Examination Category(Lifeline
Infrastructure/Equipment
Installation)
Textbook for
the Practical Examination

Ver.20220908

Chapter 5: Knowledge of Tools, Machines, Materials, and Measuring Instruments Used on
Construction Sites
5.1 Tools, Machines, Materials, and Measuring Instruments Specific to Job Categories . 108
5.1.1 Construction Machines .................................................................................... 108
5.1.2 Electrical Work ................................................................................................ 110
5.1.3 Telecommunications Work ............................................................................... 118
5.1.4 Plumbing Work ................................................................................................ 121
5.1.5 Freezing and Air Conditioning Apparatus Work .............................................. 124
5.1.6 Water Supply, Drainage, and Sanitation Facilities Installation ........................ 124
5.1.7 Heat/Cold Insulation Work .............................................................................. 125
5.1.8 Construction of Fire Fighting Facilities ........................................................... 126
5.2 Common Tools, Machines, Materials, and Measuring Instruments ............................ 127
5.2.1 Power Tools...................................................................................................... 127
5.2.2 Digging/Leveling/Compacting......................................................................... 130
5.2.3 Layout Marking/Marking Tools ....................................................................... 132
5.2.4 Measuring/Inspecting ....................................................................................... 133
5.2.5 Cutting/Bending/Breaking ............................................................................... 135
5.2.6 Tapping/Pulling ................................................................................................ 136
5.2.7 Filing/Polishing/Boring.................................................................................... 137
5.2.8 Tightening/Fixing............................................................................................. 138
5.2.9 Kneading/Mixing ............................................................................................. 139
5.2.10 Curing/Prepping ............................................................................................. 140
5.2.11 Scrubbing ....................................................................................................... 141
5.2.12 Carrying Objects ............................................................................................ 141
5.2.13 Hanging/Lifting/Pulling ................................................................................. 142
5.2.14 Work Platforms/Ladders ................................................................................ 143
5.2.15 Cleaning ......................................................................................................... 144

Chapter 6: Knowledge on Construction Site Work
6.1 Matters Common to Construction Sites ...................................................................... 146
6.1.1 Characteristics of Construction Work .............................................................. 146
6.1.2 Construction Plan ............................................................................................. 147
6.1.3 Construction Management ............................................................................... 147
6.1.4 Pre-Construction Preparations ......................................................................... 148
6.1.5 Layout Marking (Marking Out) ....................................................................... 150
6.2 Knowledge regarding Pipe Processing ....................................................................... 151
6.2.1 Processing of Carbon Steel Pipes for Piping.................................................... 151
6.2.2 Processing of Rigid Polyvinyl Chloride Pipes ................................................. 155
6.2.3 Processing of Rigid Polyvinyl-Chloride Lining Steel Pipes for Water Supply 157
6.3 Freezing and Air Conditioning Apparatus Work ......................................................... 158
6.3.1 Processing of Coated Copper Pipes for Refrigerant......................................... 158
6.3.2 Connection of Refrigerant Pipes ...................................................................... 159
6.4 Heat/Cold Insulation Work ......................................................................................... 161
6.4.1 Shapes and Types of Insulation Material ......................................................... 161
6.4.2 Example of Heat/Cold Insulation for Piping .................................................... 161
6.4.3 Example of Heat/Cold Insulation for Ducts ..................................................... 162
6.5 Lifeline Infrastructure Plumbing Work ....................................................................... 162
6.5.1 Waterworks—Ductile Iron Pipe Installation .................................................... 162
6.5.2 Waterworks and Gas—EF Connection ............................................................ 165
6.5.3 Precautions in Telecommunications Work ....................................................... 167
6.5.4 Precautions for Underground Piping Work ...................................................... 167
6.6 Architectural Sheet Metal Work .................................................................................. 169
6.6.1 Sheet Metal Processing .................................................................................... 169
6.6.2 Duct Connection Method ................................................................................. 170
6.7 Electrical Work ........................................................................................................... 172
6.7.1 Precautions in Working with High-Voltage Substations .................................. 173

6.7.2 Short-Circuit, Ground Fault and Leakage Current ........................................... 173
6.7.3 Precautions in Crimping Wires ........................................................................ 174
6.7.4 Damage to or Disconnection of Existing Underground Pipes and Overhead Wiring ............ 174

6.7.5 Precautions for Road Use................................................................................. 175
6.8 Telecommunications Work .......................................................................................... 176
6.8.1 Types of Telecommunications Facilities .......................................................... 176
6.8.2 Installation of Underground Conduits .............................................................. 178
6.8.3 Precautions during Work .................................................................................. 179
6.9 Furnace Installation..................................................................................................... 179
6.10 Fire Fighting Equipment Installation ........................................................................ 180

Chapter 7: Safety during Construction Work
7.1 Fatalities in Construction Work .................................................................................. 182
7 .1 .1 Numbers of Fatalities in Construction ........................................................... 183
7.1.2 Types of Fatal Accidents .................................................................................. 184
7.1.3 Characteristics of Lifeline Infrastructure/Equipment Installation Work with a High Number of Fatalities
187

7.2 Safety Activities at Construction Sites ........................................................................ 188
7.2.1 Cycle of Safety in Construction ....................................................................... 188
7.2.2 Safety and Health Education for Newcomers .................................................. 190
7.2.3 Newcomer Education ....................................................................................... 191
7.2.4 Safety Gear for Work ....................................................................................... 192
7.2.5 Prevention of Heat Strokes .............................................................................. 194
7.2.6 Marks Calling Attention to Work Safety .......................................................... 194
7.2.7 Understanding Human Error ............................................................................ 195

Chapter 5: Knowledge of Tools, Machines, Materials, and Measuring
Instruments Used on Construction Sites
5.1 Tools, machines, materials, and measuring instruments specific to job categories
5.1.1 Construction Machines[Yuatsu shovel] (hydraulic excavator (backhoe)) A machine that

Hydraulic excavator

performs digging and loading work using the boom, arm, and bucket,
which are operated by hydraulic cylinders, and by rotating the upper
unit. By changing attachments, it can be used in various ways as abreaker, a ripper, a crusher, etc.
[Ten’atsuki] (compactor) A machine that compacts by weight. There

Compactor

are several types, depending on the material and shape of rollers andtheir combination.
[Road roller] A compactor with steel rollers. It is used to compact
subgrade layers and aggregate base layers in pavement construction.
[Tire roller] A compactor with rubber rollers. It is suitable for ordinary
soil that is easy to compact and for crushed stones for aggregate baselayers of pavements. It is also used for machine-compacting asphalt
Tire roller

mixtures.
[Shindo roller] (vibratory roller) A compactor with vibrating steel
rollers. The vibration is normally vertical, but those that vibrate
horizontally are specifically called shindo roller (vibratory rollers).
Vibratory rollers have a strong compacting effect, even when they are

Vibratoryrollersmall in size.
[Tractor shovel] (tractor excavator) A machine with a bucket attached to the front of the tractor.
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Earth and sand can be scooped up and loaded onto dump trucks using the bucket. In addition to buckets
for excavating earth and rocks, the truck can be equipped with a fork for moving obstructing vehicles,
etc., and a water gun for firefighting. There are two types of models: the wheel type and the crawler
type.
[Wheel loader] A loading and carrying machine that run on wheels, with a large bucket in front of the
body. By moving the vehicle forward and operating the bucket and boom, themachine scoops up various materials such as earth, sand, and quarry stones
and loads them onto dump trucks or other vehicles. A wheel loader is a tractor
excavator that runs on wheels, also called a tire dozer or tire excavator.

Wheel loader[Dump truck] A vehicle used exclusively for transporting earth,Dump trucksand, rocks, etc., and is capable of unloading soil (dumping) by tilting
the bed of the truck. Often used in combination with hydraulicexcavators and wheel loaders.
[Crane] A machine that uses power to lift and transport a load
horizontally. There are several types of cranes, including tower cranes, truck cranes, and crawler cranes.
[Tower crane] A crane used in the construction of high-rise buildings. The crane section is mounted
on a supporting tower called a mast. There are two types: mast climbing, where the crane section
climbs up a jointed mast, and floor climbing, where the entire pedestal climbs up the building.
[Truck crane] A construction equipment with a crane mounted on a truck.

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[Crawler crane] A crawler-type crane. It can work in a variety of locations, including on snow andunpaved ground.

Truck crane

Crawler craneTower crane

5.1.2 Electrical Work
[Kendenki] (voltage tester) A device that checks whether or not
Voltage tester

an electric charge is present. There are low voltage testers andhigh voltage testers.
[Kensoki] (phase tester) A device to check the direction ofrotation (phase order) in the 3-phase, 2-wire power supply wiring.
[Tester/multimeter] A device to check the condition of electric circuits, voltages, etc.
[Contester] (outlet tester) A measuring instrument to check the positive/negative and grounding ofelectrical outlets.
[Clamp meter] A measuring instrument that can measure electric current by simply inserting anelectric wire between the clamps of the sensor section.
[Dendo hammer] (electric hammer) A power tool for digging through walls and slabs to clear piping
paths.
[Mawashibiki] (drywall hand saw) A saw used to make openings in plasterboard or formwork
plywood.
[Bender] A tool used to bend metal pipes.
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[Densenkan] (conduit) A metal or synthetic resin tube that can hold electric wires inside.
[Kato densenkan] (flexible conduit) A conduit that can be bent freely.
[Kinzokusei kato densenkan] (metal flexible conduit) A metal conduit that can be easily bent.

Metal conduit

Synthetic resin flexible conduit (PF conduit)[PF kan] (PF conduit) PF is abbreviation for Plastic Flexible. Synthetic resin flexible conduit without
flame resistance.
[CD kan] (CD conduit) CD is abbreviation for Combined Duct. Synthetic resin flexible conduit
without flame resistance. It is often used for underground installation in concrete.
[E kan] (E conduit) A steel conduit without threading. The thickness is the external dimension and isexpressed as E19, E25, and so on.
[C kan] (C conduit) A thin-walled metal threaded conduit, also called a thin steel conduit. Because it
is more impact-resistant and durable than synthetic resin conduit, it is used for exposed indoor piping.
[G kan] (G conduit) A thick-walled metal threaded conduit, also called thick steel conduit. The
surface is plated to provide weather resistance.
[Void kan] (cardboard tube) A tube made of paper used to make holes that penetrate slabs, beams,
walls, etc.
[Coupling] A connector that connect conduits of the same type. To connecting different types ofconduits, combination couplings are used.

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[End cover] A cover used at the point where the cable is pulled out
from the ceiling.
[Stud bar] A fitting used to easily attach a box to the wall or slab
using the wall or slab reinforcement.

End cover[Roshutsu box] (exposed box) A box is installed on the wall in avisible manner.
[Roshutsu switch box] (exposed switch box) A box to house wiring

Exposed switch box

fixtures for outlets and switches.
[Outlet box] A box used for branching and connecting wires inwiring work.
[Radius clamp] (grounding band clamp) An installation fitting forelectrically connecting steel outlet boxes and metal pipes.
[Pull box] (junction box) A box used for connecting cables to cables and for branching. Since cables
cannot be connected or branched in the conduit, this is done inside the junction box. Boxes are madeof metal or plastic.
[Nurishiro cover] (flush-mounted cover) A cover to be installed on boxes that are embedded inconcrete.
Outlet box

Junction box

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Flush-mounted cover[Box connector] A member used to connect an outlet box to a metal or PF conduit. It is attached tothe box side.
Box connector for threadless conduit

Box connector for PF conduit[Asshuku tanshi] (compression terminal) A terminal for connecting a wire to a device to anotherwire. Pressure is applied to the connection to crush the terminal and secure the wire. Various shapes
and sizes are available for different applications.
[Asshukuki] (compression tool) A tool used to join compression terminals and wires by applying
pressure to the joint.
[Acchaku penchi] (crimpers) A tool used to join crimp
Crimpers

terminals and wires by applying pressure to the joints of thecrimp terminals. Two types are available: one for terminals(with red handles) and one for ring sleeves (with yellow
handles).
[Acchaku tanshi] (crimping terminal) A terminal attached to the end of an electric wire forconnection. The cable is secured by placing it in the hole of the crimp terminal and crushing the entire
crimp terminal to secure the cable. Use the appropriate tool for the crimp terminal.
[Ring sleeve] A member used to connect multiple wires. The core wires are inserted into the ringshaped hole and crimped using a crimping tool for ring sleeves.

105[Botanshi] (rod terminal) A crimp terminal with a rod-shaped terminal end.
Crimp terminal

Ring sleeve

Rod terminal[T-gata connector] (T-connector) A connector used to crimp the bus bar and branch line whenbranching a wire from the middle of the bus bar.
[Sashikomi connector] (plug connector) A member used when

Plug connector

connecting wires. Connection can be made simply by insertingthe core wire.
[COS] Abbreviation for Change Over Switch. A changeoverswitch.
[Jiko yuchaku tape] (self-amalgamating tape) A tape that when wrapped around a pipe or otherobject while being stretched 2 to 3 times, the back and front sides of the tape adhere to each other. It
is used for water pipes and water leakage prevention.
[Secchibo] (grounding rod) A rod driven into the ground forgrounding. It is commonly made of steel with copper plating.

Grounding rod

Also called earth rod.
[Lead tanshi] (lead terminal) A member that connects thegrounding rod and ground wire.
[Handhole] A block manholes used for electrical and telecommunications wiring.
[Bell mouth] A member is used to prevent damage to the cable when pulling the cable in.
[Yobisen] (fish tape) A wire that is passed through a pipe in advance to make it easier to pass the mainline, when pulling an electric wire or cable through the pipe. The main line is connected to the fish
tape and pulled through the conduit using the fish tape.
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[Cable rack] A ladder-shaped rack used to organize many power lines and other cables together. Whenthe number of cables is small, cable hooks are used.
[Yakumono] (special-shaped part) A specially shaped member used in a specific position or for a
specific purpose.
[Tsugite] (joint) A member used to connect two parts. When connecting two cable racks, jizai tsugite(universal joint) that can be used to connect cable racks at an angle to each other can be used.
[Earth bond sen] (earth bonding wire) A connection wire used to electrically connect racks whencable racks are connected. There are also fittings called non bond tsugite (non-bonded joint) that do
not require earth bonding wires.
[Ductor channel] A member for supporting cable racks and conduit pipes. The cross section is Ushaped.
[Raceway] A member with power supply function for attaching lighting and other members. By using
suspension bolts, lights can be installed in places such as warehouses where there is no ceiling finish.
[Furetome] (brace) A member that supports the raceway at an angle to prevent it from swaying.
[Tsuri bolt] (suspension bolt) A bolt that attaches to an insert embedded in the slab. For bolts, longzen neji bolt (fully threaded bolts) without heads are used.
Example of suspension bolt support bracket[Tsuri bolt shiji kanagu] (suspension bolt support bracket] A
bracket used to hang suspension bolts from various types of steel
members and deck plates without drilling holes. Various shapes
are available depending on the mounting point.
[Double nut] Two nuts attached to prevent the nuts from loosening due to vibration.

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[Saddle] Fittings for attaching conduit pipes directly to walls

Saddleand ceilings.
[Ban] (electric control panel) A device for supplying electricity
to each device by branching the power supply. Inside are
breakers

and

other

components. Therearejiritsuban(freestanding panels) that are placed on the floor and kabekakeban (wall-mounted panels) that are
mounted on the wall.
[Channel base] A base that is inserted between the panel and the floor when a freestanding panel isinstalled.
[Zetsuen densen] (insulated wire) A wire made of copper or other material that conducts electricity
and is surrounded by an insulating sheath.
[Wire stripper] A tool used to strip coated wires of their
sheaths.
[Strip gauge] A gauge used to measure the length when
stripping the sheath of an electric wire. It is used by attaching it

Wire stripper

to a wire stripper.
[Denko knife] (electrician's knife) A knife used to peel theElectrician's knife

sheath of cables during electrical work.
[IV] Abbreviation for Indoor PVC. Vinyl-insulated wires forindoor wiring.
[VVF] Abbreviation for Vinyl insulated Vinyl sheathed Flat-type cable. An electrical wire insulatedwith flat-shaped vinyl.

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[VVR] Abbreviation for Vinyl insulated Vinyl sheathed Round-type cable. An electrical wire insulatedwith round-shaped vinyl.

VVF 1.6mm x 3 wires

VVR 1.6mm x 2 wires[EM-EEF] VVF cable with a polyethylene cover. Highly flame-resistant.
[VVF stripper] A tool to strip the outer and core insulation of VVF cables.
[CV cable] Abbreviation for Cross-linked polyethylene

VVF stripper

insulated Vinyl sheath cable. A cable that uses cross-linked
polyethylene as the insulator, which is even more flameresistant than EM-EEF. Used for wiring of electric lights,
power equipment, etc.
[CT] Electric wires covered with rubber material. Because of its excellent abrasion and impact
resistance, it is used as a portable electric cable.
[VCT] A portable electric cable with a vinyl material for the exterior. It is not only flame-resistant, butalso flexible and water-resistant.
[Kadenryu shadanki] (circuit breaker) A safety device that

Circuitbreaker

automatically shuts off the power supply to a device when an
excessive current flows through an electric circuit. Also called
breaker. Today, no-fuse breakers (NFB) are used for wiring.
[Relay] A switch that can be turned on and off by electricity.
[Thermal Relay] A relay that can interrupt a circuit when the temperature rises. Used to protect
electric motors, etc.

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[Konsento] (outlet) A socket on a wall, with a single-phase 100 V outlet for general households. There
are various types, including recessed and exposed. Recessed types are mounted on a recessed
mounting brackets.
Recessed-type

Exposed-type

Recessed mounting bracket

5.1.3 Telecommunications Work
[Closure] A box for connecting cable core wires in overhead wiring. It is installed on a utility pole.
[Cable kuridashiki] (cable feeder) A cable feederthat uses pulleys. The cable can be easily pulled out
from the cable reel.
[Tsuri sen] (suspension wire) In overhead wiring,

Cable feeder

this wire is used to prevent tension from being
applied to the cable. Also called messenger wire.
[Kinsha] (messenger pulley) A pulley used for pulling a cable to be attached to the messenger wire.
Placing the cable on the pulley portion of the wheel attached to the messenger wire makes it easier topull the cable.
[Chosenki] (tensioner) A device used in combination with a wire grip to apply tension to themessenger wire. By pulling the lever, tension can be applied to the messenger wire.
[Kakusenki] (wire grip) A tool for gripping the messenger wire
[Seiryuki] (rectifier) A device that converts alternating current to direct current.
[Chikudenchi] (storage battery) A device that can charge and store electricity.

110[Hikari fiber] (optical fiber) Optical fiber is made of two
types of quartz glass with different refractive indices. The
center part that transmits light is called the core and thesurrounding part is called the clad (cladding). It is further
Optical fiber

surrounded by a nylon membrane. It has the advantages ofbeing thin and light, having high transmission capacity, low

Fiber-optic cableloss, and non-inductive, with the disadvantage of being
susceptible to scratching, bending, and dirt.
[Hikari fiber cable] (fiber-optic cable) A cable formed bybundling optical fibers together. There are various types, such as 20-core, 100-core, and 400-core.
[Metal cable] A cable using copper for the core wire. Communication is performed by electricalsignals. Includes coaxial cables, twisted pair cables, etc.
[Dojiku cable] (coaxial cable) A cable with a structure in which an insulator is placed around a
conductor that transmits signals, and covered with another conductor. Coaxial cable is used for TV
antenna cables.

Coaxial cable

Metal cable[UTP twist pair cable] (UTP twisted pair cable) A cable made by pairing two conductors andtwisting them together. It is cheaper and softer than a coaxial cable. These cables are categorized by
maximum transfer rate. They can be used for phone calls or for networking, depending on the category.
[Jiko shiji cable] (self-supporting cable) A cable with an integrated support wire for supporting thecable. It can be mounted directly onto the utility pole. It is used for overhead wiring.
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[Hikari fiber yuchaku setsuzokuki] (optical fiber fusion splicer) A machine used to melt the tipsof two fiber-optic cables to connect them together. This connection method is called yuchaku setsuzoku(fusion splicing). Other connection methods include mechanical splicing and connection via
connectors.
[Fiber hogo sleeve] (fiber splice protection sleeve) A sleeve used to protect the joint when fusion
splicing is performed. It is shrunk by heat to be fastened to the cable. Beware that it must cover thecable before fusion splicing, because it may not be possible to cover the joint after splicing.
[Fiber holder] A device for setting optical fibers in a jacket remover, fiber cutter, or fusion splicer.
[Jacket remover] A tool used to remove the coating of optical fiber.
[Fiber cutter] A tool used to cut fiber-optic cables. When making fusion splices, a special tool isprovided to cut the cross-section of the cable perpendicularly.
[Hikari connector] (optical connector) A component forconnecting fiber-optic cables. It has the advantage of being
easy to insert and remove by hand. Types of connectors

SC connector

include SC connectors, FC connectors, LC connectors, and
MU connectors.
[Hikari power meter] (optical power meter) A device used to measure the intensity of light used for
optical fiber communications.
[Hikari pulse tester] (optical pulse tester) This tester can measure the line length of optical fibercores and whether there are any abnormalities such as loss or reflectance due to splicing. It is called
an OTDR (Optical Time Domein Reflectometer).
[Dojiku cable checker] (coaxial cable checker) A device used to check the continuity of coaxial
cables.
[Hub] A device to which wires are connected when configuring a star topology wired LAN network.
[Switching hub] One of the relay devices in a communication network. Normal hubs send the received
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data to all devices, but switching hubs check the address and send the received data to only thosedevices that need to.
[Router] A device that connects multiple different networks. Routers can be used to separate multiple
networks.
[LAN tester] A device used to check the eight wires between the modular plugs attached to both ends
of a LAN cable to ensure that the wires are not crossed or disconnected.

5.1. 4 Plumbing Work[Haikan/duct] (pipe/duct) What passes water and gas is called a pipe, and what passes air is called aduct. There are two types of ducts: rectangular ducts, which are rectangular in shape, and circular ducts(also called spiral ducts), which are round in shape.
[Pipe manriki] (pipevise) A tool used to hold pipes in place when cutting or joining pipes.
[Pipe nejikiriki] (pipe threader) A machine used to cut threads in pipes.
[Tube cutter] A tool used to cut thin-walled tubes made ofiron, steel, brass, copper, aluminum, etc.
[Tube bender] A tool used to bend copper tubes.
[Pipe cutter] A tool used to cutpipesmade of steel, brass, copper,
wrought iron, and lead. It can cut thicker tubes than tube cutters.
[Pipe wrench] A tool used to join pipes and pipe fittings by tightly
Pipe cutter

gripping and rotating round, difficult-to-grasp pipes. Also called
pairen.
[Expander] A tool used to expand the ends of copper pipes to connect them. Also called kakukanki.
[Flaring tool] A tool used to flare the ends of soft pipes such as copper pipes.
[Mentoriki] (deburring tool) This tool removes burrs from metal and PVC pipes to smooth out thesurface.

113[Suiatsu shikenki] (water pressure tester) This meter is used for water pressure testing of watersupply pipes and hot water pipes. Also called test pump.
[Seal zai] (sealant) Material used to prevent fluid leakage inside a

Sealant tapepipe when the pipe is screwed in. There are liquid sealants as well
as sealant tapes.
[Enka-vinyl jushiyo secchakuzai] (adhesive for polyvinyl
chloride resin) Material used to prevent fluid leakage inside polyvinyl chloride pipes when joining
them.
[Haikan’yo tansoko kokan] (carbon steel pipes for piping) This steel pipe is widely used for steam,water, oil, gas and air piping. There are shirokan (white pipes, with plating) and kurokan (black pipes
without plating) depending on whether they are plated or not. Also called gas pipe or SGP.
[Koshitsu poly-enka vinyl kan] (rigid polyvinyl chloride pipe) A pipe made of rigid polyvinyl
chloride resin. There are VU kan (thin-walled pipes) and VP kan (thick-walled pipes). It is gray incolor and is also called enbi pipe and enbikan (PVC pipe). It has the advantages of having a verysmooth inner surface, low frictional resistance, light weight, and being easy to process. On the other
hand, the disadvantages include being vulnerable to external shocks and heat.
[Taishogekisei koshitsu poly-enka vinyl kan] (impact-resistant rigid polyvinyl chloride pipe) A
PVC pipe that is resistant to external impact. It is dark blue in color and is called HIVP kan or HI kan.
Used in locations subject to high external impact, cold climates, etc.
[Tainetsusei koshitsu poly-enka vinyl kan] (heat-resistant rigid polyvinyl chloride pipe) A PVC
pipe with improved heat resistance. It is called HT kan (HTVP kan). It is reddish brown in color andis used for cooling and heating pipes, hot spring pipes, etc.
[Suidoyo koshitsu enka vinyl lining kokan] (rigid polyvinyl chloride-lining steel pipe for watersupply) A lined steel pipe for water supply in which the inner surface of the steel pipe is lined withrigid polyvinyl chloride. It has excellent corrosion and chemical resistance. Also called lining kan or
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VLP.
[Nejikomishiki katan chutetsusei kudatsugite] (screw-in malleable cast iron pipe fitting) A fitting
for connecting threaded pipes. There are elbows, tees, sockets, nipples, etc.
[Neji gauge] (thread gauge) This gauge is used to inspect threads used in connection of pipes, pipe
fittings, etc.
[Gas cock] (gas valve) A valve that opens and closes the gas supply pipe. There are end-of-line valves
used when connecting gas appliances such as gas stoves and gas water heaters, and mid-line valves
used in the middle of piping to open and close gas lines.
[Gas more keihoki] (gas leak alarm) A device that sounds the alarm when there is a gas leak to warnof danger.
[Sekimen cement kan] (asbestos cement pipe) A pipe manufactured by mixing asbestos, cement,
and silica sand with water. It has excellent corrosion resistance, is lightweight, easy to fabricate, andinexpensive. On the other hand, it is inferior in strength and impact resistance. Furthermore, the healthissues of asbestos inhalation on the human body have been recognized, and it is no longer being
produced.
[Ductile chutetsu kan] (ductile iron pipe) A pipe made of spheroidized graphite contained in castiron that has higher strength and toughness (toughness of the material and resistance to destruction by
external forces) than cast iron. It has the disadvantage of being relatively heavy in weight. Until around
1955, when ductile iron pipes were developed, cast iron pipes were the norm.
[Reibaiyo dokan] (copper pipe for refrigerant) A pipe used to pass refrigerant while circulating
between the outdoor and indoor units of an air conditioner. Seamless pipes made of copper and copper
alloys are used.
[Pump] A machine used to give energy to water in pipes to carry it farther or lift it from low to highplaces.

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[Flange] A ring-shaped device that is attached to the end of apipe.
[Sleeve] A conduit that is attached to the walls, floors, beams,
etc. of a building to carry piping and ducts. It is embedded
Flangebefore concrete is placed.

[Tsugite] (pipe fitting) A member that splits or bends a pipe. There are elbows that change thedirection of flow and tees that make45 degree elbow

Teebranches.

5.1.5 Freezing and Air Conditioning Apparatus Work[Air filter] A filter used to remove dust and small debris from the air.
[Fan] A machine used to give energy to the air in the duct to transport the air farther away. There are
two types of fans: blowers that send air from the outside into the room, and exhaust fans that discharge
air from the room to the outside.
[Reikyaku coil] (cooling coil) Used to cool the air temperature by bringing the air into contact with atubing through which cold water is passed, and is used for cooling the room.
[Onsui coil] (hot water coil) Used to warm the air temperature by bringing the air into contact with atubing through which warm water is passed, and used for heating the room.
[Kashitsuki] (humidifier) A device that adds moisture to dry air. Mainly used when heating the room.

5.1.6 Water Supply, Drainage, and Sanitation Facilities Installation[Eisei setsubi] (sanitation facilities) Short for water supply and drainage sanitary facilities, which116

includes water supply facilities, drainage facilities, sanitation fixtures, hot water supply facilities, gas
facilities, and fire extinguishing facilities.
[Eisei kigu setsubi] (sanitation facilities) Facilities that produce, store, and discharge cold and hot
water, such as faucets, toilet bowls, urinals, wash basins, baths, and sinks.
[Trap] Provided to hold water in a part of the drain pipe to prevent
odors and small insects from entering the room.
[Ben/damper] (valve/damper) A device (also called a valve) thatValve

stops or adjusts the amount of water in a pipe. What stops or adjusts
the amount of air in a duct is called a damper.

5.1.7 Heat/Cold Insulation Work
[Glass wool ho’onzai] (glass wool insulation) Glass (mainly recycled glass) is melted at hightemperatures to form thin fibers. It is widely used as an insulator that combines the flexibility of fiberwith heat resistance and nonflammability. There are insulation tubes, insulation strips, and insulation
panels.
[Rock wool ho’onzai] (rock wool insulation) Basalt and andesite are melted at high temperaturesand converted into fiber by centrifugal force. Because it is made from rock, it is more fire-resistant
than glass wool material and is used as a firestop sealant of fire partitioning. There are insulation tubes,
insulation strips, and insulation panels.
[Polystyrene foam ho’onzai] (polystyrene heat insulation) Polystyrene with added foaming agent(non-fluorocarbon) and flame retardant is foamed by steam heating, dried, and then steam heated again
for molding. Available in tubular or plate form. Polystyrene is often used in water supply and drainage
pipes because it cannot be used at temperatures above 70°C.

1175.1.8 Construction of Fire Fighting Facilities[Shoka setsubi] (fire extinguishing equipment) Equipment used in the event of a fire to extinguish
the fire and guide people to safety.
[Shokaki] (fire extinguisher) A portable device that extinguishes fires in the very early stages of a
fire.
[Okunai shokasen setsubi] (indoor fire hydrant system) A system operated by people for the
purpose of fire extinguishing in the initial stage of a fire. There are three types of hydrants: Type 1
hydrant, which is operated by two or more people; Type 1
hydrant with easy operability, which can be operated by one
person; and Type 2 hydrant.
[Okugai shokasen setsubi] (outdoor fire hydrant system)

Outdoor fire
hydrant system

A system installed outdoors to extinguish fires in the initialstages and to prevent the spread of fire to adjacent buildings. It is intended to extinguish fires on thefirst and second floors of buildings.
[Sprinkler setsubi] (sprinkler system) A system that is attached to fire extinguishing piping andsprays water from the ceiling in the event of fire. Sprinkler heads include closed sprinkler heads, open
sprinkler heads, and high-flow sprinkler heads.

Closed sprinkler headOpen sprinkler head

[Mizu funmu shoka setsubi] (water mist fire extinguishing system) A system designed toextinguish fires on roads, parking lots, and places where designated combustible materials are stored118

or handled.
[Awa shoka setsubi] (foam fire extinguishing system) A system designed to extinguish oil fires forwhich water-based fire extinguishing methods are not suitable. This system extinguishes fires throughthe asphyxiating effect of foam covering the fire surface and the cooling effect of the water that makes
up the foam. There are fixed and mobile types.
[Fukassei gas shoka setsubi] (inert gas fire extinguishing system) A system that extinguishes fires
by releasing inert gas to dilute the oxygen concentration in the air as well as to cool the air.
[Halogen kabutsu shoka setsubi] (halide fire extinguishing system) A system that uses halide fire
extinguishing agents. Halogen elements (fluorine, chlorine, and bromine) stop combustion by
inhibiting combustion reactions, cutting off the air supply, and lowering the oxygen concentration in
the air. Suitable for oil fires, fires involving energized electrical equipment, computers, books,
important works of art, etc.
[Funmatsu shoka setsubi] (powder fire extinguishing system) A system that uses fire extinguishing
agents in powder form. In addition to the suppression of combustion reactions by powder fire
extinguishing agents, the asphyxiating action makes it suitable for oil fires, fires involving energizedelectrical equipment, etc.

5.2 Common Tools, Machines, Materials, and Measuring Instruments
5.2.1 Power Tools
Power tools can be cordless types that use rechargeable batteries or corded types that use AC power.
[Drill driver] This electric screwdriver can be used for screwing and drilling by changing the bits.
Rotation speed and torque can be adjusted.
[Impact driver] An electric screwdriver that can tighten screws using the impact from the built-in
hammer. It has more power than a drill driver. Rotates at a constant rotation speed and torque.
119

Drill driver

Impact driver[Bit] A part attached to the tip of an electric screwdriver. Various types of bits for drilling and screws
are available. The part where the bit is attached differs between a drill driver and an impact driver.

Drill driver

Impact driver[Disk grinder] (angle grinder) This power tool can cut, grind, and remove paint from metal pipes
and concrete by changing the disc (a round, flat grinding stone for grinding and cutting) attached tothe end of the tool. The high speed torque type is suitable for metal cutting, while the low speed torquetype is suitable for grinding.
Angle
grinder

Disk[Sander] This power tool is used to polish flat surfaces by moving sandpaper. There are several typesof mechanisms for moving sandpaper, including vibrating, belt, and rotating types.
[Marunoko] (circular saw) A power tool for cutting plywood and other materials in a straight line.
Hand-held and fixed types are available. The hand-held type, when it touches the material to be cut,120may move in an unexpected direction due to a force (called kickback) that lifts it away from thematerial. This leads to many accidents, and in some cases, they can be serious, life-threatening
accidents. Before use, make sure that the safety cover is working properly.
[Marunoko guide jogi] (circular saw guide ruler) Attached to a circular saw, this ruler is used to cut
materials in a straight line.

Circularsaw

Circular saw guideruler[Shujin marunoko] (circular saw with dust collection) A circular saw that can cut while collecting
fine dust. Two types are available: one for board cutting and the other for metal cutting. There are two
types: one with a dust box to collect dust, and the other with a dust collector to be connected to thecircular saw.
[Shujinki] (dust collector) A power tool used to collect dust produced by cutting. It is used whencutting tile and concrete products to prevent cutting debris from flying out into the neighborhood.
[Kosoku setsudanki] (high-speed cutter) An electric toolthat cuts metal pipes, rebar, light steel sections, etc. byrotating a grinding stone for cutting. Much like a chip saw
cutter, but a chip saw uses a circular saw blade to cut
materials. The blades of chip saw cutters wear easily,

High-speed cutter

whereas the blades of high-speed cutters last longer.
[Recipro saw] (reciprocating saw) A power tool that cuts materials by moving a long, thin blade backand forth.
121

[Dendo block cutter] (electric block cutter) A power tool for cutting concrete.
[Kugiuchiki] (nail gun) A tool that uses the force of air pressure compressed by a compressor to drive
nails into materials. A compressor is a machine that compresses air.
[Denko drum] (cord reel) A tool for extending an outlet.

Cord reel

Nail gun5.2.2 Digging/Leveling/Compacting[Ken sukoppu] (spear head spade) A tool used for digging in the ground by placing the foot on the
top of the head. It is also called kensuko for short. Do not use as teko (lever).
[Kaku sukoppu] (square head spade) A tool used to scoop and carry soil, asphalt, etc. It is similar
to a spear head spade, but the blade edge is straight to make it easier to scoop soil and other materials.
Also, the top is rounded and does not allow for foot placement. Do not use as teko (lever). It is also
called kakusuko for short.
[Double sukoppu] (double spade) These spades can poke through the ground to dig a deep hole. The
dug soil can be grabbed under the surface and pulled out. It is used for digging holes for piles andutility poles.

Spear head spade

Square head spade

122

Double spade[Tsuruhashi] (pickaxe) A tool used for excavating hard ground and breaking up asphalt.
[Reki] (rake) A tool used to level soil, spread asphalt, and collect fallen leaves. There are various
shapes and materials, depending on the purpose. Rakes for leveling soil have many thin tines, but rakes
for asphalt have none.
[Joren] (dredge hoe) A tool used to rake up earth, sand and debris.
[Tako] (manual compactor) A tool used to beat and pack soil and other materials by weight.
[Tamper] A tool with a flat metal plate attached to the end of a long handle. It is used to compactasphalt and other materials by holding the handle and tamping theRammersurface from above.
[Rammer] A machine used to compact the ground. The weight of therammer and the force of the impactor, which moves up and down,
compact the surface. It has strong striking power and is suitable forstrong compacting. There are engine- and electric-powered types.
[Vibro-compactor] A machine equipped with an engine to compact soil and sand by its own weightand vibration. Used for compacting road aggregate base layers, road subgrade layers, backfill, etc. The
machine is pushed and pulled back and forth by hand to compact the surface. Although the impact
force is inferior to that of a rammer, a large area can be compacted at once. A similar machine is theplate compactor. A plate compactor is more suitable for flattening due to the larger area of thecompacting plate and smaller vibration.

1235.2.3 Layout Marking/Marking Tools[Sumitsubo] (line marker) A tool used for marking longstraight lines on the surface of a material.
[Sumisashi] (ink pot) The flat part of the ink pot is used fordrawing lines, and the round part (ho) is used in the same way

Line marker

as a brush.
[Chalk line] Similar to the sumitsubo line marker, but draws a line with powdered chalk.
[Laser marker] A machine that emit laser beams onto walls, ceilings, andfloors to produce horizontal, vertical, and other reference lines forconstruction. Laser beams are available in red and green. Green is relatively
easier to see in bright locations. Protective goggles for laser work are wornto prevent the laser beam from directly entering your eyes.

Laser marker[Marker pen, marking chalk] Oil-based pen for architectural use. For
example, it is used to allocate the position and pitch (distance between reinforcing bars) where thereinforcing bars are placed.
[Punch] This tool can be used to make small indentations in metal
surfaces by tapping with a hammer, or to make round holes incloth, leather, etc. The center punch is used to mark metal surfaces(this is called marking).

124

Punch

5.2.4 Measuring/Inspecting[Level] A leveling device used to determine the height necessary

Levelfor the work. Mounted on a tripod, the device is manually leveledby balancing the built-in bubble vial. A level with an automaticleveling mechanism is called an auto-level.
[Laser level] An instrument for level surveying by laser and isused to determine the height necessary for the work.
[Transit] An instrument that measures the vertical andhorizontal angles based on the viewpoint supporting a small
telescope. It is used on a tripod. These days, a digital display
type of device called theodolite is often used.

Transit[Total station] A surveying instrument that combines a lightwave rangefinder and an electronic transit. Look through the telescope and simply align the crosshairs
with the target and press the button to simultaneously measure the distance and angle from thereference point. Total stations are used in a wide range of surveying applications, including
topographic surveying, construction site location management, initial ground surveying, and fixed
point surveying.
[Mizuito] (line level) Thread used to straighten lines and match heights
when building foundations or stacking bricks and blocks. It is made of nonstretch material.

Line level[Suiheiki] (level) A tool used to check whether a construction
surface or object is level with the ground. The level is checkedby looking at the air bubble in the vial. Some use the needle tocheck the level, and some are digital levels. Levels with a builtin inclinometer are also used in residential installations.
125

Level

[Sagefuri] (plumb bob) A weight with a pointed conical tip used to checkthe verticality of a pillar or other objects. The verticality is checked byhanging it from a plumb bob holder fixed to a post using a thread andchecking if the distance between the surface to which the holder is attachedand the thread is constant.

Plumb bob

[Sashigane] (carpenter’s square) A tool made of stainless steel orothermetal, used to measure right angles. It is scaled and can also
be used to measure length. The front side is in metric scale, andCarpenter’s squarethe back side is 1.414 (√2) times the front side.
[Ogane] (triangular ruler) A large triangular ruler formeasuring right angles. It is made on site using the Pythagorean theorem, the ratio of 3:4:5 . The 3:4:5
is called sashigo at the worksite.
[Measure] (tape measure) A tape-like tool for measuring length. Sometimes referred to as makijaku(tape measure). Available in steel and vinyl.
[Convex] (retractable steel measuring tape) A measure with aConvexthin metal tape that measures length. Sometimes abbreviated asconbe, the official name is the convex rule.
[Jogi] (ruler) A tool used for measuring length and drawing
straight lines. Materials include aluminum, stainless steel, and bamboo. To avoid damaging materials
such as fittings, bamboo
rulers are used.
Aluminum ruler

Stainless steel ruler

126

Bamboo ruler

5.2.5 Cutting/Bending/Breaking[Nokogiri] (saw) A tool with many blades (called me (teeth)) on a metal plate, used to cut wood, metal,
pipes, etc. It is called noko for short.
[Hasami] (scissors) A tool used to cut objects between two blades.
[Kuikiri] (end nipper) A tool used to cut objects between theblades. Used for processing tiles, cutting wires, etc. It can also cut
the head of a nail.
[Cutter knife] (box cutter) This knife can maintain its sharpness

End nipper

by breaking off the tip of the blade.
[Tagane] (masonry chisel) A stick-shaped tool with a blade on one end that can be used to cut thinmetal by tapping it with a hammer. It is also used for hatsuri sagyo (breaking), to break concrete andmark measurements of roof tiles. Flat masonry chisel, concrete masonry chisel, carving masonry chisel
and others are available depending on use.
[Penchi] (pliers) A tool for bending, cutting, etc. There is a part for gripping with fine grooves toprevent slipping and a part with blades for cutting.

Box cutter

Masonry chisel

127

Pliers5.2.6 Tapping/Pulling[Hammer] A tool used to strike things. The material of thestriking head can be metal, rubber, or wood, depending on theintended use. Those with a metal head is sometimes calledkanazuchi.
Example of a hammer (for ringlock scaffolding)[Rubber hammer] A hammer with a rubber head. It is
Rubber hammer

characterized by its strong striking power without damaging
the material.
[Kizuchi] (wooden hammer) A hammer with a head made ofwood. Although the striking force is weaker than that of ametal hammer, it is less likely to damage the material.
[Kakeya] (large wooden hammer) A large wooden hammer used for driving stakes, etc. Kakeya isalso used to tap hozo (tenon) into hozo ana (mortise) in the wooden-frame structure method.
Wooden hammer

Large wooden hammer[O-hammer] (large hammer) A hammer with a long handle and a large head. It is used for pile driving
and demolition work.
[Bar] (crowbar) A metal tool that can be used as a lever. The L-shaped tip has a groove for removing
nails. The tip is inserted under the nail head, and the nail isremoved using the principle of leverage. The other side is either aclaw or flat like a spatula. In addition to pulling out nails, a large
crowbar can be used to lift heavy objects. It can also be inserted
128

Crowbarinto a gap for twisting and prying. A large crowbar is used in the dismantling of the formwork.

5.2.7 Filing/Polishing/Boring[Toishi] (grindstone) A tool for cutting and polishing metals, rocks, etc. The small rectangular-shaped
tools are used to sharpen the blades of nomi (wood chisels) and kanna (Japanese hand planes).
[Yasuri] (file) A tool for polishing metal and wood surfaces. There are many types of files for different
purposes, such as metal files and wood files. If chips get stuck in the grooves, a wire brush is used tocarefully remove the chips.
[Sandpaper] A type of yasuri (file) where sand or glass-like grains are applied onto the surface of
paper. There are several types of paper, including taisui paper (water-resistant paper) that resists watersand nuno paper (cloth paper) that has strength. The numbering indicate coarseness. The smaller thenumber, the coarser the grain, and the larger the number, the finer the grain, resulting in a smootherpolished surface.
[Wire brush] A stiff brush made of metal wires. It can be used to remove rust from metal, peel off
paint, and clean file grooves.
Wire brush

Wire brush129

5.2.8 Tightening/Fixing[Monkey Wrench] A wrench with a mechanism that opens andMonkey wrenchcloses. The width between the upper and lower jaws can bechanged to match the diameter of the bolt or nut. The upper jaw
is integrated with the grip, so the force should be applied to theupper jaw when turning. Because the tip is open, this tool isclassified as spanner, but it uses the word “wrench” as an exception.
[Socket wrench] A wrench used for nuts and bolts of various sizes by changing the sockets on thehead.
[Box wrench] A wrench in which the socket part for turning nuts and bolts and the handle part are
integrated as a single piece. There are L-shaped and T-shaped
Hexagon wrenchtypes.
[Rokkaku wrench] (hexagon wrench) This tool has ahexagonal hole and is used to turn bolts. Also called rokkaku bo
wrench.
[Driver] (screwdriver) A tool used to turn screws. There is a

Screwdriver

Phillips-head and a flat-blade screwdriver to fit the grooves on theheads of the screws. It is important to use the correct size to avoid
breaking the groove of the screw head (called nameru (stripping)).
The shape of the grip is also important. For example, the grip of ascrewdriver for electrical work is round and large so that the hand can easily wrap around it.

130

[Kugi] (nail) Something that is hammered in to join members together.
Depending on the application, there are various types of nails, such as

Nailscrew nails, concrete nails, casing nails, and corrugated roofing nails.
[Neji] (screw) A cylindrical or conical shaped object with a spiral groovethat is screwed into a member using a screwdriver to secure it to anothermember.
[Tapping neji] (self-tapping screw) A screw that threads its own groove into the material as it is being
screwed.
[Bolt] A type of screw. A bolt (male thread) and a nut
Bolt

Nut

(female thread) are used as a set. A washer may also be
used.

Washer

5.2.9 Kneading/Mixing[Hand mixer] A mixer for paint, mortar, and concrete. Ingredients are placed in a mortar box or bucket
and mixed with a hand mixer.
[Kakuhanki] (stirring machine) A machine for mixing liquids and construction materials. Also
called mixers, various types are used in construction sites.
[Mortar mixer] A machine that mixes cement, water, and sand to make mortar. There are two typesof power sources: one that uses a 100 V power source and the other an engine type.
[Concrete mixer] A mixer designed for concrete, with morestrength than mortar mixers.
[Batch Mixer] A mixer that mixes materials for concrete one
batch at a time.
Concrete mixer

131

[Torobako] (mortar box) A sturdy box for mixing materials to make concrete or mortar. Also known
as torobune or fune. The ingredients in the mortar box are kneaded using a stirring machine or akneading shovel.
[Furui] (sieve) A tool with a mesh that can sort materials according to size. Items to be removed aresorted according to the size of the mesh. For example, it can take excavated earth and sand and separate
fine soil from gravel.

5.2.10 Curing/Prepping[Yojoyo poly sheet] (plastic sheet for curing) Polyethylene film in sheet form. It is used for moistureproofing and waterproofing from the ground when pouring concrete, for curing when painting, and toprotect from rain and dust.
[Veneer] (plywood) Thin plywood is laid to protect the floor from scratches.
[Blue sheet] Used to protect walking areas of the floor from paint and dust.
[Hisan boshi net] (anti-scattering net) A mesh-like sheet for scaffolding that covers the entire
building. It is also used to prevent construction materials accumulated on site from scattering, andcargo from falling off the rear decks of transport vehicles.
[Suichoku yojo net] (vertical safety net) A net attached to scaffolds at construction sites to prevent
materials from flying and falling from scaffolds.
[Suihei yojo net] (horizontal safety net) A net used atconstruction sites to avoid humans and materials from falling
Horizontal safety net

from heights.

1325.2.11 Scrubbing[Brush] A tool with bundles of bristles planted at regular intervals onto the base, used for rubbing to
remove dirt. For example, in stonework, a brush wetted with water is used to remove the excess cement
slurry from between the stones.
[Sponge] Foam-molded synthetic resin such as polyurethane, wetted with water and used to remove
dirt. For example, in stonework, it is used to clean surfaces dirty from cement slurry.
[Wes] (rags) Cloth used to wipe off stains from machine oil and other liquids.
[Bucket] A container with a handle for holding and carrying water. For construction purposes, sturdy
buckets made of galvanized steel sheets are used.
[Hishaku] (ladle) A tool with a handle for ladling water.

5.2.12 Carrying Objects[Ichirinsha] (wheelbarrow) A tool for carrying items,
Wheelbarrowconsisting of a steel bucket with one wheel in the front. Used byholding the handles and pushing. It uses the lever principle withthe wheel as the fulcrum, the handles as the effort, and the bucket
as the load to make it easier to carry heavy objects. Sometimes
called neko.
[Daisha] (wheeled platform) A platform with four casters,

Wheeledplatform

used to carry objects. Some have handles, some do not. A
wheeled platform with brakes is also available.
[Sori] (sled) A tool used to move heavy objects such as stones
by putting them on top and pulling it.
[Koro] (log) A log used to move heavy objects. Several are placed parallel to each other, an object is133

placed on top, and the object is moved as the logs roll.
[Forklift] A vehicle equipped with forks that move up anddown using hydraulic pressure. Objects placed on the fork areraised to or lowered from high places.
Forklift5.2.13 Hanging/Lifting/Pulling[Winch] A machine that winds up a rope. Also called makiageki.
[Wire rope] Several high-tensile-strength steel wires are twisted

Wire rope

together to form a strand, and then several strands are twisted
together again to form a rope. It has high tensile strength,
excellent impact strength, and flexibility for easy handling.
ShackleThose with processed ends are used for slinging. There are also
ropes for anchoring.
[Shackle] A slinging fixture for connecting a wire rope or chain to a suspended load.
[Turnbuckle] A device used to tighten ropes and wires.
ShackleTurnbuckle

134[Chain block] A machine that can raise and lower heavy objects by applying the principles of leverand pulley. It is used by attaching it to a tripod, etc.

Chain block[Lever hoist] A machine that has the same mechanism as a chain
block, but is smaller than a chain block. It is used to secure the load,etc. For example, when a backhoe is loaded onto a truck fortransportation, it is also used to secure the backhoe so that it does
not move.
[Oyazuna kinchoki] (main rope tensioner) A device that

Main rope tensioner

can keep the tautness of the main rope to which the hook of
the safety belt is attached. It is used when working at heights,
such as scaffolding work.
[Tirfor] A manual winch used for pulling heavy objects. The
wire rope passed through the tirfor can be pulled strongly by lever operation. When felling a large tree,
pulling the tree with a tirfor can bring it down in the desired direction.
[Jakki] (jack) A device for lifting heavy objects with a small amount of force. The lifting mechanism
includes screws, gears, and hydraulic pressure.
[Kirin jakki] (screw jack) A device that can lift heavy objects vertically by using the thrust generated
when the screw is turned. It is also used to apply force to the left or right by placing it between two
horizontal members in soil retaining structure work.
[Lever block] A tool for lifting and securing loads. It is also used to re-align steel frames (to makethem vertical).

5.2.14 Work Platforms/Ladders[Hashigo] (ladder) A tool for climbing to high places. It is climbed by stepping onto the rungs. It

135should be set at an angle of approximately 75 degrees. If the angle is too steep, there is a risk of falling
backwards. Conversely, if the angle is small, there is a risk of the ladder breaking. Also, always workwith an assistant to support the ladder.
[Kyatatsu] (stepladder) A tool that is a combination of two ladders.
When opened, it can be used as a ladder. When using it as a stepladder,
do not sit or stand on the top. Also, do not work while straddling the
top with legs on either side, as this may upset the balance and be

Stepladderpotentially dangerous.
[Kahanshiki sagyodai] (portable elevated work platform) A tool

Portable elevatedwork platform

with a platform between two legs that extend and retract. Also known
as nobiuma. There are handrails on top of the work platform. Leaning
outward or pushing against a wall may cause loss of balance andfalling.
[Rolling tower] A platform for working at heights. There are casters
on all four corners to move it around. There are safety standards for rolling towers under the Industrial
Safety and Health Act.
[Kosho sagyosha] (aerial work platform) A vehicle equipped with a device that can raise and lower
a man basket to a height of 2 m or more.

5.2.15 Cleaning[Hoki] (broom) A tool for cleaning by sweeping. Bamboo branches, bundles of plants or synthetic
fibers are attached to the end of a stick.
[Chiritori] (dustpan) A tool for collecting dust and debris swept with a broom.

136

BroomDustpan[Blower] A blower. It is used to collect light objects such as fallen leaves by blowing them with theforce of air.

Blower137

Chapter 6: Knowledge of Construction Site Work
6.1 Matters Common to Construction Sites
Construction sites are home to technicians from many job categories. Although the work they
perform may appear to be different from each other, experienced technicians are always aware ofcertain matters. This realizes high quality and safety. This section describes matters that all technicians
should know.

6.1.1 Characteristics of Construction Work
(1) Construction work is on a build-to-order basis.
The term build-to-order refers to the manufacturing of a single product designed from scratch tomeet the customer's requirements, rather than the repeated production of the same design in factories,
as in the case of automobiles. Construction work is conducted on a build-to-order basis. They are
diverse, from large-scale to small-scale projects, and although some may appear to be similar, eachindividual project has different characteristics and conditions. It is important to have the intention ofbuilding-to-order for each customer.
(2) Construction work is subject to location constraints.
The majority of construction work is built in accordance to the unique requirements of the locationfor each property, which means that a project will never be repeated under the same conditions.
(3) Construction work is subject to nature.
Construction work is often conducted outdoors and subject to uncertain factors, such as topography,
seasons, weather and other natural conditions.
(4) Construction work is subject to social constraints.
Construction work is local production, and therefore is subject to social constraints on the site. It is
important to manage the site based on safety measures for the surrounding area and environmental
preservation measures. Applicable laws and regulations and the surrounding social environment differ
146depending on the location of construction, and construction work is expected to conform to these
constraints.
(5) Quality is created through safe process.
It is also true in construction work that the quality of the finished structure is created through theentire safe construction process.

6.1.2 Construction Plan
All construction projects have a construction plan. A construction plan is a plan for the construction
project based on the terms and conditions of the construction contract, drawings, specifications, site
descriptions, and other design documents. The construction plan is prepared considering the following
points.
> Planning within various social constraints, such as relevant laws and regulations.
> Comprehensive planning of management methods for quality, construction budget, process, safety,
and environmental preservation.
> Planning to efficiently combine construction methods to achieve good quality at minimum costthat is completed within the construction period.
> Planning for accident-free and disaster-free project that considers environmental preservation.
> Planning using the 5Ms of Construction Management. The 5Ms of Construction Management
refers to Manpower, Materials, Methods, Machinery, and Money.
> Conducting sufficient preliminary investigation to understand the local/on-site conditions, etc.,
and planning measures and management methods prior to and during construction.

6.1.3 Construction Management
Construction management is the management necessary for the contractor to complete theconstruction target in the prescribed quality in accordance with the construction plan. Construction

147

site work is conducted under the following five management indicators (called QCDSE).
[Quality]This is management to produce a finished structure that fully satisfies the quality required by theclient. Quality inspections, quality tests of materials and various construction tests as stipulated in thequality control plan are performed to control the ensure prescribed dimensions and shapes.
[Cost]
Cost is money that can be spent on site. The cost of materials, labor, and field expenses related tothe construction project are managed so that they do not exceed the construction budget.
[Delivery]
Companies coordinate with the prime contractor and other contractors in order to ensure that theirconstruction work can be performed efficiently, and manage the construction process to avoid delaysin the actual work so as to ensure completion within the construction period.
[Safety]
Necessary management is conducted to prevent accidents such as people and objects falling, and toprevent work-related illnesses such as pneumoconiosis and heat strokes. In addition, risk prediction
training in the daily cycle of safety in construction, patrols during work, safe process meetings, 5S
promotion activities, and other activities are conducted with the goal of achieving zero accidents andzero occupational injury.
[Environment]This is management to minimize the impact of construction on the environment, including noise,
vibration, and water pollution. The standards set by laws and ordinances must be observed.

6.1.4 Pre-Construction Preparations（１） Main considerations for the construction procedure manual
In order to ensure high quality in construction work for the day, it is necessary to check and correctly148

understand the construction details.
> Review and understand the terms of the construction contract.
> Review and understand the contents of the contracted construction (terms and conditions of theestimate) and the scope of work.
> Review and understand the blueprints and construction drawings.
> Review and understand the site construction conditions and site rules.
> Review and understand the work schedule with other contractors and connections withconstructions before and after the project.
> Confirm the construction procedures, allocate workers, and prepare materials and equipment.
> Confirm possession and carrying of the Career Up Card and licenses required for the work.
> Identify and understand safety issues.

(2) Pre-work inspection
When working on a construction site, workers use a variety of tools and machinery. Common
accidents for workers occur when handling tools and equipment. Be sure to conduct the following as
pre-work inspection.
> Pre-work inspection of the machinery- Confirm that machinery capable of conducting the intended work are in place, inspected, andmaintained.
> Checking of equipment, tools, and instruments- Confirm that the equipment, tools, and instruments to be used are inspected and maintained.
> Confirmation of work procedures- Confirm that the workflow is realistically feasible.
- Confirm that individual work sharing and collaborative work are assigned in a compatible
manner, and that the work assignment is correct.
149

> Confirmation of safety- Confirm that health and safety protective equipment and safety devices, etc. are being usedcorrectly.
- Confirm whether emergency responses are appropriate.

6.1.5 Layout Marking (Marking Out)
Sumidashi (sumitsuke) (layout marking (marking out)) refers to marking the location and height ofthe structure or component to be constructed on the construction site. In the entire construction processfrom beginning to completion, this is the very first step. It is the most important work that requires
quality (accuracy). Precise reference marking and reference level, axis line as per blueprints, etc. aremarked for correct positioning. For layout marking, a tool called a sumitsubo (line marker) is used,
but nowadays a laser illuminator is used to emit a laser beam to mark along the laser. The laser makes
it easy to check for level and right angles. The following are the three main types of layout marking
and marking out work.
Layout marking and marking out

Layout marking and marking out locations

work
Layout marking

Reference and parent markings for positioning, height(reference level/GL), axis line, etc.

Marking out for member fabrication

Cutting and processing dimensions of reinforcing bars,
formwork, piping, wiring, and other components;
processing dimensions of wooden workpieces; and scribe
marks on sheet-metal

Marking positioning of processed

General interior and exterior fittings, intake and exhaustparts, equipment, hardware, etc. forvents such as ventilation holes, water supply and drainage
150

installation

sanitary piping, air conditioning and sanitary equipment,
and firefighting equipment

6.2 Knowledge regarding Pipe Processing
This section describes basic matters in the processing of carbon steel pipes for piping, rigid
polyvinyl chloride pipes, and rigid polyvinyl chloride-lining steel pipes for water supply.

6.2.1 Processing of Carbon Steel Pipes for Piping
Typical joining methods for carbon steel pipes for piping include screw, welding, and mechanicaljoining methods.
(1) Screw joining method
This is a common joining method that has been used for a long time. Mainly used for 15A to 100A.
A represents the diameter of the pipe and is called A designation. The unit of measurement is in mm.
There is also B designation, which uses inches for the unit of measurement. The procedure is as follows.
(1) Pipe cutting
A band saw pipe cutting machine is used to fix the pipe horizontally, and to make a cut that isperpendicular to the pipe axis. If the cut is not made perpendicularly, it may result in angled cuts or
uneven cuts. Angled cuts of 1.0 mm or more or uneven cuts can cause water leakage.
GOOD!

BAD

Correct

Angled cut

BAD

Uneven cut

Correct and incorrect cutting ofsteel pipes(2) Threading (thread cutting)After the steel pipes are cut, the die head is attached to the pipe threader (with automatic die head)151

and the pipes are threaded. Wearing work gloves when threading may cause the hands to get entangled
in the threader. Never thread while wearing work gloves. After the threading is completed, theaccuracy of the threading is inspected with a thread gauge. Inspections are performed in these instances.
- On a minimum of first three threaded pipes- When the threaded pipe diameter is changed- According to the number of threaded pipes (e.g., for 25A, one in every 50 pipes or so)- When the lot (mainly different manufacturing dates) or the pipe manufacturer of the pipes to bethreaded has changed- When replacing the chaser (cutting tool on the threading head)(3) Preparation before screwing inOnce the steel pipes are threaded, the screwing-in process begins. Insufficient cleaning anddegreasing of screw joints can also cause water leakage, so the following preparatory work is necessary
before screwing in.
- Remove shavings, dirt, dust, and other foreign matter on the threads of the steel pipes and fittings
with a brush or rag.
- Remove oil, such as threading oil, with a degreasing cleaning agent.
- Wash away water-soluble threading oil with water, wipe with a rag, and dry.
- Never use screws that have rust on the threading.
After the preparatory work is completed, the pipes are screwed in, but before they are screwed in, asealant is applied to the screw threads. There are two types of sealants: liquid sealant and sealant tape.
(4) When using liquid sealant
Before applying the liquid sealant, thoroughly wipe off any moisture, oil, dust, etc. on the joint
surfaces once again. Stir the sealant well before use. Apply the required amount with a brush to theentire threaded portion of the pipe and fitting. Apply carefully and evenly. After using the sealant,remove any sealant from the threads of the sealant can when putting back the cap with brush before152

closing it tightly and storing in a cool, dark, well-ventilated place. In case of contact with eyes, rinse
with plenty of water and seek medical attention as soon as possible. Contact with skin may cause
irritation in some people, so wash off with soap and water.
(5) When using the sealant tape
The sealant tape is wrapped around the side to be screwed in. Since the direction of screwing isclockwise, the sealant tape is also wound clockwise. First, go around once while pressing down on thethreads and the sealant tape with your fingers. At this time, there should be about one ridge of thethreading still visible. Wrapping without leaving a ridge of threading visible may cause the sealanttape to go inside the piping. The tape should be wound about 6 to 7 times. After wrapping, use yourfingers or fingernails to better adhere the tape. Failure to do so will cause the tape to peel off during
screwing-in. The sealant tape should be wound so that the tape is pulled from the underside of the reelwhen brought to the top of the threading. Pulling from the top in this position is wrong. It is correct toleave about one ridge of the threading visible. If the tape completely covers the threading, pieces ofthe sealant tape will end up in the piping when the joints are screwed in. This can also cause the joint
to not fit smoothly.
(6) Screw-in
After the sealant is applied or wrapped, the joints are screwed in. Fix the piping properly onto thebench vise, and first, screw it into the fitting by hand. After it cannot be tightened any further by hand,use a pipe wrench with an appropriate diameter to screw it in further. Be careful not to screw in so
hard to the point of destroying the threads. The trick to the screw-in method of pipe joints is to use apipe wrench to screw in the pipe, leaving about two to two and a half ridges of the threading. Water
should be allowed to flow through the piping only after sufficient curing time has elapsed aftertightening.

(2) Welding joining method
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Welding joining methods for carbon steel pipes for piping include welding and mechanical joining.
The welding joining method is often chosen for large-diameter pipes of 100A or more and is a reliablejoining method in terms of joint strength, but it requires a high degree of skill. There are two types of
welding joining methods: gas welding joining and shielded arc welding joining.
[Gas welding joining method]
There are three methods to weld metals using heat from gases: oxyacetylene welding, oxyhydrogenwelding, and air-acetylene welding. The most commonly used of these is the oxyacetylene welding.
Gas welding is a welding method often used to weld small diameter pipes.
[Shielded arc welding joining method]
The shielded arc welding joining method, along with gas welding joining methods, is widely usedin piping work. The shielded arc welding method uses a welding rod coated with a solvent called flux
to minimize weld oxidation and other disturbances as much as possible. The combustion of the flux
shields the molten metal from air during welding. For either welding method, the process is as follows.
(1) Pipe cutting and processing of the cut
As with the screw-in method of pipe joints, steel pipes are cut perpendicularly to the pipe axis.
However, when welding joints, it is necessary to chamfer the pipe ends after cutting to improve theweld quality. Without chamfering, insufficient fusion occurs, affecting weld quality.
There are four typical types of bevels for pipe welding: square V butt, square V butt with broad root
surface, single bevel butt, and square butt (also known as dontsuke kaisaki).
Single bevel butt

Square V butt

Square butt

Square V butt with broad root surface

Typical bevels154

(2) Temporary welding
Before the main welding, a temporary welding is conducted to fix the welds in the correct mutual
position and to prevent misalignment of the bevel due to distortion of the weld.
(3) Main welding
The work to weld the entire circumference of the piping, performed after temporary welding.
Welding operations are performed by welders under a variety of conditions. To consistently achieve
good results, it is important to have sufficient experience in welding operations and to avoid creating
welding defects.

(3) Mechanical joining method
Also called mechanical joining method. Pipes are joinedusing housing pipe fittings, bend fittings, coupling fittingsand no-hub fittings.
Example of a housing pipe
fitting

6.2.2 Processing of Rigid Polyvinyl Chloride Pipes
Rigid PVC pipes are processed in the following steps.
(1) Pipe cutting
Pipes are cut perpendicularly to the pipe axis. If the cut is not straight, it will create parts that arecompletely inserted and parts that are not quite inserted when gluing, causing water leakage.
(2) Chamfering
Once the pipe is cut, both the inner and outer parts are chamfered with a box cutter so that it can beeasily inserted into the fitting. The outer part affects gluing, but also if burrs remain on the inner wall,they can cause plugging. Pipes for water supply and hot water are difficult to insert, so make sure tochamfer them well, especially the outer part.

155

(3) Marking the insertion depth
To confirm that the pipe is fully inserted into the fitting, mark the depth of insertion on the pipe side.
Inadequate insertion will cause the overall length to deviate from the plan, or it may cause leaks.
(4) Applying an adhesive to the pipe and the fitting
Wipe off any moisture or dirt from the surfaces to be coated, and apply the adhesive to both the pipe
and the fitting. The following are some things to keep in mind while coating.
> Apply thinly and evenly to the entire surface, starting with the fitting (because the pipe cannot be
put down after application)> Apply evenly only to the portion of the pipe to be inserted> Apply the coats as quickly as possible> Adhesive may drip, so protect your work area with rags, etc.
(5) Inserting the pipe into the fitting
Align the pipe with the mouth of the fitting and insert it all the way in one go, applying force. Oncethe pipe is inserted up to the mark, continue to apply force inward for about 10 seconds until theadhesive dries.
(6) Wipe off the excess adhesive
Wipe clean any adhesive that is pushed out after insertion. Not doing so will compromise theappearance, and if it drips, it will be difficult to remove later.

156

6.2.3 Processing of Rigid Polyvinyl-Chloride Lining Steel Pipes for Water Supply(1) Pipe cutting

Pipe cutter blade

Same as with other pipe materials, these pipes are cut

Outer wall of the copper pipe

perpendicularly to the pipe axis. Care must be taken to neverchoose a method that creates high temperatures in the cut
surface, such as gas cutting with oxyacetylene. In addition, using

Burr

Example of burra manual cutter and threader causes makure (burrs) to form, soother pipe cutters such as a band saw or metal saw are used to cut the pipe.
(2) Deburring
After the pipe is cut, deburr the inner wall of the pipe using a deburring reamer for line pipes or a
scraper. Do not deburr with a threader reamer. After deburring is completed, chamfer about 1/2 to 2/3of the PVC pipe wall thickness in order to connect to the pipe-end anticorrosion fitting.
(3) Threading
Threading is done in the same manner as for carbon steel pipes for piping, but if the pipe has anouter resin coating, threading is performed using a jig and tool that will not damage the outer resin
coating.

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6.3 Freezing and Air Conditioning Apparatus Work6.3.1 Processing of Coated Copper Pipes for Refrigerant
Between the outdoor and indoor units of an air conditioner, refrigerant, which transfers heat,circulates through pipes. Coated copper pipes for refrigerant are used for this purpose. Hifuku meanscovered by something. Coated copper pipes for refrigerant are
Insulation material

bendable and processed copper pipes covered with flameretardant insulating material (such as polyethylene). If left asis, condensation occurs on copper pipes depending on theoutside temperature, and in order to prevent this, they are
Copper pipe

covered with insulation material. Plumbing for freezing and air

Coated copper pipe forrefrigerant

conditioning apparatus work requires the following processing
and joining of coated copper pipes for refrigerant.
(1) Cutting the insulation material
The insulation material is cut perpendicular to the copper pipe using a box cutter. Be careful not todamage the copper pipe as this may cause gas leaks.
(2) Copper pipe cutting
Set the pipe cutter at a right angle on the copper pipe, and rotate it around the pipe while graduallytightening the hold to cut the pipe without deforming it. Never use a hacksaw or grinder for cutting,because shavings will remain inside the copper pipe.
(3) Deburring
Copper pipe cut with a pipe cutter will have makuri (burr) on the inner wall. Smoothing this out
allows smoother flaring process. Make sure to use designated tools such as reamers and scrapers forthis operation. When deburring, the copper pipe should face downward to prevent shavings and otherdebris from entering the copper pipe.
(4) Correcting roundness158

After deburring, be sure to correct the roundness with a sizing tool for refrigerant pipes or othermeans. If flaring is performed without a perfect circle, problems such as the center of the pipe being
off-center, the fitting not going in during the brazing operation, poor wax coating, etc. may occur.
(5) Bending
Coated copper pipes for refrigerant are bent to site specifications. Bending can be done by hand or
by a bender. The three points to keep in mind when bending are: do not let the pipe flatten, buckle, or
wrinkle.
[Bending by hand]
Place both thumbs on the inner side of the bend location, and bend it while gradually shifting the
thumbs toward the ends of the pipe. The minimum bending radius is six times the outer diameter forcopper pipes with an outer diameter of 6.35 to 12.7 mm, and ten times the outer diameter for copper
pipes with an outer diameter of 15.88 mm and above. The pipe should be bent a little at a time.
Flattening or buckling will occur if the pipe is bent too fast and too much, or below the minimum
bending radius.
[Bending by a bender]
To make the bend radius small and clean, use a bender appropriate for the quality and wall thicknessof the copper pipe. The minimum bending radius can be as small as 4 times the outside diameter ofthe copper pipe. The key is to avoid wrinkles.

6.3.2 Connection of Refrigerant Pipes
Two types of refrigerant pipe connection are flare and brazed connections.
(1) Flare connection

159

Flaring is a process that widens copper pipes into a

Flare nut

Flared part

trumpet shape. By tightening the flare nut, the flared
portion is crimped and acts as a seal.
Flare connection(2) Brazed connection
This is a method of connecting by melting wax andblending it into the faces to be connected. It is important that

Brazed point

there be no oxide film or foreign matter on the surface, andthat the proper brazing temperature is ensured. After
brazing, the pipe is hot, so cool it with a wet towel and check

Brazed connection

the appearance for pinholes or poor brazing.
(3) Connecting the insulation material
The insulation material shrinks by a maximum of about 2% in the longitudinal direction (about 8
cm per 4 m). Since condensation from gaps caused by shrinkage of insulation material may lead to
accidents, measures should be taken to prevent gaps. Prepare the connection surfaces on the ends bythoroughly removing dirt, grease, moisture, etc. Once the connection surfaces are prepared, butt theinsulation material end faces together so that there are no gaps between them, and wrap insulation tapewith the joint at the center line of the tape. Then, adhere the tape thoroughly by hand.

160

6.4 Heat/Cold Insulation Work6.4.1 Shapes and Types of Insulation Material
Insulation material is available in various shapes of heat-retention
tubes, heat-retention strips, and heat-retention plates. Plates andstrips are used for ducts, and tubes are used for piping. Mainly usedinsulation materials include glass wool (GW), rock wool (RW), andpolystyrene foam (PS). In addition, it consists of exterior materials
such as colored steel plates and aluminum glass cloth, and auxiliary

Chicken wire meshmaterials such as steel wire, chicken wire mesh, adhesive tape, andtacks. The method of insulation work depends on the work location.

6.4.2 Example of Heat/Cold Insulation for Piping(1) Concealed areas such as above the ceiling
Since appearance is a non-issue above the ceiling or inside the pipe shaft, no finishing materials areused. The insulation tube is wrapped in aluminum glass cloth (ALGC) or aluminum craft paper (ALK)and fixed to the pipes.
(2) Piping exposed indoors
For exposed piping indoors, such as in rooms and corridors, pipes are generally covered withsynthetic resin covers or lagging materials.
(3) Machine rooms, garages, warehouses, etc.
The insulation tubes are wrapped in aluminum glass cloth (ALGC) or aluminum craft paper (ALK).
If iron wire is used for finishing, it should be finished with PVC coated iron wire (PVC coated chicken
wire mesh) to prevent the iron wire from rusting. In the case of water supply and drainage piping,polystyrene foam insulation (PS) is used as insulation material.
(4) Piping exposed outdoors
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Since high weather resistance is required for outdoor exposed areas, the insulation tube is covered
with lagging material made of thin steel sheets processed by sheet metal work. In humid areas, theinsulation tube should be moisture-proofed with polyethylene film or similar material.

6.4.3 Example of Heat/Cold Insulation for Ducts
Heat and cold insulation work for ducts is done to prevent heat dissipation from the ducts and toprevent the air in the ducts from being heated by heat from the outside. Wrapping ducts with insulationmaterial can increase the efficiency of heating and cooling, saving energy. In addition, air conditioning
ducts without insulation work are prone to condensation.
Condensation inside and outside of ducts can cause corrosion andmold. For heat and cold insulation of ducts, insulation panels withcoated aluminum and craft paper or insulation panels withaluminum glass cloth are fixed to ducts with tacks, aluminum glass
cloth adhesive tape or chicken wire mesh. In outdoor exposed areas,
ducts should be covered with a frame made of stainless steel plate

Insulated ducts

or the like, if necessary.

6.5 Lifeline Infrastructure Plumbing Work6.5.1 Waterworks—Ductile Iron Pipe Installation
Japan experiences frequent earthquakes. Therefore, ductile iron pipes, which can protect pipes
against earthquake damage, are used. There are various types of ductile iron pipes, but GX-type ductile
iron fittings are used relatively frequently in Japan.

162

GX-type ductile iron fitting is an earthquake-resistantGX-type ductile iron fitting

fitting. This fitting has a large expansion and contraction
capability and a function to prevent the pipe from slippingout. The fitting expands, contracts, and flexes in response
to large ground movements during earthquakes. Even whenstretched to its limit, the anti-detachment function of the

Lock ring holder

Lock ringfitting will maintain the function of the piping.
The distance between the pipes will be the dimension
for possible expansion and contraction. In the event offurther elongation, the lock ring and the projection of the
spigot inside the fitting will catch and prevent the pipe

Projection of
spigotRubber gasket

Cross-sectional view of GX-type ductile
iron fittingfrom slipping out. Ductile iron pipes are joined as follows.
(1) Pipe installation
Gently lower the suspended pipe with the manufacturer's mark on the top side.
(2) Pipe cleaning
Remove any foreign matter from the groove of the socket, the area approximately 30 cm from the
spigot edge, and the socket circumference. In addition, wipe off any water from the surface where therubber gasket is to be attached.

(3) Checking the lock ring and lock ring holder

The lock ring and lock ring holder are pre-set. Check visually and by touch to see if they are properly
located in the specified groove of the socket. If an abnormality is identified, such as not being properly
placed in groove, use lock ring pliers to squeeze the split parts and so that it fits correctly in the groove
above the lock ring holder.
(4) Setting the rubber gasket
Be sure to check that the rubber gasket is labeled for GX type and of the correct nominal diameter.
Clean the rubber ring and place it inside the socket with the angled portion facing forward. Then,
163

attach it in place while pressing it by hand or a plastic hammer to ensure that there are no gaps. Afterinstallation, tap the rubber gasket with a plastic hammer to let it settle into the inside of the socket.
Further, feel the inner surface of the rubber gasket with fingers to confirm that there are no lifted parts.
(5) Applying lubricant
Use the lubricant specifically made for ductile iron pipe fittings. Apply the lubricant evenly to thetapered inner surface of the rubber gasket and the outer surface of the spigot, from the white line hear
the pipe end to the end of the pipe. Lubricant should not be applied to the inner surface of the socket
before setting the rubber gasket.
(6) Inserting the spigot
Suspend the pipes by a crane, etc., and lightly place the spigot at the mouth of the socket. At thistime, make sure that no stones, pieces of wood, or other foreign objects stick to the rubber gasket or
the spigot. Also, make sure that the angle of the two pipes are 2 degrees or less. Operate the lever hoist
and slowly insert the spigot into the socket. Of the two white lines marked on the outside surface ofthe spigot, align the end of the socket within the width of the white line closer to the socket.
(7) Checking the rubber gasket position
Check the rubber gasket position using a special check gauge. A special check gauge is used tomeasure the amount of penetration over the entire circumference of the gap between the socket andthe spigot to confirm that everything is within the acceptable range. If the entire circumference iswithin the acceptable range, the amount of penetration is measured for eight points of thecircumference and noted on the check sheet. The check sheet is a quality control document for ductile
iron pipe joining. Write down the entire joining operation.
(8) Procedure to bend piping
Straight pipe fittings can be bent to the allowable bending angle after joining. After verifying thatthe joint is correct, bend the fitting slowly, within the allowable bending angle. Instead of bending one
fitting to the allowable bending angle, bend several fittings until the desired angle is reached.
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6.5.2 Waterworks and Gas—EF Connection
Polyethylene pipes for water and gas distribution are lightweight, flexible, corrosion resistant, andhygienic pipes used for water and gas piping. In addition, this pipe material demonstrates durability
during emergencies such as earthquakes and land subsidence. Pipe material and fittings are blue forwater and yellow for gas.
Connector

In joining polyethylene pipes, there are two
methods:

electrofusion(EF)joining

Indicator

Terminal pin
Controller

andmechanical joining. EF joining is a joining
method in which the electric heating wire isheated to melt and fuse the inner wall of the pipe

EF socket

Polyethylene pipes for watersupplyfitting and the resin on the outer wall of the pipe

Electric
heating wire

EF connection of polyethylene
pipes

into a single piece. After setting a pipe (spigot)

into a pipe fitting (socket) with an electric heating wire embedded in the face to be joined, thecontroller energizes the wires to heat them.
EF joining is performed in the following steps.
(1) Pipe cutting
Cut the pipe so that the end of the pipe is perpendicular to the pipe axis. The allowable limit for
diagonal cutting of pipe is within 5 mm, regardless of the nominal diameter. Cutting tools that use
high-speed grinding wheels should not be used because their heat may deform the cut surface.
(2) Preparing the EF socket
Inspect the pipe for damage, then wipe off any soil or dirt from the pipe with paper towels or a clean
rag. Measure from the end of the pipe and draw a marker line at the specified insertion length.
(3) Scrape
Using a scraper, scrape the surface of the pipe from the end of the pipe to the marker line.
(4) Cleaning of fusion surface
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Clean the entire scraped surface of the pipe and the inner wall of the EF socket with a paper towelsoaked in ethanol or acetone.
(5) Marking
Insert the scraped and cleaned pipe into the socket and mark the pipe along the circumference of thesocket end.
(6) Inserting and joining the pipes and the fitting
Insert both pipes into the EF socket to the marked line. Then, use clamps to secure the pipes to the
EF socket.
(7) Preparing for fusion
Connect the controller power plug into an electrical outlet.

Preparation for EF
fusionTurn on the switch. Then, connect the output cable to theterminals of the fitting. Use the barcode reader attached to thecontroller to read the fusion data.
(8) Fusion
Press the start button on the controller to start energizing. Energization stops automatically.
(9) Inspection
Check that the EF socket indicators, both left and right, are pushed up. Confirm the controller
display that it has finished the process successfully. Then, remove the output cables and attach thecaps.
(10) Cooling
After fusion is completed, leave the product for a predetermined amount of time to cool. Remove
the clamps after completely cooled. Use the check sheet to note the check items for each fusion point.

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6.5.3 Precautions in Telecommunications Work
(1) Underground conduit
Where expansion or contraction of the conduit is anticipated, use fittings that expand and contract,
or other means to make connections.
(2) Cabling
Route the cable so that there is extra length of cable at the handhole near the cable pull-in and pullout ports.
(3) Optical cable underground wiring
At the handhole, secure enough length of optical cables at both the connection and pull-throughsections to prevent disconnection caused by cable kinks when the cables are moved during a disasteror similar events.

6.5.4 Precautions for Underground Piping Work
(1) Damaging or cutting existing underground pipes during excavation
During underground piping work, care must be taken to avoid damaging or cutting existingunderground pipes. Accidents involving damaging or cutting underground pipes, such as water, sewer,gas, communication, and electric conduit pipes, disrupt the lives of residents not only at theconstruction site but also over a wider area. Accidents involving damaging or cutting undergroundpipes can be caused by the following.
> Failure to follow instructions> No/inadequate exploratory survey> The location of the underground pipe differed from the drawing> Insufficient confirmation of ledgers, etc. before commencing work
> There was no entry in the road ledger> Failure to check the shape of piping bends, risers, etc.
167

> It was an underground pipe in a shallow area
> Failure to mark buried objects on the road
> Other
It is important to exchange information among the respective contractors to accurately determine
the location of existing underground structures. Prior to the start of construction, a thoroughexploratory survey will be conducted. During excavation, a steel pipe and cable detector will be used
to detect the location of existing underground pipes and conduits. If a backhoe or other machine isused for excavation, excavation should be done by hand within 50 cm around the existing undergroundpipes. Looking at accidents by type, more than half are caused by backhoes, but note that there arealso cutting accidents during excavation by hand. To prevent accidents, Underground Object
Identification Sheets as shown in the table below will be placed between underground objects and theground surface.
Color legend for Underground Object Identification Sheets

Type of buried

ColorType of buried

Color legend

equipment

legendequipment

Communication cable

Red

Sewer pipes

Brown

High-voltage and low-

OrangeGas pipes

Green

Blue

-

-

voltage power lines
Water pipes(2) Disasters related to manholes
Many disasters related to work in manholes are caused by anoxia and sulfide poisoning. Persons who
can enter manholes are those who have completed Class I and Class II skill training courses for oxygen
deficient danger operations supervisors or special
education for work at the place of an oxygen-deficient
danger. Measure oxygen and hydrogen sulfide
concentrations, and ventilate the work area so that theoxygen concentration is at least 18% and the hydrogen
168

Inside a manholesulfide concentration is less than 10 ppm. If ventilation is not possible, workers must wear airpurifying respirators and a monitor must be assigned. Falling accidents from ladders also occur due tolack of oxygen. In areas where there is a possibility of oxygen deficiency, even if the height is lessthan 2 meters, fall arrest devices should be worn. Because construction and work related to manholes
often take place on busy roads, accidents with passing vehicles can also occur. Enclosures (manhole
shields) and other security facilities will be installed around manholes, and flaggers will be posted
around the manholes.

6.6 Architectural Sheet Metal Work6.6.1 Sheet Metal Processing
Architectural sheet metal work involves cutting, bending, punching, welding, and otherwise
processing thin metal sheets to create components that meet the intended use and install them. This
work is needed in a wide range of areas, including plumbing and roofing. The basic operations required
to process steel plates are scribe marking, cutting, bending, and welding. When making products withcomplex shapes, a technique called hammering is required. This is a task that requires high skill andtherefore it will be omitted here.
(1) Scribe marking
Scribe marking is done in a single step as much as possible, using scribing needles, dividers, andmetal rulers. When making several of the same item, gauges are made for efficiency.

Scribe marking

169

(2) Cutting
The sheet metal is cut carefully, lifting the part to beretained by hand so that the scissors can easily enter.
Keep the eyes on the scribe lines and continue to cut
along the scribe lines. Cut edges are smoothed with a

Cutting

metal file.
(3) Bending
Using kage tagane (wide chisel) and a hammer, thesheet metal is tapped from the back side along thescribe line. This way, the surface can be bent slightly
Bendingin the desired direction. Next, using an anvil or thecorner of a platform called surface plate as dollies, the piece is gradually bent to the required angle bytapping it with a hammer.
Using the corner of a platform called surface plate as a dolly, the piece is gradually bent to therequired angle by tapping it with a hammer.
(4) Welding
The welding method most commonly used in sheet metal welding is the fusion welding method, inwhich a filler metal (welding rod or wire) is melted to make the joint. Secure overlapping parts using
clamps. Next, temporarily attach the joints at a 10 mm pitch. The key to this welding is to melt thewelding rod while maintaining a set distance between the parts and the fire. This work requires
concentration and is therefore performed in a comfortable position.

6.6.2 Duct Connection Method(1) Connection of square ducts
Angle flange and slip-on flange methods are available for connecting square ducts.
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[Angled flange method]
Because of its superior connection strength and airtightness, it is often used for smoke exhaust ducts,
etc. However, it is not often used for other duct connections because of the labor-intensive installation
process.

[Integral flange method]
A portion of the duct is bent to make a flange (integral flange), the integral flanges are joined
together, and the four corners of the duct are secured with special clips. Compared to the angle flange
method, this method requires less work to make flanges and is easier to install, and this is why it isoften used for ducts other than smoke exhaust.
GasketAngle flange

Integral flange

Cleat

Bolt
Gasket
Rivet

Duct
Duct

Integral flange method

Angle flange method[Slip-on flange method]
A pre-made flange is inserted into the duct and spot-welded, then tightened with bolts and nuts at
the four corners, and the flange is held together with special hardware called cleats. This method ismore efficient to manufacture than the angle flange method, and is easy to install, requiring only bolts
at the four corners. It is stronger than the integral flange method and can be considered an intermediate
method between the integral flange method and the angle flange method.
(2) Connection of round ducts
Connection methods for spiral ducts and other round ducts include the flange method and the nipple
connection method.
171

[Flange method]
A flange collar is inserted into the spiral duct, and the flanges are fixed to each other with bolts andnuts. Plate flanges are used for small ducts with diameters of 75 to 100 mm, while angle flanges areused for ducts with diameters of 200 mm or more. This method is suitable for connections that require
high strength.

[Nipple connection method]A spiral duct is connected by inserting a special fitting called a nipple into the duct, securing it at
two or three points with steel plate screws (self-drilling screws), and wrapping duct tape around it
from the outside. This connection method is relatively easy and widely used. When fixing ducts andnipples with steel plate screws, do not drive the screws directly under the ducts so as to prevent waterleakage in case water flows into the ducts.

6.7. Electrical Work
The scope of work for electrical work technicians is broad and includes piping, wiring, installationof fixtures, and installation of electrical equipment. This work characteristically uses many different
types of tools and equipment. Be careful to avoid electric shock and leakage current while working.

172

6.7.1 Precautions in Working with High-Voltage Substations
6600V electricity drawn from the power company, etc. is supplied to cubicles installed on thepremises, in the basement or on the roof of the building via PAS (Pole Air Switch, a high-voltage airinsulated switch) installed on the poles (in the case of overhead wiring). In cubicles, the received
6600V is converted to 100V or 200V. Inside, there are disconnectors
and circuit breakers to shut off electricity. To prevent industrial
accidents when working with high-voltage substations, it isfundamental to open the PAS and work while de-energized, including
cubicles. When a disconnector or circuit breaker is opened, electricity
is still flowing to the primary side of the open section. It is very
dangerous to work with an active wire (energized) on the primary side,
as it may cause a direct electric shock or an electric shock accident due to electrical discharge.

6.7.2 Short-Circuit, Ground Fault and Leakage Current
A short circuit (also called a short) is when two or more wires from two- or three-phase circuit comein contact with each other, bypassing the load. Short-circuit occurs when the wire is cut while live.
Also, wiring errors and metal parts of tools such as screwdrivers may cause short circuits.
A ground fault is when the electric current flows to the ground. The power line must be insulated
from the ground. A ground fault occurs when the grounding is done with the wrong polarity.
Leakage current occurs when the current, flowing through the intended circuit, also flows to whereit should not. This can cause electric shocks to people, fires, etc. If a building or apartment building isequipped with an earth leakage circuit breaker or ground-fault alarm, leakage current can cause theelectric circuit to be interrupted or set off an alarm. Make sure to exercise caution during renovation
projects.

1736.7.3 Precautions in Crimping Wires
Poor crimping of wires can lead to accidents caused by heat or sparks. Using a crimping tool, firmly
crimp the center of the sleeve of the crimp terminal. Also, make sure to use crimp terminals that arecompatible with the wire thickness. Note that not only the wire but also the crimp terminal itself has
an ampacity rating.

6.7.4 Damage to or Disconnection of Existing Underground Pipes and Overhead
Wiring(1) Cutting of existing underground pipes during excavation of a cable trench
A cable trench is a facility for housing above-ground utility poles and overhead power lines in anunderground space. This work is done to improve landscaping and make the roads easier to navigate.
Preliminary investigation and temporary work is required for the construction of the cable trenchbecause of the possibility of accidental cutting of existing lifeline infrastructure such as water, sewer,gas, communication, and electrical conduit pipes. For precautions in construction, refer to 6.5.4
Precautions for Underground Piping Work.

Cable trench174

(2) Accidental cutting of overhead wires
There are examples of accidents involving cutting ofoverhead wiring by construction machinery boom movements,
raising the dump truck bed, and when loading and unloading
construction machinery from construction machinery haulingvehicles. You may be asked by other contractors to install cable covers to protect overhead cables.

6.7.5 Precautions for Road Use
When working on the road, pay attention to relevant laws and regulations. General precautions are
as follows.
> The person in charge of the work will carry a road use permit. In addition, the conditions of thepermit (working hours, working conditions, etc.) should be observed.
> Security facilities are set up at the construction site to prohibit the entry of people who are not
involved in the construction.
> Traffic control personnel will be positioned to ensure that the flow of traffic is not impeded.
> Measures will be taken to ensure safe passage for pedestrians.
> Efforts will be made to minimize noise, vibration, and other impacts on nearby residents.
> When workers leave the site, excavated surfaces
should not be left as they are; they must be
backfilled or covered. If holes are to remain as
they are, security fences will be installed.
> When temporarily placing objects on the road,secure them or install security facilities aroundthem to prevent them from being scattered or
moved.
175

Construction work to eliminate
utility poles

> Caution lights should be placed to indicate the width and height of the installation site at night.

6.8 Telecommunications Work6.8.1 Types of Telecommunications Facilities
Telecommunications facilities are divided into wired communications facilities, wirelesscommunications facilities, telecommunications civil engineering facilities, switching transmission
facilities, and power facilities for communications. This section describes wired communication
facilities and telecommunication civil engineering facilities.
(1) Wired communications facilities
A network of wired transmission lines to provide telecommunications services is called accesssetsubi (access facilities).
Access facilities are divided into outdoor and indoor, and outdoor facilities are further divided into
overhead and underground. Overhead facilities are facilities attached to utility poles. The following
facilities are installed.
Overview of access facilities

Optical cable
LAN cable
Modular cable

Optical fiber
closureCommunications
building

Router (ONU)
Fiber optic outlet

Personalcomputer

Telephone

Utility pole
Conduit

Manhole[Hikari fiber cable] (fiber-optic cable) These cables pass optical signals.
[Metal cable] Cable used in communication equipment. Fiber-optic cables communicate using opticalsignals, while metal cables communicate using electrical signals.
[Closure] A box-shaped device installed at the splices or branching points of fiber-optic or metal
176

cables. Closures may be color-coded with gray for fiber-optics and black for metal cables.
[Hikikomisen] (service cable) This is the cable that draws communication lines into homes.

There is required ground clearance for overhead facilities to ensure safety. When it is over a road, aminimum of 5 meters must be maintained.

*Procedure for erecting poles
The poles are erected according to the following procedure.
1) Identify the location where the pole will be erected.
2) Check for buried objects by hand-digging or using a probe stick.
3) Excavate by hand and a pole-setting truck.
4) Erect the pole.
5) Backfill.
(2) Telecommunications civil engineering facilities
Telecommunication civil engineering facilities include conduits, manholes, handholes, cabletunnels, joint trenches, and cable trenches.
[Kanro] (conduit) This conduit connects manholes, handholes, cable tunnels, and riser poles. As ageneral rule, this refers to a pipe that has been drawn in and laid so that one section of cables can bepulled in or out without excavation.
[Manhole] A structure to provide underground access from above ground for cable pull-in, pull-out,
and connection work.
[Handhole] A small manhole provided at the junction of underground piping. Cable maintenance isperformed without people going inside.
[Todo] (cable tunnel) A tunnel to house various cables for telecommunications.
[Kyodoko] (joint trench) An underground structure in the form of todo (cable tunnel) where two or177more facilities such as telecommunications, electricity, gas, water, and sewage are accommodated.
[C.C.BOX] (cable trench) U-shaped structure to house communication and power cables as well as
power supplies for information transmission, broadcasting, road management, etc. It is set up underroads, and the U-shaped ditch is covered.

6.8.2 Installation of Underground Conduits(1) Soil cover thickness and slope of the conduit
The soil cover thickness of a conduit is the distance from the surface of the road to the top of the
conduit. The Order for Enforcement of the Road Act stipulates that, as a general rule, the thickness
should not be less than 0.8 m under roads and 0.6 m under sidewalks. The slope of a conduit is theslope of the conduit between manholes. The slope is set so that water and sediment can flow inside theconduit without stagnation.
(2) Clearance distance from underground facilities managed by other agencies
The standard clearance distances between conduits and electric, gas, water, and sewage lines are
determined as shown in the table below.

Horizontal
distance
when parallel
Verticaldistance
when crossing

Track (JR, private
railway)
1.0 m or more

1.5 m or morePowerline
Low/high voltage: more than 0.3m
Extra-high voltage: exceeding
0.6 m

Water, gas, others
0.3 m

0.15 mWhen telecommunication conduits and underground facilities managed by other agencies intersect
in close proximity, they should be constructed according to the above table, with the necessary
protection methods, after requesting the attendance of the respective managers and obtaining theirapproval.

178

(3) Various tests after conduit installation
After conduit installation, the following two tests are performed.
[Mandrel tsuka shiken] (mandrel test) A test to inspect whether the conduits are completely
connected. It is conducted by passing through a stick called a mandrel. In conduits longer than 150 m,
a mandrel with a diameter of 600 mm is passed through. If the 600 mm mandrel cannot pass througha conduit shorter than 150 m, a mandrel with a diameter of 300 mm is passed through the conduit.
[Kimitsu shiken] (airtightness test) The pressure in the conduit is set to 49 kPa and left for 3 minutes
to confirm that the pressure drop is less than 1.96 kPa.

6.8.3 Precautions during WorkSee separate sections for more information.
- Precautions for excavation work → 6.5.4- Precautions for work on manholes, cable tunnels, etc. → 6.5.4- Precautions for road use → 6.7.5

6.9 Furnace Installation
Furnace construction refers to the construction of the inside of the incinerators, annealing furnaces,
cremation furnaces, melting furnaces, electric furnaces, etc., where high temperatures are generated,using refractories. Different types of furnaces require different construction methods and techniques.
For example, if refractory bricks are used as the refractory material, bricklaying techniques are
required. The bricks used in the furnace are refractory bricks and refractory insulating bricks. The
mortar used to bond the bricks is also different from ordinary mortar; mortar made for refractory
insulating bricks. There are two types of mortar for refractory insulating bricks: heat setting refractorymortar (bakes and hardens at high temperatures) and dry air setting refractory mortar (hardens in air

179

at room temperature).
The work proceeds in the following order: layout marking, temporary enclosure erection, andbrickwork. Laying refractory bricks (brickwork) requires the highest level of skill among furnacematerials. When laying bricks, there are six things that must be observed.
> Use materials correctly.
> Make sure the dimensions are accurate.
> Apply enough mortar and make the joints uniform.
> When laying bricks to create a flat wall, make sure to stagger them.
> Do not use small bricks broken into 1/4 or less of the normal length.
> Brickwork should always be based on level and perpendicular references.

6.10 Fire Fighting Equipment Installation
Firefighting facilities are not operated in normal times; it ismostly used only during emergency situations. For waterbased hydrants, it is sometimes necessary to operate the pump
to deliver water even when there is no water in the piping on
the discharge side of the pump. For this purpose, unlike pumps
for water supply facilities, etc., a pump primer, overflow
piping to prevent water temperature increase, and performance

Part of the fire pumpequipment

test equipment are installed.
(1) Installation of a pump primer
If there is no water in the pump itself or if there is an air pocket, the pump will not be able to pumpwater even if it is operated. If the water source is lower than the pump, install a pump primer to prevent
this.
(2) Installation of overflow piping to prevent water temperature increase180

If the pump is operated when the pump discharge is closed, the pump continues to just rotate. If left
to rotate, the pump will overheat and stop. To prevent this, an overflow piping to prevent watertemperature increase is installed.
(3) Installation of performance test equipment
Performance test equipment is installed to determine if the pumps are capable of performing as
specified.
(4) Material used for piping
Piping may also be subject to high temperatures from flames when there is no water in the pipe.
Metal pipes lined on the inner wall should not be used because the lining material may melt and harden,
making it impossible to deliver water.

181

Chapter 7: Safety during Construction Work
7.1 Fatalities in Construction WorkA variety of industrial accidents occur at construction sites. Table 7-1 shows the number of fatal
industrial accidents in the construction industry in 2021 by major accident type, based on the data
released by the Ministry of Health, Labour and Welfare. Among the various types of industrial
accidents that occur, fall from heights, accidents involving construction machinery and cranes, andcrumbling/collapsing are the three major accidents in the construction industry, accounting for 4070% of all accidents. Most of the struck-by and caught-in/between/entanglement cases in the tablebelow are accidents involving construction machinery and cranes.
The most common of the three major disasters is fall from heights, occurring while working in highplaces. Aside from the three major disasters, the most common type of accident is traffic accidents that
occur while traveling on public roads. Chapter 7 describes the types and causes of accidents that occur
on lifeline infrastructure/equipment installation worksites, as well as countermeasures and how to bementally prepared.

Civil engineering work

Fall fromSlipping/tripping/falling/tippingheightsoverCrashing

Flying/falling

Crumbling/Collapsing

Struck-By

CaughtIn/Between/Entanglement

Contact with
Drowning

hot/cold
objects

Exposure tohazardous
substances,

Electric shocketc.

Traffic

Traffic

accident

accident(road)(other)

Total

19

5

1

4

13

11

15

9

4

3

2

10

1

102

Tunnel construction

0

0

0

0

1

0

0

1

０

0

0

1

0

3

Bridge Construction

1

0

0

0

2

0

1

2

０

0

0

0

0

6

Road Construction

3

0

1

1

2

1

2

0

1

0

0

5

0

17

River engineering work

1

3

0

0

1

1

1

2

0

1

0

0

0

10

Erosion-control work

2

0

0

0

0

1

0

0

0

0

0

1

0

4

Harbour/coastal

0

1

0

0

0

0

1

2

0

1

0

0

1

6

Other civil engineering

9

0

0

2

4

8

8

2

3

1

2

1

0

44

Building work

71

0

0

5

15

7

6

0

6

5

2

9

0

139

Steel frame and reinforced concrete houses

23

0

0

3

5

2

0

0

3

4

0

5

0

48

Wooden-frame house construction

12

0

0

0

1

1

0

0

0

0

1

1

0

19

Building equipment installation

8

0

0

0

2

0

0

0

0

0

1

2

0

16

Other building work

28

0

0

2

7

4

6

0

3

1

0

1

0

56

20

0

0

1

3

1

6

1

1

1

4

6

0

47

Telecommunications work

4

0

0

0

1

0

2

0

1

0

2

2

0

13

Machinery and equipment installation

4

0

0

0

1

0

0

0

0

0

0

0

0

6

Other constructions

12

0

0

1

1

1

4

1

0

1

2

4

0

28

110

5

1

10

31

19

27

10

11

9

8

25

1

288

Other constructions

Construction industry subtotal

Table 7-1 Fatal Industrial Accidents in the Construction Industry in 2021 by Major Accident Type(Compiled from the Ministry of Health, Labour and Welfare's Workplace Safety Website)182

7 .1 .1 Numbers of Fatalities in Construction
Table 7-2 shows the number of fatal accidents involving foreign workers in all industries in FY2020
and FY2021, as compiled by the Ministry of Health, Labour and Welfare. Table 7-3 shows that theconstruction industry has the highest numbers.
Accident Type
Fall from heights
Slipping/tripping/falling/tippingover
Crashing
Flying/falling
Crumbling/Collapsing
Struck-By
CaughtIn/Between/Entanglement
Exposuretohazardous
substances
Electric shockFire
Traffic accident (road)
Drowning
Other
Total

Number of fatalities
FY 2020
FY 2021
5
5
2

0

1
1
3
4

0
2
3
2

2

3

2

0

2
0
7
0
1
30

1
1
4
1
2
24

←Table 7-2 Occurrence of Fatal Accidents ofForeign Workers in All Industries

Industry Type
Manufacturingindustry
Constructionindustry
Other
Total

Number of fatalities
FY 2020
FY 2021
3

8

17

10

10
30

6
24

Table 7-3 Number of fatalities by industry[Tsuiraku/tenraku] (fall from heights) Industrial accidents caused by falling from high places,
falling down shafts during construction, or falling down a hole during excavation.
[Tento] (slipping/tripping/falling/tipping over) Industrial accidents caused by tripping over objects
or losing one's balance and falling.
[Gekitotsu] (crashing) Industrial accidents caused by a violent collision with something.
[Hirai/rakka] (flying/falling) Industrial accidents caused by loads being lifted by a crane falling, or
tools or materials falling from a high place.
[Hokai/tokai] (crumbling/collapsing) These are industrial accidents that occur when a scaffold
crumbles or a building under demolition collapses.
[Gekitotsusare] (struck-by) Industrial accidents caused by being struck by heavy machinery that is
running, by a circling bucket, etc.
[Hasamare/makikomare] (caught-in/between/entanglement) Industrial accidents caused by being
183caught or entangled in machinery.
[Yugaibutsu tono sesshoku] (exposure to hazardous substances) Industrial accidents that occur
when hazardous substances, such as chemicals, come into contact with the human body.
[Kanden] (electric shock) Industrial accidents caused by electric current flowing through the body,for example, by cutting an energized wire or touching a leaking device.
[Kasai] (fire) Industrial accidents caused by being caught in a fire started by a variety of factors.
[Kotsu jiko (doro)] (traffic accident (road)) Industrial accidents that occur while commuting to andfrom construction sites, and industrial accidents that occur when a worker is involved in a generalautomobile accident during construction work next to a road.
[Obore] (drowning) Industrial accidents that occur by falling into water in places where water ishandled, such as oceans, rivers, and sewerage works.

7.1.2 Types of Fatal Accidents(1) Fall from heights
To ensure safety when working at heights on steel towers, there is an idoyo rope (safety lanyard)that connects to the full-harness fall protection gear. Falling accidents are more likely to occur when asafety lanyard in use is removed and replaced with another safety lanyard. Keylock-type lanyards andfull-harness fall protection gear are designed so that the lanyard currently in use cannot be removed
until the next lanyard is inserted.
Overhead wiring uses aerial work platforms that provide a stable working platform, but leaning over
the railing can cause loss of balance and falling. Also, if there is no emergency stop device or operation
lever available on the working platform, a caught-between accident may occur.
Fatalities from falling from heights include falling into excavated holes. Falling can occur due toloss of balance, slipping, etc.

184(2) Traffic accidents (road)
Fatalities resulting from automobile accidents are a common occurrence in the construction industry
as a whole. Many traffic accidents occur while
commuting to construction sites, and some traffic
accidents occur when construction vehicles are travelingon public roads. Accidents include being hit by anothervehicle while loading or unloading goods on a public road, or a dump truck carrying a load of surplus
soil driving too fast and overturning on a curve.
When working on public roads, such as in pipe laying, it is easy for accidents involving ordinary
vehicles to occur. For example, if an ordinary vehicle snags a cable during overhead wiring work on autility pole, it may pull the worker down to the ground. To prevent passing vehicles from entering theworksite, security equipment such as enclosures, fences, and guards will be provided and flaggers will
be posted. It is also important that workers do not work outside the scope of the worksite.
(3) Struck-By/Caught-Between
In work performed on public roads, such as pipelaying, be careful of backhoe accidents. These areaccidents such as collision between the circling bucket
and a person, or a person getting caught between thebucket and an object. In addition, backhoe tipping
accidents are more likely to occur when loading and unloading backhoes onto and off trucks, etc. A
backhoe tipping can result in fatal accidents when someone is crushed by it.

185

(4) Flying/falling
Flying and falling accidents are caused by flying or falling
objects. For example, being struck by the object carried by acrane or becoming trapped under a falling suspended load.
Insufficient slinging, moving suspended loads, etc. can cause
accidents. The important thing is not to place yourself under
the suspended load. Accidents have also occurred due to falling tools and components to be installed.
(5) Crumbling/Collapsing
In electrical work, accidents include temporary poles breaking and collapsing, or poles on trucks
tumbling down and trapping people underneath.
(6) Electric shock
An electric shock is a strong shock that occurs when electricity passes through a person's body. By
touching a wire or device that has voltage running through it, electricity flows through the body andinto the ground. Electric shock can also be caused by other mistakes such as touching leaky equipment
or short-circuiting an electrical circuit. To prevent electric shocks, do the following.
> Work with protective equipment such as antistatic protective gear, rubber gloves to prevent electricalhazards, insulating clothing, and rubber boots to prevent electrical hazards. Even when wearing
protective equipment, parts of the body not covered by the equipment may come in contact. Choose
proper protective equipment, and consider working under de-energized conditions whenever possible.
> When energized, non-electrical workers may receive an electric shock. Inform people who are not
involved in the work, and take steps to prohibit entry to the worksite.
> Unintentionally touching something may cause an electric shock. Ensure that work is performed
under de-energized conditions.
> Electric shock accidents can also occur by falsely believing that the worksite is de-energized. In
addition to thoroughly notifying all concerned parties, also test for electrical current before work is186performed in order to confirm de-energization.
(7) Oxygen deficiency in manholes
Fatalities from oxygen deficiency and anoxia due to sulfide poisoning have occurred when working
inside manholes. In situations where oxygen deficiency occurs, fatal accidents have also occurred torescuers entering the site without using an air respirator. Refer to 6.5.4 Precautions for Underground
Piping Work for more information on disasters related to manholes.

7.1.3 Characteristics of Lifeline Infrastructure/Facility Installation Work with aHigh Number of Fatalities(1) Characteristics of and accidents in electrical work
Because electrical equipment installation deals with electricity, a fatal accident called electrocution
can occur. Replacement of high-voltage lines and overhead wiring work is performed at heights, andtherefore there is also a risk of falling accidents.
An electric shock accident can occur when cutting wires with a cable cutter. Such an accident is theresult of failure to check for de-energization, failure to use protective gear to prevent electric shock,etc.
Falling accidents occur when working at heights,
such as installing cables on utility poles. Wheneverpossible, prepare a stable working platform, such as anaerial working platform.

Work on an aerial working
platform(2) Machinery installation
When installing large machines, accidents can occur when the machine tips over and traps people
underneath.
(3) Water and sewage works
In water and sewer works, excavation work involves digging trenches in the ground to pass pipes.
187

There are several accidents associated with this excavation work. For example, there have been
accidents in which the people inside the excavated hole were buried alive when the excavated soil
collapsed. If the depth of excavation is more than 1.5 m, as a general rule, steel sheet piles are used
for soil retaining. Falling accidents can also occur due to tripping over pavement ridges, sinking aroundshuttering boards, cables, hoses, etc.
Because excavation work involves the use of backhoes, accidents related to backhoes are also likely
to occur. Examples include contact accidents caused by circling booms or being run over when backing
up. A full-time flagger is assigned to communicate
with the backhoe operator in order to ensure thesafety of those working in the trench. The backhoe
itself is also at risk of tipping over or falling into a
ditch.

Sewer manhole construction

7.2 Safety Activities at Construction Sites
Construction sites are home to technicians from many job categories. Although the work performed
may seem different, experienced technicians are always mindful of some common matters. This
realizes high quality and safety. 7.2 describes common safety activities that all technicians shouldknow.

7.2.1 Cycle of Safety in Construction
By continuing the cycle of safety in construction, we can make worksites less prone to industrial
accidents. The cycle of safety in construction is to achieve the following aims.
a. Integrate construction procedures and safety.
b. Facilitate cooperation between the prime contractor and other related subcontractors.

188

c. Make safety and health activities a habit.
d. Be inventive in taking preemptive safety measures.
e. Inform everyone of construction and safety requirements.
Various safety activities should be incorporated into daily operations at construction sites. To
prevent industrial accidents, it is important to set up and continue the daily cycle of safety inconstruction.
Cycle of Safety in Construction(1) Safety morning meeting before work
(To be participated by all prime contractors and related
subcontractors)(8) Safety check at the end of the(2) Safety meeting

workday

Daily cycle ofsafety inconstruction(7) Cleaning up your assigned(3) Inspection before starting

area

work

(4) Guidance and supervision
during work(5) Safety patrol(6) Meeting on safe processes(1) Safety morning meeting before work
All prime contractors and related subcontractors participate in the meeting, which includes apresentation on the results of the safety patrol conducted on the previous day by the worksite managers,
instructions regarding work safety for the day's work, and radio calisthenics.
(2) Safety meeting
Discussions will be led by the foremen, by job category. The training includes reviewing the resultsof the previous day's work process, hazard prediction (KY) activities related to today's work process,and newcomer education.
(3) Inspection before starting work
Before starting work, safety inspections are conducted, including inspections of the machines and189tools used, checking the work content, etc.
(4) Guidance and supervision during work
Site supervisors (foreman, operations supervisor, etc.) provide guidance and supervision toworkers.
(5) Safety patrol
Safety patrols are conducted by the worksite manager and subcontractors, and instructions andguidance are given to each foreman, etc.
(6) Meeting on safe processes
The prime contractor and each specialty contractor will communicate and coordinate with eachother regarding work on the following day, and discuss work methods, etc.
(7) Cleaning up your assigned area
Every worker is to organize, tidy, clean, and sanitize the area he/she worked in.
(8) Safety check at the end of the workday
The prime contractor and the person in charge of specialty contractor will confirm measures toprevent fire, theft, public disaster, etc.

7.2.2 Safety and Health Education for Newcomers
Safety and health education for newcomers is provided when a business hires new workers. The
implementation of safety and health education for newcomers is required by the Ordinance on
Industrial Safety and Health.
[1] Matters related to danger or harmful effect of machines, etc., or raw materials, etc., and thoserelated to methods of handling thereof[2] Matters related to performance of safety devices, harmful substance control devices, or personal
protective equipment and matters related to methods of handling thereof[3] Matters related to operation procedures190

[4] Matters related to inspection at the time of commencement of work
[5] Matters related to the causes and prevention of diseases which workers are susceptible regarding
the work[6] Matters related to keeping the workplace in order and maintenance of its sanitary conditions[7] Matters related to emergency measures and evacuation at the time of an accident[8] Beyond what is set forth in each of the preceding item, matters necessary for maintaining safety
and health related to the work

7.2.3 Newcomer education
A worker who newly enters a construction site is called a newcomer. Nearly half of all construction
site fatalities occur within one week of newly entering a site. For this reason, the Ministry of Health,Labour and Welfare has mandated newcomer education. The Guidelines for Construction Site Safety
Management by Master Employer defines the implementation standards as follows.
[Implementation of newcomer education]
In case of newly assigning any employees to work at a construction site, the related subcontractors
shall instruct their foremen, etc., to inform such workers of the following matters based on thecharacteristics of said construction site before they commence work at the site, and shall report theresults to the master employer.
[1] Conditions concerning locations where work is conducted by a mixed workforce that consistsof both the master employer's employees and the related subcontractors' employees[2] Locations that pose a danger to workers (dangerous and harmful places and no-entry zones)[3] Relationship between work processes conducted at mixed work sites[4] Evacuation methods[5] Command structure[6] Contents of the work involved and industrial accident prevention measures191[7] Rules on safety and health[8] Plans that prescribe the basic policy and goals of safety and health management at theconstruction site and other basic industrial accident prevention measures
The above will be implemented as follows.
(1) Before work on the day the contractor first enters the site to begin work
The person in charge from the construction company (builder), the foreman, and the health andsafety officer will conduct the training.
(2) Before work on the day a newcomer is added to the contractor's workforce
The foreman and the health and safety officer will conduct the training.
The training will take place in a conference or meeting room in the field office for about 30 minutes.

7.2.4 Safety Gear for Work
The photo below shows the safety gear for work. Full harness fall protection gear (1), helmet (2),hooks (3), and safety shoes (4) are the basic gear.

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[Full-Harness gata tsuiraku boshiyo kigu] (full-harness fall protection gear) The full-harness fall
protection gear prevents falls. From January 2, 2022, it is mandatory to wear it if the height of theworking platform exceeds 6.75 m. However, in the construction industry where falling accidents occur
frequently, the use of full-harness fall protection gear is required even when working at heights
exceeding 5 m. However, falling accidents do occur for those wearing but not using the gear, so be
sure to use it.

In addition, the following protective and safety equipment is used depending on the task.
[Hogo megane] (protective eyewear) These glasses are designed to protect the eyes from metal andwood dust, sparks, heat, smoke (including toxic gases), lasers and other harmful rays generated atconstruction sites and material processing sites. Select the best eyewear for your purpose.
[Hogo mask] (protective mask) A mask used to protect against dust and other debris. There aredisposable masks and those with replaceable filters. The Ministry of Health, Labour and Welfare(MHLW) sets the standard for masks. For example, inhaling dust from arc welding and rock cutting
operations over a long period of time can cause lung dysfunction (pneumoconiosis), so the use ofprotective masks is mandatory.
[Tebukuro] (gloves) Used to protect hands when performing machine/hand cut processing, painting
work, various types of installation work, and work involving chemical substances. However, gloves(work gloves) should not be used when using rotating blades such as circular saws, drilling machines,
chamfering machines, pipe threading machines, etc., because gloves (work gloves) can get entangled
in rotating blades and result in accidents.
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[Shield-mentsuki helmet] (welding helmet) A helmet with a shield attached to it, protecting the entire
face. Mainly used for welding work.

7.2.5 Prevention of Heat Strokes
Summer in Japan has many manatsubi (hot day) with temperatures exceeding 30°C and moshobi(extremely hot day) with temperatures exceeding 35°C. Work performed in hot temperatures can cause
the workers to have heat strokes. Heat stroke can cause
dizziness and fainting, muscle pain and stiffness, profuse
sweating, headache, mood discomfort, nausea, vomiting,fatigue, a sinking feeling, impaired consciousness,convulsions,

impairedlimb

movement,

high

body

WBGT measuring
instrument

temperature, and other symptoms that not only make it
impossible to continue working but can also cause death. The Japan Meteorological Agency calculates
and provides information on the predicted value of the Web Bulb Globe Temperature (WBGT) in eachregion. To reduce WBGT values, site managers install large fans, shading nets, dry mist systems, rest
areas, air conditioning equipment, water supply equipment, refrigerators, ice machines, drinking
watervending machines, etc. On extremely hot days, work start and end times may be moved up.
Workers should try to rest in a cool place, such as an air-conditioned rest area, during allotted breaktimes, and to drink water and consume salt before and after work. Also, wear breathable work clothes,safety vests that absorb heat easily, etc.

7.2.6 Marks Calling Attention to Work Safety
Marks with a green cross on a white background can be seen at various locations on the construction
site. This mark is called midorijuji (green cross) and is a symbol of safety and health. It is often

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designed together with the words anzen daiichi (safety first) because safety is the first and mostimportant thing on a construction site. Helmets and kyukyubako (first aid kit) containing medicine andtools for first aid in case of injuries are also marked with the green cross. Sometimes the safety andhealth flag, combining the green cross with shirojuji (white cross) which represents eisei (health), is
used.

Example of the green
cross
Examples of the safety
and health flag

7.2.7 Understanding Human Error
Mistakes caused by humans are called human errors. Human errors occur because we are human.
This includes not only mistakes caused by carelessness, but also those caused by tenuki (cutting
corners), skipping procedures that should have not been skipped. To avoid getting involved in or
causing accidents on construction sites, it is important to be conscious of possible human errors. In
addition, human errors not only cause accidents involving people, but also affect the quality of thecompleted construction as well as cause delays in the process. It is said that there are 12 different
causes of human error.
(1) Cognitive errors
It is a human error caused by assumptions. For example, the assumption that “such and such
instructions will be given in this situation” can lead to misreading the actual instructions and cues
given.
(2) Lack of attention
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It is a human error caused by lack of attention. Concentrating on one particular task can reduce
attention to one's surroundings and lead to accidents. For example, there are cases where a person isso focused on the work in front of him that he fails to notice the hole behind him and falls in.
(3) Attention lapse and diminished awarenessAttention lapse and diminished awareness can occur especially when engaged in simple andrepetitive tasks. When simple tasks are repeatedly performed, workers stop thinking about those tasks
but instead perform them unconsciously.
(4) Inadequate experience/knowledge
It is a human error caused by lack of experience and ignorance. This can result in improper use oftools, incorrect understanding of the work process, or inability to anticipate accidents that may be
associated with the work. KY activities before commencing work are an opportunity for seasoned
technicians to share their experience in predicting hazards. Workers can learn what to look out for,even when engaging in the task for the first time.
(5) Complacency
Humans tend to gain confidence through familiarity and, as a result, tend to be less careful or skip
steps compared to when they were beginners at that task. Accidents are more likely to occur when
workers become complacent and relaxed. No matter how familiar you are with the work, be sure topractice safe conduct, inspect tools before you work, check your safety equipment, and wear and checkthe fit of your safety gear.
(6) Group errors
It is a human error that occurs in groups. For example, when it seems that meeting the construction
deadline is unlikely, it is easy to for the overall atmosphere to lean towards condoning unsafe conduct.
While it is important to meet construction deadlines, the safety of people is of primary concern. In
addition, if accidents occur due to unsafe conduct, they can cause delays in the construction schedule.
(7) Shortcuts and omissions
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This is a human error caused by omitting necessary actions and procedures out of the desire to work
efficiently.
(8) Communication errors
This is a human error that occurs because the instructions are not clearly conveyed. Working without
understanding the instructions can lead to accidents and construction delays.
(9) Behavior based on situational instinct
It is an action that we unintentionally take when we are in a certain situation. Especially when people
are focus on one point, they become oblivious to their surroundings. For example, when a person isabout to fall from a stepladder, he/she would throw his/her tools in order to hang onto the stepladder.
An accident occurs if those tools hit another worker.
(10) Panic
Sudden surprises or panic can easily lead to spontaneous unsafe behavior or giving inappropriate
directions.

(11) Decline in physical and mental functions
What was possible when younger may no longer be possible due to aging. In particular, reduced
function in the legs and hips and vision impairment are difficult to notice because they occur gradually.
It is important to be aware of this so that you do not try uncomfortable actions or postures.
(12) Fatigue
Accumulated fatigue reduces alertness, and this can lead to accidents. It is important to take goodcare of your health on a daily basis, including proper sleep and nutrition.

“Have a safe day!”
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