Today we tested some settings of the INJ HVAC system, in order to evaluate the noise increase inside the INJ lab.

This is the timetable (UTC) of the operations:

• 07:39:40 Set to "person present in lab" mode (leave all systems in automatic mode)
• 07:56:00 Switch back to "no one in lab" mode – 15 min
• 08:10:30 Keep extraction (return air) flow rate constant + increase supply air fan to 33 Hz
• 08:20:30 Keep extraction flow rate constant + return supply air fan to baseline value (~23 Hz)
• 08:30:20 Keep supply air flow rate constant + increase extraction fan to 30 Hz
• 08:45:20 Keep supply air flow rate constant + return extraction fan to baseline value (~20 Hz)
• 08:56:30 Increase both supply and extraction fan frequencies simultaneously by 10 Hz
• 09:10:30 Restore all parameters to initial conditions – end of test

A detailed analysis will follow.

It is worth noting that some acoustic noise was detected inside the INJ lab by the microphones. This could be a consequence of the maintenance operations carried out on the platform inside the CEB.

Also note that during the automatic setting at 07:39:40 UTC, only the supply fan was adjusted by the system.