to intermediate particle sizes within the range of existing data and does not permit extrapolation to particle sizes outside the range of available data.

This document provides the background for ISO 11171:2020 and the use of µm(c) as the sole means of reporting particle size for APC particle count data. It also summarizes results of the international inter-laboratory study (ILS) of its reproducibility using SRM 2806d candidate material and suspensions of Reference Material (RM) 8632a. The ILS results provided the basis for certification of SRM 2806d used for primary calibration of APC. Their implications with respect to particle counting and filter testing are discussed in this document.

This document specifies the code to be used in defining the quantity of solid particles in the fluid used in a given hydraulic fluid power system.

This document specifies sizes and nominal working pressures for seamless and welded precision steel tubes with outside diameters in accordance with ISO 4397, and wall thicknesses and mechanical properties in accordance with ISO 3305. The nominal working pressures included in this document reflect a design factor ratio of 4 to 1 applied to the calculated burst pressures.

This document specifies acceptance and function tests for hydraulic fluid power cylinders.

This document establishes procedures for measuring the average steady-state pressure in a hydraulic fluid power conduit. It is applicable to the measurement of average steady-state pressure in closed conduits with inside diameters greater than 3 mm, transmitting hydraulic fluid power with average fluid velocities less than 25 m/s and average steady-state static pressures less than 70 MPa. It is not applicable to sensors which are flush mounted with, or an integral part of, the closed fluid conduit wall. It provides the formulae for estimating the total uncertainty in a given pressure measurement.

This document establishes general principles for the measurement of performance parameters under static or steady-state conditions. This document provides guidance on the sources and magnitudes of uncertainty to be expected in the calibration of and measurements using hydraulic fluid power components. It describes practical requirements for assessing the capability of the measuring system, and hence the level of uncertainty of the measurement system, or for assisting in developing a system which will meet a prescribed level of uncertainty.

This document describes test methods for determining the performance characteristics of electrically modulated hydraulic pressure control valves.

This document gives advice on how to conceive hydraulic systems that can be operated with increased energy efficiency while maintaining the intended functionality of the machine.

This document specifies the minimum requirements of unused fire-resistant and less flammable hydraulic fluids for hydrostatic and hydrodynamic systems in general industrial applications. It is not intended for use in aerospace or power-generation applications, where different requirements apply. It provides guidance for suppliers and end users of these less hazardous fluids and to the manufacturers of hydraulic equipment in which they are used. Of the categories covered by ISO 6743-4, which classifies the different types of fluids used in hydraulic applications, only the following are detailed in this document: HFAE, HFAS, HFB, HFC, HFDR and HFDU. Types HFAE, HFAS, HFB, HFC and HFDR are "fire-resistant" fluids as defined by ISO 5598. Most HFDU fluids, while displaying an improvement in combustion behaviour over mineral oil, fall outside this definition and are more appropriately considered as "less flammable" fluids.

This document specifies the general requirements and test methods for the design and performance of push-in connectors for use with thermoplastic tubes with outside diameters (OD) from 3 mm to 16 mm including dimensions in inches. This document is intended to establish uniform methods of testing complete push-in connector assemblies as used in pneumatic fluid power applications. It is not applicable to air braking systems.

This document specifies two methods of measuring the level of acoustic pressure at the outlet of an exhaust silencer: — the first method, called "steady-state mode", is intended to evaluate the noise level under steady state flow, i.e. constant upstream pressure (steady-state test according to ISO 6358‑1); and — the second method, called "discharge", is intended to measure the noise level during the decrease of the pneumatic pressure (discharge test according to ISO 6358‑2). This document is applicable to pneumatic exhaust silencers and devices designed to reduce the sound produced by discharges of compressed air, entering in the scope of application of ISO 6358‑1 and ISO 6358‑2.

This document specifies methods for determining, under steady-state conditions, the pressure differential caused by the flow through any given path in a hydraulic fluid power valve. Requirements for test installations, procedures and presentation of results are specified.

This document explains the use of the two acceptable methods of reporting particle size, µm(c) and µm(b), that are defined in ISO 11171:2016. It also explains the reasons for the existence of two alternative size reporting methods and its implications with respect to particle count and filter Beta Ratio data.

This document specifies a discharge test and a charge test as alternative methods for testing pneumatic fluid power components that use compressible fluids, i.e. gases, and that have internal flow passages that can be either fixed or variable in size to determine their flow-rate characteristics. However, this document does not apply to components whose flow coefficient is unstable during use, i.e. components that exhibit remarkable hysteretic behaviour (because they can contain flexible parts that deform under the flow) or that have an internal feedback phenomenon (such as regulators), or components that have a cracking pressure such as non-return (check) valves and quick-exhaust valves. In addition, it does not apply to components that exchange energy with the fluid during flow-rate measurement, e.g. cylinders, accumulators. NOTE This document does not provide a method to determine if a component has hysteretic behaviour; ISO 6358‑1 does provide such a method.

This document specifies a method for the determination of the particulate contamination level using the light extinction technique (also known as light blockage or light obscuration) either online or offline in containers. It also defines procedures for calibrating the instruments and verifying their correct operation both in the laboratory and in service. In general, the techniques described in this document are suitable for monitoring: — the general cleanliness level in hydraulic systems, — the progress in flushing operations, and — support equipment and test rigs. The use of this method is applicable to single-phase liquid systems only.

This document specifies the types and selection of hydraulic ports of gas-loaded accumulators with separator, which are used in hydraulic fluid power systems.

This document defines an identification code for hydraulic valve mounting surfaces and for hydraulic cartridge valve cavities that are defined in other International Standards (see Bibliography). This document is not applicable to mounting surfaces and cartridge valve cavities that do not conform to these International Standards. This document does not require that the hardware be marked with the identification code.

This document specifies a selection of nominal pressures for hydraulic and pneumatic fluid power connectors and associated components. NOTE There can be a need to provide a selection of nominal pressures for connectors and associated components used in applications where the external pressure on the components is greater than the internal pressure, for example vacuum service. A document that deals with this subject will be established in due course.

This document specifies methods for determining the performance and efficiency of hydraulic fluid power positive displacement pumps, motors and integral transmissions. It applies to components having continuously rotating shafts. This document specifies the requirements for test installations, test procedures under steady-state conditions and the presentation of test results.

This document specifies dimensions for metric ports for use with the adjustable and non-adjustable stud ends as described in ISO 6149‑2 and ISO 6149‑3. Ports in accordance with this document can be used at working pressures up to 63 MPa [630 bar[1]] for non-adjustable stud ends and 40 MPa (400 bar) for adjustable stud ends. The permissible working pressure depends upon port size, materials, design, working conditions, application, etc. See ISO 6149‑2 and ISO 6149‑3 for pressure ratings. NOTE The Introduction of this document gives recommendations for ports and stud ends to be used for new designs in hydraulic fluid power applications. [1] 1 bar = 0,1 MPa = 105 Pa; 1 MPa = 1 N/mm2.

This document specifies the dimensions and tolerances so as to ensure the interchangeability of pneumatic quick-action coupling plugs. It also provides specifications and application guidelines, and specifies the tests to be applied to the plugs together with sockets. NOTE 1 The construction and dimensions of sockets are left to the manufacturer's option. This document applies to cylindrical quick-action couplings for maximum working pressures of 1 MPa, 1,6 MPa and 2,5 MPa (10 bar, 16 bar and 25 bar) for use in pneumatic fluid power systems. NOTE 2 Quick-action couplings with shut-off valves for equipment for welding, cutting and related processes are covered by ISO 7289. This document applies only to the dimensional criteria of products manufactured in accordance with this document. It does not apply to their functional characteristics.

This document specifies tests, procedures and a method of presenting the results concerning the parameters that define the main characteristics to be included in the supplier's literature of lubricators conforming to ISO 6301‑1. This document can be applied: — to facilitate the comparison of lubricators by standardizing test methods and presentation of test data; — to assist in the proper application of lubricators in compressed-air systems. The tests specified are intended to allow comparison between the different types of lubricators; they are not production tests to be carried out on each lubricator manufactured.

This document specifies a reference dictionary of standardized product properties for the area of pneumatic fluid power on the basis of ISO 18582-1. The properties are determined on the basis of standardized attributes.

This document gives advice on how to conceive pneumatic systems, which under consideration of functionality and economic efficiency, can be operated with increased energy efficiency. It does not focus on compressed air generation and distribution.

This document specifies a bubble-point test method applicable to filter elements used in hydraulic fluid power systems. It can be used both to verify the fabrication integrity of a filter element (by checking the absence of bubbles) and to permit the localization of the largest pore of the filter element by determining the first bubble point. NOTE Verification of fabrication integrity is used to define the acceptability of the filter elements for further use or testing. The first bubble point is established through continuation of the fabrication integrity test. It is under no circumstances a functional characteristic of a filter element; in particular, it cannot be used to estimate filtration rating, efficiency or retention capacity and is intended to be used for information only. This document specifies a method to normalise fabrication integrity and bubble point data to a standard value of surface tension when test fluids other than 2-propanol are used.

This document establishes a convention for the identification of mounting dimensions and types used in the mounting of fluid power cylinders. It specifies a code for identifying cylinder mounting, envelope, accessory and connector dimensions, and for cylinder mounting and accessory types. This document does not represent a standard list of all fluid power cylinder mounting and accessory types.

This document specifies the mounting dimensions required for interchangeability of rod-end clevises of pneumatic cylinders. The rod-end clevises have been designed specifically for use with 1 000 kPa [10 bar1] series cylinders manufactured in accordance with ISO 6432 and ISO 15552, but this does not limit their application. The clevises are used on piston rods of pneumatic cylinders for mechanically transmitting the cylinder force. The design of the clevises is based on the maximum forces resulting from the specified internal diameter of the cylinders and pressure according to ISO 6432, ISO 15552 and ISO 21287. 1 1 bar = 100 kPa = 105 Pa; 1 Pa = 1 N/m2.

This document specifies the mounting dimensions required for interchangeability of rod-end spherical eyes of pneumatic cylinders. The rod-end spherical eyes have been designed specifically for use with 1 000 kPa [10 bar[1]] series cylinders manufactured in accordance with ISO 6432 and ISO 15552, but this does not limit their application. The spherical bearing end eyes are used on piston rods of pneumatic cylinders for mechanically transmitting the cylinder force under oscillatory rotational and tilting movements. The design of the rod-end spherical eyes is based on the maximum forces resulting from the specified internal diameter of the cylinders and pressure according to ISO 6432, ISO 15552 and ISO 21287. [1] 1 bar = 100 kPa = 105 Pa; 1 Pa = 1 N/m2.