With LHO closed over the holidays, and O3 still taking place 24/7 over the holidays, Site-Walkthrus have been schedule to be performed by operators during their shifts (DAY).  I performed one this morning per instructions here.  Since inspection of the LVEA, EX VEA, EY VEA are required, these incursions would require us to go out of OBSERVING.  I chose to lump those three inspections together to minimize/optimize time we were out of OBSERVING (where I would take H1 out of OBSERVING, walk through the LVEA, and then drive out to EY & then EX consecutively, AND then finally return H1 to OBSERVING & finish remaining items of the Walk-Through.)

This morning I had H1 down for 35min to run calibration measurements, I was going to tack on VEA incursions to this down time, but we received an Earthquake Alert, so instead, I took H1 to OBSERVING & monitored the EQ in case we needed to transition SEI_CONF to the EARTHQUAKE state (this wasn't needed).  Instead, it was observed the Calibration measurement prossibly affected Calibration Lines.  Took H1 out of Observing, fixed this, and then began VEA incursions.  Here is log:

Duration Total of Site Walk-Thru:  ~90min (18:14 - 19:45utc) 

Duration out of OBSERVING:  ~51min

• 18:10 Out of OBSERVING (first to address PCal Lines & then start Walk-thru)
• Buddy notified
• 18:15-18:28 In LVEA (H1 was in NLN, so I tiptoed!)
  • Heard a faint clicking noise while quietly walking around (appeared to come from the ceiling; I'm guessing this was HVAC-related.)
• 18:30-19:02 VPW, EX, & EY
  • At End Station VEAs, I was reluctant to enter the VEAs since I was worried about disrupting/affecting the BRS systems.  So I only entered and walked a few steps into the VEAs.  Do not see the effects of me entering the VEAs on the BLRMs seismic traces. 
  • Noticed ice build-up on various parts of half of the site Chiller dewars. 
  • EX had a few dead bugs on floor.
• 19:02 Back to OBSERVING!  (then continued with walk-thru of other buildings----I did not enter Mid Stations.)
• For RO Room at the Wood Shop building, heard water dripping, but this is from lines run to a floor drain.
• At LSB, noticed a white Nissan sedan parked in the LSB (person was in car, but no contact was made).
• Needed my FOB to swipe into the LDAS room of the VPW.
• Failed to check the janitor's closet in the Staging Bldg bottom floor.
• 19:45 Back in Control Room (texted buddy & notified LLO/Virgo Control Rooms)

Ice On Liquid Nitrogen Dewars

One item we were asked to check was the exhaust of the LN2 dewars as we drove the site.  I wasn't totally sure where the exhaust was, but eventually figured it out. 

As you inspect the dewars there is frost/ice build up at various points (i.e. input plumbing where Norco connects, output to VEAs, & output exhausts [see attached photos for examples]).  I texted Chandra and she mentioned alot of this is normal, but she said posting photos is good.  Found ice on exhausts at End Stations and LVEA.  Notes:

• At EX I tried to figure out where the exhaust was and I eventually found it, there was a block of ice connected from the exhaust port all the way to the ground---I was able to break this fairly easily. 
• CP2 exhaust had a big chunk of ice.  I was able to break connection to the ground, but was not able to break off the ice frozen to the output pipe.
• While breaking off ice to EY's dewar exhaust, noticed that this output plumbing was not secured.  So it would move like a big pendelum/spring if you touched it.
• DetChar if you see some seismic bumps around these times:  18:55, 19:30, 19:35, this is when I bonked ice chunks off the exhausts...one other instance I don't have time for.