Opened 2 years ago

Last modified 22 months ago

#3667 new enhancement

torr

Reported by: John Borsi Owned by:
Priority: minor Milestone:
Component: unit definitions Keywords:
Cc:

Description

I was a bit surprised when I was unable to find any unit corresponding to the 'Torr' in the UCUM specification. (https://en.wikipedia.org/wiki/Torr) Yes, it's almost equivalent to mm[Hg], but they aren't actually the same. I do see the Torr occasionally used in clinical practice, so this would be a nice addition to the specification.

Change History (2)

comment:1 Changed 22 months ago by Gunther Schadow

Acknowledging this ticket. I am sorry that our ticket system is still defunct because of massive spammer attack. But someone noted this ticket via email.

You say:

"Yes, it's almost equivalent to mm[Hg], but they aren't actually the same."

In order for to act, we would need a proposal or at least some detail about how they are not the same, and specifically how, when "I do see the Torr occasionally used in clinical practice," how it is then anything else that mm[Hg]?

comment:2 Changed 22 months ago by Gunther Schadow

OK, Wikipedia

"The torr (symbol: Torr) is a unit of pressure based on an absolute scale, now defined as exactly 1/760 of a standard atmosphere. Thus one torr is exactly 101325/760 pascals (~133.3 Pa). Historically, one torr was intended to be the same as one "millimetre of mercury". However, subsequent redefinitions of the two units made them slightly different (by less than 0.000015%)."

Based on this definition we could add the Torr.

But I would caution that when clinicians use "Torr" they actually mean "mm Hg" as their amount of caring about this is proportional with their experience of measuring with actual mercury columns rather than Bourdon gauge. So in some way the addition of Torr as a slightly different unit is defeating a practical purpose.

Last edited 22 months ago by Gunther Schadow (previous) (diff)
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