在截止閥管件行業(yè)中，根據(jù)公稱壓力PN的大小，我們可以把公稱壓力小于等于1.6MPa的閥門為低壓閥門，公稱壓力為2.5MPa、4.0MPa、6.4MPa的閥門為中壓閥門，同時我們也經(jīng)常會提到1.6MPa壓力、2.5MPa壓力和多少公斤壓力、多少個標(biāo)準(zhǔn)大氣壓等之類的術(shù)語，那么1MPa壓力到底有多大壓強(qiáng)，1MPa壓力等于多少公斤壓力呢蒸汽壓力為2.5㎏是表示2.5kg/cm2，是表示的單位面積上的壓力--壓強(qiáng)，通常俗稱為2.5kg壓力。新的表示方法約為0.25MPa。
換算關(guān)系：1kg/cm2=0.098MPa，因此壓力2.5kg/cm2=0.245MP，可約等于0.25MPa.ISO標(biāo)準(zhǔn)帕斯卡(1Pa=1N/m2)
1公斤力/平方厘米=98.0665千帕
粗算時常按1公斤力=10N 則:
1公斤力/平方厘米=100千帕=1bar=0.1MPa
10公斤力/平方厘米=1000千帕=1MPa
公斤的單位是質(zhì)量單位
MPA是壓力的單位
質(zhì)量m=壓力/重力加速度
壓力p=壓力/面積
這是他們之間的關(guān)系

1公斤壓力指的是1公斤重的物體作用為1cm2面積上所產(chǎn)生的壓強(qiáng)，可以想像一下，1公斤重（比兩瓶一元錢的康師傅礦泉水重略輕）的物體全部壓在一個手指頭上所產(chǎn)生的壓強(qiáng)。  我們來計算一下， 1MPa=1×106Pa 1Pa=1N/1m2  1MPa=106N/m2=106N/104cm2=100N/cm2  重力加速度g約等于9.8 N/KG，為方便計算，g按整數(shù)10。 1KG的物體重力=1KG×10N/KG=10N  1公斤壓力是1KG的重力作用于1cm2面積上產(chǎn)生的壓強(qiáng)，即 1公斤壓力=10N/cm2 1MPa=100N/cm2=10×10N/cm2 即1MPa壓力等于10公斤壓力。
單位說明：  Pa，壓強(qiáng)單位，中文名稱為“帕斯卡”，簡稱“帕”，即牛/平方米，1帕=1牛/平方米  M，數(shù)量單位，M即million，數(shù)值為一百萬  N，物理力學(xué)單位，簡稱牛，是一種衡量力的大小的單位，兩個雞蛋的重力約為1N（0.1千克的物體的重量）  m，長度單位，米 m2，面積單位，平方米 cm2，面積單位，平方厘米 KG，重量單位，千克，公斤

減壓閥標(biāo)準(zhǔn)一覽表 
標(biāo)準(zhǔn)編號  標(biāo)準(zhǔn)中文名稱  標(biāo)準(zhǔn)英文名稱  JB/T10367-2002  液壓減壓閥      GB/T12245-1989  減壓閥性能試驗方法  Methods of performance test for pressure reducing valves GB/T12246-1989  先導(dǎo)式減壓閥  Pilot-operated reducing valves  GB/T12244-1989  減壓閥一般要求  General specification for pressure reducing valves GB/T1852-1993  船用法蘭鑄鋼蒸汽減壓閥  Marine steel flanged steam pressure reducing valves  GB10868-1989  電站減溫減壓閥技術(shù)條件   Specification of the steam converting valve for fossil power stations JB/T7376-1994(2005復(fù)審)   氣動空氣減壓閥 技術(shù)條件       JB/T7310-1994(2005復(fù)審)   裝載機(jī)用減壓閥式先導(dǎo)閥     JB/T53361-1994  液壓減壓閥產(chǎn)品質(zhì)量分等(試行)    JB/T53265-1999  先導(dǎo)式減壓閥 產(chǎn)品質(zhì)量分等     JB/T2205-2000  減壓閥結(jié)構(gòu)長度       NF P43-035-2000   建筑閥門.供水減壓閥和復(fù)合供水減壓閥.要求和試驗   (Building valves - Water pressure reducing valves and combination water pressure reducing valves - Requirements and tests.)  NF A84-420-1991   氣焊設(shè)備和有關(guān)方法.減壓閥入品接頭.尺寸   (Equipment for gas welding and allied processes. Pressure regulators inlet connections. Dimensions.)  NF M88-773-1981   商用丁烷容器裝置.低壓固定調(diào)節(jié)的家用商品丁烷減壓閥   (INSTALLATIONS BURNING COMMERCIAL BUTANE. PRESSURE REGULATOR TRIP,LOW-PRESSURE FIXED FLOW,FOR COMMERCIAL BUTANE FOR DOMESTIC USE.)  NF M88-775-1990   裝液態(tài)碳?xì)浠衔锏匿撈?可移動部分和半移動部分用高壓可調(diào)減壓閥.功能.標(biāo)記、試驗   (LIQUEFIED HYDROCARBONS SYSTEMS IN CYLINDERS. FIXED  ADJUSTEMENT,HIGH PRESSURE REGULATOR FOR AND SEMI- PREMISES. CONSTRUCTION. OPERATION, MARKING,TESTS.)  NF M88-737-2003   可運輸可再填充液化石油氣瓶用減壓閥   (Pressure relief valves for transportable refillable cylinders for Liquefied Petroleum Gas (LPG).)  NF E48-423-2001   液壓傳動.減壓閥、順序閥、卸載閥、 節(jié)流閥和止回閥.裝配面   (Hydraulic fluid power - Pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves -  Mounting surfaces.)  ANSI/ASSE 1003-1995  家用供水系統(tǒng)用減壓閥  (Water Pressure Reducing Valves for Domestic Water Supply Systems)  ANSI/ASSE 1046-1990  熱膨脹減壓閥  (Thermal Expansion Relief Valve)  ANSI Z 21.22a-1999  減壓閥和真空減壓閥  (Pressure Relief Valves and Vacuum Relief Valves)  ANSI Z 21.22b-2001  熱水供應(yīng)系統(tǒng)的減壓閥  (Relief Valves for Hot Water Supply Systems (same as CSA 4.4b))  ANSI/ASTM F 1508-1997   用于蒸汽、氣體和液體設(shè)備的角型減壓閥規(guī)范   (Specification for Angle Style, Pressure Relief Valves for Steam, Gas, and Liquid Services)  ASME A112.4.1-1993  熱水器減壓閥排水管  (Water heater relief valve drain tubes) ASME PTC 25.3-1988  安全和減壓閥   (Safety and relief valves) 

ASTM E 1008-2003  地?zé)岷推渌邷匾后w設(shè)備用減壓閥體的安裝、檢驗及維修用標(biāo)準(zhǔn)實施規(guī)范   (Standard Practice for Installation, Inspection, and Maintenance  of Valve-body Pressure-relief Methods for Geothermal and Other  High-Temperature Liquid Applications)  標(biāo)準(zhǔn)編號  標(biāo)準(zhǔn)中文名稱  標(biāo)準(zhǔn)英文名稱  ASTM F 1795-2000   空氣或氮氣系統(tǒng)用減壓閥標(biāo)準(zhǔn)規(guī)范   (Standard Specification for Pressure-Reducing Valves for Air or Nitrogen Systems)  ASTM F 1565-2000  蒸汽設(shè)備用減壓閥標(biāo)準(zhǔn)規(guī)范   (Standard Specification for Pressure-Reducing Valves for Steam Service)  ASTM F 1508-1996   用于蒸汽、氣體和液體設(shè)備的角型減壓閥標(biāo)準(zhǔn)規(guī)范   (Standard Specification for Angle Style, Pressure Relief Valves for Steam, Gas and Liquid Services) ASTM F 1370-1992   船上給水系統(tǒng)用減壓閥   (Standard Specification for Pressure-Reducing Valves for Water Systems, Shipboard)  BS EN 1567-2000   建筑物閥門.減壓閥和組合減壓閥.要求和試驗   (Building valves - Water pressure reducing valves and combination water reducing valves - Requirements and tests)  BS ISO 5781-2000   液壓傳動.減壓閥、順序閥、卸荷閥、節(jié)流閥和止回閥.安裝面   (Hydraulic fluid power - Pressure reducing valves, sequence valves, unloading valves, throttle valves and check valves - Mounting surfaces)  BS ISO 6264-1998  液壓傳動.減壓閥.裝配面   (Hydraulic fluid power - Pressure-relief valves - Mounting surfaces)  prEN 14071-2000   液化石油氣（LPG）罐的減壓閥 輔助設(shè)備   Pressure relief valves for LPG tanks - Ancillary equipment  BS 6283-2-1991   熱水系統(tǒng)中使用的安全和控制裝置.壓力范圍從1bar到10bar溫度減壓閥規(guī)范   (Safety and control devices for use in hot water systems  - Specifications for temperature relief valves for pressures from 1 bar to 10 bar)  BS 6283-4-1991   熱水系統(tǒng)中使用的安全和控制裝置.第 4部分:zui大供給壓力為12bar,標(biāo)準(zhǔn)尺寸包括DN50的微量繃緊減壓閥規(guī)范   (Safety and control devices for use in hot water systems - Specification for drop-tight pressure reducing valves of nominal size up to and including DN 50 for supply pressures up to and including 12 ba)  DIN EN 13953-2003   液化石油氣(LPG)用可運輸?shù)目稍俪涫絻馄康臏p壓閥   (Pressure relief valves for transportable refillable cylinders for Liquefied Petroleum Gas (LPG); German version EN 13953:2003)  DIN EN 1567-2000   建筑閥門.水減壓閥和組合水減壓閥.要求和試驗   (Building valves - Water pressure reducing valves and combination water pressure reducing valves - Requirements and tests; German version EN 1567:1999) JIS B8652-2002   比例電動液壓減壓閥及安全閥的試驗方法   (Test methods for electro-hydraulic proportional pressure relief valves and electro-hydraulic  proportional pressure reducing and relieving valves)  JIS F0504-1989  船上機(jī)械裝置用減壓閥的應(yīng)用和壓力調(diào)節(jié)  (Application and setting pressure of relief valves for ships' machinery)  UL 1478-1995  消防泵減壓閥   (Fire pumps relief valves )  UL 1468-1995   防火設(shè)備用直接控制的減壓閥和壓力(Direct acting pressure reducing and pressure 
控制閥   restricting valves )  JIS B8666-2001  液壓動力.減壓閥.安裝表面  (Hydraulic fluid power -- Pressure-relief valves -- Mounting surfaces)  JIS B8372-1994   氣動裝置用減壓閥   (PRESSURE REDUCING VALVES FOR PNEUMATIC USE) JIS B8664-2001   液壓動力.壓力控制閥(不包括減壓 閥)、順序活門、釋荷閥、節(jié)流閥和止回閥.安裝表面   (Hydraulic fluid power -- Pressure-control valves (excluding pressure-relief valves), sequence valves, unloading valves, throttle valves and check valves -- Mounting surfaces)  JIS B8410 AMD 1-2003  水管用減壓閥(修改件1)  (Pressure reducing valves for water works (Amendment 1))  JIS B8651-2002  比例電動液壓減壓閥試驗方法  (Test methods for electro-hydraulic proportional pressure relief valves)  JIS B8410-1999   水管用減壓閥   (Pressure reducing valves for water works) ISO 15500-12-2001   道路車輛.壓縮天然氣(CNG)燃料系統(tǒng)元部件.第12部分:減壓閥   (Road vehicles - Compressed natural gas (CNG) fuel system components - Part 12: Pressure relief valve (PRV))  ISO 6264-1998  液壓傳動.減壓閥.裝配面   (Hydraulic fluid power - Pressure-relief valves - Mounting surfaces)  ISO 5781-2000   液壓傳動.減壓閥、順序閥、卸荷閥、節(jié)流閥和止回閥.裝配面  (Hydraulic fluid power - Pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves - Mounting surfaces) GB/T10868-2005   電站減溫減壓閥