.. _my-reference-databases:

Reliability Data Databases (EPRD / NPRD)
==========================================

Besides computing a failure rate from a prediction standard, Robin gives access to two field data databases published by Quanterion Solutions. Instead of deriving the failure rate from the construction and the operating conditions of the part, these databases provide failure rates observed in service for a large collection of real parts.

They are useful when the part cannot be modelled with a standard, or to contrast the result of a prediction against field experience.

Two tabs are available inside the RPA module:

- ``RPA > Electronic Data (EPRD-2014)``: The Electronic Parts Reliability Data database.
- ``RPA > Mechanical Data (NPRD-2016)``: The Non-electronic Parts Reliability Data database.

.. note::
    These two tabs are only visible for the teams whose subscription includes access to the Quanterion databases. If the option is not part of the subscription, the tabs are not displayed.

Searching the database
------------------------

The search is performed by **part description**, and it can be narrowed down with two multiple-selection dropdowns:

- **Select quality(s)**: Filters by the quality level of the parts.
- **Select environment(s)**: Filters by the environment in which the data was collected.

Click ``Search`` to run the query.

The description field accepts the wildcard character ``*``, which allows searching for parts whose exact description is not known:

+---------------------+--------------------------------------------------------------------+
| Search              | Result                                                             |
+=====================+====================================================================+
| ``ele*``            | Finds *electric*, but not *selector*                               |
+---------------------+--------------------------------------------------------------------+
| ``*ger``            | Finds *defogger*, but not *refrigerator*                           |
+---------------------+--------------------------------------------------------------------+
| ``*pr*``            | Finds *sprint*, *pressure*, ...                                    |
+---------------------+--------------------------------------------------------------------+
| ``bat*li*``         | Finds *battery, Lithium*                                           |
+---------------------+--------------------------------------------------------------------+
| ``adapter``         | Finds *Adapter*, but not *AC Adapter*                              |
+---------------------+--------------------------------------------------------------------+

.. note::
    Without any wildcard, the search looks for the exact description. Any combination of the examples above is also possible.

.. image:: img/rpa_eprd.png
    :width: 696.47pt

Results
---------

The result of the search is a table with one row per entry of the database. The information provided is:

- **Part Description**: The description of the part as recorded in the database
- **Quality Level**: The quality level of the part
- **Environment**: The environment in which the data was collected
- **Source**: The origin of the data
- **Failure rate fails per E6 units** and **Failure rate units**: The observed failure rate and the units it refers to
- **Total Failed** and **Op. Hours**: The number of failures recorded and the accumulated operating hours behind the value, which give an idea of how much evidence supports the figure

The NPRD-2016 table additionally provides the **Confidence Level** of the entry.

.. image:: img/rpa_nprd.png
    :width: 696.47pt

.. note::
    The information icon next to the ``Search`` button downloads the introduction publication of the corresponding database, developed by Quanterion Solutions, which explains the meaning of the fields and how the data was gathered.

Assigning a failure rate to a BOM item
----------------------------------------

These databases can be used as the source of the failure rate of a BOM item, in the same way as the prediction standards.

When the page is opened from the BOM, through the `Calculate failure rate` action of an item, a message at the top indicates which part the entry is being selected for, and an additional column with a selectable icon appears in the results table. Clicking it assigns that entry to the item.

After the selection, the ``Return to BOM`` button brings the user back to the Bill Of Material, where the Standard column of the item shows ``EPRD 2014`` or ``NPRD 2016`` depending on the database used.

.. note::
    An item whose failure rate comes from one of these databases has no calculation parameters, since the value is taken from field data and not computed from a model. See the :ref:`my-reference-bom` section.