A centimetre or millimetre of water (US spelling centimeter or millimeter of water) are less commonly used measures of pressure derived from pressure head.
A centimetre of water (US spelling centimeter of water)[1] is a unit of pressure. It may be defined as the pressure exerted by a column of water of 1 cm in height at 4 °C (temperature of maximum density) at the standard acceleration of gravity, so that 1 cmH2O (4°C) = 999.9720 kg/m3 × 9.80665 m/s2 × 1 cm = 98.063754138 Pa ≈ 98.0638 Pa, but conventionally a nominal maximum water density of 1000 kg/m3 is used, giving 98.0665 Pa.
Millimetre of water (US spelling millimeter of water)[3] is a unit of pressure. It may be defined as the pressure exerted by a column of water of 1 mm in height at 4 °C (temperature of maximum density) at the standard acceleration of gravity, so that 1 mmH2O (4 °C) = 999.9720 kg/m3 × 9.80665 m/s2 × 1 mm = 9.8063754138 Pa ≈ 9.80638 Pa, but conventionally a nominal maximum water density of 1000 kg/m3 is used, giving 9.80665 Pa.
centimetre, millimetre, water, centimetre, millimetre, water, spelling, centimeter, millimeter, water, less, commonly, used, measures, pressure, derived, from, pressure, head, contents, centimetre, water, millimetre, water, also, references, external, linkscen. A centimetre or millimetre of water US spelling centimeter or millimeter of water are less commonly used measures of pressure derived from pressure head Contents 1 Centimetre of water 2 Millimetre of water 3 See also 4 References 5 External linksCentimetre of water Editcentimetre of waterUnit ofPressureSymbolcmH2OConversions1 cmH2O in is equal to SI units 98 0665 Pa English Engineering units 1 422334 10 2 psiA centimetre of water US spelling centimeter of water 1 is a unit of pressure It may be defined as the pressure exerted by a column of water of 1 cm in height at 4 C temperature of maximum density at the standard acceleration of gravity so that 1 cmH2O 4 C 999 9720 kg m3 9 80665 m s2 1 cm 98 063754138 Pa 98 0638 Pa but conventionally a nominal maximum water density of 1000 kg m3 is used giving 98 0665 Pa The centimetre of water unit is frequently used to measure the central venous pressure the intracranial pressure while sampling cerebrospinal fluid as well as determining pressures during mechanical ventilation or in water supply networks then usually in metres water column It is also a common unit of pressure in the speech sciences This unit is commonly used to specify the pressure to which a CPAP machine is set after a polysomnogram 1 cmH2O conventional 98 0665 pascals 2 0 01 metre water mH2O metre water column m wc or metre water gauge m wg 10 mm wg 0 980665 mbar or hPa 0 3937008 inH2O 0 000967 8411 atm 0 7355592 torr 0 7355591 mm Hg 0 028959 02 inHg 0 014223 34 psiMillimetre of water Editmillimetre of waterUnit ofPressureSymbolmmH2OConversions1 mmH2O in is equal to SI units 9 80665 Pa English Engineering units 1 422334 10 3 psiMillimetre of water US spelling millimeter of water 3 is a unit of pressure It may be defined as the pressure exerted by a column of water of 1 mm in height at 4 C temperature of maximum density at the standard acceleration of gravity so that 1 mmH2O 4 C 999 9720 kg m3 9 80665 m s2 1 mm 9 8063754138 Pa 9 80638 Pa but conventionally a nominal maximum water density of 1000 kg m3 is used giving 9 80665 Pa 1 mmH2O conventional 9 80665 pascals 2 0 001 metre water mH2O metre water column m wc or metre water gauge m wg 0 1 cm wg 0 0980665 mbar or hPa 0 039370 08 inH2O 9 678411 10 5 atm 0 073555 92 torr 0 073555 91 mmHg 0 002895 902 inHg 0 001422 334 psiIn limited and largely historic contexts it may vary with temperature using the equation P r g h 1000 where P pressure in Pa r density of water conventionally 1000 kg m3 at 4 C g acceleration due to gravity conventionally 9 80665 m s2 but sometimes locally determined h water height in millimetres The unit is often used to describe how much water rainwear or other outerwear can take or how much water a tent can resist without leaking See also EditMillimetre of mercuryReferences Edit NOTE A centimetre of water is abbreviated as cmH2O or cm H2O a b nist gov Guide for the Use of the International System of Units SI page 47 2008 Edition NOTE Millimetre of water is also sometimes addressed as millimetres water column abbreviated as mmwg mmH2O or mmwc External links EditPressure conversion calculator at Cornell University website Retrieved from https en wikipedia org w index php title Centimetre or millimetre of water amp oldid 1128551734, wikipedia, wiki, book, books, library,
