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{{distinguish|Standard state}}
 
'''Standard conditions for temperature and pressure''' are [[Technical standard|standard]] sets of conditions for experimental measurements established to allow comparisons to be made between different sets of data. The most used standards are those of the [[International Union of Pure and Applied Chemistry]] (IUPAC) and the [[National Institute of Standards and Technology]] (NIST), although these are not universally accepted standards. Other organizations have established a variety of alternative definitions for their standard reference conditions.
 
In chemistry, IUPAC established '''standard temperature and pressure''' (informally abbreviated as '''STP''') as a [[temperature]] of 273.15&nbsp;[[Kelvin|K]] (0&nbsp;°C, 32&nbsp;°F) and an [[absolute pressure]] of 100&nbsp;[[Pascal (unit)|kPa]] (14.504 [[pound-force per square inch|psi]], 0.987 [[Atmosphere_(unit)|atm]], [[Bar_(unit)|1 bar]]).<ref name="IUPAC">{{cite book|title=IUPAC. Compendium  of Chemical Terminology|year=1997|publisher=Blackwell Scientific Publications|location=Oxford|isbn=0-9678550-9-8|url=http://goldbook.iupac.org/PDF/S06036.pdf|author=A. D. McNaught and A. Wilkinson|edition=2nd|quote=Standard conditions for gases: Temperature, 273.15&nbsp;K [...] and pressure of 10<sup>5</sup>&nbsp;pascals. The previous standard [[absolute pressure]] of 1 atm (equivalent to {{nowrap|1.01325 × 10<sup>5</sup> Pa}}) was changed to 100&nbsp;[[Pascal (unit)|kPa]] in 1982. IUPAC recommends that the former pressure should be discontinued.}}</ref> An unofficial, but commonly used standard is '''standard [[ambient temperature]] and pressure''' ('''SATP''') as a [[temperature]] of 298.15&nbsp;[[Kelvin|K]] (25&nbsp;°C, 77&nbsp;°F) and an [[absolute pressure]] of 100&nbsp;[[Pascal (unit)|kPa]] (14.504 [[pound-force per square inch|psi]], 0.987 atm). The '''STP''' and the '''SATP''' should not be confused with the [[standard state]] commonly used in thermodynamic evaluations of the [[Gibbs free energy|Gibbs energy]] of a reaction.
 
[[National Institute of Standards and Technology|NIST]] uses a temperature of 20&nbsp;°C (293.15&nbsp;K, 68&nbsp;°F) and an absolute pressure of 101.325&nbsp;kPa (14.696&nbsp;psi, 1 atm). The International Standard Metric Conditions for natural gas and similar fluids are {{convert|288.15|K|F C}} and 101.325 kPa.<ref name=ISO13443 />
 
In [[industry]] and [[commerce]], standard conditions for temperature and pressure are often necessary to define the standard reference conditions to express the volumes of gases and liquids and related quantities such as the rate of [[volumetric flow]] (the volumes of gases vary significantly with temperature and pressure). However, many technical publications (books, journals, advertisements for equipment and machinery) simply state "standard conditions" without specifying them, often leading to confusion and errors. Good practice is to always incorporate the reference conditions of temperature and pressure.
 
==Definitions==
===Past use===
In the last five to six decades, professionals and scientists using the metric system of units defined the standard reference conditions of temperature and pressure for expressing gas volumes as being {{convert|15|C|K F|2}} and {{convert|101.325|kPa|atm Torr|lk=on|abbr=on|sigfig=3}}. During those same years, the most commonly used standard reference conditions for people using the [[Imperial units|imperial]] or [[United States customary units|U.S. customary]] systems was {{convert|60|F|C K|2}} and 14.696&nbsp;[[pound-force per square inch|psi]] (1&nbsp;atm) because it was almost universally used by the oil and gas industries worldwide. The above definitions are no longer the most commonly used in either system of units.
 
===Current use===
Many different definitions of standard reference conditions are currently being used by organizations all over the world. The table below lists a few of them, but there are more. Some of these organizations used other standards in the past. For example, IUPAC has, since 1982, defined standard reference conditions as being 0&nbsp;°C and 100&nbsp;kPa (1&nbsp;bar), in contrast to its old standard of 0&nbsp;°C and 101.325&nbsp;kPa (1&nbsp;atm).<ref name="IUPAC 2">{{cite book |author= A. D. McNaught, A. Wilkinson |title=Compendium of Chemical Terminology, The Gold Book |url=http://www.iupac.org/goldbook/S05921.pdf |edition=2nd |year=1997 |publisher=Blackwell Science |isbn=0-86542-684-8 |quote=Standard pressure: Chosen value of pressure denoted by p<sup><s>o</s></sup> or p°. In 1982 IUPAC recommended the value 10<sup>5</sup>&nbsp;Pa, but prior to 1982 the value 101&nbsp;325 Pa (=&nbsp;1&nbsp;atm) was usually used.}}</ref>
 
Natural gas companies in Europe and South America have adopted 15&nbsp;°C (59&nbsp;°F) and 101.325&nbsp;kPa (14.696&nbsp;psi) as their standard gas volume reference conditions.<ref>{{cite web |url=http://www.gassco.no/sw3138.asp |title= Concepts&nbsp;– Standard cubic meter (scm) |accessdate=2008-07-25 |author=[[Gassco]] |quote= Scm: The usual abbreviation for standard cubic metre&nbsp;– a cubic metre of gas under a standard condition, defined as an atmospheric pressure of 1.01325&nbsp;[[bar (unit)|bar]] and a temperature of 15°C. This unit provides a measure for gas volume.}} {{Dead link|date=September 2010|bot=H3llBot}}</ref><ref>{{cite web |url=http://www.nord-stream.com/uploads/media/Nord_Stream_Route_Status_ENGLISH.pdf |title=Status of the Nord Stream pipeline route in the Baltic Sea |accessdate=2008-07-25 |author=[[Nord Stream]] |date=October 2007 |quote=bcm: Billion Cubic Meter (standard cubic metre&nbsp;– a cubic metre of gas under a standard condition, defined as an atmospheric pressure of 1&nbsp;atm and a temperature of 15&nbsp;°C.)}}</ref><ref>{{cite web |url=http://www.secinfo.com/dsD7y.1a.7.htm |title=Natural gas purchase and sale agreement |accessdate=2008-07-25 |author=[[Metrogas]] |date=June 2004 |quote=Natural gas at standard condition shall mean the quantity of natural gas, which at a temperature of fifteen (15) Celsius degrees and a pressure of 101.325 kilopascals occupies the volume of one (1) cubic meter.}}</ref> Also, the [[International Organization for Standardization]] (ISO), the [[United States Environmental Protection Agency]] (EPA) and [[National Institute of Standards and Technology]] (NIST) each have more than one definition of standard reference conditions in their various standards and regulations.
 
In Russia, State Standard GOST 2939-63 sets the following standard conditions: 20 °C (293.15 K), 760 mmHg (101325 N/m<sup>2</sup>) and zero humidity.
 
<center>
{| class="wikitable"
|+ '''Standard reference conditions in current use'''
 
! Temperature !! Absolute pressure !! Relative humidity
!rowspan="2"| Publishing or establishing entity
|-
!°C!!kPa!!% RH
|-
|align="center"|0||align="center"|100.000||&nbsp;||International Union of Pure and Applied Chemistry|[[IUPAC]] (STP)<ref name=IUPAC/>
|-
|align="center"|0||align="center"|101.325||&nbsp;||[[National Institute of Standards and Technology|NIST]],<ref name=NISTDataBase7>{{cite web |url=http://www.nist.gov/pml/data/star/index.cfm |title=NIST Standard Reference Database 124&nbsp;– Stopping-Power and Range Tables for Electrons, Protons, and Helium Ions|accessdate=08-07-25 |author=[[National Institute of Standards and Technology|NIST]] |year=1989 |quote=If you want the program to treat the material as an ideal gas, the density will be assumed given by M/V, where M is the gram molecular weight of the gas and V is the mol volume of 22414&nbsp;cm<sup>3</sup> at standard conditions (0&nbsp;deg&nbsp;C and 1&nbsp;atm).}}{{dead link|date=September 2013}}</ref> ISO 10780,<ref name=ISO10780>{{Cite web |author=[[International Organization for Standardization|ISO]] | title=ISO 10780:1994 : Stationary source emissions&nbsp;– Measurement of velocity and volume flowrate of gas streams in ducts |year=1994 |url=http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=18855}}</ref> formerly [[IUPAC]]<ref name=IUPAC/>
|-
|align="center"|15||align="center"|101.325||align="center"|0<ref name=Handbook>{{cite book|author=Robert C. Weast (Editor)|title=Handbook of Physics and Chemistry|edition=56th|publisher=CRC Press|pages=F201–F206|year=1975|isbn=0-87819-455-X}}</ref><ref name=ISO13443>{{cite book |title=Natural gas&nbsp;– Standard reference conditions (ISO 13443) |publisher=International Organization for Standardization |location=Geneva, Switzerland |url=http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=20461 |year=1996}}</ref>||[[ICAO]]'s [[International Standard Atmosphere|ISA]],<ref name=Handbook/> ISO 13443,<ref name=ISO13443/> [[European Environment Agency|EEA]],<ref name=EEA>{{cite book |title=Extraction, First Treatment and Loading of Liquid & Gaseous Fossil Fuels (Emission Inventory Guidebook B521, Activities 050201&nbsp;– 050303) |date=September 1999 |publisher=European Environmental Agency |location=Copenhagen, Denmark |url=http://reports.eea.eu.int/EMEPCORINAIR3/en/B521vs3.1.pdf |format=PDF}}</ref> EGIA<ref name=EGIA>"Electricity and Gas Inspection Act", SOR/86-131 (defines a set of standard conditions for Imperial units and a different set for metric units) &nbsp;[http://laws.justice.gc.ca/en/E-4/SOR-86-131/95708.html Canadian Laws]</ref>
|-
|align="center"|20||align="center"|101.325||&nbsp;||[[United States Environmental Protection Agency|EPA]],<ref name=NSPS>"Standards of Performance for New Sources", 40 CFR—Protection of the Environment, Chapter I, Part 60, Section 60.2, 1990 &nbsp;[http://a257.g.akamaitech.net/7/257/2422/08aug20051500/edocket.access.gpo.gov/cfr_2005/julqtr/pdf/40cfr60.2.pdf New Source Performance Standards]</ref> NIST<ref name=NISTJournal>{{cite journal |title=Design and Uncertainty for a PVTt Gas Flow Standard |journal=Journal of Research of the National Institute of Standards and Technology |volume=108 |year=2003 |url=http://www.cstl.nist.gov/div836/836.01/PDFs/2003/j80wri.pdf |format=PDF |issue=1}}</ref>
|-
|align="center"|25||align="center"|101.325||&nbsp;||EPA<ref name=NAAQS>"National Primary and Secondary Ambient Air Quality Standards", 40 CFR—Protection of the Environment, Chapter I, Part 50, Section 50.3, 1998 &nbsp;[http://a257.g.akamaitech.net/7/257/2422/08aug20051500/edocket.access.gpo.gov/cfr_2005/julqtr/pdf/40cfr50.3.pdf National Ambient Air Standards]</ref>
|-
|align="center"|25||align="center"|100.000||&nbsp;||SATP<ref name=NBS>{{cite journal |title=Table of Chemical Thermodynamic Properties |author=National Bureau of Standards (NBS) |journal=Journal of Physics and Chemical Reference Data |year=1982 |volume=11 |issue=Supplement 2}}</ref>
|-
|align="center"|20||align="center"|100.000||align="center"|0||[[Compressed Air and Gas Institute|CAGI]]<ref name=CAGI>{{cite web |title=Glossary |year=2002 |publisher=Compressed Air and Gas Institute |location=Cleveland, OH, USA |url=http://www.cagi.org/toolbox/glossary.htm}}</ref>
|-
|align="center"|15||align="center"|100.000||&nbsp;||[[Society of Petroleum Engineers|SPE]]<ref name=SPE>{{cite web |url=http://www.spe.org/spe-site/spe/spe/papers/authors/Metric_Standard.pdf |format=PDF |title=The SI Metric System of Units and SPE Metric Standard |at=Notes for Table 2.3, on PDF page 25 of 42 PDF pages, define two different sets of reference conditions, one for the standard cubic foot and one for the standard cubic meter |publisher=Society of Petroleum Engineers}}</ref>
|-
|align="center"|20||align="center"|101.3||align="center"|50|| ISO 5011<ref name=ISO5011>{{cite book |title=Air Intake Filters (ISO 5011:2002) |year=2002 |publisher=International Organization for Standardization |location=Geneva, Switzerland |url=http://www.iso.org/iso/en/prods-services/ISOstore/store.html}}</ref>
|-
!°F!!psi!! % RH
|-
|align="center"|60||align="center"|14.696||&nbsp;||SPE,<ref name=SPE/> U.S. [[Occupational Safety and Health Administration|OSHA]],<ref name=OSHA>"Storage and Handling of Liquefied Petroleum Gases" and "Storage and Handling of Anhydrous Ammonia", 29 CFR—Labor, Chapter XVII—Occupational Safety and Health Administration, Part 1910, Sect. 1910.110 and 1910.111, 1993 &nbsp;[http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=f169acd0f57a17565c9984fa0f57d285&rgn=div8&view=text&node=29:5.1.1.1.8.8.33.10&idno=29 Storage/Handling of LPG]</ref> [[SCAQMD]]<ref name=SCAQMD>"Rule 102, Definition of Terms (Standard Conditions)", Amended December 2004, South Coast Air Quality Management District, Los Angeles, California, USA &nbsp;[http://www.aqmd.gov/rules/reg/reg01/r102.pdf SCAQMD Rule 102]</ref>
|-
|align="center"|60||align="center"|14.73||&nbsp;||EGIA,<ref name=EGIA/> [[Organization of Petroleum Exporting Countries|OPEC]],<ref name=OPEC>{{cite web |title=Annual Statistical Bulletin |year=2004 |editor=Omar Ibrahim |publisher=Organization of the Petroleum Exporting Countries |location=Vienna, Austria |url=http://www.opec.org/library/Annual%20Statistical%20Bulletin/pdf/ASB2004.pdf |format=PDF}}</ref> U.S. [[Energy Information Administration|EIA]]<ref name=EIA>{{cite web |title=Natural Gas Annual 2004 (DOE/EIA-0131(04)) |date=December 2005 |publisher=U.S. Department of Energy |author=Energy Information Administration |location=Washington, D.C., USA |url=http://tonto.eia.doe.gov/FTPROOT/natgas/013104.pdf |format=PDF}}</ref>
|-
|align="center"|59||align="center"|14.503||align="center"|78|||U.S. Army Standard Metro<ref name=ArmyStdMetro>{{cite book|url=http://www.exteriorballistics.com/ebexplained/5th/31.cfm |title=Rifle and Handgun Reloading Manual |edition=5 |chapter= Chapter 3&nbsp;– Effects of Altitude and Atmospheric Conditions (Exterior Ballistics Section) |author=Sierra Bullets L.P.  |location=Sedalia, MO, USA-}}</ref>{{efn|The pressure is specified as 750 [[mmHg]]. However, the [[mmHg]] is temperature dependent, as mercury expands as temperature goes up. Here the values for the 0–20°C range are given.}}
|-
|align="center"|59||align="center"|14.696||align="center"|60||ISO 2314,<ref name=ISO2314>{{cite book |title=Gas turbines&nbsp;– Acceptance tests (ISO 2314:1989) |year=1989 |edition=2 |publisher=International Organization for Standardization |location=Geneva, Switzerland |url=http://www.iso.org/iso/en/prods-services/ISOstore/store.html}}</ref> ISO 3977-2<ref name=ISO3977-2>{{cite book |title=Gas turbines&nbsp;– Procurement&nbsp;– Part 2: Standard reference conditions and ratings (ISO 3977-2:1997) |year=1997 |publisher=International Organization for Standardization |location=Geneva, Switzerland |url=http://www.iso.org/iso/en/prods-services/ISOstore/store.html}}</ref>
|-
!°F!!in Hg!! % RH
|-
|align="center"|70||align="center"|29.92||align="center"|0||[[Air Movement and Control Association|AMCA]],<ref name=AMCA>ANSI/AMCA Standard 210, "Laboratory Methods Of Testing Fans for Aerodynamic Performance Rating", as implied by [http://www.greenheck.com/pdf/centrifugal/Plug.pdf http://www.greenheck.com/pdf/centrifugal/Plug.pdf] when accessed on October 17, 2007</ref>{{efn|The standard is given as 29.92 [[inHg]] at an unspecified temperature. This most likely corresponds to a standard pressure of 101.325 kPa, converted into ~29.921 inHg at {{convert|32|F|C}}.}} air density = 0.075 lbm/ft³. This AMCA standard applies only to air.
|-
|align="center"|59||align="center"|29.92||&nbsp;||[[Federal Aviation Administration]] (FAA)<ref name=FAA>{{cite book |url=http://www.faa.gov/library/manuals/aviation/pilot_handbook/media/PHAK%20-%20Chapter%2003.pdf |format=PDF |chapter=Chapter 3, Principles of Flight |title=Pilot's Handbook of Aeronautical Knowledge |publisher=Federal Aviation Administration}}</ref>
|}
 
</center>
Notes:
* EGIA: Electricity and Gas Inspection Act (of Canada)
* SATP: Standard Ambient Temperature and Pressure
 
==International Standard Atmosphere==
In [[aeronautics]] and [[fluid dynamics]] the "[[International Standard Atmosphere]]" (ISA) is a specification of pressure, temperature, density, and speed of sound at each altitude. The International Standard Atmosphere is representative of atmospheric conditions at mid latitudes. In the USA this information is specified the [[U.S. Standard Atmosphere]] which is identical to the "International Standard Atmosphere" at all altitudes up to 65,000 feet above sea level.{{citation needed|date=May 2012}}
 
==Standard laboratory conditions==
Due to the fact that many definitions of standard temperature and pressure differ in temperature significantly from standard laboratory temperatures (e.g., 0&nbsp;°C vs. ~25&nbsp;°C), reference is often made to "standard laboratory conditions" (a term deliberately chosen to be different from the term "standard conditions for temperature and pressure", despite its semantic near identity when interpreted literally). However, what is a "standard" [[laboratory]] temperature and pressure is inevitably culture-bound, given that different parts of the world differ in climate, altitude and the degree of use of heat/cooling in the workplace. For example, schools in [[New South Wales]], [[Australia]] use 25&nbsp;°C at 100&nbsp;kPa for standard laboratory conditions.<ref>{{cite book|author=Peter Gribbon|title=Excel HSC Chemistry Pocket Book Years 11–12|publisher=Pascal Press|year=2001|isbn=1-74020-303-8}}</ref>
 
[[ASTM International]] has published [[Technical standard|Standard]] ASTM E41- Terminology Relating to Conditioning and hundreds of special conditions for particular materials and [[test method]]s. Other [[standards organization]]s also have specialized standard test conditions.
 
==Molar volume of a gas==
It is equally as important to indicate the applicable reference conditions of temperature and pressure when stating the molar volume of a gas<ref>{{cite web |url=http://physics.nist.gov/cgi-bin/cuu/Results?search_for=volume+molar |title=Fundamental Physical Properties: Molar Volumes (CODATA values for ideal gases) |publisher=[[National Institute of Standards and Technology|NIST]]}}</ref> as it is when expressing a gas volume or volumetric flow rate. Stating the molar volume of a gas without indicating the reference conditions of temperature and pressure has no meaning and it can cause confusion.
 
The molar gas volumes can be calculated with an accuracy that is usually sufficient by using the [[universal gas law]] for ideal gases. The usual expression is:
 
:<math>P V = nRT</math>
 
...which can be rearranged thus:
 
:<math>\frac{V}{n} = \frac{RT}{P}</math>
 
where (in SI metric units):
{| border="0" cellpadding="2"
|-
!align=right| ''P''
|align=left|= the absolute pressure of the gas, in [[pascal (unit)|Pa (pascal)]]
|-
!align=right|''n''
|align=left|= [[amount of substance]], in [[mole (unit)|mol]]
|-
!align=right| ''V''
|align=left|= the volume of the gas, in m<sup>3</sup>
|-
!align=right| ''T''
|align=left|= the absolute temperature of the gas, in [[kelvin|K]]
|-
!align=right| ''R''
|align=left|= the [[gas constant|universal gas law constant]] of 8.3145 m<sup>3</sup>·Pa/(mol·K)
|}
 
The molar volume of any ideal gas may be calculated at various standard reference conditions as shown below:
* '''V'''/'''n''' = 8.3145 × 273.15 / 101.325 = 22.414&nbsp;m<sup>3</sup>/kmol at 0&nbsp;°C and 101.325&nbsp;kPa
* '''V'''/'''n''' = 8.3145 × 273.15 / 100.000 = 22.711&nbsp;m<sup>3</sup>/kmol at 0&nbsp;°C and 100&nbsp;kPa
* '''V'''/'''n''' = 8.3145 × 298.15 / 101.325 = 24.466&nbsp;m<sup>3</sup>/kmol at 25&nbsp;°C and 101.325&nbsp;kPa
* '''V'''/'''n''' = 8.3145 × 298.15 / 100.000 = 24.790&nbsp;m<sup>3</sup>/kmol at 25&nbsp;°C and 100&nbsp;kPa
* '''V'''/'''n''' = 10.7316 × 519.67 / 14.696 = 379.48&nbsp;ft<sup>3</sup>/lbmol at 60&nbsp;°F and 14.696&nbsp;psi (or about 0.8366&nbsp;ft<sup>3</sup>/gram mole)
* '''V'''/'''n''' = 10.7316 × 519.67 / 14.730 = 378.61&nbsp;ft<sup>3</sup>/lbmol at 60&nbsp;°F and 14.73&nbsp;psi
 
The technical literature can be confusing because many authors fail to explain whether they are using the universal gas law constant '''''R''''', which applies to any ideal gas, or whether they are using the gas law constant '''''R<sub>s</sub>''''', which only applies to a specific individual gas. The relationship between the two constants is '''''R<sub>s</sub>''''' = '''''R / M''''', where '''''M''''' is the molecular weight of the gas.
 
The [[US Standard Atmosphere]] (USSA) uses 8.31432&nbsp;m<sup>3</sup>·Pa/(mol·K) as the value of ''R'' (see [[Gas constant]]) for all calculations. However, the USSA,1976 does recognize that this value is not consistent with the values of the Avogadro constant and the Boltzmann constant.<ref name="USSA1976">[http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770009539_1977009539.pdf U.S. Standard Atmosphere], 1976, U.S. Government Printing Office, Washington, D.C., 1976.</ref>
 
==See also==
* [[Atmospheric models]]
* [[Environmental chamber]]
* [[ISO 1]]&nbsp;– standard reference temperature for geometric product specifications
* [[Standard Dry Air]]
* [[Standard state]]
 
==Notes==
{{notelist|35em}}
 
==References==
{{reflist|2}}
 
==External links==
* [http://goldbook.iupac.org/S05910.html "Standard conditions for gases"] from the [[IUPAC]] ''Gold Book''.
* [http://goldbook.iupac.org/S05921.html "Standard pressure"] from the [[IUPAC]] ''Gold Book''.
* [http://goldbook.iupac.org/S06036.html "STP"] from the [[IUPAC]] ''Gold Book''.
* [http://goldbook.iupac.org/S05925.html "Standard state"] from the [[IUPAC]] ''Gold Book''.
 
[[Category:Atmospheric thermodynamics]]
[[Category:Aerodynamics]]
[[Category:Chemical engineering]]
[[Category:Environmental engineering]]
[[Category:Gases]]
[[Category:Measurement]]
[[Category:Mechanical engineering]]
[[Category:Physical chemistry]]
[[Category:Standards]]
[[Category:Thermodynamics]]

Revision as of 11:19, 31 January 2014

Template:Distinguish

Standard conditions for temperature and pressure are standard sets of conditions for experimental measurements established to allow comparisons to be made between different sets of data. The most used standards are those of the International Union of Pure and Applied Chemistry (IUPAC) and the National Institute of Standards and Technology (NIST), although these are not universally accepted standards. Other organizations have established a variety of alternative definitions for their standard reference conditions.

In chemistry, IUPAC established standard temperature and pressure (informally abbreviated as STP) as a temperature of 273.15 K (0 °C, 32 °F) and an absolute pressure of 100 kPa (14.504 psi, 0.987 atm, 1 bar).[1] An unofficial, but commonly used standard is standard ambient temperature and pressure (SATP) as a temperature of 298.15 K (25 °C, 77 °F) and an absolute pressure of 100 kPa (14.504 psi, 0.987 atm). The STP and the SATP should not be confused with the standard state commonly used in thermodynamic evaluations of the Gibbs energy of a reaction.

NIST uses a temperature of 20 °C (293.15 K, 68 °F) and an absolute pressure of 101.325 kPa (14.696 psi, 1 atm). The International Standard Metric Conditions for natural gas and similar fluids are Template:Convert and 101.325 kPa.[2]

In industry and commerce, standard conditions for temperature and pressure are often necessary to define the standard reference conditions to express the volumes of gases and liquids and related quantities such as the rate of volumetric flow (the volumes of gases vary significantly with temperature and pressure). However, many technical publications (books, journals, advertisements for equipment and machinery) simply state "standard conditions" without specifying them, often leading to confusion and errors. Good practice is to always incorporate the reference conditions of temperature and pressure.

Definitions

Past use

In the last five to six decades, professionals and scientists using the metric system of units defined the standard reference conditions of temperature and pressure for expressing gas volumes as being Template:Convert and Template:Convert. During those same years, the most commonly used standard reference conditions for people using the imperial or U.S. customary systems was Template:Convert and 14.696 psi (1 atm) because it was almost universally used by the oil and gas industries worldwide. The above definitions are no longer the most commonly used in either system of units.

Current use

Many different definitions of standard reference conditions are currently being used by organizations all over the world. The table below lists a few of them, but there are more. Some of these organizations used other standards in the past. For example, IUPAC has, since 1982, defined standard reference conditions as being 0 °C and 100 kPa (1 bar), in contrast to its old standard of 0 °C and 101.325 kPa (1 atm).[3]

Natural gas companies in Europe and South America have adopted 15 °C (59 °F) and 101.325 kPa (14.696 psi) as their standard gas volume reference conditions.[4][5][6] Also, the International Organization for Standardization (ISO), the United States Environmental Protection Agency (EPA) and National Institute of Standards and Technology (NIST) each have more than one definition of standard reference conditions in their various standards and regulations.

In Russia, State Standard GOST 2939-63 sets the following standard conditions: 20 °C (293.15 K), 760 mmHg (101325 N/m2) and zero humidity.

Standard reference conditions in current use
Temperature Absolute pressure Relative humidity Publishing or establishing entity
°C kPa % RH
0 100.000   IUPAC (STP)[1]
0 101.325   NIST,[7] ISO 10780,[8] formerly IUPAC[1]
15 101.325 0[9][2] ICAO's ISA,[9] ISO 13443,[2] EEA,[10] EGIA[11]
20 101.325   EPA,[12] NIST[13]
25 101.325   EPA[14]
25 100.000   SATP[15]
20 100.000 0 CAGI[16]
15 100.000   SPE[17]
20 101.3 50 ISO 5011[18]
°F psi % RH
60 14.696   SPE,[17] U.S. OSHA,[19] SCAQMD[20]
60 14.73   EGIA,[11] OPEC,[21] U.S. EIA[22]
59 14.503 78 U.S. Army Standard Metro[23]Template:Efn
59 14.696 60 ISO 2314,[24] ISO 3977-2[25]
°F in Hg % RH
70 29.92 0 AMCA,[26]Template:Efn air density = 0.075 lbm/ft³. This AMCA standard applies only to air.
59 29.92   Federal Aviation Administration (FAA)[27]

Notes:

  • EGIA: Electricity and Gas Inspection Act (of Canada)
  • SATP: Standard Ambient Temperature and Pressure

International Standard Atmosphere

In aeronautics and fluid dynamics the "International Standard Atmosphere" (ISA) is a specification of pressure, temperature, density, and speed of sound at each altitude. The International Standard Atmosphere is representative of atmospheric conditions at mid latitudes. In the USA this information is specified the U.S. Standard Atmosphere which is identical to the "International Standard Atmosphere" at all altitudes up to 65,000 feet above sea level.Potter or Ceramic Artist Truman Bedell from Rexton, has interests which include ceramics, best property developers in singapore developers in singapore and scrabble. Was especially enthused after visiting Alejandro de Humboldt National Park.

Standard laboratory conditions

Due to the fact that many definitions of standard temperature and pressure differ in temperature significantly from standard laboratory temperatures (e.g., 0 °C vs. ~25 °C), reference is often made to "standard laboratory conditions" (a term deliberately chosen to be different from the term "standard conditions for temperature and pressure", despite its semantic near identity when interpreted literally). However, what is a "standard" laboratory temperature and pressure is inevitably culture-bound, given that different parts of the world differ in climate, altitude and the degree of use of heat/cooling in the workplace. For example, schools in New South Wales, Australia use 25 °C at 100 kPa for standard laboratory conditions.[28]

ASTM International has published Standard ASTM E41- Terminology Relating to Conditioning and hundreds of special conditions for particular materials and test methods. Other standards organizations also have specialized standard test conditions.

Molar volume of a gas

It is equally as important to indicate the applicable reference conditions of temperature and pressure when stating the molar volume of a gas[29] as it is when expressing a gas volume or volumetric flow rate. Stating the molar volume of a gas without indicating the reference conditions of temperature and pressure has no meaning and it can cause confusion.

The molar gas volumes can be calculated with an accuracy that is usually sufficient by using the universal gas law for ideal gases. The usual expression is:

PV=nRT

...which can be rearranged thus:

Vn=RTP

where (in SI metric units):

P = the absolute pressure of the gas, in Pa (pascal)
n = amount of substance, in mol
V = the volume of the gas, in m3
T = the absolute temperature of the gas, in K
R = the universal gas law constant of 8.3145 m3·Pa/(mol·K)

The molar volume of any ideal gas may be calculated at various standard reference conditions as shown below:

  • V/n = 8.3145 × 273.15 / 101.325 = 22.414 m3/kmol at 0 °C and 101.325 kPa
  • V/n = 8.3145 × 273.15 / 100.000 = 22.711 m3/kmol at 0 °C and 100 kPa
  • V/n = 8.3145 × 298.15 / 101.325 = 24.466 m3/kmol at 25 °C and 101.325 kPa
  • V/n = 8.3145 × 298.15 / 100.000 = 24.790 m3/kmol at 25 °C and 100 kPa
  • V/n = 10.7316 × 519.67 / 14.696 = 379.48 ft3/lbmol at 60 °F and 14.696 psi (or about 0.8366 ft3/gram mole)
  • V/n = 10.7316 × 519.67 / 14.730 = 378.61 ft3/lbmol at 60 °F and 14.73 psi

The technical literature can be confusing because many authors fail to explain whether they are using the universal gas law constant R, which applies to any ideal gas, or whether they are using the gas law constant Rs, which only applies to a specific individual gas. The relationship between the two constants is Rs = R / M, where M is the molecular weight of the gas.

The US Standard Atmosphere (USSA) uses 8.31432 m3·Pa/(mol·K) as the value of R (see Gas constant) for all calculations. However, the USSA,1976 does recognize that this value is not consistent with the values of the Avogadro constant and the Boltzmann constant.[30]

See also

Notes

Template:Notelist

References

43 year old Petroleum Engineer Harry from Deep River, usually spends time with hobbies and interests like renting movies, property developers in singapore new condominium and vehicle racing. Constantly enjoys going to destinations like Camino Real de Tierra Adentro.

External links

  1. ↑ 1.0 1.1 1.2 20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.

    My blog: http://www.primaboinca.com/view_profile.php?userid=5889534
  2. ↑ 2.0 2.1 2.2 20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.

    My blog: http://www.primaboinca.com/view_profile.php?userid=5889534
  3. ↑ 20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.

    My blog: http://www.primaboinca.com/view_profile.php?userid=5889534
  4. ↑ Template:Cite web Template:Dead link
  5. ↑ Template:Cite web
  6. ↑ Template:Cite web
  7. ↑ Template:Cite webTemplate:Dead link
  8. ↑ Template:Cite web
  9. ↑ 9.0 9.1 20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.

    My blog: http://www.primaboinca.com/view_profile.php?userid=5889534
  10. ↑ 20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.

    My blog: http://www.primaboinca.com/view_profile.php?userid=5889534
  11. ↑ 11.0 11.1 "Electricity and Gas Inspection Act", SOR/86-131 (defines a set of standard conditions for Imperial units and a different set for metric units)  Canadian Laws
  12. ↑ "Standards of Performance for New Sources", 40 CFR—Protection of the Environment, Chapter I, Part 60, Section 60.2, 1990  New Source Performance Standards
  13. ↑ One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting

    In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang

    Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules

    Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.

    A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running

    The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more

    There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang
  14. ↑ "National Primary and Secondary Ambient Air Quality Standards", 40 CFR—Protection of the Environment, Chapter I, Part 50, Section 50.3, 1998  National Ambient Air Standards
  15. ↑ One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting

    In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang

    Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules

    Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.

    A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running

    The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more

    There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang
  16. ↑ Template:Cite web
  17. ↑ 17.0 17.1 Template:Cite web
  18. ↑ 20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.

    My blog: http://www.primaboinca.com/view_profile.php?userid=5889534
  19. ↑ "Storage and Handling of Liquefied Petroleum Gases" and "Storage and Handling of Anhydrous Ammonia", 29 CFR—Labor, Chapter XVII—Occupational Safety and Health Administration, Part 1910, Sect. 1910.110 and 1910.111, 1993  Storage/Handling of LPG
  20. ↑ "Rule 102, Definition of Terms (Standard Conditions)", Amended December 2004, South Coast Air Quality Management District, Los Angeles, California, USA  SCAQMD Rule 102
  21. ↑ Template:Cite web
  22. ↑ Template:Cite web
  23. ↑ 20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.

    My blog: http://www.primaboinca.com/view_profile.php?userid=5889534
  24. ↑ 20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.

    My blog: http://www.primaboinca.com/view_profile.php?userid=5889534
  25. ↑ 20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.

    My blog: http://www.primaboinca.com/view_profile.php?userid=5889534
  26. ↑ ANSI/AMCA Standard 210, "Laboratory Methods Of Testing Fans for Aerodynamic Performance Rating", as implied by http://www.greenheck.com/pdf/centrifugal/Plug.pdf when accessed on October 17, 2007
  27. ↑ 20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.

    My blog: http://www.primaboinca.com/view_profile.php?userid=5889534
  28. ↑ 20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.

    My blog: http://www.primaboinca.com/view_profile.php?userid=5889534
  29. ↑ Template:Cite web
  30. ↑ U.S. Standard Atmosphere, 1976, U.S. Government Printing Office, Washington, D.C., 1976.
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