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AUSTRALIAN
NATIONAL UNIVERSITY System Design Note 4.15 Created: 1 May 2002 Last modified: 3 May 2002 |
NIFS SAFETY REVIEW
Peter J. McGregor
Research School of Astronomy
and Astrophysics
Institute of Advanced
Studies
Australian National
University
Revision History
|
Revision No. |
Author & Date |
Approval & Date |
Description |
|
Revision 1 |
Peter J. McGregor 11 September 2001 |
Jan van Harmelen 11 September 2001 |
Original document. |
|
Revision 2 |
Peter G Conroy 02 April 2002 |
Peter J. McGregor 01 May 2002 |
Updated following CDR. |
Contents
2.2 Applicable
Safety Documents
2.3 Division of
Responsibilities
3 Organization of
the NIFS Safety Review
4.1.8 Protection of
Delicate Components
4.1.11 Stability of
Handling Trolleys
4.3.5 Overheating
Prevention and Protection
4.3.8 Helium
Pressure Interlock
4.3.10 Access to the
Instrument
4.4.1 Protection
Against Thermal Shock
4.5.1 Protection
Against Surface Contamination
4.6.1 Components
Controller (CC)
4.6.2 OIWFS Components
Controller (OIWFS-CC)
4.6.3 Instrument
Sequencer (IS) to Detector Controller (DC)
4.7.1 Protection
Against Overpressure
4.9.1 Coolants for
Thermal Enclosures
4.9.2 Coolants for
Detector Controllers
5.2.1 Transportation
Between the Dome and the Instrument Preparation Room
5.2.2 Changing the
Orientation of the Instrument
5.2.3 Personnel
Protection from Moving Mechanisms
5.2.5 Change of
Components on the Telescope
5.2.6 Use of the
Engineering Interface
5.3 Service and
Support Related Issues
5.3.1 Vacuum Pumping
the Cryostat
5.3.3
Assembly/Disassembly of NIFS
5.3.4 Personnel
Protection from Internal Moving Mechanisms
5.4.2 Condition of
NIFS During Shipping
6 Safety Related
Documentation and Training
1 Purpose
This documents identifies safety issues associated with the assembly, preparation, servicing, and operation of the Gemini Near-infrared Integral Field Spectrograph (NIFS).
2 Introduction
The Near-infrared Integral Field Spectrograph (NIFS) is a facility Gemini instrument. Safety in the NIFS context involves assessing risks to personnel, the instrument, the telescope, and the Gemini North facility. Potential safety risks occur during initial assembly and testing of the instrument, transportation of the instrument to Mauna Kea, preparation and servicing of the instrument prior to observing, installation of the instrument on the telescope, servicing of the instrument while at the telescope, and during normal operation of the instrument on the telescope.
Initial assembly and testing of NIFS will adhere to the safety standards of the Australian National University (ANU).
The Gemini Environmental ICD specifies the environment in which other NIFS operations will be performed.
2.1 ANU Safety Policy
ANU will ensure that to the best of its ability the NIFS instrument will conform to all relevant site safety requirements applicable to Mauna Kea. ANU will also ensure that the NIFS instrument conforms to both Gemini and ANU safety documents where applicable.
2.2 Applicable Safety Documents
The following is a partial list of relevant safety documents. The list is expected to change as the project evolves:
Gemini
Documents
Gemini
Project Safety Program, PG-PM-G0009
Gemini
Instrument Safety Policy, PG-I-G0010
Science
and Facility Instruments to Facility Handling Equipment Interface Control
Document, ICD 1.9/2.7
Gemini
Electronic Design Specification, SPE-ASA-G0008
Gemini
Facility Handling Equipment and Procedures for Instrumentation, ICD-G0015
Gemini
Acronym Glossary, PG-S-G0008
OSHA
Documents (www.osha.gov)
OSHA
Regulations (Standards - 29 CFR)
Part
1910 Occupational Safety and Health Standards
Subpart G -
Occupational Health and Environmental Control
(1910.94 to
1910.98)
Subpart J - General Environmental Controls (1910.144, 1910.145,
1910.147)
Subpart M -
Compressed Gas and Compressed Air Equipment
(1910.166 to 1910.169)
Subpart S -
Electrical (1910.301 to 1910.399)
2.3 Division of Responsibilities
This document identifies safety issues associated with the NIFS instrument. A safety audit table is included in §7. This table identifies the responsibility for the indicated safety issue.
The NIFS vacuum jacket, environmental cover on the cryostat window, and integration frame have been duplicated directly from NIRI designs without reanalysis. The integrity of these designs is assumed, based on acceptance of NIRI.
3 Organization of the NIFS Safety Review
The NIFS Safety Review consists of the following:
Section 4: Design Safety Requirements
This section lists the design requirements relating to safety. The design of the instrument as it relates to these issues is discussed. This includes design principles for those items for which detailed design work is incomplete.
Section 5: General Safety Issues
This section discusses those safety issues relating to transportation of NIFS, preparation of the instrument on site, servicing of the instrument on site, and normal operation on the telescope. General considerations on handling are discussed in this section.
Section 6: Safety Related Documentation and Training
Section 7: NIFS Safety Audit Table
4 Design Safety Requirements
4.1 Mechanical
4.1.1 Structural Integrity
A safety factor of at least 4 has been used in determining safe levels of stress on components unique to NIFS. Components duplicated from NIRI have not been reanalyzed (see §2.3).
Relevant documents:
1. Gemini Instrument Safety Policy, PG-I-G0010, Revision A.
4.1.2 Weld Joints
Load bearing welded joints exist only in the integration frame portion of the instrument. Welding practice is as per relevant Australian standards.
1. Australian Standard 1554.1-1985.
4.1.3 Bolts
Metric fasteners of adequate strength are
used throughout NIFS. Minimum thread depths in structural elements are as used
in NIRI. Critical torques are identified in the relevant manuals and drawings.
Relevant documents:
1. Gemini Instrument Safety Policy, PG-I-G0010, Revision A.
2. Australian Standard 1420-1973 - ISO Metric Hexagon Socket Head Cap Screws
4.1.4 Materials
No restricted materials are used in NIFS.
1. Gemini Electronics Design Specification, SPE-ASA-G0008, Revision 9, Section 4.5.
4.1.5 Corrosion
Corrosion is controlled in NIFS by the use of "non-corrosive" materials, passivation of the material surface by painting, and by protection of critical surfaces during transportation. Non-corrosion resistant steels are protected by priming and painting or by wax coating. Fasteners and bearings are typically stainless steel.
4.1.6 Sharp Edges
Standard fabrication practice is followed in NIFS to prevent danger from sharp edges.
Relevant documents:
1. Gemini Instrument Safety Policy, PG-I-G0010, Revision A.
4.1.7 Handling Fixtures
NIFS is compatible with Gemini specified handling fixtures. No special equipment is required to handle NIFS. A storage trolley and trolleys to handle the cryostat and thermal enclosures are provided. Refer to §4.1.9 and §4.1.10.
Relevant documents:
1. Science and Facility Instruments to Facility Handling Equipment Interface Control Document, ICD 1.9/2.7, Revision C.
2. Gemini Facility Handling Equipment and Procedures for Instrumentation, ICD-G0015, Revision C.
4.1.8 Protection of Delicate Components
Shielding and covers are provided where necessary to prevent damage to delicate components during handling.
A protective cover is provided for the entrance window to the cryostat. The window is exposed only during operation of NIFS on the telescope or during servicing. In the event of a power failure, the motor drive can be overridden and the Environmental Cover may be closed by hand to protect the window. To minimize contamination, a continuous flow of dry ionized air is provided for the window when installed on the telescope.
The instrument is normally shipped under vacuum to minimize possible contamination. An activated charcoal getter is provided to minimize contamination.
Relevant documents:
1. Gemini Instrument Safety Policy, PG-I-G0010, Revision A.
4.1.9 Storage Trolley
A storage and transport trolley is provided with NIFS. This trolley is used to integrate the instrument parts and then to carry the fully integrated instrument into the Gemini dome elevator for transport between the instrument laboratory and the dome floor. Once in the dome a beam crane will transfer the instrument to one of the Gemini air pallets for presentation to the ISS.
This trolley has locking polyurethane wheels 200 mm in diameter to enable it to cross the elevator door-floor gap without undue difficulty. All of the wheels have castor action to permit x,y mobility. Two of these castors have castor-pivot locks to aid steering the 2200 kg trolley and instrument over long distances.
The trolley contains an open shelf onto which all necessary fastening hardware and tools for mounting the instrument to the telescope can be stored. Diagrams showing how the instrument is to be mated to the trolley will be fixed to the trolley.
Relevant documents:
1. Gemini Electronic Design Specification, SPE-ASA-G0008, Revision 9.
2. Gemini ICD 1.9/2.7 Facility Handling Equipment.
4.1.10 Equipment Trolleys
Wheeled handling trolleys are provided for individual handling of the NIFS cryostat and thermal enclosures. A flat bed three-part trolley is provided for rotating the cryostat to service the spectrograph side of the cold work surface.
4.1.11 Stability of Handling Trolleys
NIFS is compatible via the integration frame with the Gemini-specified handling trolleys. The stability of NIFS in the optical-axis-vertical position atop one of the Gemini handling trolleys is marginal. For optimum stability during handling without exciting a rocking mode, the ratio of height (to center of gravity) to width of the handling trolley should be about 1. The height-to-width ratio of NIFS in the vertical transportation mode is about 0.6. Extreme care is therefore required in any horizontal movement of NIFS when in the optical-axis-vertical position. Servicing and handling of NIFS is normally performed on the handling trolley in an optical-axis-horizontal position, which meets the stability criterion.
Care must be exercised when transporting the thermal enclosures on the wheeled handling trolleys provided. The tall enclosures could topple if an obstruction was encountered on the floor (uneven flooring or a cable) while being wheeled along at more than a slow speed.
The flat bed three-part trolley for rotating the cryostat has a more conservative height-to-width ratio.
Relevant documents:
1. Gemini Facility Handling Equipment and Procedures for Instrumentation, ICD-G0015, Revision C.
4.2 Mechanism Operation
4.2.1 Loss of Power
Loss of power does not cause any mechanism in NIFS to move. The NIFS mechanisms maintain position when power is removed. Application of power does not induce sudden movement of any mechanism. There are no mechanism interferences.
4.2.2 Hazard to Personnel
An external motor and shaft assembly on the NIFS Environmental Cover is provided with a cover to protect personnel from inadvertent contact. Protective housings are provided around the mechanisms inside the cryostat to minimize contact during servicing. The Environmental Cover on the cryostat entrance window is a hazard to personnel since it may move at any time. A warning label is placed adjacent to the Environmental Cover on the ISS interface plate to indicate this hazard. The Environmental Cover is not exposed to personnel access during normal operation of NIFS on the telescope.
Relevant documents:
1. Gemini Instrument Safety Policy, PG-I-G0010, Revision A.
4.2.3 Labeling of Mechanisms
Protective warning labels in English and Spanish are provided where necessary on all mechanisms. Lift points are labeled. Labels indicating mechanism weights are provided to ensure proper use of handling equipment.
Relevant documents:
1. Gemini Instrument Safety Policy, PG-I-G0010, Revision A.
4.3 Electrical
4.3.1 Grounding
The mains earth ground connection will be through the primary power cord(s). This will ensure that the instrument is always grounded while power is applied to the instrument. However, if the instrument is installed on the telescope, the instrument will also be at earth ground through the telescope structure as required by the IGPO
NIFS has two thermal enclosures that will be supplied with 110 V AC power. Each of these enclosures will have the AC power internally distributed through the use of power strips inside each rack. The chassis within the thermal enclosures will be grounded through their associated power cords. In addition, the thermal enclosures will be grounded at the AC power entry point, near the circular connectors as supplied by the IGPO. Since the overall thermal enclosures are grounded through the rack frame, a secondary safety ground is present for any metallic chassis assembly.
Any enclosure, chassis, panel, or door that has a component using AC power attached to it, must have a ground wire connected to it. This wire may be integrated with its associated power cord.
All enclosures, chassis, panels, and doors will have a ground wire attached in such a manner that if the component is removed the ground wire remains attached. Ground wires may incorporate means for easy disconnection, to be used when items need to be removed fully.
Ground points shall consist of a bare metal pad with either a tapped hole or a stud to allow for attaching the ground wire. Alternatively, the ground connection is integrated with the associated AC power cord.
Ground wires between enclosures shall be GREEN or GREEN/YELLOW, 14 AWG or heavier stranded wire.
The mains ground wire shall be attached to a terminal point and all enclosure grounds will be distributed from there.
A ground point shall be supplied on the cryostat case near the detector I/O connectors so that the cryostat can be grounded while maintenance is performed when the detector cables leading to the SDSU-2 controller or the SDSU-2 controller power cord are disconnected. This will minimize the possibility of ESD damage to electronic components during maintenance.
Before disconnecting or connecting any cables to the cryostat, a ground wire to a ground point located off the instrument must be connected to the grounding point near the access port. This ensures that the instrument is at a ground potential. The ground wire must be attached in such a manner that it cannot be accidentally disconnected.
Shorting plugs shall be supplied as necessary. These plugs (spectrograph detector and OIWFS detector) must be installed any time that the associated cable leading to the detector is removed for any reason. These shorting plugs are permanently attached to the cryostat ready for immediate deployment. Shorting plugs shall remain in place at all times while the instrument is in transit.
Relevant documents:
1. Cassegrain Rotator to Science Instruments Interface Control Document, ICD 1.5.1/1.9.
2. Science and Facility Instruments to System Services Interface Control Document, ICD 1.9/3.6.
4.3.2 Power
Where possible, power should be disconnected before performing work on the instrument. If it is necessary to perform maintenance while the instrument is under power, at least two people must be present at all times.
All enclosures that have AC voltage within them shall have the appropriate warning signs or labels in English and Spanish that clearly state the potential of a hazardous condition within such enclosures. These signs shall be permanently attached and clearly visible.
The power input side of the main power switch and the incoming power line connections have physical protection against accidental contact.
Any terminals that have AC power on exposed lugs shall have a non-conductive shield installed to prevent the possibility of accidental shock.
Any shield shall have a label that identifies the voltage level present at the terminal. Also a label shall be placed on or next to the component that is shielded so that when the shield is removed the voltage level is still identified.
Before removing or connecting any cables ensure that the power is OFF.
Relevant documents:
1. Science and Facilities Instruments to System Services Interface Control Document, ICD 1.9/3.6.
4.3.3 High Voltage
The ionizing bar in the dry air system attached to the NIFS cryostat entrance window is powered from a 7.5kV 5mA AC source. Warning labels in English and Spanish adjacent to the Environmental Cover will identify this hazard.
The ionizing bar can be disabled by disconnecting its 115 V supply cable.
Relevant documents:
1. Gemini Instrument Safety Policy, PG-I-G0010, Revision A.
2. Gemini Electronic Design Specification, SPE-ASA-G0008, Revision 9, Section 4.8.4.
4.3.4 Over-Current Protection
The NIFS electronics modules are each provided with circuit breakers for over-current protection. These are in addition to the circuit breakers on the Gemini-provided thermal enclosures.
Circuit breakers are readily accessible and clearly identified by labels, on the assembly drawings, and in the relevant manuals. All circuit breakers and fuses are labeled as to their interrupting capability. The labels also appear on the panel beside the device to allow identification of a replacement should the device be destroyed by fault level currents.
1. Gemini Instrument Safety Policy, PG-I-G0010, Revision A.
2. Gemini Electronic Design Specification, SPE-ASA-G0008, Revision 9, Section 4.8.4.
4.3.5 Overheating Prevention and Protection
The thermal enclosure power distribution strips contain over-temperature switches to interrupt the supply in case of overheating. These switches reset when the temperature drops sufficiently.
The control system incorporates a temperature sensor for each thermal enclosure. Gemini software can monitor these temperatures through the NIFS CC SAD.
4.3.6 Interlock Protection
There is no known possibility of damage to the instrument by operation of any mechanism or combination when in place on the telescope. Therefore, interlock protection on mechanisms is not required. Interlocks are provided to disable telescope motion when the doors of the thermal enclosures are not fully closed.
4.3.7 Cryocoolers
It is important that the proper procedures be followed at all times while working on the cryocoolers. This will prevent damage to the units and injury to personnel.
A permanent label will be attached to the gas lines to identify the supply and return lines.
Documentation will be provided that details the proper methods to perform maintenance on the units. If necessary, personnel should be trained by the cryocooler supplier. Only trained personnel should be allowed to work on the cryocoolers.
4.3.8 Helium Pressure Interlock
A differential pressure switch is mounted on NIFS and connected between the low and high pressure helium gas lines. This switch connects to the Gemini Helium Protection System. The Gemini Helium Protection System only supplies 115 V power to the cryocooler drive frame in the CC thermal enclosure when the helium pressure is normal and shuts down the cryocooler microstepper drives if the helium supply fails.
Relevant documents:
1. Science and Facility Instruments to System Services Interface Control Document, ICD 1.9/3.6.
2. The Gemini Helium Protection System, draft July 2001.
4.3.9 Detectors
The spectrograph and OIWFS detectors may be destroyed through an ESD event. The spectrograph and OIWFS SDSU-2 controllers are mounted on the cryostat vacuum jacket near the detector I/O connectors to reduce the exposure of these detectors to outside ESD sources. Though the controllers provide some protection for the detectors, good ESD handling practices should always be followed when working around the detector or controller connections.
Before removing any cables from the cryostat, verify that there is no power being applied to the instrument. As each detector connector is removed, immediately install the shorting connector that is associated with that connection.
4.3.10 Access to the Instrument
The NIFS cryostat cannot be serviced on the telescope. There is reasonable access to external thermal enclosures when on the telescope. All connections on the outside of the cryostat vacuum jacket can be made when the instrument is on the telescope. The two detector controllers on NIIFS can be serviced or removed when the instrument is on the telescope. There is access to the necessary ISS break out panels when NIFS is in place on the telescope.
Relevant documents:
1. Cassegrain Rotator to Science Instruments Interface Control Document, ICD 1.5.1/1.9.
2. Science and Facility Instruments to System Services Interface Control Document, ICD 1.9/3.6.
4.3.11 Cable Ratings
All cables are specified to meet either UL or MIL-STDs. Insulation is selected on the basis of meeting the environmental requirements and the intended use of the cable. Information on cable lifetime under the Gemini telescope environmental conditions is limited. Cables are selected on the basis of the "best estimate" of conditions, since there are no current standards for high altitude cables.
All electrical equipment is supplied for 115V AC 60 Hz operation.
Relevant documents:
1. Science Instruments to System Cables Interface Control Document, ICD 1.9/3.8.
4.3.12 Connectors
MIL-STD connectors are used on all external cabling. Connectors for use within the cryostat are selected on the basis of ANU standard practice for cryogenic operation.
Relevant documents:
1. Science Instruments to System Cables Interface Control Document, ICD 1.9/3.8.
4.3.13 Component Ratings
Components are specified for operation at both sea level and the appropriate Gemini environment specification.
Certain commercial components are not guaranteed to operate below 0 degrees C.
Relevant documents:
1. Gemini Environmental Requirements, ICD-G0013, Revision B.
4.3.14 Fans
There are fans within the thermal enclosures and attached to the SDSU-2 controllers for the spectrograph detector and the OIWFS detector. All of these fans are fully enclosed under normal operating conditions.
Relevant documents:
1. Gemini Instrument Safety Policy, PG-I-G0010, Revision A.
4.4 Optics
4.4.1 Protection Against Thermal Shock
The NIFS optics are configured so that no optical components are subject to thermal shock. Temperature sensors are located on the cold work surface plate to monitor the cool down and warm up processes. The highest rate of temperature change occurs on accelerated warm up. The rate of temperature rise is limited by the heater power.
4.5 Detector
4.5.1 Protection Against Surface Contamination
The NIFS spectrograph detector is provided with a detector housing handling tool and a protective cover for use when the instrument is being serviced. This cover must be installed on the detector housing during disassembly. The cover is indicated in the relevant assembly drawing and manual.
4.6 Software
4.6.1 Components Controller (CC)
There is no mechanical interference between NIFS spectrograph components against which the CC must guard.
The remnance effects in the spectrograph detector are minimized by not allowing the detector to become saturated. Consequently, the NIFS software moves the filter wheel to its blocked position before moving the focal plane mask wheel, and returns the filter wheel to its original position once the focal plane mask wheel movement is completed.
The CC controls the spectrograph detector temperature and will not allow the device to be activated or operated if it is unsafe to do so.
The CC also ensures that the spectrograph detector is always warmer than the instrument body during cool down and warm up operations.
4.6.2 OIWFS Components Controller (OIWFS-CC)
There are no mechanical interferences between NIFS OIWFS components against which the OIWFS-CC must guard.
4.6.3 Instrument Sequencer (IS) to Detector Controller (DC)
There are no safety issues relating to the spectrograph detector against which the IS must guard.
4.7 Vacuum
4.7.1 Protection Against Overpressure
The NIFS vacuum pumping port contains a free plug that acts as an overpressure release during normal operation. This plug will vent under a positive pressure of ~30 kPa. A Leybold vacuum lock fitting attaches to the vacuum pumping port and is used to remove and replace this plug under vacuum. A safety guard is supplied that must always be attached to the vacuum port via a 40KF flange coupler when the vacuum lock is removed. This safety guard prevents possible high velocity expulsion of the plug and subsequent injury to personnel should an overpressure situation occur.
Relevant documents:
1. Gemini Instrument Safety Policy, PG-I-G0010, Revision A.
4.7.2 Safety During Pumping
There is no overpressure safety fitting on NIFS when it is attached to a vacuum pump as the free plug is held in the vacuum lock. Most commercial turbopump systems contain a release valve in the rotary backing pump that will release at about 200 kPa (2 atmospheres). In the unlikely event of an overpressure occurring during pumping of NIFS this valve should open. It is assumed that the NIFS vacuum jacket is safe under a positive pressure of 200 kPa. Care must be taken when backfilling the cryostat with nitrogen through the gas bleed valve to ensure that a positive pressure is not applied to the vacuum jacket.
4.7.3 Use of Cryogens
No cryogenic liquids are used in NIFS.
4.8 Pneumatics
4.8.1 Compressed Air
Relevant U.S. standards on compressed air safety are used in the air flushing system on the entrance window to the NIFS cryostat.
Relevant documents:
1. Gemini Instrument Safety Policy, PG-I-G0010, Revision A.
2. OSHA Regulations, Subpart M - Compressed Gas and Compressed Air Equipment (1910.166 to 1910.169).
4.9 Coolants
4.9.1 Coolants for Thermal Enclosures
The only shut-off facilities for coolants for the thermal enclosures are the double-ended shut-off connectors, which will be clearly marked and accessible.
Relevant documents:
1. Science and Facility Instruments to System Services Interface Control Document, ICD 1.9/3.6.
2. Cassegrain Rotator to Science Instruments Interface Control Document, ICD 1.5.1/1.9.
4.9.2 Coolants for Detector Controllers
The coolants for the thermal enclosures also pass through heat exchangers attached to the SDSU-2 detector controllers for the spectrograph detector and the OIWFS detector. These heat exchangers are attached to the outside of the SDSU-2 controllers. Swagelock double-ended shut off fittings are used to allow leak-free disconnection of these coolant lines.
1. Gemini Instrument Safety Policy, PG-I-G0010, Version A.
4.9.3 Coolant Lines
Relevant U.S. standard practice will be followed in selecting coolant lines.
5 General Safety Issues
5.1 General Procedures
The following is a list of general procedures that are required for the operation of NIFS:
1. General procedures for packing/unpacking and transportation of NIFS.
2. General procedures for assembly/disassembly and servicing of NIFS.
3. General procedures for cool down and warm up for NIFS.
4. General procedures for installation of NIFS on the telescope.
5. General procedures for operation of NIFS.
5.2 Instrument Related Issues
5.2.1 Transportation Between the Dome and the Instrument Preparation Room
NIFS will normally be transported on its supplied service trolley from the instrument preparation room to the telescope. This trolley is designed to carry NIFS via the Gemini elevator. There are no added safety issues associated with this movement above those mentioned in ICD-G0015.
5.2.2 Changing the Orientation of the Instrument
NIFS is a duplicate of NIRI externally. No special equipment is required to change the orientation of the instrument for mounting on any ISS port.
Relevant documents:
1. Gemini Instrument Safety Policy, PG-I-G0010, Revision A.
5.2.3 Personnel Protection from Moving Mechanisms
The only external mechanical component that presents a hazard to personnel is the Environmental Cover over the entrance window to the cryostat. This is provided with a warning label (§4.2.2).
5.2.4 Electrical Shock
The design principles of §4.3 of this document should prevent any risk of electrical shock in normal operation.
5.2.5 Change of Components on the Telescope
NIFS contains no components that are routinely changed while the instrument is on the telescope.
Relevant documents:
1. Gemini Instrument Safety Policy, PG-I-G0010, Revision A.
5.2.6 Use of the Engineering Interface
The Engineering Interface software does not allow the operator to bypass any safety interlocks in the operational software.
Relevant documents:
1. Gemini Instrument Safety Policy, PG-I-G0010, Revision A.
5.3 Service and Support Related Issues
5.3.1 Vacuum Pumping the Cryostat
The NIFS vacuum pump requirements are the same as for NIRI.
5.3.2 Warm Up Procedures
Sensors within the instrument monitor warm up rates.
A pressure sensor is located on the cryostat to monitor internal pressure. The warm up procedure requires monitoring of internal pressure during warm up. If, during the warm up process, the internal pressure rises above 1 Torr, then pumping on the vacuum jacket is necessary to minimize detector contamination.
5.3.3 Assembly/Disassembly of NIFS
Assembly and disassembly of NIFS are normally performed in the optical-axis-horizontal position, with the instrument removed from the telescope and positioned on the storage trolley.
Procedures for assembly/disassembly will be provided in the NIFS manuals.
NIFS cannot be safely serviced in any other position than when on its storage trolley and in the optical-axis-horizontal position.
Lifting points are clearly indicated on assembly drawings and manuals. Lifting points are clearly labeled on all components.
NIFS is designed to disassemble into a series of structural modules for servicing after the cryostat vacuum jacket is removed.
Assembly/disassembly of NIFS should be performed in a Class 10,000 clean facility to minimize contamination of the optics and cryogenic mechanisms.
Removal of the cryostat vacuum jacket end plates requires handling equipment. Lift points are provided on the end plates by attaching the rotation trunnions. The masses of important NIFS parts are displayed on a label on the vacuum jacket center section.
5.3.4 Personnel Protection from Internal Moving Mechanisms
Internal mechanisms may be exposed when the cryostat is disassembled. Depending on the extent to which the instrument has been disassembled, there may be a risk to personnel if these mechanisms move unexpectedly. Only properly trained personnel following standard procedures provided in the NIFS manuals should perform servicing of the instrument. It is not appropriate to attach warning signs within the cryostat due to the cryogenic nature of the environment.
5.3.5 Electrical Shock
Only properly trained personnel following standard procedures provided in the NIFS manuals should perform servicing of the instrument and override of any electrical safeties and interlocks.
5.4 Safety of NIFS in Transit
5.4.1 Shipping Container
The shipping containers are designed to provide shock and vibration isolation for the instrument, complete enclosure of the instrument, and some environmental protection. Tilt and shock watches inside and outside of the shipping container will be provided to monitor handling.
5.4.2 Condition of NIFS During Shipping
NIFS is normally shipped warm and with an internal vacuum to minimize contamination. (Airlines permit shipping in this configuration.)
No mechanical lock-outs or safeties are provided.
Shorting plugs are provided on detector connectors during transportation. These plugs are clearly labeled and identified in the relevant NIFS manuals.
The Environmental Cover on the entrance window of NIFS will be removed and packed separately during transportation. The exposed window will be covered by the trunnion support and trunnion during transport.
Protective covers and plugs will be placed on the vacuum port, compressed air lines, helium lines for the cryocoolers, coolant lines, and electrical connectors during transportation. These covers and plugs will be clearly labeled and identified in the relevant NIFS manuals.
Lift points on the outside of the cryostat will be clearly labeled and identified in the relevant NIFS manuals.
Unpacking procedures will be provided in the relevant NIFS manuals. These procedures will include equipment weights, identification of lift points, and any special handling requirements.
A set of standard tests to determine the condition of the instrument after shipping will be provided in the relevant NIFS manuals.
6 Safety Related Documentation and Training
6.1.1 Documentation
This safety review document will be updated as needed.
6.1.2 Training
ANU will provide training to Gemini personnel as required to ensure that NIFS is used in a safe manner.
7 NIFS Safety Audit
The following tables summarize the safety concerns and topics listed in the NIFS safety review: