## 5 Results
### Phase II: Requirements Elicitation
#### 5.2.2 FRAM Model
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**N\({}^{o}\)**} & \multirow{2}{*}{**Function**} & \multicolumn{2}{c}{**Variability**} \\ \cline{3-4}  & & **Regarding Time** & **Regarding Precision** \\ \hline \multirow{2}{*}{1} & \multirow{2}{*}{Record place in CISI} & On time & Imprecise \\  & & This function does not vary regarding time & Requests may fill the place of \\  & & & service wrongly. \\ \hline \multirow{2}{*}{2} & \multirow{2}{*}{Record service in CISI} & \multirow{2}{*}{On time} & Imprecise \\  & & This function does not vary regarding time & Requests often describe service in an \\  & & & ambiguous or incomplete way because \\  & & & they do have not enough knowledge to \\  & & & describe the service properly \\ \hline \multirow{2}{*}{3} & \multirow{2}{*}{Monitor CISI for new requests} & Too late & Precise \\  & & The function can be impacted by delays, & This function does not vary \\  & & since the maintenance supervisor has other & regarding precision \\  & & assignments out of the office. & \\ \hline \multirow{2}{*}{4} & \multirow{2}{*}{Analyze service description} & Too late & Acceptable \\  & & This function may consume some time due & The service description may not be \\  & & to adjustments to understand and clarify & comprehensible by the maintenance \\  & & the service description. This scenario may & supervisor. Then, to clarify the service \\  & & entail delays in downstream functions. & description, he needs to contact \\  & & & the requestor. \\ \hline \multirow{2}{*}{5} & \multirow{2}{*}{Select service group} & \multirow{2}{*}{On time} & Imprecise \\  & & This function does not vary regarding time & The unsuccessful outcome in upstream \\  & & & function 5 can entail an imprecise \\  & & & decision regarding the service group. \\ \hline \multirow{2}{*}{6} & \multirow{2}{*}{Select a working team} & Too late & Acceptable \\  & & The function triggering time often depends & In CISI, the field for technicians’ selection \\  & & on the availability and qualification of & does not allow the user to select more \\  & & technicians. This scenario submits the & than one technician. Then, \\  & & maintenance supervisor to trade-offs, & the maintenance supervisor adapts the \\  & & since he needs to select an & WO form, recording the technicians’ \\  & & alternative technician. & names in the field “observation”. \\ \hline \multirow{2}{*}{7} & \multirow{2}{*}{Receive additional details and \multirow{2}{*}{update data in CISI}} & Too late & Acceptable \\  & & Using e-mails or calls to receive a reply can & Once the requestor’s answer is \\  & & entail delays in downstream functions. & satisfactory, this information is enough to \\  & & & support the service analysis. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Potential variability identified in the work order issuance for the maintenance in HVAC systems. In work order issuance, the maintenance supervisor needs to resort to some adjustments during this process due to IT system limitations. For example, the interviewed supervisor reported that the requestor often describes the service in CISI ambiguously or incompletely. In this context, the maintenance supervisor needs to use their expertise and ability to ensure the issuing of WO in the shortest time possible. On this subject, the supervisor said: _\"If we were to follow the process through CISI, there would be no time to cope with the occurrence [... ] Sometimes the customer calls for urgent maintenance. I need to move teamwork to the site quickly [... ] some situations cannot wait a long time, like a defect in an air conditioning for an important laboratory\"_. The function \"analyze service description\" is considered critical because it is prone to spread variability along with the maintenance working of HVAC systems. In the worst scenario, this function may receive an unsatisfying outcome from the upstream function \"receive the request from customer\".