construction safety - part 10 (fire)

8/11/2019 Construction Safety - Part 10 (Fire)

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14. Fire Prevention



What is fire?

Fire is a chemical reactionbetween a flammable orcombustible substance andoxygen.

It is frequently referred to as“rapid oxidation with theevolution of light and heat”.



Triangle of Fire

1. Oxygen

2. Heat 3. Fuel

To produce fire,

three things mustbe present at the

time:



Classes of fire

Class A Class B Class C Class D

Wood,

paper,dried

grass,

etc.

Gasoline,

kerosene,paints,

thinners,

oil, etc.

Overload

electricalwires and

equipment

Magnesium

sodium,potassium,

etc.



Fire Prevention and Control

Provide for early detection

Prevent the outbreak of fire

Prevent the spread of fire

Provide for prompt extinguishment

Provide for prompt and orderly evacuation



Fire Prevention

• Store gasoline or otherflammable liquids insafety can outdoors or inapproved storage

facility• Don’t store LPG tanks

inside buildings

• Ensure that leaks and

spills of flammablematerials are cleaned upproperly



Extinguishment of Fire

Removal of fuel

Limiting supply of oxygen

Cooling the heat



Extinguishing medium

Class A – water is the best medium

Class B

–

metal cover, wet sack, towel cloth orblanket, sand and soil

Class C – main switch is the first consideration, then

apply what is for Class A or B



Fire Prevention

Fire Extinguisher

Provide fire extinguishersnear all welding, solderingand other sources of ignition

Keep it easy to see and toreach in case of emergency

Provide one within 30 m reach

of employee at least for every250 sq m of building area



Fire Prevention

Types of Portable FireExtinguishers

Water

FoamCarbon Dioxide

Dry chemical

Halogenated agents



Fire Prevention

Train the

worker the

PASS methodto extinguish

fire



14. Underground Services



CONSEQUENCES IF DAMAGED:

Hazards

+ Penalty

+ No Service

+ Burden of

Restoration ____________________________________

= B I G P R O B L E M




Personnel engaged in working in theunderground services have a particularresponsibility to identify and evade thisconsequence.

The safe system of work has three basicelements:

–Plans and Mark-outs

–Cable and Pipe Location Devices

–Safe Digging Practices




Plans and Mark-out

Plans

Before starting the job on a particular site, locate

first the position of the underground services. The

owners should be consulted.

Owners of services are supposed to provide plans(normally the as-built drawings), which show the

line and depth of all their known services buried in

the construction site.

Mark-out

Mark-out the location of existing underground

service on the site.



Cable and Pipe Location

Devices• The position of any services in or near the

proposed work area should be pinpointed as

accurately as possible by means of a locating

device, in conjunction with any available drawing

or other suitable information.

• Plans will help the operator using the locator to

identify exact location before excavation starts.

• Do not rely solely on cable and pipe location

devices for the detection and location of existing

services.



Safe Digging Practice

In conjunction with location devices andplans, trial holes by careful hand excavationare essential before any work is commenced.

Hand digging must continue until all theservices have been found.

If there is any doubt as to where the servicesare located, stop work and consult with the

service owner.



Installation of New Services Near the Existing

Services

Where it is reasonably practicable to laynew services alongside existing

services, the utility provider planning

the new installation should aim to check

that it is separated from existing buried

services, while leaving as much room as

practicable for other future services.




Services

Electricity CablesWhere any service has been installed, always assume

these services to be alive from the moment that they

have been laid.

Gas Pipes

All gas pipes should be located by hand digging before

mechanical excavation begins. No manhole, chamber

or other structure should be built over, around orunder a gas pipe and no work should be carried out

which results in a reduction of protection over a pipe.




Services

Water PipesSafe digging practices should be followed, using handtools is practicable.

At bends in water mains, provide thrust blocks.

In pipe construction, secure adequate cover and

proper backfill compaction before opening the valves.

Sewer Lines

Harmful gases are developed inside the pipelines thatcan cause serious injuries.

Workers may enter sewer manholes only afterthorough check and appropriate PPE.




Services

AS-BUILT DRAWINGS

Prepare as-built drawings indicating allservices, the old and the newly installed

services.

Each line should be properly identified inthe as-built drawing.

Archive the drawing properly for futurereference.



Points to ponder:

Accidents don’t just happen,they are caused by …

persons doing

unsafe acts … or

by persons doing actsunder

unsafe conditions or ...

by persons doing unsafe actsunder

unsafe conditions.

construction safety - part 10 (fire)

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