定价： 843元 / 折扣价： 717 元 加购物车

5.1 This test method covers the measurement of thermal properties for engine coolants (aqueous or non-aqueous) and related fluids.5.2 With each single measurement, the thermal conductivity (λ) and thermal diffusivity (α) are measured directly, and volumetric heat capacity (VHC) is determined by the relationship:5.3 The test method is transient and requires only a small amount of specimen and a short duration of time (0.8 s) to run a measurement. These attributes minimize heat convection in the liquid.5.4 The brief application of current to the sensor wire adds very little heat to the test specimen and ten repetitive tests may be applied at 30 s intervals without causing any significant convection or temperature drift.1.1 This test method covers the use of a transient hot wire liquid thermal conductivity method and associated equipment (the System) for the determination of thermal conductivity, thermal diffusivity and volumetric heat capacity of aqueous engine coolants, non-aqueous engine coolants, and related fluids. The System is intended for use in a laboratory.1.2 The System directly measures thermal conductivity and thermal diffusivity without the requirement to input any additional properties. Volumetric heat capacity is calculated by dividing the thermal conductivity by the thermal diffusivity of the sample measured.1.3 This test method can be applied to any aqueous or non-aqueous engine coolants or related fluid with thermal conductivity in the range of 0.1 to 1.0 W/m∙K.1.4 This test method excludes fluids that react with platinum.1.5 The range of temperatures applicable to this test method is –20 to 100 °C.1.6 This test method requires a sample of approximately 40 mL.1.7 The System may be used without external pressurization for any fluid having a vapor pressure of 33.8 kPa (4.9 psia) or less at the test temperature.1.8 For a fluid having a vapor pressure greater than 33.8 kPa (4.9 psia) at the test temperature, external pressurization is required (see Annex A2).1.9 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.1.10 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.11 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车

定价： 590元 / 折扣价： 502 元 加购物车

5.1 The solar reflectance of a building envelope surface affects surface temperature and near-surface ambient air temperature. Surfaces with low solar reflectance absorb a high fraction of the incoming solar energy. Sunlight absorbed by a roof or by other building envelope surfaces can be conducted into the building, increasing cooling load and decreasing heating load in a conditioned building, or raising indoor temperature in an unconditioned building. It can also warm the outside air by convection. Determination of solar reflectance can help designers and consumers choose appropriate materials for their buildings and communities.5.1.1 The solar reflectance of a new building envelope surface often changes within one to two years through deposition and retention of soot and dust; microbiological growth; exposure to sunlight, precipitation, and dew; and other processes of soiling and weathering. For example, light-colored “cool” envelope surfaces with high initial reflectance can experience substantial reflectance loss as they are covered with dark soiling agents. Current product rating programs require roofing manufacturers to report values of solar reflectance and thermal emittance measured after three years of natural exposure (2, 3). A rapid laboratory process for soiling and weathering that simulates the three-year-aged radiative properties of roof and other building envelope surface materials expedites the development, testing, and introduction to market of such products.5.2 Thermal emittance describes the efficiency with which a surface exchanges thermal radiation with its environment. High thermal emittance enhances the ability of a surface to stay cool in the sun. The thermal emittance of a bare metal surface is initially low, and often increases as it is soiled or oxidized (4). The thermal emittance of a typical non-metal surface is initially high, and remains high after soiling (5).5.3 This practice allows measurement of the solar reflectance and thermal emittance of a roofing specimen after the application of the simulated field exposure.5.4 This practice is intended to be referenced by another standard, such as ANSI/CRRC S100, that specifies practices for specimen selection and methods for radiative measurement.1.1 Practice D7897 applies to simulation of the effects of field exposure on the solar reflectance and thermal emittance of roof surface materials including but not limited to field-applied coatings, factory-applied coatings, single-ply membranes, modified bitumen products, shingles, tiles, and metal products. The solar reflectance and thermal emittance of roof surfacing materials can be changed by exposure to the outdoor environment. These changes are caused by three factors: deposition and retention of airborne pollutants, microbiological growth, and changes in physical or chemical properties. This practice applies to simulation of changes in solar reflectance and thermal emittance induced by deposition and retention of airborne pollutants and, to a limited extent, changes caused by microbiological growth.1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 646元 / 折扣价： 550 元 加购物车

定价： 843元 / 折扣价： 717 元 加购物车

4.1 When choosing a thermal insulation product or combination of products, physical, chemical and mechanical properties and the significance of those properties should be considered. ASTM test methods are usually performed under laboratory conditions and may not accurately represent field conditions depending on process temperature, environment, and operating conditions. Performance results obtained using ASTM test methods can be used to determine compliance of materials to specifications but do not necessarily predict installed performance. Values stated in the ASTM material standards are those that apply to the majority of materials and not to any specific product; other tested values may exist for specific material applications.4.2 Design of thermal insulation systems requires the understanding of process requirements, temperature control, heat loss criteria, control of thermal shock, and mechanical forces on insulation generated by thermal gradients and wind environmental conditions. Sometimes, the mechanical design of piping and equipment needs to be modified to support insulation adequately and provide for insulation weatherproofing. Process requirements may dictate the control of critical temperature to prevent freezing, maintain viscosity, or minimize internal corrosion. When handling heat transfer fluids such as ethylene oxide or hot oils, the selection of insulation materials and the insulation system design becomes critical. whereby If these fluids are absorb in insulation materials, the fluid flash point could be below the fluid operating temperature. Specified heat gain or heat loss and acceptable surface temperatures could also dictate thermal design of insulation systems. Environmental corrosivity, high wind, and extreme ambient temperatures affect the selection of weatherproofing and methods of its securement. A combination of these factors plays a significant role in the selection of insulation materials and application methods to provide long-lasting trouble-free service.4.3 Application methods are generally defined by the purchaser's specifications. However, some specialty insulation systems, such as prefabricated insulation panels for ductwork, precipitators, and tanks, will also have supplemental installation requirements specified by the insulation system manufacturer. defined by the specification of the manufacturer.4.4 In any application of thermal insulation, the insulation requires protection of some type, be it protection from the elements such as rain, snow, sleet, wind, ultraviolet solar radiation, protection from external forces that can cause mechanical damage, vapor passage, fire, chemical attack, or any combination of these. This protection can be provided in by metal, plastic, coated or laminated composites or both, mastic coatings, or a combination of the above depending upon the application, service, and economic requirements. Considering the enormous overall cost of a new facility, and comparing the initial cost of the insulated portion as a small percentage of that overall cost with the substantially increased operating cost as a result of inefficient insulation protection, it is common sense to provide only the best insulation system available and the best protection for that long-term investment consistent with the appropriate design and economic requirements. Usually a new facility is very expensive and the initial cost of the insulation portion is a small percentage of that overall cost. However, increased operating costs can result from inefficient protection.4.5 Bid invitations should contain information necessary to determine how guarantees of materials and application will be resolved.4.6 It is recommended that the purchaser provide a quality assurance program that defines the inspection of all materials, material safety data sheets (MSDS), and specific application procedures before and during progress of the insulation work.4.7 During contract negotiations, the contractor and purchaser should discuss and agree to the procedures to be adopted for suitable periodic inspection and maintenance of the insulation systems to ensure that the initial performance of the material will be maintained. And, where applicable, they should agree to the methods of repair and replacement to be adopted in case damage occurs during service or overhaul.1.1 This guide covers information on selection of insulation materials, systems design, application methods, protective coverings, guarantees, inspection, testing, and maintenance of thermal insulation primarily for industrial applications in a temperature range of –320 to 1200°F (–195.5 to 648.8°C).1.2 This guide is intended to provide practical guidelines, by applying acceptable current practice while indicating the basic principles by which new materials can be assessed and adapted for use under widely differing conditions. Design engineers, the general contractors, the fabricators, and the insulation contractors will find this guide helpful.1.3 Although some insulation system designs can serve as fire protection, this guide does not address the criteria specific to that need. API 521 Guide for Pressure-Relieving and Depressuring Systems is recommended as a reference for fire protection. This guide will however address the fire properties of insulation materials.1.4 This guide is not intended for commercial, architectural, acoustical, marine, vehicle transport, or military use.1.5 This guide does not address insulation system design for refractory linings or cold boxes whereby these are typically package units and of a proprietary insulation design.1.6 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 843元 / 折扣价： 717 元 加购物车

定价： 515元 / 折扣价： 438 元 加购物车

定价： 590元 / 折扣价： 502 元 加购物车

定价： 515元 / 折扣价： 438 元 加购物车

定价： 590元 / 折扣价： 502 元 加购物车

1.1 This practice establishes methods for thermal vacuum bakeout of spacecraft and spacecraft components.1.2 This practice defines the equipment, environment, and certification criteria for each type of bakeout.1.3 The methods defined in this practice are intended to reduce component outgassing rates to levels necessary to meet mission performance requirements of the contamination sensitive hardware. Times, temperatures, and configurations contained in this document have been found to provide satisfactory results. Experienced operators may find that other, similar times, temperatures and configurations have provided satisfactory results. If deviations from these criteria are deemed appropriate, they should be detailed in the bakeout report.1.4 This practice describes three bakeout methods: Method A, using prescribed time and pressure criteria; Method B, using prescribed QCM stabilization rate criteria; and Method C, which measures the QCM deposition rate.1.5 Determination of the acceptable molecular outgassing, selection of the bakeout method, and determination of the specific test completion criteria are the responsibility of the user organization.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车

定价： 515元 / 折扣价： 438 元 加购物车

定价： 515元 / 折扣价： 438 元 加购物车

定价： 515元 / 折扣价： 438 元 加购物车

定价： 590元 / 折扣价： 502 元 加购物车