Author Topic: Component Quantity and Units  (Read 174 times)

rezvan

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Component Quantity and Units
« on: May 02, 2022, 04:58:49 PM »
Dear Adam,

I hope my so many questions do not bother you.

Regarding the quantity and unit of the components, for one like "C10.11.001a" which is the wall partition, in the CMP_marignals_LET file, you defined ft2 (square feet) as the unit; however, in the bldg_repair_DB_FEMA_P58_2nd.csv file the repair cost is based on 100 LF which is similar to "Normative Quantity Estimation Tool".

I just wanted to make sure whether the users should follow the units provided in the bldg_repair_DB_FEMA_P58_2nd.csv file or any related unit is acceptable.

Another example is "D5012.021a" which is low-voltage switchgear. Based on the FEMA documentation the quantity should be based on 250 AMP, but you defined "EACH" in the bldg_repair_DB_FEMA_P58_2nd.csv file. Does "EACH" mean each of 250 AMP? since the same repair cost is defined for 250 AMP in FEMA documentation.


Thank you so much,
 Pooya
« Last Edit: May 02, 2022, 11:21:58 PM by rezvan »

adamzs

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Re: Component Quantity and Units
« Reply #1 on: May 03, 2022, 06:12:41 AM »
Hi Pooya,

Thank you for these questions; I can assure you, they are very well received and welcome. Please don't hesitate to ask.

The short answer is that you do not need to worry about what the unit specified in the database as long as you use the same type of unit (i.e., length, area, volume, etc.).

The C10.11.001a is a perfect example of a case where I did not follow that rule: I should've used 'ft' for the partition walls. Pelicun cannot convert between area and length units because it does not know what the missing dimension of the partition wall should be. You can see all of the available units in the base.py module of Pelicun here: https://github.com/zsarnoczay/pelicun/blob/develop/pelicun/base.py#L576
I will fix the portion wall units and update the notebook.

In the databases, I kept the units used in the original document to show that a person who develops fragility or consequence functions does not need to worry about what units they used to define those functions because pelicun will automatically perform the conversions in the background.

As for the low-voltage switchgear, the units provided in the FEMA P58 documentation are somewhat misleading. I double-checked this with researchers who were involved in the development of the P58 methodology: all components that have TN, AP, CF, or KV units should be calculated as if they had EA. The rationale is that you would need to know how many of those equipment you have rather than providing a measure of their weight, capacity, or performance. That's why I replaced these measures with EA even in the supporting database.

I hope this helps and thanks for catching that error with the ft2.

Let me know if you have more questions.

Adam