Metre sea water

foot sea water
foot sea water
	Pressure gauge on Siebe Gorman manual diver's pump calibrated in fsw and psi
General information
Unit of	pressure
Symbol	fsw
Conversions
1 fsw in ...	... is equal to ...
SI units	≈ 3064.3 Pa
CGS units	≈ 30643 Ba
U.S. customary	≈ 0.44444 psi

metre sea water
metre sea water
	Hyperbaric chamber pressure gauge calibrated in msw and bar
General information
Unit of	pressure
Symbol	msw
Conversions
1 msw in ...	... is equal to ...
SI units	= 10000.0 Pa
CGS units	= 100000 Ba
U.S. customary	≈ 3.263 fsw; ≈ 1.45038 psi

The metre (or meter) sea water (msw) is a metric unit of pressure used in underwater diving. It is defined as one tenth of a bar.^[1]^[2]

The unit used in the US is the foot sea water (fsw), based on standard gravity and a sea-water density of 64 lb/ft³. According to the US Navy Diving Manual, one fsw equals 0.30643 msw, 0.030643 bar, or 0.44444 psi,^[1]^[2] though elsewhere it states that 33 fsw is 14.7 psi (one atmosphere), which gives one fsw equal to about 0.445 psi.^[3]

The msw and fsw are the conventional units for measurement of diver pressure exposure used in decompression tables and the unit of calibration for pneumofathometers and hyperbaric chamber pressure gauges.^[4]

^ ^a ^b US Navy Diving Manual 2016, Table 2‑10. Pressure Equivalents..
^ ^a ^b Cite error: The named reference IMCA D022 was invoked but never defined (see the help page).
^ Page 2-12.
^ US Navy Diving Manual 2016, Section 18‑2.8.3.

[FOOTNOTE''US_Navy_Diving_Manual''2016Table_2‑10._Pressure_Equivalents.-1] US Navy Diving Manual 2016, Table 2‑10. Pressure Equivalents..

[IMCA_D022-2] Cite error: The named reference IMCA D022 was invoked but never defined (see the help page).

[3] Page 2-12.

[FOOTNOTE''US_Navy_Diving_Manual''2016Section_18‑2.8.3-4] US Navy Diving Manual 2016, Section 18‑2.8.3.

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