Re: [GlueX] HALL D COMPLEX CONCEPT DRAWINGS COMENTS

[Elton Smith <elton@jlab.org>]

Eric, Elliott and I met this afternoon and went over his comments on the
civil drawings. We had a very fruitful discussion. I am putting these down
for reference as we gather information to pass back to civil. See below

Elton Smith
Jefferson Lab
elton@jlab.org
(757) 269-7625

On Fri, 2 Sep 2005, Eric Scott wrote:

> Comments on Hall D Complex:
>
> We still have the beam 12' above the floor. Is this necessary?
>
The nominal design is for the gas cerenkov counter, so it is consistent
with the project. If a decision on the DIRC is made at a later time this
could be reconsidered. However, we note that the present value is
conservative and will work in either case.

> For better visualization and comments it would be nice if the equipment
> was overlaid.  We would need two different views:  Running condition and
> Extracted or opened maintenance condition.  Some indication of the cryo
> runs would also be useful.  (A3, A5)

Agreed. Especially as we proceed with more details of placement of
utitilities.

>
> An elevator between the counting house and the hall would be nice. Its
> only about 14' from the floor of the counting house to the hall floor,
> but the only way to move one rack or a couple of power supplies into the
> hall is to carry them down the stairs or open the large door.
>

Pathway connections between the counting house and the hall clearly need
to be reviewed, including emergency exits. Likely the existing stairway
will be moved closer to the counting house and enlarged with options for
moving equipment in/out of Hall D.

> The rollup door access to the hall is a low spot, water management /
> drains? (A1)

Civil is aware of these issues, with (flood) experience in existing
halls.

>
> On the TOPO site plan it indicates that a ditch runs right through the
> hall site. Where is this ditch being diverted to, or is it? (A1)
>

Considerable site preparation is necessary in advance of actual Hall D
civil construction. Drainage for that whole area including adjacent land
from the city of NN is part of the planning.

> How does the cryo run to the Solenoid? Where are its control racks going
> to be located? There was an upper story room over the counting house for
> this at one point. (A3) Is everything moved to the CRYO PLANT? (C1)
>
The cryo plant is the responsibility of accelerator and they need
considerable footprint (as in the drawing) for the refigerator and
associated equipment. All cryo controls will be there in that building and
it replaces a shed that was on the original drawings outside on the north
west side of Hall D. Controls and power supply for the magnet itself may
be located elsewhere. A location for the power supply needs to added to
the drawings.

> Is there supposed to be an access labyrinth into the collimator
> enclosure next to the hall? (A3)
>
Richard has been working on the space needs and layout of the collimator
enclosure.

> The south H.M. Door needs an access labyrinth. (as drawn we have a large
> ODH area with one exit stair access only...)
>
Our understanding is that the is not needed, only a fence surrounding the
ramp. We should consider an emergency exit on the south west side of the
building.

> Railroad rails embedded in the floor for the downstream equipment to
> ride on would help. (A3)
>
We need to develop a scheme for moving the downstream detectors.

> Grounding system in the floor of the hall? (A3)
>
Preliminary designs by Chris have been discussed with civil. More work
needs to be worked out, e.g. connections of grounds to accelerator and
tagger building, etc., and included onto the drawings.

> How much wasted space is over the crane (8'?)? Can we move it up and
> give ourselves a little more hook height? (A5)
>
We specify the clear hook height. Actual building size depends on actual
design, space for vents, etc. (We will ask civil why there is so much
space there).

> The "normal access" to the tagger is past the beam line through the
> tunnel extension. It looks like it would be very tight to carry any
> equipment through there. (A6)
>
The access to the tagger building is a real concern. The downstream
enclosure must have permanent magnets, beam pipe, monitors, etc. Therefore
there is less room than even indicated on the drawing. We should consider
moving the exit to the main room; also consider a personnel access door on
the south side next to the roll up door.

> Don't we need a cable tray/ pipe that runs between the hall and the
> Tagger enclosure? (A2, A6)
>
We need to think about this, but an additional 6-8" pipe running the
length of between the tagger and Hall D building might be needed for
cables. (Are there any signals that need to be run here?)

> Are we planning on putting the Tagger magnet power supply in with the
> Tagger? Or should there be a power supply shed somewhere? (A6)
>
The tagger power supply will go in one of the service buildings.

> Why is the counting house only one story? It looks cramped now and we
> are not even using it yet. (A7)

The layout of the counting house has not been looked at very carefully and
this needs to be done.
>
> 6 office spaces, no meeting space. No visiting user areas or provisions
> for future downstream experiments. (A7)
>
see previous note.

> The counting room has provisions for a depressed floor with access
> flooring but no mention of labyrinth penetrations into the hall for
> direct wiring. (A7)
>
Penetrations between counting room and Hall need to be defined. The layout
and size of the depressed floor area needs to be specified. Elliott will
get a footprint for the required size of the online farm as well as the
control area in the Hall B counting room.

> There is no door or elevator between the control room and the hall. (A7, A3)
>
See previous comment

> There is no shower in the counting building. (A7)
>
Somebody needs to make a strong argument for a shower in this building.

> Windows in the control room looking outside? (A7)
>
We will inquire about options/cost of windows.

> Cheers,
>
>     Eric
>
>
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