MINUTES - meeting on cleanliness improvement in Central Hall -
Held on Jan 19th, 2015, 14h00 - Seminar Room
Partecipants:
F.Carbognani, M.Ciardelli,  V.Dattilo, A.Pasqualetti, R.Passaquieti, P.Popolizio, D.Soldani 

(minutes by FC ans VD)

-Introduction
Contamination control is of crucial importance to prevent mirror degradation and damage.  In particular, aLigo found that permanent damage of dirty optics begins to occur at ~92W/mm^2.  For AdV, at Pin=125W, we will have ~100W/mm^2 for the arm mirrors and ~1100 W/mm^2 for the I_IMC_diedro.
Thanks to the recent works for improving the air cleanliness the in the Central Hall (elog #31938), we have gained about 2 orders of magnitude in the  airborne particle concentration  (#31943,  #31945, #31957).  Now it is therefore time to act coherently on the improvement  of other relevant aspects and to define and adopt suitable procedures.  The list of discussed and agreed actions is the following:

#1- removal of trashable material;  moving  of the unused material (like the old TCS components currently on the East terrace) out of the Central Hall;  find a solution for the packaging of those bulky and important components (like o-rings and baffles) currently stored on the terraces having a non-compatible package (wood or cardboard):  proposed solutions are replacement of the package with a compatible one, or at least to cover them with a plastic sheet.

#2- vacuum cleaners: taking into account that even those ones equipped with an HEPA filter and those  with water filtration system presents an excess of particle concentration at their outlet (measured with our particle counter), a centralized vacuum cleaner system has been proposed.  Indeed, it is a standard solution for clean environments, with no risk of re-inject particles in the clean area. The vacuum inlets, where to connect the hose and the accessories for cleaning, should be located close to each tower base and also below the platform.   M.Ciardelli will investigate this solution and prepare a detailed proposal.

#3- extraordinary cleaning:  special cleaning of the bridge crane, upper part of the "locale camion" roof, of the terrace at N-W (ie the one where is placed the UTA of the tower clean air) will be organized and performed ASAP.  The special cleaning of the remaining parts will be performed after the actions in #1 and the "dirty works" of VAC (ie works on links and relevant part of platform, installation of cable trays and of LN2 pipes, ...); estimated time for their conclusion is about 1 month.

#4- procedures:  in addition to the pre-existing rules, the trend is to ask to wear  a scrub for accessing the Central Hall.  Linked to this, we should enlarge the Blue Area, in particular, up to the room where is hosted the DAQ UTA  (this implies to wear the blue overshoes to go into the DAQ room, along the stairs, etc).  Before introducing this updated procedure, we will equip the DAQ UTA with the furniture to allow  the wearing of the overshoes and the hanging of jackets and other coats; among the furniture, a few lockers are also advisable to allow people to temporary leave personal objects in a safe way.

#5 - particle counters:  a futher portable particle counter would be useful to extensively monitor  the contamination level in more points and during particular activities --> we will proceed with the procurement of a second Fluke 985 particle counter.  Concerning the network of remote particle counters and their acquisition though the Virgo DAQ, a model was identified about 2 years ago by VD, and  one counter purchased (model 5104 by Lighthouse) , unfortunately the activity is currently in standby for the lack of manpower.  We will make an effort to install and integrate this  device.

#6 -further actions (miscellaneous):
- installation of a protective "umbrella" on the crane blocks (just above the hook) to shield from fall of lubricant losses (grease);
- access door on the East terrace sometimes found open --> prevent it by installation of a door closer;
- the air filters at the outlets grid of the Central Hall are visible dirty -->  ask for replacement with new ones.