ISO 1 is an international standard set by the International Organization for Standardization that specifies the standard reference temperature for geometrical product specification and verification. The temperature is fixed at 20 °C, which is equal to 293.15 kelvin and 68 degrees Fahrenheit.[1]

Due to thermal expansion, precision length measurements need to be made at (or converted to) a defined temperature. ISO 1 helps in comparing measurements by defining such a reference temperature. The reference temperature of 20 °C was adopted by the CIPM on 15 April 1931, and became ISO recommendation number 1 in 1951.[2] It soon replaced worldwide other reference temperatures for length measurements that manufacturers of precision equipment had used before, including 0 °C, 62 °F, and 25 °C. Among the reasons for choosing 20 °C was that this was a comfortable and practical workshop temperature and that it resulted in an integer value on both the Celsius and Fahrenheit scales.

See also


  1. ^ "ISO 1:2016 - Geometrical product specifications (GPS) -- Standard reference temperature for the specification of geometrical and dimensional properties". 2016-08-26. Retrieved 2016-09-15.
  2. ^ Ted Doiron: 20 °C—A Short History of the Standard Reference Temperature for Industrial Dimensional Measurements. Journal of Research of the National Institute of Standards and Technology, Vol. 112, No. 1, January–February 2007.
Bill Turner (public servant)

William Terry "Bill" Turner (1 December 1887 – 26 January 1959) was a senior Australian public servant. He was Comptroller-General of Customs between 1949 and 1952, heading the Department of Trade and Customs.

C. E. Owen Smyth

Charles Edward Owen Smyth (1 January 1851 – 1 October 1925) was an Irish-born South Australian public servant.


A cleanroom or clean room is a facility ordinarily utilized as a part of specialized industrial production or scientific research, including the manufacture of pharmaceutical items and microprocessors. Cleanrooms are designed to maintain extremely low levels of particulates, such as dust, airborne organisms, or vaporized particles. Cleanrooms typically have an cleanliness level quantified by the number of particles per cubic meter at a predetermined molecule measure. The ambient outdoor air in a typical urban area contains 35,000,000 particles for each cubic meter in the size range 0.5 μm and bigger in measurement, equivalent to an ISO 9 cleanroom, while by comparison an ISO 1 cleanroom permits no particles in that size range and just 12 particles for each cubic meter of 0.3 μm and smaller.

County administrative boards of Sweden

A county administrative board (Swedish: länsstyrelse) is a Swedish Government Agency in each of the counties of Sweden, led by a governor (Swedish: landshövding) appointed by the government for a term of six years. The lists of gubernatorial officeholders, in most cases, stretches back to 1634 when the counties were created by Chancellor Axel Oxenstierna.

The main responsibilities of the county administrative board is to coordinate the development of the county in line with goals set in national politics. In each county there is also a County Council which is a policy-making assembly elected by the residents of the county.

The capital of a county is in Swedish called residensstad ("residence city") because it is the seat of residence of the governor. Each county also has a letter code, which is used for identification and forms part of the ISO 3166-2 standard.

International Organization for Standardization

The International Organization for Standardization (ISO ) is an international standard-setting body composed of representatives from various national standards organizations.

Founded on 23 February 1947, the organization promotes worldwide proprietary, industrial and commercial standards. It is headquartered in Geneva, Switzerland, and works in 164 countries.It was one of the first organizations granted general consultative status with the United Nations Economic and Social Council.

List of International Organization for Standardization standards

This is a list of published International Organization for Standardization (ISO) standards and other deliverables. For a complete and up-to-date list of all the ISO standards, see the ISO catalogue.The standards are protected by copyright and most of them must be purchased. However, about 300 of the standards produced by ISO and IEC's Joint Technical Committee 1 (JTC1) have been made freely and publicly available.

Macrophage migration inhibitory factor

Macrophage migration inhibitory factor (MIF or MMIF), also known as glycosylation-inhibiting factor (GIF), L-dopachrome isomerase, or phenylpyruvate tautomerase is a protein that in humans is encoded by the MIF gene. MIF is an important regulator of innate immunity. The MIF protein superfamily also includes a second member with functionally related properties, the D-dopachrome tautomerase (D-DT).Bacterial antigens stimulate white blood cells to release MIF into the blood stream. The circulating MIF binds to CD74 on other immune cells to trigger an acute immune response. Hence, MIF is classified as an inflammatory cytokine. Furthermore, glucocorticoids also stimulate white blood cells to release MIF and hence MIF partially counteracts the inhibitory effects that glucocorticoids have on the immune system. Finally trauma activates the anterior pituitary gland to release MIF.


The metre (British spelling and BIPM spelling) or meter (American spelling) (from the French unit mètre, from the Greek noun μέτρον, "measure") is the base unit of length in the International System of Units (SI). The SI unit symbol is m. The metre is defined as the length of the path travelled by light in a vacuum in 1/299 792 458 second.The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole – as a result the Earth's circumference is approximately 40,000 km today. In 1799, it was redefined in terms of a prototype metre bar (the actual bar used was changed in 1889). In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. In 1983, the current definition was adopted.

The imperial inch is defined as 0.0254 metres (2.54 centimetres or 25.4 millimetres). One metre is about ​3 3⁄8 inches longer than a yard, i.e. about ​39 3⁄8 inches.

Object identifier

In computing, object identifiers or OIDs are an identifier mechanism standardized by the International Telecommunications Union (ITU) and ISO/IEC for naming any object, concept, or "thing" with a globally unambiguous persistent name.

Omega loop

The omega loop is a non-regular protein structural motif, consisting of a loop of six or more amino acid residues and any amino acid sequence. The defining characteristic is that residues that make up the beginning and end of the loop are close together in space with no intervening lengths of regular secondary structural motifs. It is named after its shape, which resembles the upper-case Greek letter Omega (Ω).

Online Certificate Status Protocol

The Online Certificate Status Protocol (OCSP) is an Internet protocol used for obtaining the revocation status of an X.509 digital certificate. It is described in RFC 6960 and is on the Internet standards track. It was created as an alternative to certificate revocation lists (CRL), specifically addressing certain problems associated with using CRLs in a public key infrastructure (PKI). Messages communicated via OCSP are encoded in ASN.1 and are usually communicated over HTTP. The "request/response" nature of these messages leads to OCSP servers being termed OCSP responders.

Some web browsers use OCSP to validate HTTPS certificates. However, the most popular browser, Google Chrome, only uses CRL.

Photographic Activity Test

Photographic Activity Test is an ISO [1] standard test detailed in ISO 18916:2007 (E). Previous versions of the standard were numbered ISO 14523:1999(E); however, it was updated and renumbered in 2007.

The test evaluates materials for archival quality and their use in photographic enclosures. Many different types of materials can be tested including: paper, boards, plastic, adhesives, pens, stickers, labels, paints and inks. The test involves incubating samples and detectors in a high-temperature, high-humidity accelerated aging environment.

Provinces of Cambodia

Cambodia is divided into 25 provinces (Khmer: ខេត្ត, khaet, singular and plural). The capital Phnom Penh is not a province but an autonomous municipality and is included as the 25th province since it is administered at the same level as the other 24 provinces.

Phnom Penh has both the highest population and the highest population density, but is the second smallest in land area. The largest province by area is Mondulkiri and the smallest is Kep which is also the least populated province. Mondulkiri has the lowest population density despite being the largest province.

Each province is administered by a governor, who is appointed by the Ministry of Interior.

Cambodia is subdivided into 163 districts (srok, ស្រុក). The 12 districts of Phnom Penh are called khan (ខណ្ឌ), but even in official documents they are sometimes misidentified as srok. The number of districts in each province varies, from two in the smallest provinces to 14 in Battambang, Prey Veng, and Siem Reap. Further subdivision levels are khum (ឃុំ)(subdistricts), sangkat (សង្កាត់)(quarters) and finally, phum (ភូមិ) (villages). In Phnom Penh there are no khum.

Room temperature

Colloquially, room temperature is the range of air temperatures that most people prefer for indoor settings, which feel comfortable when wearing typical indoor clothing. Human comfort can extend beyond this range depending on humidity, air circulation and other factors. In certain fields, like science and engineering, and within a particular context, room temperature can mean different agreed-on ranges. In contrast, ambient temperature is the actual temperature of the air (or other medium and surroundings) in any particular place, as measured by a thermometer. It may be very different from usual room temperature, for example an unheated room in winter.

Sigma-2 receptor

The sigma-2 receptor (σ2R) is a sigma receptor subtype that has attracted attention due to its involvement in diseases such as cancer and neurological diseases. It is currently under investigation for its potential diagnostic and therapeutic uses.Although the sigma-2 receptor was identified as a separate pharmacological entity from the sigma-1 receptor in 1990, the gene that codes for the receptor was identified as TMEM97 only in 2016. TMEM97 was shown to regulate the cholesterol transporter NPC1 and to be involved in cholesterol homeostasis. The sigma-2 receptor is a four-pass transmembrane protein located in the endoplasmic reticulum. It has been found to play a role in both hormone signaling and calcium signaling, in neuronal signaling, in cell proliferation and death, and in binding of antipsychotics.

Standard conditions for temperature and pressure

Standard conditions for temperature and pressure are standard sets of conditions for experimental measurements to be 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 changed the definition of standard temperature and pressure (STP) in 1982:

Until 1982, STP was defined as a temperature of 273.15 K (0 °C, 32 °F) and an absolute pressure of exactly 1 atm (101.325 kPa).

Since 1982, STP is defined as a temperature of 273.15 K (0 °C, 32 °F) and an absolute pressure of exactly 105 Pa (100 kPa, 1 bar).STP 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 1 atm (14.696 psi, 101.325 kPa). This standard is also called normal temperature and pressure (abbreviated as NTP).

The International Standard Metric Conditions for natural gas and similar fluids are 288.15 K (15.00 °C; 59.00 °F) and 101.325 kPa.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) – standard cubic meters per second (sm3/s), and normal cubic meters per second (nm3/s). 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 always incorporates the reference conditions of temperature and pressure.


Temperature is a physical quantity expressing hot and cold. It is measured with a thermometer calibrated in one or more temperature scales. The most commonly used scales are the Celsius scale (formerly called centigrade) (denoted °C), Fahrenheit scale (denoted °F), and Kelvin scale (denoted K). The kelvin (the word is spelled with a lower-case k) is the unit of temperature in the International System of Units (SI), in which temperature is one of the seven fundamental base quantities. The Kelvin scale is widely used in science and technology.

Theoretically, the coldest a system can be is when its temperature is absolute zero, at which point the thermal motion in matter would be zero. However, an actual physical system or object can never attain a temperature of absolute zero. Absolute zero is denoted as 0 K on the Kelvin scale, −273.15 °C on the Celsius scale, and −459.67 °F on the Fahrenheit scale.

For an ideal gas, temperature is proportional to the average kinetic energy of the random microscopic motions of the constituent microscopic particles.

Temperature is important in all fields of natural science, including physics, chemistry, Earth science, medicine, and biology, as well as most aspects of daily life.

Tool steel

Tool steel refers to a variety of carbon and alloy steels that are particularly well-suited to be made into tools. Their suitability comes from their distinctive hardness, resistance to abrasion and deformation, and their ability to hold a cutting edge at elevated temperatures. As a result, tool steels are suited for use in the shaping of other materials.

With a carbon content between 0.5% and 1.5%, tool steels are manufactured under carefully controlled conditions to produce the required quality. The presence of carbides in their matrix plays the dominant role in the qualities of tool steel. The four major alloying elements that form carbides in tool steel are: tungsten, chromium, vanadium and molybdenum. The rate of dissolution of the different carbides into the austenite form of the iron determines the high-temperature performance of steel (slower is better, making for a heat-resistant steel). Proper heat treatment of these steels is important for adequate performance. The manganese content is often kept low to minimize the possibility of cracking during water quenching.

There are six groups of tool steels: water-hardening, cold-work, shock-resistant, high-speed, hot-work, and special purpose. The choice of group to select depends on cost, working temperature, required surface hardness, strength, shock resistance, and toughness requirements. The more severe the service condition (higher temperature, abrasiveness, corrosiveness, loading), the higher the alloy content and consequent amount of carbides required for the tool steel.

Tool steels are used for cutting, pressing, extruding, and coining of metals and other materials. Their use, such as the production of injection molds, is essential, due to their resistance to abrasion, which is an important criterion for a mold that will be used to produce hundreds of thousands of moldings of a product or part.

The AISI-SAE grades of tool steel is the most common scale used to identify various grades of tool steel. Individual alloys within a grade are given a number; for example: A2, O1, etc.

Tool steel is the hardest type of steel.

Woodridge, Illinois

Woodridge is a village in DuPage County, Illinois, with portions in Will and Cook counties, and a south-western suburb of Chicago. It uses the 630 and 331 area codes. The population was 32,971 at the 2010 census. Woodridge is the home of the Home Run Inn pizzeria chain and was the home of Pabst Brewing Company from 2006-2011.Woodridge was incorporated on August 24, 1959, with less than 500 residents, on a wooded area of high ground overlooking the DuPage River's East Branch. Woodridge is a young community with the vast majority of its homes, businesses, and churches constructed after the 1950s. Woodridge was founded by a housing developer, Albert Kaufman, who was largely responsible for the creation of the village.

In July 2007, Woodridge was ranked No. 61 on Money magazine's "100 Best Places to Live".

ISO standards by standard number

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