This chapter provides guidelines for adjusting your work surface to increase your comfort and safety. It also contains environmental specifications and regulatory statements. The following topics are covered.
You can increase the comfort and safety of your work environment, and decrease your chances of repetitive strain injuries by following the guidelines given below. These guidelines help you create a healthy and productive work environment.
To browse through additional information on setting up your workstation area, taking frequent breaks, exercises you can do, and practicing safe work habits, click Hardware Central . If your web browser is not loaded, it takes a few seconds to load. (This option is not available if you're viewing this on a remote server.)
Table 6-1 shows recommended guidelines for furniture and system adjustment, as developed by the American National Standards Institute (ANSI).[3]
Local Visual Display Terminal (VDT) guidelines issued by country, state, or municipality may apply and supercede the guidelines in Table 6-1.
Table 6-1. ANSI/HFS 100-1988 Guidelines for VDT Workplace Adjustment
Adjustment | Small Female cm (in) | Midpoint cm (in) | Large Male cm (in) |
|---|---|---|---|
Seat pan height | 40.6 (16.0) | 46.3 (18.2)
| 52.0 (20.5)
|
Work surface height (keyboard and mouse) | 58.5 (23.0) | 64.75 (25.5)
| 71.0 (28.0)
|
Screen viewing height | 103.1 (40.6) | 118.1 (46.5)
| 133.1 (52.4)
|
Screen viewing distance | >30.5 (>12) | >30.5 (>12)
| >30.5 (>12)
|
Screen viewing | 0-60 degrees | 0-60 degrees
| 0-60 degrees
|
Adjustment parameters are defined in Figure 6-1. Guidelines are shown for small females (standing height of 150 cm, or 59 in) and large males (standing height of 185 cm, or 73 in). Midpoints are also interpolated for persons of more average height.
Figure 6-1. Basic Parameters of Visual Display Terminal Workstation Adjustment (Adapted From ANSI/HFS 100-1988)
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If you work on a CAD system, you may feel more comfortable using the ranges of adjustment shown in Table 6-2.
Table 6-2. Workstation Adjustments Preferred by CAD Users[a]
Adjustment cm (in) | Mean cm (in) | Range cm (in) |
|---|---|---|
Seat pan height | 54 (21.3) | 50-57 (19.7-22.4) |
Work surface height | 73 (28.7) | 70-80 (27.6 -31.5) |
Monitor center above floor | 113 (44.5) | 107-115 (42.1-45.3) |
Screen viewing | 70 (27.6) | 59-78 (23.2-30.7) |
Work surface tilt | 8.6 degrees | 2-13 degrees |
Monitor tilt[b] | -7.7 degrees | -15 - +1 degrees |
[b] negative tilt = a forward monitor inclination (top of the screen toward the operator) | ||
The following topics are covered in this section:
The O2 workstation conforms to several national and international specifications and European Directives listed on the “Manufacturer's Declaration of Conformity.” The CE mark insignia displayed on each device is an indication of conformity to the European requirements.
 | Caution: This product has several governmental and third-party approvals, licenses, and permits. Do not modify this product in any way that is not expressly approved by Silicon Graphics. If you do, you may lose these approvals and your governmental agency authority to operate this device. |
The model number, or CMN number, for the O2 workstation is on the system label underneath the workstation.
You need to know the CMN number for downloading the Manufacturer's Declaration of Conformity from the World Wide Web. You also need to know the CMN number to determine the class of your O2 workstation. Match the CMN number underneath your workstation with the CMN number on the Class A FCC Declaration of Conformance or Class B FCC Declaration of Conformance on the following pages. The model number for Class A begins “CMNB015A” and the model number for Class B begins “CMNB015B.”
Manufacturer's Declaration of Conformity
A “Manufacturer's Declaration of Conformity” is available on the World Wide Web. Look on the system (regulatory) label underneath your workstation to determine your CMN (model) number. You need this number to identify the Declaration of Conformity on the Web.
To locate the information on the World Wide Web, enter the following in your browser location window:
http://www.sgi.com/Products/compliance/index.html
Locate and print or save your Declaration of Conformity. Make a note of your CMN number and the date of the Declaration of Conformity here for future reference.
Table 6-3. Class A FCC Declaration of Conformance
Trade Name | Silicon Graphics, Inc. |
Product | Computer Graphics Workstation |
Model Number | CMNB014A |
Date of Conformance | 10/96 |
Responsible Party | Silicon Graphics, Inc. |
Address | 2011 North Shoreline Boulevard, |
Telephone | (415) 933-1071 |
This equipment complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.
 | Note: This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures: |
Reorient or relocate the receiving antenna.
Increase the separation between the equipment and receiver.
Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
Consult the dealer or an experienced radio/TV technician for help.
Caution: The user is cautioned that changes or modifications to the equipment not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment.
This device complies with the Class A limits of Part 15 of the FCC Rules. Operation is subject to the following two conditions:
This device may not cause harmful interference.
This device must accept any interference received, including interference that may cause undesired operation.
This Class A digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations.
Cet appareil numérique né met pas de perturbations radioé lectriques dé passant les normes applicables aux appareils numériques de Classe A préscrites dans le Règlement sur les interferences radioé lectriques établi par le Ministrère des Communications du Canada.
This device complies with Class A electromagnetic emissions limits of C.I.S.P.R. Publication 22, Limits and Methods of Measurement of Radio Interference Characteristics of Information Technology Equipment; and VCCI Class A limits.
 |
 |
The equipment described in this guide generates and uses radio frequency energy. If it is not installed and used in accordance with the instructions in this guide, it can cause radio and television interference.
This equipment has been tested and complies with the limits for a Class A computing device in accordance with the specifications in Part 15 of FCC rules. These specifications are designed to provide reasonable protection against such interference in an industrial or office installation. However, there is no guarantee that the interference will not occur in a particular installation. This system is not certified for home use.
You can determine whether your system is causing interference by turning it off. If the interference stops, it was probably caused by the workstation or one of the peripherals. To tell if the interference is caused by one of the peripherals, try disconnecting one peripheral at a time to see if the interference stops. If it does, that peripheral is the cause of the interference.
If your workstation does cause interference to radio or television reception, try to correct the interference by using one or more of the following suggestions:
Turn the television or radio antenna until the interference stops.
Move the workstation to one side or the other of the radio or television.
Move the workstation farther away from the radio or television.
Plug the workstation into an outlet that is on a different circuit from the radio or television. (That is, make certain the workstation and the radio or television are on circuits controlled by different circuit breakers or fuses.)
For additional information you can check the FCC Web site by entering the following address in your Web browser location window:
http://www.fcc.gov/Bureaus/Compliance/WWW/tribook.html
Table 6-4. Class B FCC Declaration of Conformance
Trade Name | Silicon Graphics, Inc. |
Product | Computer Graphics Workstation |
Model Number | CMNB014B |
Date of Conformance | 10/96 |
Responsible Party | Silicon Graphics, Inc. |
Address | 2011 North Shoreline Boulevard, |
Telephone | (415) 933-1071 |
This equipment complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.
| Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures: |
Reorient or relocate the receiving antenna.
Increase the separation between the equipment and receiver.
Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
Consult the dealer or an experienced radio/TV technician for help.
Caution: The user is cautioned that changes or modifications to the equipment not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment.
This device complies with the Class B limits of Part 15 of the FCC Rules. Operation is subject to the following two conditions:
This device may not cause harmful interference.
This device must accept any interference received, including interference that may cause undesired operation.
This Class B digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations.
Cet appareil numérique né met pas de perturbations radioé lectriques dé passant les normes applicables aux appareils numériques de Classe A préscrites dans le Règlement sur les interferences radioé lectriques établi par le Ministrère des Communications du Canada.
 |
This device complies with Class B electromagnetic emissions limits of C.I.S.P.R. Publication 22, Limits and Methods of Measurement of Radio Interference Characteristics of Information Technology Equipment; and Japan's VCCI Class 2 limits.
The equipment described in this guide generates and uses radio frequency energy. If it is not installed and used in accordance with the instructions in this guide, it can cause radio and television interference.
This equipment has been tested and complies with the limits for a Class B computing device in accordance with the specifications in Part 15 of FCC rules. These specifications are designed to provide reasonable protection against such interference in an industrial or office installation. However, there is no guarantee that the interference will not occur in a particular installation. This system is not certified for home use.
You can determine whether your system is causing interference by turning it off. If the interference stops, it was probably caused by the workstation or one of the peripherals. To tell if the interference is caused by one of the peripherals, try disconnecting one peripheral at a time to see if the interference stops. If it does, that peripheral is the cause of the interference.
If your workstation does cause interference to radio or television reception, try to correct the interference by using one or more of the following suggestions:
Turn the television or radio antenna until the interference stops.
Move the workstation to one side or the other of the radio or television.
Move the workstation farther away from the radio or television.
Plug the workstation into an outlet that is on a different circuit from the radio or television. (That is, make certain the workstation and the radio or television are on circuits controlled by different circuit breakers or fuses.)
For additional information you can check the FCC Web site by entering the following address in your Web browser location window:
http://www.fcc.gov/Bureaus/Compliance/WWW/tribook.html
The O2 workstation is FCC-compliant under test conditions that include the use of shielded cables between O2 and its peripherals. Your O2 workstation and any peripherals you purchase from Silicon Graphics have shielded cables. Shielded cables reduce the possibility of interference with radio, television, and other devices. If you use any cables that are not from Silicon Graphics, make sure they are shielded. Telephone cables do not need to be shielded.
The monitor cable supplied with your system uses additional filtering molded into the cable jacket to reduce radio frequency interference. Always use the cable supplied with your system. If your monitor cable becomes damaged, a replacement cable should be obtained from Silicon Graphics.
Silicon Graphics designs and tests its products to be immune to the effects of electrostatic discharge (ESD). ESD is a source of electromagnetic interference and can cause problems ranging from data errors and lockups to permanent component damage.
It is important that while you are operating your O2 you keep all the covers and doors, including the plastics, in place. The shielded cables that came with the workstation and its peripherals should be installed correctly, with all thumbscrews fastened securely.
An ESD wrist strap is included with some products, such as memory and graphics upgrades. The wrist strap is used when installing these upgrades to prevent the flow of static electricity, and it should protect your system from ESD damage.
[3] American National Standard for Human Factors Engineering of Visual Display Terminal Workstations. ANSI/HFS 100-1988. Available through the Human Factors Society, Inc. P.O. Box 1369, Santa Monica CA 90406, USA.