hazards in road work

At road work zones protection is neccery against a number of risk And  hazard including: 


Different type of collisions,involving traffic participants road workers and or work vehicles.


Obstacles within the work area,such as trucks,materials and construction mechines.

Other hazards within the work area such as removed surface  or holes for the renewal of cables.


Emergency situations , disabled vehicles or dealing with run off road incidents.

Under Pinning

Under pinning involves stabilizing adjacent structures ,foundations and other instructions that  may have an impact on the excavation.As the term indicates underpinning is a procedure in which the foundation is physically reinforced.Underpinning should be conducted only under the direction and with the approval of a registered professional engineer.

Benching

There  are two type of benching ,simple and multiple.The type of soil determines the horizontal to vertical ratio of the benched side.As a generlal rule the bottom  vertical heightr.. of the trench must not exceed
 4 feet for the first trench.Subsequent benches may be up to a maximum of 5 feet vertical in type.A soil and 4 feet in type  b soil to a total trench depth of 20 feet .All subsequent benches must be below the maximum allowable slope for that soil type .For type B soil the trench excavation is permitted in cohesive siol.                                                                                                                                                e

Pre excavation requirments

In order to carryout the excavation work safety and to minimise the risk .the following factors shall be concidered before the excavation starts.

Size and purpose of excavation.

Nature of the ground including the proximityof made up ground.

Stability of adjuscent structures.Position of underground obstructions such as pipes ,electric cables and other utilities.

Position of structures of archieological and historical interest.

wether and moisture conditions high water table.

Sourse of soil vibration (high way traffic,mechinery etc.)

Adjucent road and fott path.

Method of excavation.

Slopping

Slopping is method of excavation in which the sides of  an excavation are laid back to safe angle to prevent cave ins. Trench boxes are generally used in open  areas but they also may be used in combination with slopping and benching.The boxes should extend atleast 18 inches above the surrounding area, if there is slopping towards excavation.This can be accomplished by providing a benched are adjusted to the box.Earth excavation to a depth of 2 feet below the shield is permitted.

Shieldingf

Shielding with a trench box can protect the workers in a trench from cave in.Trench box are different from shoring. Instead  of shoring up or otherwise supporting the trench face ,They are intended primarily to shield workers from cave in and similar incidents.The excavated area beet ween the out side of the trench box and  the face of the trench should be as small as possible.The space between    trench box and the excavation side are back filled to prevent  lateral movement of the box.Shields may not be subjected to load exceeding those which the system was designed to withstand.

Shoring

Shoring is the provision of support system for trench faces used to prevent movement of soil.,under ground utilities,road ways and foundations.Shoring is used when the location or depth of the cut makes,slopping back to the maximum allowable slope-impractical. Shoring system consist of posts, wale  , straits and sheeting. 


Three basic type of shoring's are :

 Timber. 

Hydrolic. 

Pneumatic.

protective system (methods of excavation)

Different protective systems are used in excavation to prevent any accident like cave in using different systems for excavation can be called as a method of excavation.They are ; shielding ,sloping ,shoring ,benching.the determination of angle of slopes ,benches or the choice and design of other protective systems shall be based on the evaluation of pertinent factors such as : type of soil,depth of excavation, possible variations in water content of the materiel while the excavation is open.Anticipated changes in materiel from the exposure to air,sun or water.Loading imposed by structures,equipment,overlying material or stored material ,vibration  from the equipment ,blasting, traffic-or other sources.

Just look forward; What are you see now, Where is the beginning ,Let start our safety from there.

Emergency rescue

Emergency rescue equipment is required when a hazardous atmosphere exits or can  reasonably be expected to exit. 

Requirements includes   :

Respirators must be of the type suitable for the exposure.Employees must be trained in their use and  a respirator program must be instituted. Attended life lines  must provided when employees enter bell bottom pier holes ,deep confined spaces or  the similar hazards .Employees who enter confined space must be trained.

Mobile system warning

The following steps should be taken to prevent vehicles from accidently falling in to trench. Barricades must be installed where necessary.Hand or mechanical signals must be used as required.Stop signals must be installed if there is danger of vehicles falling in to the trench.Soil should be graded away from the excavation.this will help in vehicles control and channelling of run off water.

Exposure to vehicles

Procedures to protect employees from being injured or killed by vehicle traffic include : 

Providing employees with  & requiring them to wear warning vests or other suitable garments marked with or made of reflective or high visibility materials.


Requiring a designated ,trained flag person  along with signs,signals and barricades when necessary.

Exposure of falling loads

Employees must be protected from loads or objects falling from lifting or digging equipment. Procedures includes:


 Employees are not permitted to work under raised loads.

Employees are required to stand away from equipment that is being loaded or UN loaded. 

Equipment operators or truck drivers may stay in their equipment during loading or unloading.

If the  equipment is properly     equipped with a   cab shield or adequate canopy.

Surface crossing of trenches

Surface crossing should be discouraged.If  needed ,vehicle crossing must be designed by and installed  under the supervision of registered professional engineering .Walk ways or bridges must be provided for foot traffic.The surface shall:

have minimum clear width of 20 inches be fitted with standard rails extended a minimum of 24 inches past the surface edge of the trench.

Special health and Safety consideration (Excavation

Surface crossing of trenches. 

Exposure to falling loads. 

Exposure to vehicles .

Warning systems for mobile equipment's. 

Hazard atmosphere.

Emergency rescue.

Water accumulation.

Inspection.

Hazard associated with excavation works

The major hazards associated with excavation works are Includes: 

Collapse of side in (cave in).

Persons falling in to excavations .

 Striking underground utilities.

Persons in excavations being struck by falling materiel.

Building or structures collapsing due to excavations.Flooding .

 poisoning  due to ground conditions or fumes from plane plant running in to excavations.

Plant sinking in to unstable ground.

Ingress & egress in excavation

Access to and exit  from the trench require the following conditions:


Trenches 4 feet or more in depth should be provide with a fixed means of egress.

Spacing between larders or other means of egress  must be such that a worker will not have to travel more than  25 feet laterally to the nearest means of egress.

 Ladders must be secured & extend a minimum of 36" above the landing.


 Metal larders should be used with caution, ,particularly when electrical utilities are present.

Protective system

Protective systems are the methods of excavation will be decided with the situation and class of soil.

 Required for excavations 4 feet or greater in depth.

 Protective system refers to a method of protecting employees from cave ins from materiel that could fall or roll from an excavation face or in to an excavation and from the collapse of adjacent structures. 


Protective system iuncludes support  systems, sloping ,benching,shielding systems and other systems that provide the necessary protection.

safety in excavation works

Following are the general requirements for an excavation work. 

Identification of soil.Decision chart.

Soil classification. Daily inspection.

Special safety & health consideration.

Protective systems.




 An excavation is any man made cut, cavity,trench or depression  in an earth surface that is formed by earth removal.

Domestic safety

                           we are use different type of equipments & tools in our home, shop  etc. But how much it is safer ,any body have no idea. Every one should  do our equipment is safe. So   you must learn about the product in detail with its trouble shooting . Keep it from children . this is the first step for domestic safety of our equipment. do correct procedure about  the operation ,its reccomended by by manufacturer only.

major causes of crane accidents

Major causes of crane accidents are ;

 Contact WITH POWER LINES. 
Over TURNS. 
Mechanical failures.
Falls.

Accidents occur due to the following reasons: 
Instability: Unsecured load,load capacity exceeded or ground not level or too soft.

 Lack of communication: the point of operation is a distance from the crane operator or not in fall view of the operator.
Lack of the training. 
Adequate maintenance & inspection.

Rescue team

 Duties & responsibilities of rescue team :


Familiar with the confined space and potential rescue problems.

Trained in first aid and CPR. 

Understand confined space entry procedures.

Knows how to rescue practises the rescue procedures  regularly at the spaces. 

Knows  symptoms and  treatment of hazardous exposure.

Entry supervisor

The duties of entry supervisor are the following: 

Authorizes  the confined space entry . 

Sees that all test And procedures  are done .

Oversees follow up tests  done during the entry.

Terminate the entry permit when work is done or if a problem develop.

Determines that all team members and equipment are in place and ready.

The entrants

Following are the duties &responsibilities of entrants:


 Enter the confined space to work.
Sign in and out  at the log.
Know the hazard of the space.
Understand the information on the entry permit . 
Personnel check to see that  all listed hazards are controlled.
Wear all required safety equipment and PPE.
Stay in contact with the attendant at all times.
Inform attendant when self commissioning exit.

The attendent

Following are the duties are the function of an attendant: 

Remain station out side the confined space  at all times during entry operations.
Maintaining an accurence count of all persons inside confined space.
Recognize potential permit space hazards & monitor conditions to ensure that a safe atmosphere remains.
Prevent entry of unauthorized  personnel in con fined space.
Maintain continuous communication with authorised entrants.
Authorise evacuation of confined spaces when hazardous conditions or permit valuation exit.
Contact advanced rescue personnel in case of an emergency.

The qualified person

                                         Qualitative or competitiveness person will be an employee who by virtue of training and or experience is capable of authorising confined space entry.He is who determines atmosphere conditions and  validating an entry permits .He has the  authority to cancel  or terminate entry permits at his discretion if hazardous condition arise or are suspected.




 Duties are following are the qualified person:


Use & calibration monitoring equipment.
Hazard communication.
Respiratory protection.
Permit authorization& termination.
Hazard recognition.
Contacting advance Rescue personnel in case of an emergency.

Confined space entry team

Following are the personal or team  getting involved in a confined space entry.




Qualified person
 Attendants 
Entrants 
Entry supervisor 
Rescue & emergency service

Consideration will all so given to the following content of the confined space:

Partitions ,which may be in the space creating areas with different atmospheres.

Potential for dripping of liquids from over head trays or compartments.

Potential for retention of vapour pockets due to partitions.

Internal coasting ,which may give off toxic vapours if heated or damaged.

Potential toxic vapours  from cleaners or welding.

Sludge & scale which may give off vapours when disturbed.

Mechanical and structural hazards.

Suitable means of ingress and egress.

prequation

                                    Sufficient access to the confined space access / egress point will be maintained for rescue vehicles and personnel.Self contained breathing apparatus will be available at entry to confined space .RESCUE BREATHING APPARATUS WILL HAVE A RESUSCITATOR ATTACHMENT .SO THAT AIR CAN BE ADMINISTERED AS SOON AS THE VICTIM IS REACHED AND IN CASES WHERE THERE WILL BE DIFFICULTIES OR DELAYS IN MOVING VICTIMS.Erection of signs at the entry of all open man holes,tunnels ,vessels ,stating danger ,confined space:Do not enter or similar appropriate wording.Erection signs at manhole ,covers ,severs,tanks and vessels stating men working,confined space ,Do not close.

There will be radio communication beet ween the safety watch & site safety supervisor.As supplement to radio communications an air horn or portable siren will be used by the workers inside the confined space to alert the safety watch in case of an emergency .Where possible a life line  will run from the access / egress point to the location of the workers to felicitate rescue operations.Where practical ,each worker will wear harness attached to the life line facilitate efficient rescue operations.Trained personal out side the confined space will aid an rescue operations.

Confined space

                                    Purging the air out of the space with inert gas such as nitrogen or CO2.Ventilation's to keep the fuel vapours below the LEL.Eliminating sources of ignition such as friction,Sparks,open flames & sparks from exhaust or electrical equipment.Bonding & grounding vessels to reduce static electricity.Shutting of torch valves at a point out side the confined space will be left unattended for any length of time,such as a lunch brake.Torches & hoses will be removed from the confined space when left over night.Take no smoking policy around the confined space.Storing all combustible & flammable material out side the confined space  until ready for use.Leaving gas cylinder & welding machine outside.

Responsibility of safety watch

                                                              Maintaining a log of all personnel inside the confined space.Workers will sign in and out each time they enter or leave the confined space.Has  ion his possession,a functioning air horn with which to enunciate any emergency or evacuation procedures.Remaining at the assigned post at all times that personnel are inside the confined space.Ensuring that all personnel whop enter the  confined space have the appropriate PPE.Being familiar with the emergency reporting procedures & assisting with rescue operations.The safety watch will ensure that the precribed  rescue equipment is on hand.

Lighting & safety watch (confined space)

                                  Explosion proof lighting will be used where there is a potential for flammable products to be present.All 110 volts lighting will be protected by Ground fault interrupters  and bird caged.In case of presence of flammable gas,it is advisable to use 24 volts.All personnel in confined space & the safety watch will carry portable lighting in case of power failing.All confined space entries shall have a safety watch posted immediately outside the confined space,who will be able to communicate with workers inside.He should be readily visible and identifiable by reflective vests.

Some important procedure to prior the entry

                                                In addition to standard Ppe an assessment  will be carried out to determine4 additional PPe requirements.Such as fall protection , Respiratory protection etc.Workers will be trained in the proper use of all ppes  & will be familiar with their limitations.Natural ventilation in confined space is minimal.There fore ventilation by mechanical means shall all ways be made available.

                                                Ventilation equipment will be positioned so that contaminated air such as  exhaust gasses and welding fumes are not drawn in to the confined space .Equipment used in or near a flammable atmosphere will be explosion proof.Steam or inert gas purging is recommended for removing flammable vapours.Where purging & ventilation are not adequate to provide sufficient atmosphere.Workers will use a suitable breathing apparatus prior to entry in to a confined space the atmosphere will be tested,and then again predetermined intervals.

Confined space (permit& planning)

                                    Prior to all confined space entries ,a confined space entry permits /safe work permit should be obtained.The pre requisite for such permit will be a written proceedure detailing the workers works .



Which will include:

Assessment of the hazards(JSA)
zero energy state requirements.
Identification of parties responsible to open & close the confined space.
Daily permits requirements.
Ventilation requirements.
Lighting requirements.
Tools & equipments.
Fire protection.
Rescue equipment & plan.

Confined space hazards

The confined space exists potential hazards.They are : 

                                                        Oxygen deficiency due to  rust formation ,chemical reaction,combustion or absorption.Any reduction in oxygen in the atmosphere below 19.5 % can impair performance by causing fatigue and loss of reasoning ability.


                                                         Oxygen enrichment through accidental ventilation with oxygen or leaks in Oxy Acetylene equipment will increase flammability of materials.Oxygen level in the confined space should not be more than 23.5% . 
                                                     
                                                         Fire & explosion may be occur .Toxic substances present.

Falling of objects as a result of materiel or equipment brought into a limited volume of space that requires more than one working level.

Mechanical equipment that forms of these normal process will be isolated so that it does not energize automatically or accidentally.

Electrical shock could result  from preferment installations  or from defective temporary equipment,tools cords & lighting's.

Confined space

                                                       Confined space is identified as any area  which limited means of access / egress and  the area is subjected to :

Oxygen deficiency.
Accumulation of flammable vapors.
Any airborne contaminates that exceeds established permissible exposure limited(PEL)vapor air mixture will ignite & burn only with in a specified range of composition which will be above LEI & above UEL.


                                                     The lower flammability limit or lower explosive limit is the minimum volume percent of the fuel that will support combustion below the LEL.The mixture with air is too lean.


                                                  Upper flammability limit is the  maximum volume of  percent fuel that will support combustion & the upper explosion limit is the maximum volume percentage of fuel that will support an explosion.Above the UEL and / UFL,the mixture with air is too rich.Examples : Tanks.vessels,pipe ,duct,inlet basins,utility vault,collection basins,sludge pits,trench,boiler and tube areas ,Silo.

The impotrtance of designer,supervisor, contractor(safety)

                                            The designer should give priority to generic solutions. That is those that protect all people at work rather than solutions that only protects those individuals has overall responsibility for coordinating the health safety aspects of the design and planing phase.This include ensuring as far as is reasonable practicable ,those designers duties are met and that the initial health & safety plan is prepared.In addition the planning supervisor is also responsible for ensuring the health safety file is prepared and for notifying projects to HSE.



                                            The principle contractor s the in charge  of the site . The principle contractor is responsible for developing & completing the initial health & safety plan for the construction phase and once work is commenced should help the planning supervisor collate information for the health & safety file.All contractors that they provide adequate information & training for to their employees regarding health safety environment policies.

Management controls in civil works (safety)

                                                        Due to the nature of both the risks involved & the practise of using multiuple contractors and sub contractors in construction works,the basis of safety lies very much with management control.They place duties on construction companies and individuals who evolved in construction work from the planning & desighn stages through copletion & handover.



The regulation that applay to any construction work excluding: 



Work other than demolition,that does not last longr than 30 days or does not involve more than four people.
Work for domestic client.
Work carried out inside offices & shops or similsr pewrmises with out interupting the normal activities in the permises &with out seperating the construction activities from the other activities.



                                                            The client is the pertson or organisation commissioning the construction work.In the case of an individual or non specilist organisation ,a client agent may be appointed to assume the duties and responcibilities.On completion of the project ,the health & safety file ,which is made & kept during the work must be given to the client ,who must then retain it permenently. The designer must ensure ,sdo far as is resonably practicable ,that all structure are designed to avoid or where this is not possible to mininmise risks to health & safety while they are being builtr,maintained & eventually demolished.

Electrical works

Major works are involve construction of substations;power supply lines installation to substations,distribution cable works ,installation of transformer stations,inters connecting cable works,installation of electrical safety gears and switches,testing of installations & electrical equipments,final installation of electrical accessories &keeping the system ready for commissioning etc. 


The expected hazards in electrical projects 

Falling of people from heights.
Electrical shock.
Injury to workers . 


The remedial measures 


Proper tools are to be used.Works above 1.8 meters are to be considers as working at height, and in this case proper scaffolding with guard rails or fall arrest systems are to be provided.For buried cables warning tapes,route markers,marking tiles to be provided inside trench before back filling.All persons at site should use PPEs.Only the ladders with insulation pads can only be used in electrical works or it is better to use fiber ladder.

safety messures (mechanical works)

Good house keeping at site at all times and removal of waste in time .
Provide fire fighting facilities in hot work areas. 
All the workers are to provide with cover all and other required ppes likes safety helmets, safety gloves , safety shoes ,safety goggles etc.
People working at height should be given safety belts and the work above 1.8 meter height to be carried out with the healp of scaffolding platforms.
AVOID WORK UNDERNEATH HEAVY PIPES ,LOADS WHEN LI8FTING IT WITH CHAIN BLOCK OR CRANE OR HIAB.
Welderts are to use aprons while welding in O/H positions.
For heavy lifting operations with crane, a rigging study is to be made and all rigging operations to be carried out under the supervission of a rigger superwiser or grade 1 rigger.
The crane should have valid certificate of worthiness and all the lifting  tools & tackels should have valid inspection certificates or stamping on the items.
Safe working loade is an important concept for lifting operations.
The skilled workers in the work area are to be trained in the use of fire figfhting equipments.
Out triggers are to be  fully extended to avoiding tipping of crane.
Flame arresters to be provided for gas cutting set.

The expected hazardfs involved in mechanical works

Injury to workers during handling of materials. 
Hands or legs caught underneath loads.Burns ,electric shock during welding works and other hot works ,short cir cute & fire incide4nts.
Collapse of cranes & other lifting equipments.
Failiear of lifting tools & tackles.
Eye injury due to falling particles during grinding,grit blasting & power brushing.
Suffocation due to excessive smoke or dust during welding & blasting operations.
Swinging of load and hitting on existing facilities during rigging operation in strong wind.
Welders trapped underneath pipes during welding works -as support are moved.
Back fire and explosion of compressed gasses during oxy -acetylene flame cutting.
Hazards due to smoking in prohibited areas.
Hazards due to bursting of pipe lines during hydro testing at high pressure range.

Civil works (safety)

The expected hazards in civil works:


Hitting of existing under ground facilities during excavation.
Falling of objects( tools, equipments,materials)on people.
Falling of people from top.Foot & hand injuries.
Eyes affected with grout or cements.Slipping & falling.
Collapse of soil during excavation.
Collapse of crane,hoist and other hang earth moving equipments,vehicles and equipments falling into excavated trench etc.

 The remedial safety measures: 


 Get proper work permit where applicable.
Locate existing under ground facilities from the latest plan drawing .
Take trial pits before excavation .
Provide proper grounding for jack hammers when in use.
Fabricate the boundary of excavation & in case of road excavation,provide flickering lamps on both sides during night together with road barriers and sign .
Provide adequate access larders,scaffolding people working at height more than 1.8 meter should be provide with safety belts.
All workers should be provide personnel protective equipments.
Sufficient shoring,De watering & disposal of excavated materials in proper places.
All the equipment and tools used for construction work should be properly maintained.
SWL of the lifting ropes to be followed strictly.

Construction of foam type extinguisher

                                 In this 95-97% of water & 3-5% of foam making compound is filled in the container. 

Top cover is made of brass or steel.
Co2 cartridge is used is of 120 gm with a pressure of 35 bar or 51 bar. 
Co2 cartridge is used to pressurize  & expel the solution which is coupled to the head .
The knob or squeezing lever fitted in the cap punters    the Co2 cartridge.
An FMB is attached to the hose for making the foam from the solution with air to make foam.


Operation of foam type extinguisher 

 Remove the safety clip / pin strike the knob/squeeze.Hold the hose to direct the foam to the seat of fire in a sweeping mode by taking support of a wall or such surface to avoid mixing up of foam with the oil.

Mechanical foam type extinguisher

In this type foam is produced from a foam solution as distinct from the  chemical form extinguisher,which is not there in use now.When the extinguisher is operated the foam solution is expelled by compressed air or by the gas  released from  a cartridge.




 THE FOAM CONCENTRATES MAY BE USED IN THE FOLLOWING TYPES : 


PROTEIN FOAM   :                                    MADE FROM ANIMAL FAT.

FLURO PROTEIN FOAM   :                         PROTEIN FOAM ADDED WITH FLUOROCARBONS. 

SYNTHETIC FOAM        :                           FOAMING AGENTS SIMILAR TO HAIR SHAMPOO OR  WASHING LIQUIDS. 

FILM FORMING FOAM  :                              AFFF & FFFP.


 ALCOHOL RESISTANT :                               P,FF OR FFFP CONCENTRATES WITH   POLYMERIZED LIQUIDS ADDED.

General safety rules for individual

Every one should behave and respect others. 
Follow and complies National rules and regulations. 
Every citizen should protect our national integrity and prevent outside evils. we have the right to safe our nation and our surroundings. 
We do our obligation to right and hand with right knowledge. Plant trees and participate in forestation and it lead to protect our environment from natural disaster.




                                            Don't kill animals and birds. In the case of family we should planed and active in following and ensure family safety. For family safety we can provide insurance for every one of the member of the family. For our home protection we must ensure to use advanced safety measures such as camera , intellectual, anti theft information devices and fire prevention system also install in your house. We should ensure safety in every discipline and every step of the journey. That is ensure safety in home , office , on children's matters , out side the home , driving etc . Today ensure our safety we can live tomorrow

Care & maintanance of extinguisher

                                              At least ones in a weak check the nozzle outlet and vent holes on the threaded portion of the cap[ for clogging.Check the plunger can be raised to the fully exerted position and that is to be cleaned if necessary.Once in a three months ,dismantle the components ,check for any damage,clean & grease them as required,stir the solution in the container with clean and dry stick.






                                               Annually operate 50 % of extinguisher and check  it project to the distance of not less than 6 meter for a minimum period of 30 seconds. Clean the extinguisher thoroughly and examine their inside for rust & corrosion .Subject rusty & corroded extinguisher to pressure test , even if they are not due for it and their performance otherwise satisfactory. Carry out the pressure test every 2 years  on which extinguisher by means of hydraulically test pressure is 17.5kg/cm2 and is applied for 2.5 minutes.

Operation & Recharge of water type extinguisher

Operation 

 Carry the extinguisher to the place of fire. Check the tightness of the cap.Remove the safety clip or safety pin. Strike opr squeeze the operating head,keeping your head away from the trajectory of the extinguisher head.Direct the water to the seat of fire in a sweeping mode.


 Recharge 



After making sure that the vent holes are free .Unscrew the head. Unscrew the gas cartridge.Clean the container properly and refill it with pure water up to the marking.Add anti freezing chemical if required.Check the plunger for its service ability.Clean and grease if required.Screw a new CO2 cartridge on  to the head .Replace or screw the head tighten it. The recharging date should be written on  the extinguisher. Check the rubber hose    for its operational purpose.Blow through the hose pipe.

Construction of Water type extinguisher

These extinguisher are cylindrical in shape. Outer container is made of mild steel & treated for anti corrosion.Contains 9 ltrs of pure water.The outer container is pressure tested for 350 PSI. CO2 cartridge stored in the cylinder by coupling it to the operating head. Operating head which is with a plunger & striking knob or squeezing lever is screwed to the outer container. The knob is protected with a safety clip or safety pin to prevent accidental operations. There are three vent holes provided on to cap to allow the pressure to be released  by which explosion hazard of the extinguisher can be avoided.

Type of extinguishers

Basically five type of extinguishers & they are: 

Water type
 Form type
 Dry chemical powder extinguishers 
 CO2
 Halon type. 


                                                           Water type & form type DCP extinguishers are basically gas cartridge type.CO2 and Halon are stored pressure type. Every one must have the knowledge in construction ,operation of an extinguisher,maintenance /recharge of an extinguisher.


Water type extinguisher. 


                                                           The extinguisher will have an operating head ,it is punching type or squeezer type .The operation of both types are different but the operation will be same that a pin in the operating head is piercing the CO2 cartridge coupled to the operating head.Water type extinguishers are normally used in a Class A Fire.

Proportion of discharge

Water & Form -95%

Powder type & Halons - 85% 

CO2 - 75%
Delay in operation: 



                                Not more than 4 seconds should lapse between the operation of the control mechanism & commencement of the discharge from extinguisher.

Color of portable extinguisher:

                              Water type extinguisher  Signal red Form type extinguisher Pale cream  Dry chemical powder  French blue  Halogenated hydro carbon  Emerald green CO2 Black with silver neck .But in general all extinguishers are painted red.

Minor fire fighting appliances

                                                Fire fighting equipments come in the form of fire buckets, fire blankets or portable fire extinguishers which may be portable or wheeled to carry it to operate in a place of fire. These are called generally minor fire fighting appliance. 

 

Portable fire extinguishers.

 

 

                                              Fire extinguishers come in variety of types and sizes. the working principles of extinguishers are based on Gas cartridge & Stored pressure.

FIRE FIGHTING TECHNIQUES

The success or failier of the fire fighting will largely depends on : 

Fire protection arrangements provided.
Provision of the fire equipments & early warning devices.
Conducting training . maintenance of fire fighting equipments.
                                                        


                                                         We have classified the fire in to four classes.,now we can consider the fire into two type.Such as Major fire & Minor fire. 
                                                  Major fire fighting appliances.


                                                         There are fixed fire fighting installations like Sprinklers ,Dranchers,TOTAL FLOODING SYSTEM ETC.WHICH MAY BE INTEGRATED TO AUTOMATIC FIRE / OR SMOKE DETECTION .these kinds of the fire fighting appliances .These equipments will work automatically or can be created manually.

Carbon dioxide

                                                             CO2 is an excellent smothering agents for extinguishing fires.Its about 1.5 times heavier than air. It can easily be liquefied and bottled normally under pressure of approximately 150to 200 bars. 






                                                                When used on fire the liquid CO2 gas taking away some heat.The gas extinguishers the fire by smothering it is a quick clean and non - conductor of electricity. It is comparatively non-toxic& does not harm most of the materials. It does not leave any residue. It can be stored for long period and it is easily available .CO2 is very effective in enclosed areas.It cannot penetrate in to any places that cannot be reduced by other means.It does not damage delicate machinery & instruments. It can be used safely on electrical equipments & panels.CO2 is highly ashipciating and cannot be detected by smell or colour. About 9% concentration causes unconsciousness .Any compartment which has been flooded with CO2 must be fully ventilated before entering without wearing  breathing apparatus.




                                                                 When liquid Co2 is released from a pressurised storage cylinder there is an extremely rapid expansion from to gas   which produce a refrigerating effect that convert part of CO2 in to snow. This snow which has a temperature of -79 degree Celsius,soon sublimes( changes directly from solid to gas ). This sublimation produce some cooling effect but it is the smothering effect of the gas ,which is of primary importance in the extinguishing process. At normal temperature & pressure the expansion ratio of CO2 is 1:450.

Beating Out

Small fires in materiel such as textile etc.may be extinguishing by beating them out .Beating is also the method normally employed to extinguish crop and other similar fires in rural areas when water is readily not available.

Blanketing

                                                   Another method by which fire may be extinguished,especially for persons whose clothing is on fire,is by blanketing.The person should be lay down & covered or rolled in rug,coat, jacket,woolen blanket etc.Oil fires in puns and small utensils can be smothered with an asbestos blanket or similar materiel .





                                                     Fire blankets are available in two specification such as light duty & Heavy duty.Light duty fire blankets are used for extinguishing small fires.Containers of cooking oils or fires in clothing worn in people.Heavy duty fire blankets are used for industrial applications to resist penetration by molten metal while cutting or welding and to protect against radiant heat ,it can be also be used for light duty application.

Vapurising Liquids

                                The halogenated hydrocarbon used for extinguishing fires have the property of vaporizing readily when heated and are , there fore generally known as vaporizing liquids.They form a dense heavier than air ,cloud of non flammable vapor which use only blanket fire but also interferes with the chemical reaction of flame propagation in the burning materials .Vaporizing liquids are non conductors of electricity & does not damage electronic equipments.Their Great draw back is their toxicity.Some well known extinguishing media such as CTC & Methyl Bromide have been withdrawn from use due to their toxicity. Freon type vaporizing liquids are presently used as they are less toxic.The most common substance used are Bromochloro Difluro methane (BCF)Bromotri Fluro methane(BTM).



                                   Halogenated extinguishing agents are hydrocarbon in which are more halogen atoms have been replaced by atoms from the halogen series.The replacement confirms non -flammability & Flame extinguishing property to many of the resulting compounds.The use of halogenated hydro carbons as fireTextinguishing media is not permitted in accommodation and living spaces.Halon produce some adverse effect on the atmosphere.It cause depletion of the ozone layer.It is partially responsible for the noticeable warning of the earths atmosphere .Now a days Halon is almost replaced by FM 200(HEPTA FLURO PROPANE).

Extinguishing Media (SAND)

Some burning materials such as metals  ,which cannot be extinguished by the use of water,may be dealt with by means of dry earth , dry sand ,powdered graphite, powdered talc , soda ash or lime stone all of which act as a smothering agent.Dry sand may also be used  to prevent burning liquids. Such as paints & oils , from flowing down drains ,basements etc. 


*Sand should never be used for extinguishing fires in machinery  such as electronic motors.

Extinguishing media (FORM)

Liquids having a specific gravity lower than that of water are much difficult for extinguishing with the use of water. When water is put to the burning surface of a liquid, it lower the temperature momentarily and then sinks below the surface of the liquid. Form is relatively insoluble in most liquids and because of its light weight , floats on the surface of the liquids. It forms a blankets capable of covering the surface of the burning liquid & so extinguish  the fire .It also forms a radiant heat barrier , which is of importance in extinguishing oil and petrol fires.

Extinguishing media (water)

                                       Water is the cheapest and most readily available medium  for extinguishing fires of a general nature. If more water is used than what is actually required to contain and extinguish fire, the surplus will drain off or will sweep through floors & may cause more damage to goods and property than that caused by fire itself. 
*The method of using water to extinguishing a fire various according to the size of the fire.
* If  only a small quantity of water is required , portable extinguishers expelling water may be used.
* If the fire is beyond the control of hard appliances ,hose reals may be used. 
*For major fires when grater quantities of water are necessary ,high capacity pumbs may be employed.
*A variation in the application of the water used can be made by means of nozzles that produce jets or sprays. 

Steam





                                  Steam in large quantities can be used to smother in fire .In situations where it is readily available .It can be used in fixed installation. Ships & industries having individual compartment are adapting steam to fill the compartment under pressure.

Classification of Fire

Fires are classified according to the type of fuel, which are burning .Fire can be classified  in to four  they are : Solid Fire Liquid Fire and liquifiable solid fire Gaseous Fire Metal Fire.


 Fire Type                                              Fire involving            fire fighting

Class A Fire                                                Solid materials                     Cooling

Class B Fire                                                Liquids or liqufieble solids.
                                                                (Grease,wax)              Smothering


Class C Fire                                                Gas                             Starvation ,Inhibition

Class D Fire                                                Metals                         Inhibiting    

Inhibiting

                                       Checking or stopping the exothermic reaction of substances which contains oxygen within them is known as inhibiting. Certain materiel contain oxygen in themselves. Such materials when on fire cannot be extinguished by smothering as they release oxygen from them.Examples are , Gun powder, TNT and RD X etc. Such fires are due to self -sustaining ,continuous  heat producing (exothermic) chemical reactions.In such fires extinguishing is possible only by breaking the chemical chain reaction.This type of extinguishing is called Inhibiting.

Smothering

To use on metal fires such as Uranium, Plutonium and Magnesium,a powders compound TEC has been discovered .This powder ,Ternary Etetic Chloride is applied by means of a gas cartridge pressurized extinguisher.As the fusing temperature of the powder is in the range of 580 degree celcious.It shall form a crust over the burning metal and thus exclude oxygen.The vigorous discharge of an inert gas such as  Carbon dioxide, Nitrogen etc. is also smothering the atmosphere.

Smothering

Limitation or removal of oxygen from the scene of fire is known as smothering.If the oxygen content of the atmosphere in the immidiate neighbour hood of burning material can be sufficiently redused  will cease . The general procedure is to prevent the access of fresh aie  to the seat of the fire. The principle of smothering is employeed on a small scale in snuffing a candle & on a large scale in capping a burning oil well.Form & Dry chemical powders are generally used  for smothering . The powder has a cooling effect in addition to its smothering effects.To use on metal fires.