标准编号:	GB/T 12242-2021
中文名称:	压力释放装置 性能试验方法
英文名称:	Pressure relief devices—Performance test code
中标分类:	J16    阀门
行业分类:	GB    国家标准
ICS分类:	13.240 13.240    超压防护 13.240
发布机构:	国家市场监督管理总局 国家标准化管理委员会
发布日期:	2021-03-09
实施日期:	2021-10-1
标准状态:	valid
替代旧标准:	GB/T 12242-2005 压力释放装置 性能试验规范
翻译语言:	英文
文件格式:	PDF
中文字符数:	58000 字
翻译价格(元):	4060.0
交付时间:	付款后 1 个工作日

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative. This standard is developed in accordance with the rules given in GB/T 1.1-2020 Directives for standardization — Part 1: Rules for the structure and drafting of standardizing documents. This document replaces GB/T 12242-2005 Performance test code — Pressure relief devices. In addition to a number of editorial changes, the following technical changes have been made with respect to GB/T 12242-2005: a) Terms and definitions of field testing and opening pressure have been added, and the term and definition of reclosing pressure-relieving device have been changed (see Clause 3 herein; Clause 3 of 2005 Edition); b) The diameter requirements for the test vessel for the operational characteristics and flow capacity testing have been deleted (4.2 in 2005 Edition); c) The requirements for the installation of orifice plates and measurement of flow have been added [see 5.2.4.3f)]; h) The requirements of “procedure” in test procedure have been modified (see 5.4 herein; 5.4 of 2005 Edition); e) The resistance test requirements of different non-reclosing pressure relief devices have been added (see 5.4.8.5); f) The test requirements for measuring the set pressure of non-reclosing pressure relief device with incompressible fluid have been added (see 5.4.9). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this standard shall not be held responsible for identifying any or all such patent rights. This standard was proposed by the China Machinery Industry Federation. This standard is under the jurisdiction of the National Technical Committee on Pressure Relief Devices of Standardization Administration of China (SAC/TC 503). This standard was first issued in 1989 (GB/T 12242-1989). Its first revision was issued in 2005, and this is the second revision. Pressure relief devices — Performance test code 1 Scope This code specifies the test methods of the operation performance test (including mechanical characteristics), flow capacity and resistance coefficient of pressure relief devices. This code is applicable to the situation where the test procedure has various inlet and outlet conditions and the test medium is steam, gas (air) or liquid (water) with known physical properties; the pressure relief devices include reclosing pressure-relieving devices and non-reclosing pressure relief devices, as follows: a) safety valve; b) rupture disk device; c) breaking/shear pin device; d) fusible plug device. Other pressure relief devices may be tested provided all parties to the test agree to accept the provisions of this code. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 2624.1 Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full — Part 1: General principles and requirements GB/T 2624.2 Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full — Part 2: Orifice plates GB/T 12241 Safety valves — General requirements GB/T 12243 Spring loaded safety valves   3 Terms and definitions For the purposes of this document, the terms and definitions given in GB/T 12241 and the following apply. 3.1 General terms 3.1.1 pressure relief device device designed to prevent internal medium pressure from rising above a predetermined maximum pressure in a pressure vessel exposed to emergency or abnormal conditions 3.1.2 pressure relief valve; PRV valve designed to prevent internal medium pressure from rising above a predetermined maximum pressure in a pressure vessel exposed to emergency or abnormal conditions 3.1.3 field testing testing of a pressure relief device installed on a system to determine some or all of its operating characteristics 3.1.4 in-service testing testing of a pressure relief device installed on and protecting a system, using system pressure or an external pressure source, with or without an auxiliary lift device to determine some or all of its operating characteristics 3.1.5 flow capacity testing testing of a pressure relief device to determine its operating characteristics, including measured relieving capacity 3.1.6 bench testing testing of a pressurization system to determine the set pressure and closure member tightness of pressure relief device 3.2 Types of pressure relief devices 3.2.1 reclosing pressure-relieving device pressure relief device designed to actuate on inlet static pressure and reclose after normal conditions have been restored Note: There are direct spring-loaded, pilot-operated and power-actuated types in the structural type. 3.2.2 non-reclosing pressure relief device pressure relief device designed to actuate and remain open after operation. A manual resetting means may be provided. Note: Non-reclosing pressure relief devices include rupture disk device, breaking pin device, buckling pin device, shear pin device and fusible plug device. 3.2.2.1 rupture disk device non-reclosing pressure relief device actuated by the static differential pressure between the inlet and outlet of the device and designed to function by the bursting of a pressure containing disk 3.3 Dimensional characteristics of pressure relief devices 3.3.1 discharge area minimum sectional area of fluid flow path during valve discharge 3.3.2 nozzle area minimum cross-sectional area of flow between valve inlet end and closure member sealing surface 3.3.3 nozzle diameter diameter corresponding to the nozzle area 3.3.4 curtain area area of the cylindrical or conical discharge opening between the seating surfaces created by the lift of the disk above the seat Note: See Figure 1 for curtain area.   Keys: L——lift; D——smallest diameter at which seat touches disk; DB——other diameter of frustum of cone; B——slant height of frustum of cone; θ——seat angle; R——radius. Note: Curtain area is the discharge area unless the disk attains sufficient lift for the nozzle area to become the smallest sectional area of the passage. Figure 1 Typical curtain areas of safety valves 3.3.5 lift actual travel of the disk away from closed position   3.3.6 rated lift design lift at which a valve attains its rated relieving capacity 3.3.7 seat angle angle between the axis of a valve and the seating surface Note: A flat-seated valve has a seat angle of 90°. 3.4 Dimensional characteristics of non-reclosing pressure relief devices 3.4.1 net flow area area that determines the flow after a non-reclosing pressure relief device has operated Note: The (minimum) net flow area of a rupture disk is the calculated net area after a complete burst of the disk, with appropriate allowance for any structural members that may reduce the net flow area through the rupture disk device. 3.5 Operational and flow capacity characteristics of pressure relief devices 3.5.1 set pressure value of increasing inlet static pressure at which a pressure relief device displays one of the operational characteristics as defined under opening pressure, popping pressure, start-to-leak pressure, burst pressure, or breaking pressure (The applicable operating characteristic for a specific device design is specified by the device manufacturer.) 3.5.2 over pressure pressure increase over the set pressure of a pressure relief valve, under which the lift of safety valve reaches the value specified by the manufacturer Note: over pressure is usually expressed as a percentage of set pressure. 3.5.3 re-seating pressure value of decreasing inlet static pressure at which the valve disk reestablishes contact with the seat or at which lift becomes zero 3.5.4 blowdown difference between set pressure and re-seating pressure Note: Blowdown is expressed as a percentage of set pressure or in pressure units.   3.5.5 relieving pressure set pressure plus over pressure 3.5.6 flow-rating pressure inlet stagnation pressure at which the relieving capacity of a pressure relief device is measured 3.5.7 back pressure static pressure existing at the outlet of a pressure relief device due to pressure in the discharge system 3.5.8 built-up back pressure pressure existing at the outlet of a pressure relief device caused by the flow through that particular device into a discharge system 3.5.9 superimposed back pressure the static pressure existing at the outlet of a pressure relief device at the time the device is required to operate Note: It is the result of pressure in the discharge system from other sources. 3.5.10 burst pressure value of inlet static pressure at which a rupture disk device functions 3.5.11 specified burst pressure of a rupture disk device value of increasing inlet static pressure, at a specified temperature, at which a rupture disk is designed to function 3.5.12 breaking pressure value of inlet static pressure at which a breaking pin, buckling pin device or shear pin device functions 3.5.13 secondary pressure pressure existing in the passage between the actual discharge area and the valve outlet in a pressure relief valve 3.5.14 simmer pressure audible or visible escape of fluid between the seat and disk at an inlet static pressure below the set pressure of pressure relief valve and at no measurable capacity Note: It applies to safety relief valves on compressible-fluid service. 3.5.15 theoretical relieving (discharge) capacity calculated capacity of a theoretically perfect nozzle having a minimum cross-sectional flow area equal to the nozzle area of a pressure relief valve or net flow area of a non-reclosing pressure relief device Note: It is expressed in gravimetric or volumetric units. 3.5.16 measured relieving (discharge) capacity relieving capacity of a pressure relief device measured at the flow-rating pressure Note: It is expressed in gravimetric or volumetric units. 3.5.17 rated relieving capacity; certified discharge capacity portion of the measured relieving capacity permitted by the applicable code or regulation to be used as a basis for the application of a pressure relief device 3.5.18 equivalent calculated capacity calculated capacity of a pressure relief device when the service conditions for pressure, temperature or medium are different from the applicable conditions of rated relieving capacity 3.5.19 rated coefficient of discharge ratio of rated relieving capacity (certified discharge capacity) to theoretical relieving (discharge) capacity 3.5.20 chatter abnormal rapid reciprocating motion of the movable parts of a pressure relief valve in which the disk contacts the seat 3.5.21 flutter abnormal, rapid reciprocating motion of the movable parts of a pressure relief valve in which the disk does not contact the seat 3.5.22 reference conditions those conditions of a test medium which are specified by either an applicable standard or an agreement between the parties to the test, which may be used for uniform reporting of flow capacity testing results 4 General provisions 4.1 The measurement deviation of this standard test is as follows: for the flow capacity testing, the deviation of the final flow capacity measurement shall not exceed ±2.0% of the measured value; for the operational characteristics testing, the deviation of the pressure measurement shall not exceed ±0.5% of the measured value; for the in-service testing and bench testing, the deviation of the pressure measurement shall not exceed ±1.0% of the measured value. 4.2 To carry out the test specified in this code, the testing facility shall have the pressure and sufficient capacity required by the pressure relief device under test and meet the test requirements of the relieving pressure of the pressure relief device or pressure relief valve. The duration of the test shall be that required to obtain the necessary performance and capacity data under stable conditions. Operating conditions shall be maintained in accordance with the requirements of the procedure used. 4.3 Field installation or abnormal operating conditions may adversely affect the function of the pressure relief device. It is not the intent of this code to attempt to assess the suitability or reliability of the pressure relief device under such conditions. 4.4 It should also be noted that if the temperature of the medium used to test the pressure relief device differs substantially from the temperature to which the pressure relief device is subjected while in service, the functional characteristics will be different from the test pressures, i.e., opening, blowdown, and burst pressure. In this case, it is necessary to develop appropriate corrections for the pressure relief device under test to account for these differences which is outside the scope of this code 4.5 This code provides recommended test procedures and instrumentation for testing devices. Other test procedures or instrumentation may be used provided they can be demonstrated as having accuracy and reliability at least equal to the requirements of this code. If another procedure or instrumentation is used, this must be agreed in writing by the parties to the test prior to the test. 4.6 The test results shall be reported as measured and calculated. Only tests which comply fully with the mandatory requirements of this code may be designated as tests conducted in accordance with this code. 4.7 Special consideration should be given to adequate design and over pressure protection to the piping system and components, safe discharge from the pressure relief devices undergoing test, and the high noise level usually associated with the discharge of pressure relief devices. The interested parties to the test should assure the testing facility meets the minimum mandatory requirements.

Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 General provisions 5 Operational characteristics and flow capacity testing of pressure relief devices 5.1 Test apparatus and instruments 5.2 Methods of measurements 5.3 Requirements for test installation 5.4 Test procedure 5.5 Computation of results 5.6 Test summary report 6 In-service and bench testing 6.1 Instruments and methods of measurements 6.2 In-service testing procedures 6.3 Bench testing procedures 6.4 Seat tightness test 6.5 Computation of results 6.6 Test summary report Annex A (Informative) Test report form Annex B (Informative) Test summary report form Annex C (Informative) Examples of flow error determination

压力释放装置 性能试验方法 1 范围 本文件规定了压力释放装置的动作性能试验(包括机械特性)、排量及阻力系数的试验方法。 本文件适用于试验程序有各种进口和出口条件状况，试验介质是使用其物理性质已知的蒸汽、气体(空气)或液体(水)；包括重闭式和非重闭式压力释放装置，如下： a) 安全阀， b) 爆破片装置， c) 折断/剪切销装置， d) 易熔塞装置。 当试验有关各方同意接受本文件的条款时，本文件也可适用于其他压力释放装置。 2 规范性引用文件 下列文件中的内容通过文中的规范性引用而构成本文件必不可少的条款。其中，注日期的引用文件，仅该日期对应的版本适用于本文件；不注日期的引用文件，其最新版本(包括所有的修改单)适用于本文件。 GB/T 2624.1 用安装在圆形截面管道中的差压装置测量满管流体流量 第1部分：一般原理和要求 GB/T 2624.2 用安装在圆形截面管道中的差压装置测量满管流体流量 第2部分：孔板 GB/T 12241 安全阀 一般要求 GB/T 12243 弹簧直接载荷式安全阀 3 术语和定义 GB/T 12241界定的以及下列术语和定义适用于本文件。 3.1 通用术语 3.1.1 压力释放装置 pressure relief device 用来在压力容器处于紧急或异常状况时防止其内部介质压力升高到超过预定最高压力的装置。 3.1.2 压力释放阀 pressure relief valve；PRV 用来在压力容器处于紧急或异常状况时防止其内部介质压力升高到超过预定最高压力的阀门。 3.1.3 现场试验 fleld testing 为确定压力释放装置的某些或全部工作特性而对安装在系统上的压力释放装置进行的试验。 3.1.4 在用试验 in-service testing 为确定压力释放装置的某些或全部工作特性，利用系统压力或使用外部压力源(使用或不使用辅助提升装置)对安装在系统上正在对系统实施保护的压力释放装置进行的试验。 3.1.5 排量试验 flow capacity testing 确定压力释放装置的工作特性包括测量排量的试验。 3.1.6 工作台上定压试验 bench testing 为确定压力释放装置的整定压力和关闭件密封性而在一个加压系统上进行的试验。 3.2 压力释放装置类型 3.2.1 重闭式压力释放装置 reclosing pressure ：Relieving devices 设计为由进口静压力驱动并在恢复正常工况后重新关闭的压力释放装置。 注：结构类型有弹簧直接载荷式、先导式、动力操作式。 3.2.2 非重闭式压力释放装置 non-reclosing pressure relief device 一种在动作后仍保持开启的压力释放装置，可以提供人工重置的手段。 注：非重闭式压力释放装置有爆破片、折断销、弯折销、剪切销、易熔塞。 3.2.2.1 爆破片装置 rupture disk device 由装置进出口静压差驱动的非重闭式的压力释放装置，其功能系通过承压片的爆破而实现。 3.3 压力释放装置的特性尺寸 3.3.1 排放面积 discharge area 阀门排放时流体通道的最小截面积。 3.3.2 流道面积 nozzle area 阀门进口端至关闭件密封面间流道的最小横截面积。 3.3.3 流道直径 nozzle diameter 对应于流道面积的直径。 3.3.4 帘面积 curtain area 当阀瓣在阀座上方升启时，在其密封面之间形成的圆柱面形或圆锥面形排放通道面积。 注：帘面积见图1。 平面密封阀门帘面积＝πDL 锥面密封阀门帘面积＝πB(D＋DB)/2 球面密封阀门帘面积＝πB(D＋DB)/2 标引序号说明： L——开启高度； D——阀座阀瓣接触面最小直径； DB——锥面通道另一直径； B——锥面通道斜高； θ——密封面斜角； R——半径。 注：帘面积系排放面积，除非阀瓣达到足够开高，使流道面积成为通道最小截面积。 图1 安全阀帘面积的典型示意图 3.3.5 开启高度 lift 阀瓣离开关闭位置的实际行程。 3.3.6 额定开高 rated lift 使阀门达到其额定排量的设计开高。 3.3.7 密封面斜角 seat angle 阀门轴线与密封面间的夹角。 注：平面密封阀门的密封面斜角为90°。 3.4 非重闭式压力释放装置的特性尺寸 3.4.1 净流通面积 net flow area 非重闭式压力释放装置动作之后决定流量的面积。 注：一个爆破片的(最小)净流通面积是其完全破裂后的计算净面积，它带有适当的允差，因为爆破片的某些结构件可能减小其净流通面积。 3.5 压力释放装置的动作和排量特性 3.5.1 整定压力 set pressure 压力释放装置升高的进口静压力，在该压力下装置呈现出定义为开启压力、突跳压力、开始泄漏压力、爆破压力、折断压力中一种动作特性(对一个特定的装置设计，其适用的动作特性由装置的制造厂规定)。 3.5.2 超过压力 over pressure 超过压力释放阀整定压力的压力增量，在该压力增量下，安全阀达到制造厂规定的开启高度。 注：超过压力通常用整定压力的百分数表示。 3.5.3 回座压力 re-seating pressure 压力释放阀排放后阀瓣重新与阀座接触，即开启高度变为零时的压力。 3.5.4 启闭压差 blowdown 整定压力同回座压力之差。 注：启闭压差以整定压力的百分数或以压力单位表示。 3.5.5 排放压力 relieving pressure 整定压力加超过压力。 3.5.6 额定排放压力 flow-rating pressure 测量压力释放装置排量时的进口静压力。 3.5.7 背压力 back pressure 由于在排放系统中存在压力而在压力释放装置出口产生的静压力。 3.5.8 排放背压力 built-up back pressure 由于介质流经压力释放装置进入排放系统而在该装置出口处产生的压力。 3.5.9 附加背压力 superimposed back pressure 压力释放装置即将动作前在其出口处存在的压力。 注：附加背压力是由其他压力源在排放系统中引起的。 3.5.10 爆破压力 burst pressure 当爆破片装置动作时，其进口静压力。 3.5.11 爆破片装置的规定爆破压力 specified burst pressure of a rupture disk device 爆破片装置升高的进口静压力，在规定的温度下爆破片设计在该压力爆破。 3.5.12 折断压力 breaking pressure 当折断销装置、弯折销装置或剪切销装置动作时，其进口静压力。 3.5.13 二次压力 secondary pressure 在压力释放阀的实际排放截面与出口间的通道中存在的压力。 3.5.14 前泄压力 simmer pressure 一个低于压力释放阀整定压力的进口静压力，在该压力下，安全阀关闭件密封面间发生可由听觉或视觉感知的介质泄出，但没有可测量的排量。 注：前泄压力仅适用于可压缩介质用的安全阀。 3.5.15 理论排量 theoretical relieving( discharge) capacity 其流道最小截面积等于压力释放阀流道面积或等于非重闭式压力释放装置净流通面积的理想喷管的计算排量。 注：理论排量以重量单位或容积单位表示。 3.5.16 实测排量 measured relieving( discharge) capacity 在额定排放压力下测量的压力释放装置排量。 注：实测排量以重量单位或容积单位表示。 3.5.17 额定排量 rated relieving capacity； certified discharge capacity 实测排量中由适用的规范或标准允许用作压力释放装置应用基准的部分。 3.5.18 当量计算排量 equivalent calculated capacity 当压力、温度或介质等使用条件与额定排量的适用条件不同时，压力释放装置的计算排量。 3.5.19 额定排量系数 rated coefficient of discharge 额定排量同理论排量的比值。 3.5.20 频跳 chatter 压力释放阀阀瓣快速异常地来回运动，运动中阀瓣接触阀座。 3.5.21 颤振 flutter 压力释放阀阀瓣快速异常地来回运动，运动中阀瓣不接触阀座。 3.5.22 基准状况 reference conditions 由适用的标准或由试验各方间的协议规定的试验介质状况，可用来统一排量试验的结果。 4 总则 4.1 本文件试验的测量偏差规定如下：对于排量试验，最终排量测量的偏差应不超过测量值的±2.0％；对于动作性能试验，压力测量的偏差应不超过测量值的±0.5％；对于在用试验及工作台上定压试验，压力测量的偏差应不超过测量值的±1.0％。 4.2 进行本文件规定的试验，试验装置应具备被试验压力释放装置所要求的压力和足够容量，应满足压力释放装置或压力释放阀排放压力的试验需要，试验持续时间应满足在稳定状况下取得必要的动作性能和排量数据的需要。应按试验程序的要求保持试验运行条件。 4.3 现场安装或非正常运行条件可 能会对压力释放装置的功能产生不利影响。评估压力释放装置在这类条件下的适用性和可靠性不属于本文件的范围。 4.4 如果压力释放装置试验所用介质的温度同装置在实际使用时承受的温度之间存在较大的差别，其实际使用时的功能特性如开启压力、启闭压差和爆破压力等将不同于试验得出的特性。考虑这些不同而对试验条件下的压力释放装置作适当修正的内容也不属于本文件的范围。 4.5 本文件提供推荐的试验程序和测试仪表。其他的试验程序和测试仪表只要能证明具有至少与本文件要求等同的精度和可靠性，则可以使用。如果要使用其他的程序和仪表，则应在试验之前征得试验有关各方的书面同意。 4.6 应按测量和计算来对试验结果作出报告。当试验完全符合本文件的强制性要求时，才可以被指认为按照本文件进行的试验。 4.7 试验的有关方应对管道系统和部件的设计和超压保护、试验中压力释放装置的安全排放以及通常伴随着排放的高噪声等给予特别的考虑，以保证试验装置满足最低强制要求。 4.8 试验各方在进行试验之前应就下列事项达成协议： a) 试验目的； b) 试验场所，试验各方，试验和试验监督人员； c) 在额定排放压力下试验流体的基准状况； d) 试验所用的测试方法、仪表和设备(仪表的校准应按5.1.2)； e) 被试装置的数量、通径、类型、状况、来源、整定压力和预期排量； f) 书面的试验程序，该程序应包括为满足试验目的所应进行的观测和所应记录的读数。 4.9 试验监督试验人员的资格和职责： a) 试验监督人员应接受过热力学和流体力学的教育，并具有流体流量测量的实际经验，还应具有监督试验的经验。 b) 试验过程中，试验监督人员应全过程观察试验情况操作的人员，应完全了解进行这些操作的正确方法。 c) 试验监督人员应负责保证书面的试验程序得到遵循，应签署试验报告或验证报告。 5 压力释放装置动作性能及排量试验 5.1 试验装置和仪表 5.1.1 试验装置 试验装置的布置见图2～图7及图9。 大于2DN 大于10DN 大于3DN 增压阀可选位置 导流板 标引序号说明： 1——补压阀； 2——旁通阀； 3——导流器； 4——温度测点； 5——压力仪表； 6——流量计； 7——温度测点； 8——被试压力释放装置的试验容器； 9——疏水阀； 10——温度测点或热量计安装位置； 11——被试压力释放装置； 12——开高测量装置； 13——温度仪表； 14——压力仪表。 图2 流量计方法，背压为大气时推荐的试验布置 大于2D 出口管应为水平布置或向下倾斜，并可以伸缩 标引序号说明： 1——开高测量装置； 5——蒸汽冷凝器； 2——被试压力释放装置； 6——称量容器； 3——被试压力释放装置的试验容器； 7——磅秤。 4——温度测点或热量计安装位置； 图3 称量冷凝液方法，背压为大气时的推荐试验布置 出口管应为水平布置或向下倾斜 标引序号说明： 1——开高测量装置； 4——称量容器； 2——被试压力释放装置； 5——磅秤。 3——被试压力释放装置的试验容器； 图4 称量液体(水)方法，背压为大气时的推荐试验布置 通大气或接受容器 标引序号说明： 1——开高测量装置； 5——疏水阀； 2——被试压力释放装置； 6——背压容器压力控制阀； 3——被试压力释放装置的试验容器； 7——压力仪表； 4——背压容器； 8——背压供给控制阀(快开式)。 图5 具有附加背压时的推荐试验布置 通大气或接受容器 标引序号说明： 1——开高测量装置； 2——被试压力释放装置； 3——被试压力释放装置的试验容器； 4——压力仪表； 5——背压容器压力控制阀。 图6 具有附加背压时的推荐试验布置 可选取压口 标引序号说明： 1——被试压力安全阀； 2——被试非重闭式装置； 3——被试压力释放装置的试验容器。 图7 非重闭式压力释放装置与安全阀组合的推荐试验布置 5.1.2 仪表 5.1.2.1 仪表校准 试验中使用的仪表及备用仪表应有编号或作其他明确标记。仪表依照其类型不同应按5.1.2.2～5.1.2.7进行校准。有关的仪表校准记录应保存以供有关方面查阅。 5.1.2.2 压力测量仪表 压力测量仪表的精度等级应不低于0.5级。压力测量系统应包括两只压力测量仪表，以便在试验中进行互校。压力测量仪表应按国家有关规程进行校准或检定。 5.1.2.3 温度测量仪表 温度测量仪表的分辩率应不低于0.5℃。温度测量系统应包括两套温度测量仪表，以便在试验中进行互校。温度测量仪表应按国家有关规程进行校准或检定。 5.1.2.4 开高测量仪表 开高测量仪表的分辩率应不低于0.02mm。开高测量仪表应在每次试验或一系列试验的前后进行精度检查。 5.1.2.5 重量秤 在试验程序中用来称量冷凝液重量的重量秤，其指示部件的最小刻度值应小于或等于预期载荷的0.25％。用于本文件试验的重量秤应在每次或一系列试验之前按国家有关规程在足够的点位，上进行校准，以保证其在预期使用范围内的精度。 5.1.2.6 蒸汽热量计 蒸汽热量计应分别在其安装之时和在规定的周期内进行校准。当测量结果显示其读数有明显错误时或在重新安装后，应再进行校准。