Contents
Safety in Cement Plant
Contents
• Processes Involve
• Hazards Involve in Operation
• Safety Counter Measures
Summary Of Process
Cement is typically made from limestone and clay or shale. These raw materials are extracted from the quarry crushed to a very fine powder and then blended in the correct proportions.
This blended raw material is called the ‘raw feed’ or ‘kiln feed’ and is heated in a rotary kiln where it reaches a temperature of about 1400 C to 1500 C. In its simplest form, the rotary kiln is a tube up to 200 meters long and perhaps 6 meters in diameter, with a long flame at one end. The raw feed enters the kiln at the cool end and gradually passes down to the hot end, then falls out of the kiln and cools down.
The material formed in the kiln is described as ‘clinker’ and is typically composed of rounded nodules between 1mm and 25mm across.
After cooling, the clinker may be stored temporarily in a clinker store, or it may pass directly to the cement mill.
The cement mill grinds the clinker to a fine powder. A small amount of gypsum – a form of calcium sulfate – is normally ground up with the clinker. The gypsum controls the setting properties of the cement when water is added.
Safety- Hazards
In all the cement production processes there are hazards that can be classed in:
o Safe behaviour
o Environment, Work and Passage Areas
Routine and general hazards such as:
o Safety labelling
o Personal Protective Equipment (PPE)
• Special hazards during the cement production phases such as:
o Quarrying
o Crushing
o Clinker production
o Milling processes at raw mill, cement milling and coal milling
o Material transport
o Storage
o Use of hazardous material
o Isolation
• Special hazards as a result of the work environment:
o Dust
o Noise
o Fire
o Emergency response
Environment, work and passage Areas
• The environment should be free from obstacles.
• All tools should be placed to their respective tool box.
• All equipment and tools should be placed away from the work area to avoid obstacles incase of emergency.
• All emergency exits including fire exits should be free from obstacle, and should have proper signage and emergency lights.
• Roads and path of trucks should be free from pedestrians and should also have proper signage and traffic warnings.
Safety Labeling
• Attach labels and safety pre-cautions to serve as a guide to the workers.
• Attach directions and labels for emergency exits.
• Place the label to where they are easily seen lest they become useless.
• All workers should have their own materials according safety operations and others.
• All workers should be supervised by a safety engineer and should wear proper ppo (personal protective gear) before going to work.
• Safety precautions should be placed in the entrances or doors to serve as a reminder to the workers.
• Equipments should also have labels and warnings for basic operations.
• Warnings should be placed in dangerous areas such as sink holes in quarry, excavation, slippery places or roads .hot bodies, etc.
Special hazards during the cement production phases
Quarrying
HAZARDS:
• Common hazards associated with the heavy plant (e.g. dumper trucks, front loading shovels, fork lift trucks) used in quarrying and bulk material transport include vehicle impact and twisted ankles during embarking and disembarking. Vehicle impact as the potential for particularly high severity incidents, in quarries.
• Vehicular accidents.
• Risk of possible falling objects.
• Hazardous fumes in the mine or quarry. E.g. coal gas.
• Helicopter Over flight Hazard.
• Risk of falling from high places.
SAFETY COUNTER MEASURES:
• Proper signs and safety precautions.
• Proper lightings.
• Proper and frequent maintenance of vehicles and other heavy equipments. This really helps a lot in reduction of possible risks and hazards just like unexpected mechanical equipment failures.
• Phones are prohibited in the site. This may cause disturbance to the workers.
• Always wear safety gears especially hard caps to protect you to unexpected falling objects.
• Flying over the near the site is really dangerous because of thinness of the atmosphere that may lead to stall.
• Stay away from heavy equipments, the driver has limited eye site. Install rear cameras to reduce risk in traffic.
• Always wipe or clean the head lights and back lights of heavy equipments. Dust is always present in cement industry, it might cover the lights of heavy equipments.
• Always wear safety harness when working in high places.
Crushing
HAZARDS:
• Physical direct contact to the machine might injure you.
• Falling objects are also present in this process.
• Traffic hazards are also present.
SAFETY COUNTERMEASURES:
• Always stay away from the machine when it is operating.
• Wear safety equipments.
• Always be attentive of possible unexpected scenarios.
• Proper slogans should be where it can be easily seen.
• Stay away from heavy equipments, the driver has limited eye site. Install rear cameras to reduce risk in traffic.
Clinker Production
HAZARDS:
Incidents and injuries resulting in burns arise from contact with hot clinker or cement powder. Hazards are particularly associated with hot cement kiln dust (CKD), and dust on preheater systems. Chemical (alkali) burns may also result from contact with CKD.
Raw Mill and Preheater Tower:
Material in the mill is at temperatures up to 120ºC, in the
tower the material can be as hot as 900ºC. Contact with the material is more likely when: Clearing blockages in the tower where there is the potential for it to flush through the process
During rodding and cardoxing where it can be ejected over a wide area.
Hot Clinker: Contact is possible in the:
x clinker cooler building
x along the clinker pan conveyors
x in the clinker dome
x along the belts to the cement mills
Precipitator and By-Pass Dust:Contact is possible when:
x access is required to the precipitator hoppers
x working on the screws and drag chain conveyors
x maintaining the dust transfer pumps
Hot Cement:Contact is possible when:
x accessing the cement transfer lines
x working on the packers
x carrying out work on the cement screw conveyors and drag chains
SAFETY COUNTERMEASURES:
• Eliminate the hazard (install insulators)
• Reduce the risk at source
• Isolate people from the hazard
• Control the risk by other means
• Protect yourself with the correct PPE
Material transport
HAZARDS:
• Traffic hazards
SAFETY COUNTER MEASURES:
• All categories of vehicle, including self-propelled mobile plant, must not be operated unless: vehicle is fit for purpose, inspected and confirmed to be in safe working order .
• Number of passengers does not exceed manufacturer’s design specification for the vehicle .
• Loads are secure and do not exceed manufacturer’s design specifications or legal limits for the vehicle
• Seat belts are installed and worn by all occupants
• Safety helmets are worn by riders and passengers of motorcycles, bicycles, quads, snow-mobiles and similar types
• of vehicle
• Drivers must not be authorized to operate the vehicle unless:
• They are trained, certified and medically fit to operate the class of vehicle .
• They are not under the influence of alcohol or drugs, and are
• Not suffering from fatigue
• They do not use hand-held cell phones and radios while driving.
• (best practice is to switch off all phones and two-way radios when driving)
Storage
Hazards:
• A confined space is any space of an enclosed nature where there is a risk of death or serious injury from hazardous substances or dangerous conditions. The risks in confined spaces arise due to
• Entry into any confined space cannot proceed unless:
• all other options have been ruled out permit is issued with authorization by a responsible person(s)
• permit is communicated to all affected personnel and posted, as required
• all persons involved are competent to do the work
• all sources of energy affecting the space have been Isolated
• testing of atmospheres is conducted, verified and
• repeated as often as defined by the risk assessment
• stand-by person is stationed
• unauthorized entry is prevented
• Lack of oxygen Poisonous gas, fumes or vapour Liquids and solids, which can fill the space suddenly Fire and explosions
• Dust Hot conditions
To minimize the risks associated with confined entry:
• Avoid entry to confined spaces e.g. by doing the work from outside.
• Blockages can be cleared in silos by use of remotely operated rotating flail devices, vibrators or air purgers.
• Inspection, sampling and cleaning operations using the right equipment.
• Remote cameras can be used for internal inspection of vessels.
• Make sure combustible material are separated according to it’s kind and store them in a cool dry place.
Use of hazardous material
Hazards:
• Possible poisoning due to inhalation of hazardous materials.
• Irritation
• Possible direct contact of material or chemical to the eyes.
• Direct contact may cause skin disorders.
SAFETY COUNTER MEASURES:
• wear proper ppo (cloves, goggles, boots, hard cap , etc.)
• Incase of irritation do not use alcohol, use water instead.
• Incase of eye irritation, do not rub your eyes, rinse with water and call a physician immediately or go to clinic.
• Incase of poisoning, call a physician .
Isolation
• Any isolation of energy systems; mechanical,electrical, process, hydraulic and others, cannot proceed unless:
• the method of isolation and discharge of stored energy are agreed and executed by a competent person(s)
• any stored energy is discharged
• a system of locks and tags is utilized at isolation points
• a test is conducted to ensure the isolation is effective
• isolation effectiveness is periodicallymonitored
Electrical Isolation
• Electrical Isolation:
• Turn off electrical isolating switches,
• ensure that local isolation is effective,
• some machinery requires sub station isolation.
• Each worker should have his own key ensuring isolation.
Special hazards as a result of the work environment:
o Dust
o Noise and vibration
o Fire
o Emergency response
Dust
• Inhalation might cause elevated chronic obstructive lung diseases.
SAFETY:
• It is good practice to limit dust levels and employee exposure both in terms of employee health and good housekeeping.
• Appropriate respiratory protection should be worn where work has to be carried out in dusty areas in cement plants,
Noise and Vibration
• Too much exposure to sounds and vibrations might deafen workers.
SAFETY COUNTER MEASURE:
• Wear earplugs that are appropriate to your ear.
• Improved noise personal protective equipment is also helping reduce the effects of exposure.
• Regularly monitor employee auditory functions to ensure this does not exceed natural decline with age.
Fire
Unexpected explosions may occur when highly combustible materials are exposed to heat due to confined places.
SAFETY MEASURES:
• Plastics: Recycled plastics are normally used in shredded form and conveyed pneumatically. There can be considerable associated dust requiring eye protection and breathing masks as well as full body clothing, metal silos and ducts need electrical earthing to prevent an explosion hazard. Fire protection is also required, as well as evacuation instruction in the case of fire, as smoke vapours can be toxic.
• Solvents: Recycled solvents must be rigorously sampled at intake because of variable chemical and physical composition in order to determine health precautions. Most solvents are toxic and may be flammable. Therefore health precautions are similar to those used in the source industry (e.g. chemical, pharmaceutical) Intake and storage systems must be designed for safe, automated handling, with spill, fire and explosion protection, with an associated emergency plan. Health procedures require eye protection, breathing masks and full cover clothing.
• Used Oils: Used oils will need to be checked for PCB content, which will determine precise precautions required. Requirements are generally similar to those for solvents, with similar health precautions.
Emergency Response
• Fire and emergency procedures
• First aid facilities
• Environmental emission controls
• Emergency response team.
• Emergency plan
Please provide safety check list for cement industries. Only safety check list name