sx-8 instllation planning manual(e) r2

7/31/2019 SX-8 Instllation Planning Manual(E) R2

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U0ME-G1AZ102E2

SX-8

INSTALLATION PLANNING

MANUAL

U0ME-G1AZ102E2


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U0ME-G1AZ102E2

The information disclosed in this document is the property of NEC Corporation (NEC) and/or its

licensors. NEC and/or licensors, as appropriate, reserve all patent, copyright, and other

proprietary rights to this document. Including all design, manufacturing, reproduction, use andsales rights thereto, expect to the extent said rights are expressly granted to others.

The information in this document is subject to change at any time, without notice.

Copyright 2004

NEC Corporation


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This manual describes the planning and construction of the NEC computer system. In order toachieve the highest computer system performance, all efforts should be made to meet the

environmental standards specified in this manual.

This manual is organized as follows.

Chapter Title Contents

1 Outline of Facility PlanningExplains the general planning stepsfor installation.

2 Architectural EquipmentExplains the examination stepsfor architectural equipment.

3 Air Conditioning Installation Explains the examination stepsfor the installation of air conditioning.

4 Power Supply FacilitiesExplains the examination stepsfor power supply facilities.

5 Automatic Operation FacilitiesExplains the examination stepsfor automatic operation facilities.

6 Safety Measures Explains the examination steps for safety measures.

7 Work AssignmentExplains the standard work responsibilitiesof the customer and NEC during installation ofthe computer.

8Requirementsfor Individual Devices

Explains the requirements for individual devices.

9 Device SpecificationsDescribes the specificationsand structural standards of each device.

10 Computer LayoutDescribes the installation restrictionsand typical computer layouts.

11 Appendix

Initial version issued in October 2004

2nd version issued in October 2005

If you have any suggestions or requests, or come across any uncertain points in this manual, please

fill out the Users Comments Form at the end of this volume and hand it over to the responsible

marketing personnel or systems engineer.


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Contents

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1.1 Planning Steps 1- 21.2 Schedule 1- 3

1.2.1 Schedule Outline 1- 31.3 Outline of Facilities 1- 5

1.3.1 Location (Regional Characteristics 1- 51.3.2 Building Requirements 1- 51.3.3 System Designed for Advanced Level of Public Applications 1- 6

2.1 Planning the Computer Room 2- 22.1.1 Computer Room 2- 32.1.2 System Layout 2-102.1.3 Installation Environment 2-11

2.2 Additional Rooms 2-172.2.1 List of Additional Rooms 2-172.2.2 Layout of Additional Rooms 2-18

2.3 Delivery Planning 2-202.3.1 Delivery Methods 2-202.3.2 Delivery Entrance and Route 2-212.3.3 Elevator 2-23

3.1 Air Conditioning Systems 3- 23.1.1 Outline of Air Conditioning Systems 3- 23.1.2 Selection of Air Conditioning Systems 3- 7

3.2 Air Conditioner Specifications 3- 83.2.1 Features of Air Conditioning Installation for Computer Room 3- 83.2.2 Air Conditioning Installation Specifications Required for Computer 3- 9

3.3 Temperature and Humidity Requirements 3-123.3.1 Temperature and Humidity Requirements for Computer Equipment 3-123.3.2 Temperature and Humidity Requirements for Media 3-13

3.3.3 Method of Cooling the Computer Equipment 3-143.4 Temperature and Humidity Requirements for Computer Room 3-15

3.4.1 Facility Reference Values and Scope of Facility Recommendation 3-153.4.2 Facility Reference Value Locations 3-173.4.3 Installation Location of Temperature and Humidity Sensor 3-173.4.4 Air Conditioning Control Design Values 3-18

3.5 Calculation of Air Conditioning Capacity 3-193.5.1 Air Conditioning Capacity 3-19

3.6 BackupAir Conditioner 3-203.7 Inspection and Control 3-21

3.7.1 Facility Inspection 3-21

3.7.2 Necessity of Temperature and Humidity Control 3-21


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Contents

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3.7.3 Temperature and Humidity Control Position 3-213.8 Trial Operation 3-223.9 Notes on Start-up Time of Cold Season Operation 3-23

3.9.1 Condensation Mechanism 3-23

3.9.2 Notes on the Start-up Time of Air Conditioner Operation 3-233.10 Ventilation Facility 3-24

4.1 Power Supply Facility Method 4- 24.1.1 Type and Special Features of Power Supply System 4- 24.1.2 Selection of Power Supply Facility Method 4- 4

4.2 Power Supply Requirements of the Computer 4- 84.2.1 Power Supply Requirements 4- 84.2.2 Grounding Requirements 4-10

4.3 Computation of Power Supply Facility Capacity 4-13

4.3.1 Computation of Facility Capacity 4-134.3.2 Confirmation of Rush Current Value 4-134.3.3 Computation of Uninterruptible Power Supply (UPS) Capacity 4-14

4.4 Power Distribution Board for Computer System 4-154.4.1 Circuit Breaker 4-164.4.2 Grounding Terminal 4-164.4.3 Grounding Method 4-164.4.4 Installation Location of Power Distribution Board 4-164.4.5 Protection against Lightning 4-174.4.6 Grounding 4-174.4.7 Inspection and Control 4-17

4.4.8 Specifications for Device Power Supply Cable 4-194.5 Emergency Power Off 4-21

4.5.1 Triggering of EPO 4-214.5.2 Construction of Emergency Power Off Facilities 4-22

5.1 Scope of Automatic Operation Facilities 5- 25.1.1 Function of Auxiliary Facilities Necessary for Automatic Operation 5- 25.1.2 Operation Method 5- 35.1.35.1.4

Measures against AbnormalityCautions

5- 45- 5

5.2 Automatic Operation Controller 5- 65.2.1 Connection with Auxiliary Facilitiesand External sensor 5- 65.2.25.2.35.2.4

Connection with Auxiliary FacilitiesElectric Circuit RequirementsPower Distribution Diagram

5- 65- 75- 7

6.1 Protection against Fire 6- 26.1.1 Points to Note for Protection against Fire 6- 26.1.2 Fire Prevention 6- 36.1.3 Initial Fire 6- 3


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6.1.4 Fire in a Wide Area 6- 46.1.5 Automatic Fire Alarm System 6- 56.1.6 Fire Extinguisher 6- 66.1.7 Fire Extinguishing Equipment 6- 6

6.1.8 Evacuation Facilities 6- 96.2 Protection against Earthquakes 6-10

6.2.1 Seismic Resistance of the Computer 6-106.3 Protection against Lightning Damage 6-116.4 Protection against Flood Damage 6-126.5 Protection against Crime 6-13

6.5.1 Protection of Computer Room against Crime 6-136.5.2 Entry Control Device 6-136.5.3 Security Alarm System 6-14

7.1 Customer Responsibility 7- 27.2 NEC Responsibility 7- 2

8.1 Remote Maintenance System 8- 18.1.1 Power Supply for ALIVE Modem 8- 1

9.1 Specification List 9- 19.2 Plan View 9-14

10.1 Layout Requirements 10- 110.2 Layout of the Main Devices and Maintenance Area 10- 210.3 Critical Point in Deciding Layout 10- 3110.4 Limitations on Cable Length 10- 31

11.1 Units 11- 211.1.1 SI Units 11- 211.1.2 Conversion Coefficients between SI Units Used in Manual And

Conventional Units 11- 511.2 Air Conditioning Installation Related 11- 7

11.2.1 A convert ofthe Display to SI Unit System 11- 711.3 Power Supply Facility Related 11- 8

11.3.1 Input Power Noise Type 11- 811.3.2 UPS Operation Methods 11-1211.3.3 UPS Motion Interpretation 11-1511.3.4 An Example of a Layout Diagram 11-1711.3.5 Large Capacity UPS 11-1811.3.6 UPS Installation Environment 11-22


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Outline of Facility Planning

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This chapter provides an outline of the facility planning required before the introduction of a

computer system, including the selection of an installation site, the computer room location,

facility layout and power supply and air-conditioning equipment.

In planning these facilities, not only the system scale but also reliability and operationality must

be set as important items to be examined. See Chapter 2 and subsequent sections for more

information on each step.


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Planning a computer installation begins with the selection of an installation site. Plans must

then be drawn up for the computer room location, layout of the facilities, and power supply and

air-conditioning equipment.

Location and building requirements

Identifying additional rooms and their layout

Communication facilities (LAN and remote

diagnosis

Installation environment and space

Floor constructions, room partitions, ceiling,

walls and windows

Safety and cleaning

Power supply and air-conditioning room

Operator room and other additional rooms

Air-conditioning system, cooling capacity and

reserve air conditioner

Temperature and humidity control

Power supply system, transformer capacity

and reserve power supply

Power distribution board, grounding and

automatic operation control panel

Lighting and electrical outlets

Computer room facilities

Planning the computerroom

Facilities in additionalrooms

Air-conditioning

Power plant

Final decision on layout

Determination of workschedule and assignments


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Specific schedules depend on the system configuration, but installation of NECs computer system

generally requires a period of six months to one year from the time plans are drawn up until the

installation is complete. A recommended schedule is outlined in the next section. This schedule

should be followed as closely as possible.

Problems arising from individual system scales and building construction should be resolvedthrough consultations between the customers installation manager and an NEC

representative,and reviewed before finalizing the schedule.

Studies and decisions on the computer system to be installed are made during this period.

The following tasks must be performed at this time:

(a) Appointment of an installation manager

(b) Determination of the system configuration

(c) Determination of the installation site

(d) Drafting of layout plans

(e) Drafting of facility and equipment specifications and introduction plans

(f) Placement of orders for a private (backup) generator

(g) Placement of orders for customer-made facilities

All facility specifications must be determined during this period, and all orders placed

actual construction beings at this stage.

(a) Determination of the layout

Computer system cables are ordered at this stage, so subsequent layout changes must

be avoided from this point on.

(b) Placing of orders for facilities and equipment

Placement of orders for computer room partitions, free access floor and ceiling.

Final confirmation of the power plant equipment specifications and placement of

orders

Final confirmation of the air conditioning installation equipment specifications andplacement of orders

Final confirmation of the specifications of other related facilities and equipment and

placement of orders

(a) Determination of delivery method and route

(b) Checking the progress of the construction

The computer room (room partitions and floors) and facilities (such as power supply and

air conditioning) should be checked carefully against the system specifications.


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All construction and installation must be completed by this stage. This site must be ready

for the delivery of the computer equipment.

(a) Trial operationRun a trial operation of each facility and finally confirm whether or not the operation is

performed as per the initial specifications (such as the set control value).

(b) Cleaning

The air conditioner must be started to remove any dust in the air conditioner ducts and

under the floor (space between the free access floor and the floor foundation). Run the

air conditioner in new buildings for the purpose of dehumidification.


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Installation of the computer system and related facilities in the following locations should be

avoided.

If installation in such a location is unavoidable, the appropriate safety precautions must be takenbefore system installation.

(a) Basements are vulnerable to flooding, and top floors are susceptible to water seepage

and severe damage by earthquakes.

(b) If the system is installed on the first floor, precautions must be taken to prevent

flooding and damage from outside (traffic, stone throwing, etc.).


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As systems designed for an advanced level of public applications and systems located at the

banks and hospitals play an extremely important role in our social life, and the shutdown of such

systems must be avoided by all means.

Accordingly, improving the reliability of the entire system including the facilities is required

through such means as the employment of redundant design which requires the installation ofbackup facilities as well as the construction of a substitution center to improve the reliability and

construction of dual systems.


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Architectural Facility

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This chapter describes the architectural facility such as the installation environments of the computerroom, additional rooms and computer equipment when the computer system is introduced.

The architectural plan includes, as important items, the installation performance which considers the

system configuration (such as the size and weight of individual equipment), and operationality and

safety which take the information and personnel flow into consideration.

*SX-8 is large equipment.


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Equipment to be installed in offices consumes low electrical energy and generates little heat. The tem-

perature and humidity requirements are less strict than those applicable to large equipment. Accord-ingly, no particular problems are anticipated when such equipment is installed in offices. Whether or

not such equipment can be installed in offices must be determined by taking the installation space,

the power supply capacity, the air conditioning capacity, safety (protection from fires and crimes) and

other factors into consideration. Please note that you are requested to observe the requirements for

the installation environment (to be described later) such as radio waves and vibrations.

When many servers and Visual Display Terminals (VDTs) are installed in an office, this may result in

insufficient power supply and air conditioning capacities. In such a case, please hold thorough con-

sultation with the section responsible for facility installation and the building Management Company.

In planning the computer room, it is important to clarify both operation plans, and plans for adding

new facilities on the short-term basis (one to two years), or for replacing the computer after a longer

period (four to five years). Special consideration must be given to adding and replacing equipment,

and to the reservation of adequate space for increasing the capacity of the original facilities.


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(a) Loading capacity

Depending on the system scale (configuration), large and heavy equipment must meet therequirements for the computer room.

Table 2-1 Loading Capacity of the Floor

Room Type Loading Capacity Remarks

Office 300 kg/ (min.)Small (light) equipment receiving power from thepower outlet

Computer room 500 kg/ (min.) Medium and large (heavy) equipment

(b) Construction

Table 2-2 Floor Construction

System Features Application Level

Covering cables

An inexpensive method that involves the installation of theequipment directly on the floor and the protection of inter-connecting cables and power cables by the cable cover.As the cable cover projects out from the floor, this system is

not recommended for places where there is large vehicularand human traffic.

Small equipmentand terminals(Fig. 2-1)

Free access floor

A method which involves the installation of the raised floor

and the laying of interconnecting cables and power cablesbetween the floor and the raised floor.Can also be used as the air duct to blow chilled air when

under-floor air conditioning is introduced.(*1)Since the floorboards that form the raised floor can be re-

moved at any place, it makes modifications to the equip-ment layout easy.As the cables are located underneath the raised floor, there

are no projections from the floor, thus ensuring safety.

Medium andlarge equipment

Prerequisitewhen under-floorair conditioningis introduced.(Fig. 2-2)

(*1) The floor must be dustproof to avoid the accumulation of dust.


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(c) Structural drawing of the floor

Fig.2-1 Covering Cables

Fig.2-2 Free access floor

Cable

200 mm

600 mm

50 mm

Cable cover

350450mm

450 or 465 mm


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(d) Maximum load on the free access floor

The maximum load on the free access floor must meet the following conditions.

Table 2-3 Allowed Load on the Free Access Floor

Free Access FloorSystemAllowed Load Flexion

Remarks

Free access floor 500 kg (min.) 1.5 mm (max.)The installation of large equipment(heavy) is set as the precondition.

(e) Covering material of the free access floor

The covering material of the free access floor should produce little dust. To prevent the

build-up of static charge, an anti-static treatment should be used for the floor. It is also ne-

cessary that no metal surface should be in direct contact with the floor. An exposed metal

surface may result in a failure in maintaining an appropriate level of leak resistance, caus-ing safety problems.

If a carpet is to be laid out in an ordinary office in which the equipment is installed, use an

anti-static carpet that produces little dust.

Table 2-4 Ohmic Value of Free Access Floor

Item Ohmic Value Range

Surface resistance of the free access floor material 1106 9.9109

Volume resistance of the free access floor material 1106 9.9109

To reduce the build-up of static charges or decrease the static charges built up, electrically

conductive pads must be installed between the free access floor and the support to maintain

electrical conductivity between free access floor materials and between the free access floor

and the support.

Table 2-5 Leak Resistance of Free Access Floor

Item Ohmic Value RangeBetween free access floormaterials

Leak resistanceBetween the free accessfloor and the support

1.0106 (max.)

A maximum range of 1.010

3

is recommended.


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Fig. 2-4 Schematic Drawing of Electrically Conductive Pads

f) Floor Elevation

Similar to the free access floor, a double floor can be built to use the space between the base

floor and the top-surface floor for the laying of cables and the installation of the air ducts

for the air conditioner. In this case, the floor elevation must meet the following conditions.

Table 2-6 Floor Elevation

Floor Elevation (Head Space)System

Lower limit Recommended valueRemarks

Free access floor 300 mm (min.) 350450 mm Medium and large systems

Sufficient space is required between the base floor and the top-surface floor, the two of

which combine to form the double floor, to ensure that the cables and the pipes will notblock the air flow from the air conditioner and that the space is fully utilized as the air

duct.

Fig. 2-5 Area functioning as the Air Duct in the Double Floor

Free access floor

Electricallyconductive pad

FloorSupport height

Floor slab

Free access floor

h2 Area to functionas the air duct h Floor height

Cables h1

Floor slab h1 Area for cables

h = h1 + h2 h1: Cable height (Target value 100200mm) h2: Air duct height (Target value 200mm (min.))


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When seismic floor is introduced as protection against earthquakes, the area that can be

used for cables and the air duct decreases because the seismic isolator and the beam for sup-

porting the top-surface floor are additionally installed in the double floor. We, therefore,

recommend that the top-surface floor elevation be set at a minimum value of 500 mm, in this

case.

(g) Opening of the free access floor (floor cut)

Observe the conditions listed below for boring holes into the free access floor (floor cut) for

the passage of cables and air ducts for cooling the equipment. Moreover, a perforated floor

results in a reduction in the allowable load on the free access floor. It is, therefore, neces-

sary for adding spare support and for supporting the free access floor. Contact the floor

manufacturer for more information.

Do not cut the entire side of the four sides.

Do not cut two corners out of the four corners.

Do not cut the floor in such a way as to significantly reduce the floor strength.

Do not cut the floor in such a way that the floor cannot be supported by the support.

Do not cut the floor in such a way as to cause problems when computer equipment is to be

installed.

Do not cut the floor at a location significantly far from the position where the opening for

the passage of equipment cables into the floor and the cooled air inlet are located.

Do not cut the floor at a location which is within 100 mm of the equipment.

Fig. 2-6 Examples of Floor Cutting Not Recommended

Base NG NG NG


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(h) Dimensions and the weight of the free access floor

The free access floor may have various cut area sizes. The floor is opened or closed when

the equipment size is changed, cables are to be laid when the equipment is added, moved or

replaced, or the top-surface floor is replaced. In these cases, if the cut floor area is too large,

the equipment legs may be on the free access floor, making it impossible to open the floor or

the heavy weight of the floor may result in poor operationality. On the other hand, if thecut floor area is too small, a large number of supports will be required for supporting the free

access floor, making it difficult to use the space within the double floor effectively.

Table 2-7 Dimensions and Weight of Free Access Floor

Item Free Access Floor

Dimensions 450 600 mm

40 kg/ (max.)Weight

10 kg/ floor board (max.)

(i) Air conditioning grill

Free Access floor air conditioning may require an air conditioning grill for adjusting the tem-

perature distribution in the room or to effectively cool the equipment which requires a large

air capacity.

There are various types of air conditioning grills with numerical apertures, ranging from

20% to 80%. It is recommended that the numerical aperture be adjusted by combining a

grill of large numerical aperture with an aluminum shutter for air conditioning.


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The wall surface must be of a material that exhibits excellent sound absorption and heat insula-

tion performance and which minimizes dust formation or adhesion.

The wall surface must be of a material that is less likely to allow static charges to build up since

static electricity is generated through friction between the human body and clothing.

It is recommended that the computer room be window less. However, if the computer room has

windows, they must be built with a structure that prevents heat loss and dust entry. Double

windows or double-sealed windows are required where dust, salty air, and corrosive gases are

present. In this case, we also recommend that measures be taken to seal the windows or

shut-off direct sunlight.

At least 2,300 mm of effective height from the free access floor surface to the ceiling is recom-

mended as the ceiling height (a height of 2,500 mm is ideal). A double ceiling should be built.

It is also recommended that an exhaust grill be installed above equipment that generates a large

amount of heat so as to let the exhaust be effectively sucked into the air conditioner.

It is recommended that lighting in the computer room and the VDT room be in the range be-

tween 300 and 750 lx (lux) at an elevation of 85 cm above floor level. The use of lighting equip-

ment with a louver for glare prevention is also recommended when a large number of VDT

equipment is installed.

It is recommended that lighting is arranged in such a way that it can be turned off in the absence

of personnel or lighting in the equipment area where no regular operations are conducted can be

turned off for the purpose of energy conservation.

The computer room must be clean at all times. It is also necessary to keep out rats (which cause

damage to the cables) and harmful insects. If some chemical materials are used in computer

room, the type of the material should be informed NEC.

It is necessary to build electrical outlets for maintenance operations in the computer room in or-

der to use the maintenance equipment such as measuring instruments and the vacuum cleaner.


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Examine the topics listed below when planning the system layout.

It is also necessary to ask the building designer or the building manager to check the layout after it is

completed, and then finalizes the plan.


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The computer can operate normally at a maximum dust level of 0.3 mg/m3.

It is recommended that the maximum dust level be maintained at a value of 0.15 mg/m3

in theoperator-working environment.

Electrically conductive dust may cause short-circuits and magnetic dust may cause access error

of magnetic media even when the dust level is within the specified range. Dust prevention

measures may be required in certain cases. Also note that when the humidity level in the com-

puter room is high, the dust may absorb moisture and the amount of dust accumulation may in-

crease, resulting in clogging of the computer air filters or short-circuits in the computer caused by

moist dust.

To keep the computer room clean, it is necessary to eliminate dust using the air conditioner fil-

ters and removes dust from the floor or under the floor by regularly cleaning the computer room.

Entering the computer room with shoes on and leaving the computer room door open must be

strictly prohibited. Other measures such as the prohibition of smoking in the computer room (as

smoking may result in secondary damage caused by cigarette ash) must also be adopted.

When planning to use a dust collector, do not use an electrical dust collector (as the electrical dust

collector discharges electricity when it collects dust, and generates ozone that may cause the

rusting of the computer.)


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If the computer is installed near a noxious gas source, the gas concentration must be minimized

to protect operator health and prevent computer corrosion. Special precautions must be adopt-

ed near coast, Hot Springs or hot spring facilities.

Ensure that the concentration of corrosive gases in the computer room is maintained at or be-

low the allowed values shown in Table 2-8.

Table 2-8 Allowed Concentration of Corrosive Gases for the Computer

Corrosive Gases Allowed ConcentrationSalinity (NaCl) 0.08 mg/m3

Sulfur dioxide (SO2) 0.2 PPM

Hydrogen sulfide (H2S) 0.1 PPM

Nitrogen dioxide (NO2) 0.5 PPM

Ozone (O3) 0.1 PPM

Keeping the atmospheric pressure in the computer room higher than that of the open air pre-

vents the open air containing corrosive gases from entering the computer room. However, this

requires constant feeding of air into the computer room to maintain a certain pressure differ-

ence. If a corrosive gas source is located near the air intake, this causes these corrosive gases

to be sucked in. Accordingly, a thorough pre-investigation of the area around the computer

room is required. In addition, the level of airtightness of the computer room must be im-

proved.

The computer will operate normally if the vibrational acceleration amplitude of the installation

floor surface is below 2.45 m/s2 (245 gal).

In order to prevent damage to the computer due to sliding and falling when the vibrational am-

plitude exceeds 2.45 m/s2(245 gal) or prevent injuries from the sliding and falling of the equip-

ment and the fittings, we recommend that seismic prevention measures be taken. (See 6.2

Protection against Earthquake.


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Ensure that the field intensity of the incoming radio waves at the place where the computer is

installed is less than a maximum value of 1 V/m(120dBV/m).

However, in places where strong radio waves are generated (for example, in the vicinity of abroadcasting and a communication antenna or a radar station), or when a high-frequency de-

vice is installed on the same floor as the computer, radio waves can affect computer operation.

In such cases, contact NEC since works such as shielding of the computer room may be re-

quired.

Radio equipment such as cellular phones may affect the computer operation. Therefore, re-

frain from using such equipment in the computer room in accordance with the service condi-

tions set out in Table 2-9.

Table 2-9 Restrictions of Radio Equipment usage in the Computer Room

Radio EquipmentRestrictionsof equipment

usageNotes

Cellular phonesTransceivers operated

on the citizens bandCommercial radiosAmateur radios

ProhibitedThe computer may malfunction.Please power off the equipment at bringing it intothe computer room.

Cordless telephoneoperated on low elec-

tric powerTransceiver operated on

low electric power

Permitted

Do not let the main body or the antenna of theequipment contact the computer or the signal cable.

The radio noise generated by the computer may cau-se noise to enter the speaker voice or reception fail-ure.


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(a) Storage site for magnetic media

The information stored in magnetic recording media may be damaged if they are kept in a

place where the external magnetic field exceeds 4000 A/m (50 Oe: Oersted). Accordingly,

avoid storage in such places.

(b) Effects of the external magnetic field on the CRT

Since the CRT characters and graphics by deflecting the electron beams in the horizontal

and the vertical directions using the magnetic field created by the deflecting coil, its screen

display is affected by the external magnetic field. Moreover, with the introduction of higher

resolution displays, these displays are more likely to be affected by the smaller magnetic

fields.

Although the extent of the effect on the CRT depends on the type of magnetic field, the fol-

lowing phenomena are anticipated.

(1) AC magnetic field

Causes screen flickering.

Sources that generate the AC magnetic fields include the cables and the AC power

supply transformers.

In addition, the deflecting coil of the CRT itself generates magnetic field. Therefore,

when CRTs are placed next to each other, they may interfere with each other, causing

the flickering of the screen.

(2) DC magnetic field

Causes color deviation, shift or tilting of the screen.

Sources that generate the DC magnetic fields include the cables and the DC power

supply transformers, metal plates magnetized by welding or bending and speaker

magnets.

(c) Allowed magnetic field value for the CRT display

The CRT display performance may be affected in the proximity of cables and power trans-

formers carrying large electric currents and magnetized metals.

The intensity of magnetic field that affects the CRT display performance slightly varies, de-

pending on the CRT size and type, the nature of screen display, and the type of magnetic

field. Values indicating the level where the color display performance is not generally af-

fected are shown below.

(1) AC magnetic field: 0.4 0.6 A/m( 5 7 mOe ) (max.)

(2) DC magnetic field: 31.8 39.8 A/m( 400 500 mOe ) (max.) *1

( 1 A/m = 4 10-3Oe: Oersted) *2


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*1: The value of the DC magnetic field includes the earths magnetism

*2: Magnetic flux density Gauss (gauss) Magnetic-field intensity (Oe) in the air

(d) Protection of the CRT from magnetic fields

(1) Isolation of the sources generating magnetic fields

Move the transformers and power cables carrying large electric currents away fromthe computer room.

In addition, a secondary problem of magnetic flux leakage from the power cables

caused by electrical leakage is present. In a case like this, it is necessary to remove

problem sections in the facility.

(2) Isolation of the CRT from the sources generating magnetic fields

In case the sources generating magnetic fields cannot be isolated from the computer

room, move the CRT away from such sources. Since the magnetic field intensity

drops significantly as the CRT is moved away from the sources generating magnetic

fields, move the CRT away till it is no longer affected by the magnetic fields.

(3) Protection by a magnetic shield

Store the CRT in a magnetic shield case made of magnetic materials of high magnetic

permeability and low coercive force such as amorphous and permalloys. Generally,

the shielding of the CRT from magnetic fields is more effective and less expensive than

protective measures against magnetic field sources.

(4) Change in the display

Change the display to the liquid crystal display or the plasma display both of that are

not affected by magnetic fields.


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The computer may malfunction if an electrostatically charged human body or truck comes in

contact with the computer enclosure due to electrostatic discharge.

Although its value differs from person to person, when the electrostatic voltage of the humanbody exceeds 2 kV, the shock of electrostatic discharge or the radiation of electric discharge is

felt by one. Under these conditions, the computer is likely to malfunction.

It is recommended that the built-up voltage of the human body in the computer room should

have a maximum value of 1 kV.

To reduce the generation of static electricity, it is necessary to adjust humidity in the computer

room at a level between 40% and 60% and use a floor material which is less likely to generate

static electricity and has high electrical conductivity (See 2.1.1. (1). (e) Covering material of the

free access floor). In addition, the operator must wear clothes less likely to generate static

electricity and shoes have high electrical conductivity. Other effective measures include the

laying of anti-static mat, limiting the access route so that the trucks will not come in contact

with the computer and the installation of the tire guard around the computer.

Moreover, the application of an anti-static agent to the floor is also effective. However, note

that this only produces a temporary effect and that its effect is reduced when the humidity lev-

els are low.


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It is necessary to analyze the processing mode of the computer room and identify the necessary rooms

(additional rooms).

Table 2-10

Name ofAdditional Room

Application Remarks

Operation roomFor system operationIn addition, management.

Programmer room For the preparation of business programs.

Magneticmedia storage

For the storage of backup media. Magnetictapes, CGMT and other magnetic media arestored.

Must have a fire resistantstructure and the samefloor elevation as the com-

puter room.Consumable stor-age

For the storage of printer paper.

Maintenance room

For the storage of maintenance parts,equipment, and the analysis of failurecauses.This room is not necessary if no maintenanceparts or equipment is required.

Must have an area of 20 to30 fitted with a workbench, cabinet, telephone,electrical outlets andother relevant equipment.

Power supply room(including batteryroom)

For the installation of the power plant, suchas the UPS, for the computer.With an increase in system scale, a privatepower generation room or a storage batteryroom will also be required.

Air conditionerroom

For the installation of the air conditioner forthe computer room.When a package-type air conditioner is in-stalled in the computer room, this room isnot required.

OthersNap room, conference room and storage roomfor the fittings.


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After completing the identification of the additional rooms, it is necessary to determine the layout of

the additional rooms. It is necessary to examine the topics listed below and draw up a line of flow

before finalizing the layout.

Table 2-11

Examination Items Points to be ConsideredData flow Amount of data input and output processing

Routing for operatorRouting for operator must be taken into consideration, including thetransport of media and consumables and emergency evacuation.

Ease of equipment workand labor conservation

The distance between rooms can be minimized by arranging addi-tional rooms such that the computer room is located at the center.


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Fig. 2-7 Layout Example of Computer Room and Additional Rooms


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When planning to transport the computer, the power plant equipment, air conditioning installation and

other equipment, it is necessary to, first of all, check the delivery entry, the delivery route and the avail-

ability of the elevator, depending on the dimensions and weight of the equipment.

SX-8 is large equipment. Refer to Chapter 9.Since the equipment is transported by a vehicle such as a trailer, parking space or space enabling the

unloading of the equipment is also necessary.

Three methods as shown below are available for transporting the equipment to the second or higher

floors of the building. In view of the workability, safety and cost of delivery, we recommend delivery

using the elevator.

We recommend this method in view of the workability, safety and the cost of delivery.

It is necessary to check that all the equipment to be transported has dimensions and weight com-

patible with the elevator to be used.

For bringing in equipment using a crane, you are requested to contact NEC beforehand as scaf-

folding or removal of the window frame may be required depending on the building structure.

Delivery of heavy equipment via the staircase using human power is difficult. It also entails

shocks and vibration that may damage the equipment. In addition, large stairway width as well

as a large amount of space is required at each turn of the stairway.


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The entrance sizes are generally as follows. It is necessary to measure the dimensions of all

equipment to be brought in.

Table 2-12

Entrance(Minimum value) (*1)Installation Site

Effective width HeightOffice 900 mm (min.) 1,800 mm (min.)

Small equipment 900 mm (min.) 1,800 mm (min.)Medium equipment 1,200 mm (min.) 1,800 mm (min.)Computer room

Large equipment(*2) 1,200 mm (min.) 1,850 mm (min.)

(*1) It is necessary to check the dimensions of all equipment to be brought in since spe-

cial equipment or certain entrance structure may make delivery impossible even

when the entrance meets the requirements of the values shown above.

(*2) SX-8 is large equipment.


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The corridor and the corner used to bring in the equipment must have enough space.

When the floor is inclined (sloping), or when a new slope is to be built along the route leading to

the equipment installation site, the inclination angle must not exceed a maximum value of 10 .

Table 2-13

Classification(*1)Item

Small equipment Medium and large equipmentWidth 1,400 mm (min.) 1,700 mm (min.)

CorridorHeight 1,800 mm (min.) 1,850 mm (min.)

Floor slope Inclination angle 10 (max.)

(*1) It is necessary to check the dimensions of all equipment to be brought in since

special equipment or certain entrance structure may make delivery impossible

even when the entrance meets the requirements of the values shown above.

Fig. 2-8 Floor Slope (Reference Value)

Table 2-14

Floor slope(Inclination angle: )

Elevation difference(h)

Slope length(L)

150 mm 950 mm (min.)300 mm 1,900 mm (min.)400 mm 2,550 mm (min.)

10

500 mm 3,200 mm (min.)


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The elevator entrance dimensions are generally as follows. It is necessary to measure the dimensions

of all the equipment to be brought in.

Table 2-15Elevator Entrance Dimensions (*1)

Equipment ClassificationWidth Depth Height

LoadingCapacity

Equipment to be installedin general offices

9 0 0 m m(min.)

1,400 mm(min.)

1,800 mm(min.)

6 0 0 k g(min.)

Small equipment9 0 0 m m(min.)

1,600 mm(min.)

1,800 mm(min.)

9 0 0 k g(min.)

Medium equipment1,200 mm(min.)

1,800 mm(min.)

1,800 mm(min.)

1,000 kg(min.)

Large equipment1,200 mm(min.)

2,200 mm(min.)

1,850 mm(min.)

1,800 kg(min.)

(*1) It is necessary to check the dimensions of all the equipment to be brought

in since special equipment or certain entrance structure may make deliv-

ery impossible even when the entrance meets the requirements of the val-

ues shown above.

(*2) SX-8 is large equipment.


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Air Conditioning Installation

U0ME-G1AZ102E23-1

This chapter describes issues related to the installation of the air conditioning, required when the

computer system is introduced.

As the temperature and humidity conditions produced by the air conditioning are the major factors

ensuring the stable operation of the computer system over an extended period, it is necessary to fully

examine various points including the space required for the extension of the air conditioning equipment,

while taking into consideration the installation of backup air conditioner required during regular facility

inspection and system failure as well as the extension of the computer system in the future.

It is also necessary, at the same time, to examine issues related to the work environment of the operators

and measures against static electricity, condensation and corrosion.


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Air Conditioning Installation U0ME-G1


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Disadvantages

1) It is necessary to set up equipment in the order of installation elevation, more

specifically, installation should start from equipment with smaller installation

elevation to those with larger installation elevation from the front of the air

conditioner to the farther end of the room, or equipment should be set up in a

direction which is vertical to the air conditioner (restrictions in the layout).2) Heat is likely to accumulate locally in the room, making it difficult to evenly

distribute temperature and humidity.

3) It may result in an uncomfortable work environment if, for example, the air blows

towards the operator.

Fig. 3-1 Direct Blowing System

Air blowing

Return

Airconditioner

Equipment Equipment


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A system that involves the blowing of air into the room from the air conditioner installed in the

computer room or in another room through the duct laid in the ceiling.

Advantage

As the air is blown through the ceiling duct, the temperature and humiditydistribution in the room can be relatively uniform.

Disadvantages

1) Since a ceiling duct is required for blowing air from the ceiling, introduction of this

air conditioning system is more expensive than the direct blowing system.

2) As the outlet of the air from the ceiling is fixed, this air conditioning system

presents certain layout restrictions regarding the extension and the movement of

the equipment.

3) Since a large volume of air is required to blow when the heat load increases, this is

likely to result in an uncomfortable work environment. For example, air may blow

towards the operator or the blowing noise may increase.

Fig. 3-2 Ceiling Duct System

A system that involves the blowing of cooled air adjusted by the air conditioner from below the

floor to the computers and the surrounding areas using the space built in the double floor as the

air duct.

(a) Direct air blowing

Advantages

1) This air conditioning system places no restrictions on the extension or the movement of

the equipment.

2) As air is directly fed to the equipment, maintaining the temperature and humidity

of blowing air constant ensures efficient operation.

3) As air is not directly blown towards the operator, this air conditioning system can

create a comfortable work environment.

Airblowing

Return

Aircon

ditioner

Equipment Equipment

Air duct


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Disadvantages

1) A double floor is required to be built.

2) Fluctuations in the temperature and the humidity of blowing air produce the direct

effect. (As the operator is unable to recognize any fluctuations in the temperature and

humidity of blowing air, NEC recommend that a temperature and humidity monitor be

installed.)

Return

Air blowing

Temperature and humidity sensor

Aircondit

ioner

Equipment Equipment

Fig. 3-3 Direct Air Blowing

(b) Indirect air blowing

Advantages

1) This air conditioning system sets no restrictions on the extension or the movement of the

equipment.

2) Fluctuations in the temperature and humidity of blowing air produce the indirect effect.

Disadvantages

Despite the installation of the under-floor air conditioner, direct feeding of air to the

computers is disabled.

Fig. 3-4 Indirect Air Blowing

Return

Air blowing


Airconditioner

EquipmentEquipment


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A system that combines systems set out in (1) and (2) above, to apply under-floor air conditioning

for the equipment and freestanding air conditioning for the operator.

Advantage

This system provides the computer and the operator with their ideal environments.

DisadvantagesIntroducing this system is expensive.

Fig. 3-5 Combined Use of Under-floor and Free Standing Air Conditioning systems

Non-operation system Operation system

Return

Airblowing


Aircon

ditioner

Equipment Equipment Equipment

Aircon

ditioner

Air blowing duct


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The following points must be checked and examined regarding the selection of the air conditioning

system.

Fig. 3-6 Flow Chart for Selection of Air Conditioning System

(*1) This applies to the distributed installation of the PC servers, the PCs and otherterminals on the desk and does not apply to the installation of the host computer.

Is Cooling N

Load greater than 25,000 kJ/h?

Is Cooling NY Load greater than

200 kJ/hm2?

Free Access N System available? Y Use of the Building Air conditioner(*1)

Y ( Actions against heat

accumulation required.)

Temperature Is thereand Humidity levels are N any space for N

controlled within the the ceiling duct?recommendation?

Y

Y

Divided into NOperation and Non-operation

systems?

Operation System: Under-floor Ceiling Duct System Direct Blowing

Ceiling Duct System Direct Air Blowing System

Non-operation System : SystemUnder-floor Direct Air Blow


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The air conditioning equipment for the computer must meet specifications that are different from those

applicable to general air conditioning equipment which concern with the system operation format and

quality.

Therefore, even if the cooling capacity of the currently installed air conditioning is sufficient for

processing the calorific value of the system, it does not necessarily mean that it can be used as it is.

Since the air conditioning equipment for the computer has features that are districted from air

conditioning equipment for office applications as listed below, special air conditioning equipment is

required for the computer.

Temperature and humidity control for offices are adjusted primarily for the people working in the

room.

Temperature: Winter period: 20 to 22 Summer period: 26 to 28

Humidity: 40 to 70 %RH(With temperature set as the priority control item, humidity

is left to be set accordingly.)

In comparison with the offices in general, it is necessary to control the computer room in a way

that temperature and humidity come within a specified range throughout the year.

While the heat load in offices (resulting from human activities, lighting and so forth) ranges

between 200 and 400 kJ/hm2, the heat load in the computer room ranges between 1,200 and

2,000 kJ/hm2, a large fraction of which is accounted for by the calorific value of the equipment.

As mentioned in (2) above, the calorific value of a room is extremely large. Even during the

winter period, heat accumulated in the room is larger than the heat escaping outside, causing the

room temperature to increase beyond the operating temperature range of the computer.

Accordingly, cooling is required throughout the year.

The daily operation time in the computer room is longer than that in offices. It is also necessary

to implement air conditioning in a way to meet the system operation schedule, such as the

operation on holidays and uninterrupted operation during the day and the night.

The building air conditioner is designed for the benefit of the human residential environment.

Its operation time is limited and heating is applied during the winter period. Therefore, it is not

possible to compensate for any capacity deficiency in the air conditioner for the computer using

the building air conditioner.


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While office rooms in general use the freestanding system, the computer room uses the

under-floor system because the under-floor system demonstrates flexibility concerning the

extension or the movement of the equipment.

The calorific value of the computer is larger than the value set as the target for building air

conditioning. Accordingly, cooling is also required during periods other than summer.

Air conditioners in general are used for the benefit of the human residential environment.

However, the computers are often running during a night and holidays in the absence of people.

Accordingly, air conditions capable of being operated in accordance with the system operation

format is required.

To ensure the stable operation of the computer for an extended period, it is necessary to introduce

a system such as the air conditioner for the computer that enables multistage, fine temperature

and humidity control.


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A drop in the humidity level of the room is likely to cause static charges. The clothes, shoes and

floor materials generate static charges. This must be taken into consideration. Controlling the

humidity can reduce them. According, the humidifying function is required. Feed water for the

humidifier (tap water) contains impurities such as calcium and magnesium. When suchimpurities are released in the air, they adhere to the interior of the computer in the form of white

powder (scale), causing negative effects. The table below lists various humidifier systems for

reference.

Table 3-1 Humidifying System

Humidifying System (*1) Treatment for Humidifier Feed Water

Vaporization typeVaporizes the water containedin the filter to humidify the air.

PanEvaporates water and releasesthe vapor to humidify the air.

E

vaporation

type

Vapor sprayEvaporates water and releasesthe vapor from the nozzle tohumidify the air.

As this system causes scale toaccumulate in the humidifier, filtrationof the water using the water softeneror the demineralizer is required toremove the impurities.

UltrasonicVibrates the ultrasonicoscillator and sprays atomizedwater to humidify the air.

Atomization

type

Water spraySprays the pressurized waterfrom the tip of the nozzle tohumidify the air.

As this system causes scale to bereleased in the air, filtration of thewater using the demineralizer isrequired to remove impurities.

(*1) In hard water (meaning that water includes a large proportion of calcium andmagnesium) area, regular maintenance (facilities to treat the humidifier or the feedwater for the humidifier) is required, no matter which system is adopted.

Although the computer generates a sensible heat load, relative humidity in the computer room

may increase, for example, on rainy days, when humidity increases (highly humid air enters from

outside). The dehumidifying function is required to remove such moisture.

A dehumidifying capacity for the sufficiently removal of moisture entering the computer room is

required regardless of the system structure (scale).

The temperature in the computer room may be lower than the operating temperature range of

the computer at the time of system booting during the winter period. In this case, it is necessary

to increase the room temperature by heating up to the operating temperature range of the

computer before booting the system.


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The equipment temperature at the time of start-up during the winter period is equal to the room

temperature. When the air conditioning equipment is run in this state, heating and

humidifying operations are run, causing air of high temperature and humidity to come in contact

with the equipment causing dew condensation on the equipment surface or in the interior of the

equipment. To prevent this from happening, humidifying operation must be delayed or excludedwhen the air conditioner is run in the heating mode.

Dust is generated, though small in quantity due to the computer room carpeted and the use of

paper by the printer. In addition, dust is brought into the computer room as a result of entry

and exit of personnel. Dust adheres to the filter in the computer and blocks the cooling of the

equipment. Accordingly, the air conditioning equipment must capture the dust in the computer

room. As the electrical dust precipitator generates ozone that causes equipment deterioration, use

of the electrical dust precipitator must be avoided.

In case the air conditioner fails, the room tem


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The temperature and humidity requirements for the media are as shown in Table 3-3.

Table 3-3 Temperature and Humidity Requirements for Media

MediaType Item When used When stored Remarks

Temperature 5 to 35 -40 to 45

1/4 inchCGMT Relative

humidity20 to 80 %RH 20 to 80 %RH

Must be stored in an accessory casethat comes with the media withoutfail.The wet-bulb temperature must bekept at 26 WB or below.


Printerpaper Relative

humidity30 to 70 %RH 30 to 70 %RH

Due to the presence of temperaturedifference between the storage siteand the operation site, ensure thatthe media attains the temperatureand humidity of the operation site.

Temperature 10 to 32 -10 to 40 Printerinkribbon

Relativehumidity

30 to 70 %RH 30 to 90 %RH


FD Relativehumidity

8 to 80 %RH 8 to 80 %RH

Before using the stored FD media,keep it for a minimum of five minutes(which is set as the time forrestoration and adjustment) for it toattain the temperature and humidityvalues of the operation site.

Temperature 15 to 32 0 to 40 Optical

disk

Relative

humidity 20 to 80 %RH 10 to 80 %RH

Dew condensation must not be

allowed to form.


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Each computer is equipped with cooling fans. Several fan locations and air flow direction types are

available because certain computers are built with special structures, for example, designed to

minimize the noise generated by the fan based on the assumption of equipment installation in general

office rooms, or designed to minimize the air to be blown towards the operator.

Fig. 3-7 Fan Location and Air Flow Direction of the Equipment

(Intake Surface/Exhaust Surface)

Base/top

Front/back

Fan


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The temperature and humidity values of the computer room must meet the following requirements in

order to ensure equipment reliability and comfort in the operator work environment as well as to prevent

static charges, dew condensation and corrosion.

Note, however, that even though temperature and humidity values in the computer room are within therange of temperature and humidity requirements for the computer (allowed values), deviation from the

recommended values for an extended period in the facilities may produce deterioration in equipment

reliability and create operator discomfort.

Temperature and humidity must be controlled in the computer room in a manner to take both the

equipment and operator into consideration.

Fig. 3-8 Design Values and Control Ranges of the Equipment and Air Conditioning equipment

(1) Facility design value

This sets the target value for air conditioning equipment design. This also sets thepreset sensor values for air conditioning equipment.

(2) Air conditioning design value

This sets the control range for the design of the temperature and humidity control

circuit for air conditioning equipment.

Since the accuracy of the temperature and humidity control system depends on the

accuracy of the control circuit, the sensor performance and the installation location, a

range which includes deviation to a certain extent from the facility design value is set.

< Computer >

Temperature and Humidity range at the time of halt (Tolerance)

Temperature and Humidity

range at the time of operation (Tolerance)

Facility reference value

Air conditioning design value

Recommended range for the facility

Control range during equipment operation

Control range during halt

HotCold


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(3) Recommended range for the facility

This sets the range of daily temperature and humidity control of the air conditioning

equipment as well as sets the recommended range for system operation.

It is recommended that air conditioning equipment be normally used within this range.

(4) Control range during equipment operation and halting

This sets the range of temperature and humidity control during equipment operation and

halting.

This setting enables a quick detection of any abnormality in the air conditioning

equipment and the temperature and humidity environment of the computer installation

site, making it possible to take relevant measures.

Table. 3-4 Recommended Range for the Facility

Computer RoomAir Conditioning System Office Small

EquipmentMedium-sized

EquipmentLarge

Equipment

Temperature 20 to 28 Freestanding Relative

humidity40 to 70 %RH

To set within the rangeshown on the left.

Temperature 16 to 25 16 to 20 Under-floor Relative

humidity 55 to 70 %RH 55 to 70 %RH

TemperatureJoint useabove of thetwo systems

Relativehumidity

As per the values set for the freestanding and theunder-floor systems.

The under-floor system should be necessary with the SX-8 model A. And direct air-blowing system is

used for SX-8 itself. (Refer to the "3.1.1 Outline of Air Conditioning Systems".)

(a) The air conditioner equipment, which satisfies the temperature humidity condition of SX-8 and the

amount of device place point wind, can be prepared for. Moreover, it must be able to cool down the

amount of fever of SX-8. (Refer to the "3.3.1 Temperature and Humidity Requirements for Computer

Equipment", "3.5.2 Computation of Air Conditioning Capacity" and "9.1 Specification List".)

(b) The Intake area of 300 mm and more can be secured in the circumference. (Refer to the "10.2 Layout

of the Main Devices and Intake Area".)


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A point located at an elevation of one meter from the floor surface and 0.5 meter away from the

equipment.

However, this point should not be in the direct proximity of the exhaust from the equipment.

A point where the air blows out from the floor cut.

As per (1) and (2) above.

The installation location of the temperature and humidity sensor depends on the air conditioning

system.

A point located at a height between one and 1.5 meters above the floor surface for recording the

average temperature and humidity of the room.

The setting of the temperature and humidity sensor must be adjusted every time the equipment

layout is changed or the equipment is extended or moved. In this case, it is recommended that

the temperature and humidity sensor be installed at the intake of the air conditioner rather than

on the wall or the column of the computer room in order to facilitate adjustment.

Also note that if the temperature and humidity sensor is set up in a location of stagnant air flow,

such as at a location enclosed by partitions, temperature and humidity control will be disabled.


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U0ME-G1AZ102E23-18

A point located within two meters from the air conditioner outlet.

Note that temperature and humidity control will be disrupted, when the air flow from another air

conditioner comes in contact with the temperature and humidity sensor set as the target or when

the air flow from the air conditioner does not come in direct contact with the temperature and

humidity sensor because it is blocked by a cable.

Air

conditioner

Within

Free access floor

Temperature and

humidity sensor

Fig. 3-8 Under-floor Temperature and Humidity Sensor Position

As per (1) and (2) above.

It is necessary to adjust the settings of the temperature and humidity sensor so that the temperature

and the humidity values of the airflow from the air conditioner will come within the range

recommended for the facility at the reference point. The temperature and humidity control ranges in

this instance are as follows.

Table 3-5 Set Values for Temperature and Humidity Control Sensor of Air Conditioning Installationand Control Range

Sensor Setting

Recommended Values

Control Range for Sensor

Setting ValuesTemperature Humidity Temperature Humidity

Freestanding system 23 50 %RH 2 10 %RH

Under-floor system 18 65 %RH 1 5 %RH

Joint use of freestanding andunder-floor air conditioningsystems

As per the values set for the freestanding and the under-floorsystems.


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The cooling capacity of air conditioning equipment is determined by the following factors.


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NEC recommend that a backup air conditioner be made available in case one of the air conditioners used

for actual operation fails or is inspected for maintenance, in order to prevent the halting of the system

operation.

Regarding the installation of the backup air conditioner, NEC recommend that three to five air

conditioners be put together to form a zone group and that one backup air conditioner be installed foreach zone group because a backup air conditioner located at a large distance from the failed air

conditioner cannot function as a substitute.

In addition, operating air conditioners in rotation within each zone helps average out the load on air

conditioners.

Fig. 3-10 Example of Backup Air Conditioner Installation

The example above shows the segmentation of the equipment into zones, A/C #1 to #3 and #4 to #6, and

the installation of a backup air conditioner for each zone.

It is necessary to lay out the backup air conditioner (#3 and 6 in Fig. 3-10) in such a way that they are

not located next to each other between neighboring zones because if A/C #3 and 4 function as the backup

air conditioners, the center of the room will not be cooled sufficiently, causing a local rise in temperature.

Rotation direction Rotation direction

Operated

A/C #1 #2 #3 #4 #5 #6 Halted

(Backup airconditioner)

Zone 1 Zone 2


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To ensure the stable operation of air conditioning equipment for an extended period, it is important to

carry out regular inspection and daily temperature and humidity control of the equipment.

NEC recommend that a regular inspection (including the cleaning of the air filter and the humidifier)

be implemented in order to ensure the maintenance of the equipment.

A regular inspection involves works that must be contracted out to the air conditioner manufacturer as

well as works that can be performed by the operator such as the cleaning of the air filter.

Implementation of such inspection and cleaning prevents the occurrence of problems.

NEC recommend that temperature and humidity be monitored and recorded regularly using a

self-recording thermometer and hygrometer. Daily monitoring of temperature and humidity enables

the early detection of abnormality in the air conditioner equipment and keeping of records enables

comparison with the past performance. Use of such information will contribute towards stable system

operation.

Temperature and Humidity Control Position are typically around the cooled air intake of the CPU and

the DKU. See Table 3-4 for control values.

Fig. 3-11 Temperature and Humidity Control Position

Floor grill Free access floor

Air blowing

Self-recording thermometer and hygrometer Base floor

Airconditioner

Equipment


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A trial run must be carried out without fail before the system is installed, in order to remove any dust

remaining in the air conditioner or the duct and to check that the set values for the temperature and

humidity control sensor indicate the specified values.

It is also necessary to make adjustments again using the actual heat load when the system is introducedin order to confirm that temperature and humidity values come within the recommended range for the

facility.


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As dew condensation may form on the computer surface or in the interior of the computer at the time of

start-up of the air conditioner during the cold season, it is necessary to implement a control for the delay

of the humidifier operation. This control is particularly required when the air conditioner operation is

halted over the long vacation.

When the air conditioner starts operating, the temperature of the air that blows out from under the

floor increases till it reaches the set value. When the room temperature increases, this reduces

relative humidity, causing the humidifier to be activated and shifting the air conditioner into the

heating and humidifying operation mode (blowing of air of high temperature and humidity). However,

as the computer (the metal parts in particular) has a large heat capacity and the equipment

temperature gradually increases without following the pattern of the room temperature change, air of

high temperature and humidity, blown out from the air conditioner, is cooled on the equipment surface

or interior to form dew condensation in the computer.

To prevent dew condensation mentioned in the preceding section from forming, it is necessary

to implement a control that the humidifier will not be activated when the air conditioner is run in the

heating mode.

It is necessary to gradually increase the room temperature (at the rate of within 10 /h) till it reaches

the range of equipment temperature requirement (15 to 32 ), leave the equipment in that state for 30

minutes to one hour without activating the humidifier, and then, enable the humidifier to be activated

to implement temperature and humidity control. Note, however, that the period for which the

equipment is left to adjust with the surrounding environment depends on the building structure and

other factors.


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U0ME-G1AZ102E23-24

It is reported that in order to maintain a comfortable work environment for the operators who work in

the computer room, fresh air intake at the level of 20 m3 / person for every 1 hour must be maintained (to

reduce the concentration of dust and carbon dioxide in the room to the level considered harmless).

However, the number of personnel per unit area of the computer room is significantly smaller than thatof the general office rooms and the entry into and the exit from the computer room ensures sufficient

ventilation, leading us to believe that the operator work environment is not likely to deteriorate.

To maintain fresh air intake, temperature and humidity control, and the removal of dust and corrosive

gases must be thoroughly implemented.


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Power Supply Facilities

U0ME-G1AZ102E24-1

This chapter describes the issues related to the power supply facilities required when the

computer system is introduced.

It is necessary to design the power supply facilities after fully examining the power supply

facility capacity required to achieve the stable operation of the computer system as well as

future extension of the computer system, when planning to introduce a new computer

system.


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U0ME-G1AZ102E24-2

Power supply systems as shown in Table 4-1 are available when the power supply

facilities for the computer system are examined. Please examine the adoption of a

power supply system which meets the power source quality and the power supplyrequirements of the computer for the computer room currently used.

Table 4-1 Type and Special Features of Power Supply System

Power supply system

Item

Uninterruptiblepower supplywith Engine

Generator

Uninterruptiblepower supply

Commercialpower supply

Voltage stabilization

Frequency stabilization

Voltage imbalanceimprovement

Waveform distortionimprovement

Actions againstinstantaneous power failure

Actions against long-timepower failure

(*3)

Absorption of the powersource noise

Conversion of frequency(50Hz60Hz or 60Hz50Hz)

Floor space Large Small None

Applicable power unit EG(*1),UPS(*2) UPS(*2) -

Configuration example See Fig. 4-1. See Fig. 4-2. See Fig. 4-3.

*1: EG: Engine enerator

*2: UPS: ninterruptible ower upply

*3: Covers power failure within the rated time of the uninterruptible power supply

Remarks::Improvable :Conditionally improvable :Cannot be improved


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U0ME-G1AZ102E24-3

Rectifier Inverter AC

switch

Powerdistributionboard

Uninterrupted by-pass change-over circuit

By-pass circuit for maintenance

Battery

Computer

s

Other loads

Sharedtransformer Transformer

Fig. 4-2 Uninterruptible Power Supply System

Uninterruptedchange-over switch

Manual change-overswitch

Highvoltage

Rectifier InverterACSwit

ch

Powerdistribution

boardUninterrupted by-pass

change-over circuit

By-pass circuit for maintenance

Battery

Co

mputers

Air conditioning equipment

Emergency lighting, etc.

High

voltage

Engine-basedpower

generatingequipment

Other loads

Sharedtransformer

Transformer

Fig. 4-1 UPS and Uninterruptible Power Supply Systemof Engine-based Power Generating Installation

Uninterrupted

change-over switch

Manual change-over switch

Powerdistributionboard

Computers

High

voltage

Other loads

Sharedtransformer Transformer

Fig. 4-3 Commercial Power Supply Direct Connection System


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U0ME-G1AZ102E24-4

Table 4-2 Procedures for Selecting Power Supply System

Points to be examined

Quality of SuppliedPower (*1)

System Tolerance againstOperation Suspension and

Stoppage

Procedure

Power SupplySystem

Commercialpower supply. (*2)Within the range ofrated voltage 5%.

An average of three stoppagesper month does not causeproblems(except for power failure).

Start Directconnectionto commercialpower supply

Large voltagefluctuations.Power supplynoise generated.

Planned stoppage ispermissible.

UPS(*3)

Even 24 hour instantaneousstoppage is not permissible. UPS(*3)

*1: Voltage measured at the output terminal of the transformer for the computer

or at the branching point of the output.

*2: The case where a range of rated voltage 5% is entered by adjusting the tap

of the transformer is included.

*3: UPS: ninterruptible ower upply


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U0ME-G1AZ102E24-5

(a) The calculation of the load capacity must take the facility capacity and the effect

of rush current into consideration. See 4.3 Computation of Power Supply

Facility Capacity.

(b) A remote control panel may be required, which enables the monitoring of the

activation and deactivation of the power supply unit, and alarms in the computerroom.

(c) Monitor (detect) the voltage and frequency at the power distribution board located

close to the computer.

(d) In the case of a power shutdown (including shutdowns due to failures), halt the

power quickly, without reducing it.

(e) See Appendix 11.3 Power Supply Facility Related for more specific UPS

specifications.

The engine generator capacity must be large enough to supply power to the air

conditioner, lighting and other facilities needed for system operation.

When the commercial power supply direct connection system is used, pay attention to

the following points.

(a) Thoroughly check the quality of the power supply to be used for the computer, and

verify that there is nothing abnormal. See Appendix 11.3.1 Input Power Noise

Type.

(b) The main power supply circuit of the power distribution board must have an

MCCB (with SHUNT) of the voltage trip type.

(c) If other loads exist in parallel with the power supply circuit for the computer, the

power consumption of these loads should be small.

(d) A lightning arrester must be installed on the output side of the incoming

transformer.

(e) The downstream side of the power supply system for the computer system should

not be grounded. Each device that configures the computer system has a noise

filter for preventing problems caused by noise. The noise filter connects the power

line and the ground with a capacitor. Therefore, if one of the downstream lines of

the power supply system is grounded, an earth current flow. As this current

activates the alarm unit to trigger alarm and generates electric potential in the

device enclosure causing operator discomfort, the downstream side of the power

supply facilities must not be grounded to cut off the earth current.


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U0ME-G1AZ102E24-6

Fig. 4-4 Example of Single-point Grounding

Fig. 4-5 below shows an example where the downstream side is ungrounded to cut

off the earth current.

Fig. 4-5 Example where Downstream Side is not Grounded

Notes

(1) Consult an NEC sales representative for installing a leakage current

alarm or a leakage current breaker. If grounding the downstream

side of the power supply system is necessary for such installation, the

neutral point of the downstream side must be grounded. (When a

power supply system of the ungrounded type is used, installation of a

current leak alarm or leak current breaker is not normally required.)

(2) Use of a power distribution board with a built-in transformer NEC

have a power distribution board with a built-in transformer composed

of an isolation transformer and a power distribution board available.

Fig. 4-6 below shows an example of use of a power distribution boardwith a built-in transformer.

Transformer Computer

Noise filter

Earth current

TransformerComputer


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U0ME-G1AZ102E24-7

Fig. 4-6 Example of Use of Power Distribution Boardwith a Built-in Transformer

Power receiving transformer

Power distribution board

with a built-in transformer

Other loads

Other loads

Tocomputer


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U0ME-G1AZ102E24-8

The power supply requirements of the computer at the incoming terminal are as shown

in the table below.

Table 4-3 Power Supply Requirements of the Computer

Item Power Suppl y Requi remen ts of the Comput er

PhaseSingle phase,2 wires

3 phase,3 wires

3 phase,4 wires

Voltage(average value)

100~120V10%200~240V10%

200~240V10% 400V10%

100~120V+15%,-20%200~240V+15%,-20%

200~240V+15%,-20% 400V+15%,-20%Voltage

(instantaneousvalue) (Fluctuation time: less than0.5 seconds)

Frequency(average value)

50Hz or 60Hz1Hz

Frequency(instantaneousvalue)

50Hz or 60Hz1Hz to -2.5Hz(Fluctuation time: within one second)

Maximum inter-Phase voltagedeviation

Within 10V(three phase)

Waveformdistortion factor

Within 8%

GroundingGrounding for the computer

(Grounding resistance: less than 100)

*: A voltage drop of 2% must be anticipated between the power distribution board and

the device.

The equipment operated at 100~120V must register a voltage level of 100~120V

10% at the electrical outlet.

Electrical outlet

Power

distribution

board

Single 100~120V +

One ground line

(*1)

100~120V10%

Single-phase

100~120V

Computer

Power

supply

facility

(*2)

*1:Grounding for the computer

*2:Grouding for safety


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U0ME-G1AZ102E24-9

When the voltage of a device electrically fed by the breaker is measured at the

breaker terminal located on the side of the power distribution board, the voltage

tolerance must be set at 10% and 8% by taking the voltage drop of 2% over the

cable into consideration.

When the voltage of a device electrically fed by the breaker is measured at the

breaker terminal located on the side of the power distribution board, the voltage

tolerance must be set at 10% and 8% by taking the voltage drop of 2% over the

cable into consideration.

Three phase 200~240 V +

one ground line

T

RComputer

+10%

- 8%200~240V

Power

distribution

boardThree-phase

200~240V

S

200~240V10%

Power

supply

facility

Three phase 400 V +

one ground line

T

RComputer

+10%- 8%400V

Power

distribution

boardThree-phase

400 V

S

400V10%

Power

supply

facility N

Single phase 200~240 V +

one ground line

RComputer

+10%- 8%

200~240V

Power

distribution

boardSingle phase

200~240V

S

200~240V10%

Power

supply

facility


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U0ME-G1AZ102E24-10

Prepare a dedicated grounding wire for the computer system up to the power distribution

board used for the computer system. This grounding wire must have an earth

resistance of 100 or less.

See (a) of (2) Grounding Requirements for the thickness of the grounding wire.

In principle, the computer must be grounded by a dedicated grounding wire.

The computer is grounded for the following purposes.

(a) Reduction of grounding voltage

Grounding the computer at low resistance reduces the contact voltage when

voltage is applied to the frame by the dielectric breakdown of the equipment and

the electric circuit

sx-8 instllation planning manual(e) r2

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