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Environmental Monitoring (Environmental Monitoring)

Paoletti, Soldani, Fiori, Tringali - 13:38 Tuesday 07 October 2025 (67876)

Speed-up test of HVAC INJ machine

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.

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Comments to this report:

Paoletti - 14:26 Wednesday 08 October 2025 (67885)

Below are the useful time windows for analysis (all times in UTC on October 7th), selected to avoid, as much as possible, noise from maintenance activities:

Quiet: 02:00:00 + 600s
Step 1: 07:49:00 + 300s
Step 3: 08:18:00 + 120s
Step 5: 08:30:45 + 120s
Step 7: 09:04:05 + 120s

Fiori, Passaquieti, Tringali, Soldani - 16:06 Tuesday 04 November 2025 (68091)

This morning, we performed a test to evaluate the impact of the air duct valves' operation on the noise in the Laser Laboratory.
The valves under study control the supply and return air flux in the vicinity of the optical bench area.
The valve openings were actuated via the Kieback & Peter control interface, Figure 1 and 2.
A value of 0% corresponds to a fully closed valve, while 100% corresponds to a fully open valve.
The opening of these two valves is set to 100% for the supply line and 0% for the return line in SCIENCE mode operation.
During the whole test, the fan frequency for the supply air unit was kept fixed at 23.0 Hz, and that of the return air unit at 20.4 Hz, respectively.
Below is the list of actions performed during the test (see Figure 3):

Time (UTC)	Supply valve opening (%)	Return valve opening (%)	Note
09:53	70 %	0%
10:07	50%	0%	VAC pump in SIB2 room switched-off at 10:08 UTC
10:14	10%	0%
10:22	100%	0%
10:23	100%	90%
10:28	100%	0%
10:34	100%	50%
10:53	100%	10%	restarted at 10:50 UTC of the Bacnet server to recover HVAC_INJ* sensors
11:00	100%	0%
11:04	5%	0%
11:10	100%	0%	SCIENCE mode operation

It is worth noting that during the test, a replacement of the split units was ongoing in the Injection electronic room (Piscina) and human activity was present in the Central Building.

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