# How do i add ml/m2 in the archetype designer

**Category:** [Archetype Designer](https://discourse.openehr.org/c/archetype-designer/30)
**Created:** 2023-02-20 14:51 UTC
**Views:** 596
**Replies:** 5
**URL:** https://discourse.openehr.org/t/how-do-i-add-ml-m2-in-the-archetype-designer/3592

---

## Post #1 by @SevKohler

I wanted to add that using curly braces, but its a Volume/Area which is not allowed with curly braces.
VOLUME/MASS works but only with cm2.
Any other option left other then the change request for the xml in jira ? 

related: https://discourse.openehr.org/t/adding-to-the-dv-quantity-units-options/1964

---

## Post #2 by @siljelb

Hi Severin! What's the use case of the unit? :smile:

---

## Post #3 by @SevKohler

MRI parameters like an stroke volume index

---

## Post #4 by @siljelb

[quote="SevKohler, post:3, topic:3592"]
stroke volume index
[/quote]

Thanks, that clarifies the use case! The correct way to get this change into the units xml file is, as you say, to raise a jira PR asking for this to be added, and then notifying Better that a new version of the file is available.

As for the details, a new property is probably needed, something like
```xml
<Property id="91" Text="Volume per Area" openEHR="761" />
```

...and a few new units for the property:
```xml
<Unit property_id="91" Text="m³/m²" conversion="1" primary="true" UCUM="m3/m2"/>
<Unit property_id="91" Text="L/m²" conversion="1" coefficient="-3" primary="false" UCUM="mL/m2"/>
<Unit property_id="91" Text="mL/m²" conversion="1" coefficient="-6" primary="false" UCUM="mL/m2"/>
```

---

## Post #5 by @SevKohler

I cannot find the jira link would you be so nice and provide it to me ?

---

## Post #6 by @siljelb

Sorry, it's this project: [Specification PR tracker - Issues - openEHR JIRA (atlassian.net)](https://openehr.atlassian.net/jira/software/c/projects/SPECPR/issues)

To expedite the change you can also create a branch and pull request here: [openEHR/specifications-TERM: openEHR terminology-related specifications (github.com)](https://github.com/openEHR/specifications-TERM)

You can use this PR and pull request as templates if you like:
* [[SPECPR-409] A few errors and an editorial change in PropertyUnitData.xml - openEHR JIRA (atlassian.net)](https://openehr.atlassian.net/browse/SPECPR-409)
* [Removed AGPL message and fixed the two errors in SPECPR-409 by siljelb · Pull Request #7 · openEHR/specifications-TERM (github.com)](https://github.com/openEHR/specifications-TERM/pull/7)

---


**Canonical:** https://discourse.openehr.org/t/how-do-i-add-ml-m2-in-the-archetype-designer/3592
**Original content:** https://discourse.openehr.org/t/how-do-i-add-ml-m2-in-the-archetype-designer/3592