Hazardous Zones Fully Automated Control Access · access when equipment is under fully automatic control and the design impacts of personnel access into hazardous areas. In fully

Project Documentation Document SPEC-0133

Revision B

Advanced Technology Solar Telescope 950 N. Cherry Avenue Tucson, AZ 85719 Phone 520-318-8102 [email protected] http://atst.nso.edu Fax 520-318-8500

Hazardous Zones Fully Automated Control Access

Scott Bulau, Pat Eliason, Steve Hegwer, Rob Hubbard, Paul Jeffers,

Heather Marshall, LeEllen Phelps, Steve Shimko, Tim Williams

April 11, 2012

Name Signature Date

Approved By : Stephan Shimko

Safety Officer S. Shimko 09 Jul 2012

Approved By: Simon Craig

Sr. Systems Engineer S. Craig 10 Jul 2012

Approved By: Thomas Rimmele

Project Scientist T. Rimmele 13 Aug 2012

Released By: Joseph McMullin

Project Manager J. McMullin 15 Aug 2012


SPEC-0133, Revision B Page ii

REVISION SUMMARY:

1. Date: January 6, 2012

Revision: Draft

Changes: Rough Draft for internal review

2. Date: February 7, 2012

Revision: A

Changes: Initial release

3. Date: April 11, 2012

Revision: B

Changes: Changed title and terminology from “operations” to “fully automated control”

throughout document; Clarify access hazard issues to nasmyth platforms, coudé lab and

mezzanine level through discussions with the science group. Clarified the access ways into the

ground floor inner coudé pier area. Replaced some of the figures.

4. Date: April 11, 2012

Revision: B (Special)

Changes Converted document from a Technical Note to a Specification per SEIC request.


SPEC-0133, Revision B Page iii

Table of Contents

Preface ......................................................................................................... 1

1. ATST HAZARD ZONES ........................................................................................ 2 1.1 NOTES ON REGULATIONS REGARDING PERSONNEL ENTRY IN TO HAZARDOUS AREAS ..... 2

2. ENCLOSURE - UPPER LEVELS .......................................................................... 5 2.1 GENERAL ............................................................................................................... 5 2.2 HAZARDS AND CONTROLS ........................................................................................ 5 3. TELESCOPE FLOOR LEVEL ............................................................................... 6 3.1 GENERAL ............................................................................................................... 6

3.2 HAZARDS AND CONTROLS ........................................................................................ 6 3.2.1 Telescope Level Fixed Floor to Telescope Azimuth Floor ............................................... 7 3.2.2 Telescope Azimuth Floor to Telescope Movement Envelope .......................................... 7 3.2.3 Telescope Azimuth Floor to Telescope Nasmyth Platforms ............................................ 8 3.2.4 Telescope Level Fixed Floor to Enclosure Floor ............................................................. 8 4. SERVICE RING ACCESS PLATFORM ............................................................... 10

4.1 GENERAL ............................................................................................................. 10 4.2 HAZARDS AND CONTROLS ...................................................................................... 10 5. CATWALK LEVEL ............................................................................................... 11

5.1 GENERAL ............................................................................................................. 11 5.2 HAZARDS AND CONTROLS ...................................................................................... 11

6. ENCLOSURE SERVICE RING ........................................................................... 13 6.1 GENERAL ............................................................................................................. 13 6.2 HAZARDS AND CONTROLS ...................................................................................... 14

7. ENCLOSURE CABLE WRAP LEVEL.................................................................. 15

7.1 GENERAL ............................................................................................................. 15 7.2 HAZARDS AND CONTROLS ...................................................................................... 15 8. UTILITY FLOOR LEVEL ...................................................................................... 16

8.1 GENERAL ............................................................................................................. 16 8.2 HAZARDS AND CONTROLS ...................................................................................... 16

9. COUDÉ FLOOR LEVEL ...................................................................................... 17 9.1 GENERAL ............................................................................................................. 17 9.2 HAZARDS AND CONTROLS ...................................................................................... 17 10. MEZZANINE FLOOR LEVEL .............................................................................. 19 10.1 GENERAL ............................................................................................................. 19

10.2 HAZARDS AND CONTROLS ...................................................................................... 19 11. GROUND FLOOR LEVEL ................................................................................... 21 11.1 GENERAL ............................................................................................................. 21

11.2 HAZARDS AND CONTROLS ...................................................................................... 21 12. SUMMARY TABLE OF HAZARDOUS ZONES ACCESS ................................... 23


SPEC-0133, Revision B Page 1 of 24

Preface

The ATST team performed Preliminary Hazard Analysis (PHA) per MIL-STD 882 on each of the

subsystems and included all phases of the project: construction (CONST), integration testing and

commissioning (IT&C), maintenance (MAINT) and operations (OPS). This technical note focuses on

access when equipment is under fully automatic control and the design impacts of personnel access into

hazardous areas. In fully automatic control, the telescope, enclosure, coudé rotator, cable wraps and other

equipment will be able to track, slew and move under script control and remote means. Also, power and

other hazardous energy sources can be introduced into equipment automatically. Hazardous zones most

likely needing to be accessed during fully automatic control addressed herein include the telescope floor

level, coudé rotator and the enclosure. By addressing the issue as fully automatic control access, it

encompasses requirements for IT&C, maintenance and operations access. Formerly we utilized the term

operations (vs. fully automated control) and it caused much confusion over the many definitions and uses

of the word operations.



1. ATST HAZARD ZONES

There are multiple hazardous areas in the ATST and support facilities, this document address only areas

of hazard during fully automated control. In particular, areas in current design that needed ATST input on

hazards requiring mitigation due to the presence of personnel. Most areas are simply too hazardous to

allow personnel entry during fully automated control. Some areas such as the telescope enclosure floor

level and coudé rotator will have the need for personnel entry during under some circumstances. Starting

from the upper enclosure moving down, we will discuss each area and the design conclusions for each.

See the summary table section 12 at the end of this discussion.

1.1 NOTES ON REGULATIONS REGARDING PERSONNEL ENTRY IN TO HAZARDOUS AREAS

OSHA requires protection of workers from harm in the workplace and has many regulations, standards

and interpretations in place. Also, national standards like NFPA, NEC, ANSI, IBC and ASME are

Figure 1. ATST Hazardous zones

Ground floor

inner pier

Mezzanine level

Coudé level

rotator

Utility level

TMA cable wrap

Services ring access

platform level

Telescope level

Enclosure upper levels

Enclosure cable

wrap level

Catwalk level



required by OSHA by direct or inferred reference. Despite this plethora of laws and standards, nothing

captures all specific hazard controls needed in a large, unique observatory.

Early on, the ATST engineering team realized that the OSHA Lockout Tagout (LOTO), OSHA Machine

Guarding regulations and the National Electric Code (NEC) standards did not provide enough direction

and selected the ANSI/RIA R15.06, American National Standard for Industrial Robots and Robot

Systems - Safety Requirements, as a key, nationally recognized standard for safety issues working inside

a “giant robot” observatory.

The ANSI/RIA R15.06 standard provides us with, in some cases,

more applicable direction than OSHA, and a key provision of

which is slow speed control. This is a mode of robot motion control

where the speed is limited to 250 mm/sec (10 in/sec) to allow

persons sufficient time to either withdraw from hazardous motion

or stop the equipment. Another key provision is clearance such that

the equipment shall be installed to provide a minimum clearance

from the operating space of 0.45 m (18 inches) from areas of

building, structures, utilities, and other machines that may create

trapping or a pinch point.

Note that for maintenance work, the slow speed control function in

conjunction with a local control “hand paddle” will enable

personnel to trouble shoot moving equipment such as the cable

wraps. Other appropriate specific hazard controls such as

temporary barriers, detailed procedures, specific training etc. would

be required.

Also, note the OSHA Lockout Tagout standard is required for service and maintenance and the machine

or equipment must be de-energized and all potentially hazardous energy rendered safe. Interlocks do not

constitute LOTO unless the minor servicing exception to the OSHA standard is met. Minor tool changes

and adjustments, and other minor servicing activities that take place during normal production operations,

are not covered by the LOTO standard if they are routine, repetitive, and integral to the use of the

equipment for production, provided that the work is performed using alternative measures which provide

effective protection.

To prevent and/or control entry into hazardous areas during fully automated control several methods can

be employed depending on the hazards and the frequency of access. The team has designed an interlocked

trapped key system for the frequented areas. These are sophisticated interlocks to stop and/or slow motion

before unlocking for entry. Other less frequented areas can be interlocked-locked to prevent or stop

movement without a locked time delay and have a simple physical lock. Emergency exits would be

interlocked-monitored to stop motion if opened but not locked to prevent exit, only locked for entry. See

section 12.

There are hazardous zones that are interlocked for access only during maintenance that require a daily

inspection. During the preconditioning mode, before anything starts moving and the thermal systems are

operating, an operator will perform a general inspection. For example, this would include a visual

inspection of equipment in the Enclosure Service Ring, Enclosure Cable Wrap Level and the Telescope

Mount Assembly (TMA) cable wraps to verify that none of the hoses are leaking, etc. These inspections

fall under the minor servicing exemption and alternative protection measures are provided through the use

of interlock trap keys so there is no inadvertent motion.

ANSI/RIA R15.06



Other hazards such as rotating floors have not made it into any standards that we’ve been able to locate.

Moving walkways have a recommended maximum entry of about ½ walking speed or about 500 mm/sec.

Consultation with manufacturers of large rotating floors/turntables confirmed this max speed “rule of

thumb” for walking into rotating floors.

In summary, for fully automated operational access by personnel into hazardous zones, the motion must

be speed inhibited to <250 mm/sec, have minimum clearance from the operating space of 0.45 m, and

present no other severe hazard due to the equipment, or configuration of the space and moving items.



2. ENCLOSURE - UPPER LEVELS

2.1 GENERAL

The enclosure upper levels for the purpose of this section include the upper platforms, TEOA platform

and the lifting platform. This does not include the enclosure floor on the telescope level (see below,

section 3). Entry is through the elevator or the stairway (doors 701A and 701B) on to the telescope level

fixed floor from the “dog house” (fig.4). There are two (2) exit doors to the catwalk.

2.2 HAZARDS AND CONTROLS

There are numerous serious hazards here to both personnel and equipment (including the primary mirror)

so there is no personnel entry allowed during fully automated control. The stairs will be protected by

gates that can be locked/interlocked (TBD) for fully automated control. The two exit ladder doors shall be

alarmed / monitored.

Figure 2. Enclosure upper level platforms Figure 3. Enclosure upper level exit ladder



3. TELESCOPE FLOOR LEVEL

3.1 GENERAL

The telescope floor level hazardous zones include the fixed floor, telescope azimuth floor, telescope

movement envelope, telescope nasmyth platforms and the enclosure azimuth floor. Entry is through the

elevator or the stairway (doors 701A and 701B) on to the fixed floor from the “dog house”.

Figure 4. Doors 701B and 701A onto telescope level


Entry on to the fixed floor during fully automated control presents no serious hazards as the telescope

movement envelope does not reach it and equipment on the rotating floors (telescope and enclosure) shall

be kept at least ~500 mm from the edge of the fixed floor. Note that the stairway/elevator “doghouse” is

close to the enclosure floor. Also, from the top of the doghouse the telescope movement envelope can be

reached.

Figure 5. Telescope floor level



3.2.1 Telescope Level Fixed Floor to Telescope Azimuth Floor

The Telescope Azimuth Floor is 12.5 m in diameter and moves in sync with the telescope motion and

presents a rotational floor hazard. The max speed of the telescope azimuth motion is 2 deg./sec which is

219 mm/sec, well below the RIA slow speed control (see table 1).

Telescope Az Floor 12.5 m dia.

deg/s RPM mm/s m/s Dia - m Circ - m m/deg

2 0.33 219 0.22 12.5 39.4 0.11

1.5 0.25 164 0.16 12.5 39.4 0.11

1 0.17 109 0.11 12.5 39.4 0.11

0.5 0.08 55 0.05 12.5 39.4 0.11

Table 1. Telescope azimuth floor motion speed analysis

3.2.2 Telescope Azimuth Floor to Telescope Movement Envelope

Most of the telescope motion is beyond the reach of personal on the floor except between the telescope

altitude-bearing towers. This area presents many crush hazards as does the area around the M5-M6 optics

tower*. No entry is allowed during fully automated control and this area is to have physical barriers

installed to prevent inadvertent entry. Barriers such as sensor pads or light curtains probably could not

react fast enough to prevent entry into the hazard area prior to a complete telescope stop. Some type of

removable and lockable/interlocked physical barriers seems the most plausible at this time. These barriers

would also be useful for hazard control during construction, IT&C and maintenance.

*In the area between the Mount Altitude bearing towers there are a number of pieces of equipment that as

the Mount moves in altitude sweep close to both the Telescope floor and also close to the M5/M6 Tower.

These are OSS Electronics Rack and Platform, OSS Main Counterweights, M1 Air Handler (location under

discussion) and parts of the OSS main structure.

The access to the GOS is via the OSS Platform. To get from the Nasmyth Platform to the OSS platform,

they have to lined up i.e. the Mount parked at 104 deg Alt. Then it is possible to walk from the Nasmyth

Platform to the OSS platform. This platform rotates with the mount and so at other angles the platform is

not horizontal and the access of the platform may be blocked by mount structure.

The access to M5 and M6 is via a deployable bridge that extends from the OSS platform. Once the OSS

platform is aligned to Nasmyth then then it would be possible to extend the walkway to access the M5/M6

on the top of the tower. The extended platform is directly in the path of the tower as the altitude axis moves

from 104deg so has to be retracted to reach lower elevations.

These access provisions are provided for normal maintenance and were not designed for working on the

systems while under TCS control (fully automated control) which could invoke a slew at any time. For

these activities it would be necessary to implement ‘other protective’ means which could be a combination

of local enabled slow speed operation with temporary access via scaffolding. The same issue exists for

encoder alignment where access is needed to an area that has intrinsic crush hazards but must be able to

move the axis while adjusting. This is not ‘normal’ inspection / maintenance and so falls under the ‘specific

job hazard and alternative protection means.



Figure 6. Telescope azimuth floor, movement envelope and Nasmyth platform access

3.2.3 Telescope Azimuth Floor to Telescope Nasmyth Platforms

No personnel shall be allowed access to the telescope nasmyth stairs and platforms during fully

automated control. There are severe pinch and crush hazards* on the nasmyth platform from the

movement of the altitude axis. These stairways shall be gated and locked for fully automated control.

*The Hazards on the Nasmyth Platform are currently the different relative motion of the OSS trunion and

the bearings system, the manual drive gear, brake discs / brake mechanism, encoder and encoder read head

brackets. The most straightforward way to protect personnel from these mechanisms is to limit access to the

nasmyth platform during fully automated control.

The access as described here does not prohibit working on systems on the Nasmyth Platform, what it does

is inhibit the altitude axis from moving.

If during IT&C some of the thermal systems need adjustment during tracking then a specific job hazard

analysis would be required and then ‘alternative protection’ means would be implemented.

3.2.4 Telescope Level Fixed Floor to Enclosure Floor

The inner diameter of the telescope level enclosure floor is 19.3 meters and has a designed maximum

speed of 2 deg./sec, 337 mm/sec, above the RIA safe control speed (see table 2). Also, with the doghouse

so close to the enclosure floor, it is imperative that no equipment on the enclosure shall be within 450 mm

of the edge of the fixed floor.

Enclosure Floor 19.3 m inner dia.


2 0.33 337 0.34 19.3 60.6 0.17

1.75 0.29 295 0.29 19.3 60.6 0.17

1.5 0.25 253 0.25 19.3 60.6 0.17

1 0.17 168 0.17 19.3 60.6 0.17

0.5 0.08 84 0.08 19.3 60.6 0.17 Table 2. Enclosure floor motion speed analysis



Various means to reduce or eliminate this hazard were analyzed to include both procedural controls

(disallow entry during slews) and engineering controls (slow speed control). Although slow speed control

has the potential for cost and operations impact, engineering solutions are a more effective way to control

hazards than procedures.

Figure 7. Telescope floor level

The operational impact of enclosure slow speed control was analyzed and documented in TN-0003, Alt-

Azimuth Blind Spot and the ATST. Maximum speed is used at noon to reposition the enclosure aperture

for the afternoons observing. In summary of TN-003, the operational impact of speed limiting the

enclosure while personnel are on the telescope level is negligible. See TN-0003 in C:\ATST File

Vault\SysDocs\1.0 Tel\1.1 TMA\Docs & Images\Tech Notes & Reports\TN-0003-Zenith Blind Spot.

The enclosure design has passed FDR and the contractor has included slow speed control under a

category of Special Operations. Design and budget impacts to introducing a speed limiting device to the

enclosure motors cannot be analyzed fully at this point.



4. SERVICE RING ACCESS PLATFORM

4.1 GENERAL

The service ring access platforms are entered from two stairways in the enclosure cable wrap level. No

personnel shall be allowed entry during fully automated control.

Figure 8. Stairs and service ring platforms on cable wrap level


TMA power and electronics racks hang down into this area creating serious fall, crush and pinch hazards.

Entry to this level is controlled by enclosure cable wrap level doors 501 and 502. These shall be

interlocked to prevent entry during fully automated control.

Figure 9. Service ring platform (safety rails not shown)



5. CATWALK LEVEL

5.1 GENERAL

The catwalk is affixed to the S&O building and personnel are exposed to the rotating enclosure. It

provides access to the lower enclosure. There are ladder ways down to the ground level with landings and

exit doors at lower levels (fig. 12).

Figure 10. Door 402D on utility level up to the catwalk level


The catwalk is directly exposed to the rotating enclosure exterior. During fully automated control no

personnel shall be allowed onto the catwalk and door 402D interlocked and emergency exit doors shall be

alarmed and monitored.

Figure 11. Enclosure catwalk



Figure 12. Exterior ladder ways to the catwalk level

Door 402B

Door 308D

Door 210B

Secure ladder

way



6. ENCLOSURE SERVICE RING

6.1 GENERAL

The enclosure service ring is only accessed from the Services Ring Access Platforms (See Section 0



Service Ring Access Platform) and no entry is allowed during fully automated control.

Figure 13. Enclosure service ring


Entry to this level is controlled by enclosure cable wrap level doors 501 and 502. These shall be

interlocked to prevent entry during fully automated control. Entry into the enclosure services ring space

itself requires use of an interlocked trapped key.



7. ENCLOSURE CABLE WRAP LEVEL

7.1 GENERAL

The enclosure cable wrap level is accessed through doors 501, 502 and two (2) hatches to the outer utility

level below.

Figure 14. Doors 502A and 501A to the Cable wrap level (Note the stairs up to service ring platforms)


Due to the numerous pinch and crush hazards of the cable wrap and enclosure equipment no operational

entry is allowed. Doors and hatches shall be interlocked to prevent entry during fully automated control.

Figure 15. Enclosure cable wrap level



8. UTILITY FLOOR LEVEL

8.1 GENERAL

This level includes an inner and outer pier area. The inner pier will be separated by a safety barrier to

prevent inadvertent entry, since the walls were removed from the design. The inner area contains the

mount cable wrap and is accessed by gate “404A”. The outer pier has several doors and has access to the

emergency exterior ladder ways.

Figure 16. Gate “404A” into the Utility inner level


Serious crush and pinch hazards exist around the TMA cable wrap. No personnel access is allowed into

the utility level inner pier during fully automated control and gate at former location of door 404A shall

be interlocked. Access is allowed to the utility level outer pier.

Figure 17. Utility level inner pier and TMA cable wrap



9. COUDÉ FLOOR LEVEL

9.1 GENERAL

The coudé floor level has an inner and outer area. The inner rotator area presents the most needs for

access to a hazardous zone during fully automated control. Instrument scientists and engineers desire

regular access to the coudé rotator during some operations. The lab can be entered by doors 307A, 308C

and the “rec room” ladder way (TBD).

Figure 18. Doors 307A and 308C into the Coudé lab

Depending on the type of operations, the probability for entry differs. During diffraction limited seeing, in

general, no personnel would be present in the coudé rotator. During seeing limited operations, personnel

are likely present and during coronal observations personnel frequent the area.

There is a fixed floor and a rotating floor 16.5m in diameter. During tracking, the speed of the rotator is

well below the RIA slow speed control (table 3). When repositioning the rotator for calibration and

instrument changes, the maximum speed is 6 deg./sec, 865 mm/sec. This exceeds the RIA slow speed

control if personnel are present.

Coudé Rotator Floor 16.5 m dia.


6 1 865 0.87 16.5 51.9 0.14

4 0.67 577 0.58 16.5 51.9 0.14

2 0.33 288 0.29 16.5 51.9 0.14

1.75 0.29 252 0.25 16.5 51.9 0.14

1 0.17 144 0.14 16.5 51.9 0.14

0.5 0.08 72 0.07 16.5 51.9 0.14

Table 3. Coudé rotator motion speed analysis


The outer pier presents no additional hazards during fully automated control and can be entered. The

coudé lab rotator floor edge area has the potential for serious crush and pinch hazards and there the rotator



should be speed inhibited to 1.75 deg./sec (250 mm/sec) when personnel are in the coudé lab. For

example the WFC optical bench is very close to the outer edge of the rotating floor. For a worker be in

the coudé lab, and for it to be able to rotate, it would have to be in slow speed control (<250mm/sec) and

safety procedures (TBD) to be followed prior to rotation. Railings have been discussed but these could

present crush or pinch hazard themselves, depending on where there are placed.

Equipment should not be installed with 450 mm of moving equipment. The impact to efficiency to

reposition the rotator for the slow speed control is about 63 seconds longer (115 sec vs. 52 sec) for a 180

degree rotation than the 6 deg./sec speed (per MT Mechatronics). Other hazard controls are also required

such as high visible marking, audible move warnings, bump sensors, barriers etc. (TBD).

Figure 19. Coudé Lab Rotator



10. MEZZANINE FLOOR LEVEL

10.1 GENERAL

This level includes an inner and outer pier area. The inner area contains the underneath of the coudé

rotator and the instrument cabinets and is accessed by doors 209A and 210A. Also contains in the

“recreation room” in the center of the rotator structure which has ladder access to the coudé level.

Figure 22. Doors 209A and 210A to the mezzanine level

Figure 20. Mezzanine Level coudé lab instrument racks


During fully automated control the floor is stationary and the rotator structure and instrument cabinets

rotate creating pinch and crush hazards. Someone standing or on a ladder on the fixed floor working on

the electronic cabinets that could move and impact a worker and cause a fall and/or catch on something

and pinch/crush hazard, etc. During fully automated control or any motion controlled from outside the



room the inner pier mezzanine level shall not be accessible to personnel and the entry door(s) shall be

interlock to prevent entry.

The addition of video and audio communication will help protect workers, but this control alone does not

adequately mitigate the hazard of accessing the cabinets that can move “unexpectedly” from a fixed floor.

Purely procedural mitigations (make sure you check the cameras) should not to be used as the only

control of such a serious hazard.

The rec room is an extension of the coudé lab rotator and can be accessed from the coudé lab ladder way.

It can be accessed while continuing to operate in the reduced speed mode (which is well above max

required tracking velocity). The door from the coudé “rec room” to the mezzanine should be

locked/interlocked (TBD) during normal operation to prevent personnel exiting to the mezzanine with the

coudé rotator in motion.

Figure 21. Coudé “rec room” door and ladder way



11. GROUND FLOOR LEVEL

11.1 GENERAL

This level includes an inner and outer pier area and the inner coudé pier. The inner coudé pier area

contains the coudé rotator cable wrap and is accessed by door 110 A. The center of the inner coudé pier

cable wrap area is accessible from the ladder from the coudé pier inner mezzanine level above, which in

turn is accessed from two hatches and ladders in the “rec room” floor.

Figure 24. Door 110A into the ground level, coudé inner pier


During fully automated control the inner coudé pier shall not be accessible to personnel and the entry

door shall be interlocked to prevent entry. The two hatches in the “rec room” floor shall be interlocked

and perhaps padlocked as well.



Figure 23. Ground floor inner pier rotator cable wrap



12. SUMMARY TABLE OF HAZARDOUS ZONES ACCESS

ATST Hazardous Zones - Fully Automated Control Access 03/20/12

Hazard Areas

Access Doors it – interlock trap key

il- interlocked locked

im – interlock monitored

Personnel Access Notes

(Telescope/coudé level personnel access

adversely affects observations)

Fully

Auto.

Control

Speed Limited

Move/Tracking

< 250 mm/s

Enclosure

Upper

Levels

Exterior 701A - it

701B - it

Exit 1 - im

Exit 2 - im

Enclosure stair - il

No

Upper

Platforms

Stairs to be gated and interlocked locked

(TBD), Vent gates platforms

TEOA

Platform

TEOA interlocked

Lifting

Platform

Telescope

Floor Level

Fixed Floor 701A - it

701B - it

Az tower barriers - il

Nasmyth stairs - il

Enclosure stair - il

Yes N/A

Telescope

Azimuth

Floor

Yes N/A

Tele.

Movement

Envelope

No N/A

Physical barriers (removable) will prevent

entry between towers “crush zone” and to

be interlocked locked (TBD)

Tele.

Nasmyth

Platforms

No N/A

Stairs to be gated and interlocked locked

(TBD)

Enclosure

Azimuth

Floor

TBD Yes

Stairs to upper platforms to be gated and

interlocked locked (TBD)

Service Ring

Access

Platform

501A - it

502A - it No

Access from enclosure cable wrap level

stairs

Catwalk

Level

Exterior 402D - im TBD

Access from utility level outside stairs.

Outside ladder to grnd/mezz/ coudé/util

/catwalk levels

Enclosure

Service Ring

501A - it

502A - it No

Access from enclosure cable wrap level

Only major maintenance access

Enclosure

Cable Wrap

Level

501A - it

502A - it

Hatch 1, 2 - im No

Inner Pier: access from 501A & 502A

Outer Pier: ladders from utility level,

Ladder hatches are interlocked in the

Enclosure LIC.



ATST Hazardous Zones - Fully Automated Control Access 03/20/12

Hazard Areas

Access Doors it – interlock trap key

il- interlocked locked

im – interlock monitored

Personnel Access Notes

(Telescope/coudé level personnel access

adversely affects observations)

Fully

Auto.

Control

Speed Limited

Move/Tracking

< 250 mm/s

Utility Floor

Level

Inner Pier

404A – it

(now 403A) No

MAINT mode only – LOTO; Mount cable

wrap

Outer Pier

402A - im

402B - im

402C - im

402D - im

Yes

Ladder (1 ea.) to coudé level. Outside

ladder to ground/ mezzanine/ coudé/

utility /catwalk levels

Coudé Floor

Level

Coudé Lab,

Rotator and

Fixed Floor

307A - it

308C - im No Yes

Other hazard controls also required: high

visible marking, audible move warnings,

bump sensors, barriers etc.

Outer Pier

308D - m

308E - m

305F - m Yes

Ladders (1ea) to outer utility level and (2

ea) outer mezz. level. Outside ladder to

ground/ mezzanine/ coudé/ utility /catwalk

levels

Mezzanine

Floor Level

Inner Pier

209A - it

210A - im

Rec room - im

No

Coudé Rotator to be inhibited or locked out

for access.

Coudé Pier

Inner

Mezzanine

2 hatches in Rec

room floor - il No

Allows access to ground floor inner pier –

center of cable wrap

Outer Pier

210B - m

211A - m Yes

Ladders (2 ea) to outer coudé level.

Outside ladder to ground/ mezzanine/

coudé/ utility /catwalk levels

Ground

Floor Level

Coudé Pier

Inner

110A - it No

Coudé Rotator to be inhibited or locked out

for access; rotator cable wrap

Center of

Coudé Pier

ladder No

Accessed by ladders from Coudé pier inner

mezzanine level

Outer Pier 109A,B,C Yes No interlock/monitoring needed

Outside

ladder

N/A - im Yes

Needs security “gate/door” on ground

level. Ladder to mezzanine, coudé, utility

and catwalk levels

Documents

Hazardous Zones Fully Automated Control Access · access when equipment is under fully automatic control and the design impacts of personnel access into hazardous areas. In fully