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Saturday, December 30, 2017

Occupational Safety and Hazard Assessment in Steam Boilers

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The National Board Inspection Code (NBIC) and Factories and Machinery Act (Malaysia) recognized the potential hazards of steam boilers and established various codes and regulations pertaining to controlling the hazards and minimizing risks. Each year, the authorized inspectors inspect fireside and waterside for defects, scaling, and corrosion. Each year, all essential valves and fittings are dismantled for inspection. Plate thickness is checked, boiler water analysis results are reviewed, and indeed, the authority enforces rigorous maintenance on steam boilers but still, various boiler accidents happened. One might wonder why. The reason lies in one salient factor: human error is the leading cause of boiler accidents. One statistic indicated that 83% of boiler accidents were a direct result of human errors due to lack of knowledge and awareness. Although inspection has become stricter, the local authority does not cover inspection on boiler safety controls and all routine or non-routine activities. OSHA can only provide guidelines for safety in the workplace but ensuring the implementations is beyond their scopes.
The fundamental cause of hazards in an organization is organizational inadequacies. The inadequacies can be related to safety controls, safe operating procedures (SOP), hazard and risk assessment and controls, and training or awareness. With inadequacies, employees usually do not realize the hazards and consequences of their actions. Therefore, to minimize or eliminate risks exposed to all employees, contractors, and visitors in their activities, an organization should establish occupational health and safety (OHS) management system. Only through OHS that hazards can be recognized, and safety and health risks can be assessed and properly addressed. The management can set objectives, provide suitable controls, provide sets of procedures (SOP's), organize training programs, and establish safety performance evaluation.
Boilers have many potential hazards that must be controlled by safety devices and safe work practice. Before identifying the hazards, one must understand the meaning of hazards. In this context, hazard is defined as "a source or situation with a potential for harm in terms of injury or ill health, damage to property, or a combination of these". To begin identifying hazards, the management must know what activities are involved. Activities can be divided into two categories which are routine and non-routine. Routine activities include daily operation, chemical preparation, and fuel storage and handling, while non-routine activities include boiler overhaul, confined space entry, and emergency response. The first stage in hazard identification is a selection of job to be analyzed.
The management is to select the key activities first, such as daily operation and chemical preparation. In the second stage, OHS management is to break the activities into logical steps. The logical steps must be unique to the activities, and trivia activities such as switching on lights should be avoided. Examples are taking data from various meters during operation, or pouring boiler chemicals into a jar. In the third stage, the management is to identify hazards and determine the corresponding risks in each step. When preparing boiler chemicals, the boiler operators are exposed to corrosive liquid spill and acid gas release. Risk is the consequence, and in this case, the risks are eyes lesion and pain, burn injury, or cancer if handling hydrazine. High noise level which is above 85 dBA is an example of hazard in daily operation and the risk is obvious, which is deafness. In stage four, the management is to develop risk elimination or reduction measures.
For high noise level, risk elimination or reduction measures would require path noise control such as acoustic insulation (lining) or acoustic partition, enclosure for the noise-radiating source, increase pipe size to reduce steam turbulence, or install noise diffuser. The best approach is to control noise at source, such as installing silencer, changing equipment for example changing normal pressure reducing valve (PRV) to low-noise PRV. Other risk controls for high noise level would be wearing personal protective equipment (PPE) or reducing exposure time. The most common hazard for boiler operation is low water and the risk could be a permanent damage to the boiler or explosion. Modern boilers are usually equipped with automatic level controllers, low water level burner interlocks, low water alarm, and regular checking of gage glasses by the boiler operators. All these are risk controls by safety devices. Working in confined space is a non-routine activity, the hazard associated with it is physical injuries or fatalities due to asphyxia or poisonous gas, and the current risk control is following the guidelines of confined space entry, which shall not be covered here.
In pouring the chemical into a jar, the hazard is chemical splashes to eyes, and the risk is eye lesion and injury. From this, the risk control would be wearing safety goggles. Another example of daily operation is blowing down. Blowdown can cause spillage of hot water, which is the hazard, and may scald boiler operators, which is the risk. The example of risk control is blowing down into the blowdown chamber instead of directly into the atmosphere thereby reducing potential spillage of hot water to the surrounding.
In the final stage, after job safety analysis is completed for each activity, the activities, hazards and risks, and the corresponding risk controls should be documented for reference. Based on that, safe operation procedures can be established to ensure risks at the workplace can be eliminated or minimized. Training must be conducted by the competent person-in-charge to all boiler operators to explain in detail the hazards, risks, controls, procedures and responsibility as well as accountability.
For any organization which does not have structured OHS management system, I would recommend OHSAS 18001 or MS 1722 certification. OHSAS 18001 or MS 1722 provides a set of procedures and tools to promote continual improvement through hazard identification, risk assessment, and control of risk in a very systematic way. Apart from these benefits, I noticed with the implementation of OHSAS 18001 standards, the management and employees in my organization have improved significantly in their understanding of health and safety legislation as well as the ability to demonstrate compliance.
Hisham Hashim is a proud author of 101 Q&A Practical Knowledge of Steam Boilers e-book and writes articles on various subjects in steam boilers, safety, and environment. He has strong hands-on experience in preparation, development, and implementation of ISO 9001, ISO 14001, and OHSAS 18001. He also participates actively in HSE audits as the lead auditor, and proposes corrective actions on noncomformance. To learn more about all aspects of steam boilers, from operation, maintenance, boiler water treatment, to boilers codes and safety, visit his website at [http://www.boiler-ebook.com] for further information.


Boiler Service For Boiler Safety

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A boiler is a closed vessel in which water or other liquids are heated. When most people hear 'boiler' they think of their hot water tank at home which heats their radiators and shower. In the past, boilers have been associated with injuries and even deaths due to a number of factors which meant they were not 100% safe for use. Today's boilers are technologically sound and any accidents that happen are rare and could often have been prevented had a boiler service being carried out.
Inside a boiler there is pressurized steam which is created as the water heats up. If there is any defects in your boiler this can lead to serious injuries, the most common happening to be burns. Faults in the boilers include poorly welded seams and hinges which can come open if the pressure inside the cylinder gets too high. If the boiler is old it might be made out of thin or brittle metal which can rupture after heavy usage or if the temperature gets too hot. A regular boiler service will help you to avoid accidents such as these, and will keep your hot water system in tip-top condition.
Another safety issue that boilers can present is running dry. If there is a leak in the system somewhere or the boiler is allowed to empty of all of its liquid, the metal shell is exposed to intense heat. The next time any water hits the shell an explosion will occur and the whole boiler could blow up.
If you have a boiler in your house that is out of warranty, it is unlikely that the provider will be held accountable should something go wrong. Spending a few pounds a year on an annual boiler check-up could save you hundreds of pounds should something serious go wrong, and could end up saving your life if a defect is found.
In November 2007 Christine Goodall from Gloucestershire died along with her pet dog when a boiler behind her fireplace exploded. The water inside had expanded as the tank got hotter and caused the metal to rupture, which led to Mrs Goodall's death.
The boilerguide, a leading online resource for homeowners and industry workers recently reported that 1 in 5 home owners are not aware of when their boiler should be serviced. This could leave many houses without central heating in the winter months and make your living condition extremely uncomfortable.
Author Mark Woodcock is a Webmaster of a wide variety of online speciality shops including a very popular site offering a Boiler Service. Visit http://www.eagaheat.com today.


4 Dangers Of Using A Faulty Boiler

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A machine such as a boiler can be faulty, caused by several factors including the operation, design, structure, and its maintenance. These machines can sometimes become faulty from years of involuntary neglect or in this case, ignoring boiler repair. When it comes to these types of failures, there is no potentially dangerous equipment operating in an industrial manufacturing facility than power generating equipment. The boiler is known to be the largest and most expensive equipment but also the most dangerous, if mishandled. Here are some of these dangers.
· Fuel explosions
This has to be the most dangerous situations you may face when using a faulty boiler. The effect is the same as that of a fuel explosion in an oven! The boiler could have operational problems that occur either while using it or during manufacturing. To eliminate such occurrences, always buy a steam boiler from a legitimate manufacturer. If properly operated and maintained, the possibility of a fuel explosion is virtually reduced.
· Inadequate water blow down
For a boiler to last long and perform its blow down practices, high quality feed-water is required. The unwanted solids in the boiler water are reduced by the blow down system which should properly run at all times. Should the boiler exceed the limits, potential problems such as corrosion, scale and sludge formation, moisture carry over due to foaming, and poor steam drum performance will occur.
· Poor feed water quality
Feed water should always be treated to protect the boiler from corrosion and buildup of solid deposits on the tubes. Water in the boiler is vaporized to steam and leaves the solids in form of scale the areas where there is a high rate of heat transfer. This can result to an insulating layer that prevents the water to eliminate heat from the surface of the tube. If it worsens with time, the tubes are eventually going to overheat and cause permanent damage. To prevent deposits on tubes, maintain low levels of solids. The higher the pressure and temperature of the boiler, the more feed-water treatment is encouraged.
· Low-water incidence
Boilers have furnace temperatures exceeding 1800 F. Therefore, you can imagine the damage that would be caused if near low water conditions exist. The main reason boilers can withstand these extreme temperatures is the presence of water in all the boiler tubes when a fire is present at all times. In a matter of minutes, constant firing during a low water condition will literally melt the steel boiler tubes.
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Article Source: http://EzineArticles.com/7953581

Is a Steam Boiler a Time Bomb?

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Before answering the question, let us examine the following scenarios: On Dec 29, 2009, a boiler exploded at a palm oil mill in Sabah, Malaysia, killing one boilerman and injured many others. On September 24, 2010, nine people were killed and four others injured when a boiler exploded in an aluminum plant in Xiaoyi City, China, and on Feb 22, 2011 in Talkatora Industrial Estate in Uttar Pradesh, India, three persons were killed and six received serious burn injuries following a huge boiler explosion in Kiran Plywood Factory.
Based on those incidents, despite having various protections and inspections by local jurisdictions, we can conclude that explosion is actually not very rare in modern boilers. It happened almost every year although today, the casualty did not exceed 20 people per year. The good news about boiler explosion is that it can be prevented. The bad news however, some personnel are not aware of the mechanism of boiler explosion and tend to stick to the routine they have been practicing for years, and thus accident happens. So the answer is, yes and no.
Investigations after investigations were made and human errors seem to be the main cause for boiler explosion. Other causes are inadequate boiler operating procedure, improper boiler maintenance, or inoperative boiler controls and safety devices. Therefore, special considerations must be made on standard operator training.
The topic of boiler explosion is too broad to be covered in a short article; therefore, I shall only discuss the causes of fireside explosion, since furnace explosion is more common than waterside explosion. First of all, what is fireside explosion? Well, in a fireside explosion, an accumulated combustible mixture ignites almost simultaneously, creating a force which exceeds the yield strength of the boiler furnace, casing or uptake, causing catastrophic structural damage. The sudden load explosion in the boiler furnace can be heard miles away.
The principal cause of furnace explosion for oil-firing boiler is the accumulation of unburned fuel in the furnace due to incomplete or non-ignition. The accumulated oil on the hot furnace floor begins to volatize and releases its combustible gases when the operator initiates another trial for ignition. When the mixture of unburned fuel with air is in explosive proportion, explosion will occur. Explosive proportion is where the lower explosive limit (LEL) of diesel fuel marine (DFM) is 0.6% by volume vapor to oxygen. Once the LEL is reached, explosion may occur. Maximum explosion normally occurs at 2.0% by volume DFM vapor to oxygen.
There are many ways the oil may enter the furnace in an unburned state. Poor atomization can cause discharge of unburned oil into the furnace. There are three ways of atomizing fuel, which are forcing under pressure of 5 to 15 bars, steam atomizing, ranging from 5 bars to 10 bars of steam, and mechanical atomization (rotary cup atomizers) with a rotary cup rotates at 8,000 rpm. Obviously, if the atomizing pressure is too low, oil cannot atomize properly and much oil will drop on the furnace floor in an unburned state. Sometimes atomizing steam can be wet due to high condensate which is often due to poorly insulated steam line or malfunctioned steam traps, which can result in loss of atomization.
Most importantly, atomization is affected by the viscosity of the oil which in turn affected by the temperature. To prevent this, the oil tips must be clean, the oil temperature must be correct to keep the oil at oil firing viscosity of 200 to 220 SSU (Saybolt Seconds Universal), and the atomizing steam (or air) pressure and fuel oil pressure must be properly adjusted. This means that the oil must be heated up to 60oC for light oil and as high as 95oC for heavy oil.
Fuel inlet valve can also be a problem. Fuel can also enter the furnace through leaky fuel inlet valves on idle burners. Sometimes, the fuel inlet valve cannot secure fuel supply to atomizers promptly when fires are extinguished or there is a slight delay in fuel shut off if the flame extinguished unexpectedly.
During starting up, sometimes difficulty is experienced in establishing ignition due to failure of photocell or flame scanner (or other mechanical problems) that can prompt the boilermen to attempt starting up the boiler for several times, which resulted in pool of unburned fuel to be accumulated after each trial.
Failure to purge furnace properly, including furnace, boiler and uptake areas can also cause boiler explosion. During boiler startup, purging sequence is required to drive out all combustible and explosive gas from the furnace through the uptake before ignition. Purging sequence must be sufficient. As a rule of thumb, an ideal purging should give five changes of volume. For a large boiler, normal set time would be 20 minutes while for a medium or smaller, a shorter time may be required, and the air flow must be low, which is only 25% of the normal full-load air. Purge air requirement is normally 4 SCFM for light fuel or 15 SFCM for heavy fuel. A word of caution, never bypass the purging sequence by all means.
Learn how flame impingement and soot blowing can contribute to fireside explosion. Besides overpressure, learn how low water and other causes can cause waterside explosion and implosion. And most importantly, know the ways to prevent boiler explosion from me in detail.
My name is Hisham Hashim, a competent steam engineer, and I have vast experiences working with power boilers including solid fuel and natural gas boilers. I have successfully trained many engineers and boilermen to obtain their competency certifications. Whether you are sitting for your First Grade, Second Grade, or even Boilerman Certificate of Competency, whether this is your first try or your third try and no matter which country's exam you're taking, I have the tools and information you require to pass your boiler licensing examination with flying colors. For further information, visit [http://www.boiler-ebook.com]


Boiler Explosions

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A boiler, also known as a steam generator, is a closed compartment in which water, or sometimes another fluid, is heated. The heat is used to produce steam, which in turn is used to power an engine or for heating applications. Historically, boilers have been known to cause devastating explosions, and although modern boilers are designed and assembled with caution regarding worker safety, sadly, catastrophic explosions may still occur if a boiler fails.
Boiler Failure
Older-model boilers often have a lack of structural integrity that can cause explosions. If a boiler is made of a brittle, thin metal shell, it can rupture. If seams are poorly riveted or welded, they may come apart. If a tube collapses or becomes dislodged, dangerous steam and smoke can spray out and injure anyone in the near vicinity. Or, if the water drains from a boiler and new water is added, the new water may evaporate on contact with the hot shell and cause and explosion. Failures in large boilers that offer a large amount of energy to operate factories can destroy entire buildings.
General reasons for boiler failure include:
  • An excess of pressure within the boiler
  • A lack of water inside the boiler, causing the vessel to overheat
  • Defective construction or lack of maintenance, causing pressure vessel failure
Why Boilers are Dangerous
Many people underestimate the dangers of boilers, thinking that water and steam can only do so much damage. However, the boiling water inside of a boiler has enough energy to power entire engines, machines, and even large factories. A failed boiler can cause devastating injuries, loss of life, and loss of property.
Some basic boilers contain pressurized water held at a temperature of about 300 degrees Fahrenheit. If somehow the boiler looses pressure suddenly, all of the water would instantly evaporate into steam. Water in its gaseous state takes up around 1,600 times as much space as water in liquid form. If a leak occurs in a boiler, this evaporation and expansion of water into steam can take place less than one second, producing a giant explosion.
Modern boilers contain many safety features to reduce the risk of explosions, including:
  • Safety valves, which can be adjusted to release steam before a buildup of pressure
  • Fusible plugs, which may overheat, melt, and produce a whistling noise to warn workers when a problem occurs
  • Ties, also known as stays, which attach the boiler casing to its exterior compartment and prevent warping.
To learn more about boiler explosions and injuries, visit the Explosion Victims Resource Center [http://www.explosionvictimresourcecenter.org/].
Michael Enfield


Electrostatic Precipitators for Pollution control

Electrostatic Precipitators for Pollution control
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