NAME:MUHAMMAD FAIQ DANIAL BIN NOR ISAAM
MATRIC NO:012015051800
SUBJECT:INDUSTRIAL HYGIENE(YOS10603)
LECTURER:ANIS ZAKIAH BINTI MAZLAN
SLOGAN:SAFETY TOOLS ARE YOUR BEST RULES
What is a confined space?
A confined space is an enclosed or partially enclosed space that:
is not primarily designed or intended for human occupancy
has a restricted entrance or exit by way of location, size or means
Can represent a risk for the for the health and safety of anyone who enters, due to one or more of the following factors:
o its design, construction, location or atmosphere
o the materials or substances in it
o work activities being carried out in it, or the
o mechanical, process and safety hazards present
Confined spaces can be below or above ground. Confined spaces can be found in almost any workplace. A confined space, despite its name, is not necessarily small. Examples of confined spaces include silos, vats, hoppers, utility vaults, tanks, sewers, pipes, access shafts, truck or rail tank cars, aircraft wings, boilers, manholes, manure pits and storage bins. Ditches and trenches may also be a confined space when access or egress is limited.
What are the hazards in a confined space?
All hazards found in a regular workspace can also be found in a confined space. However, they can be even more hazardous in a confined space than in a regular worksite.
Hazards in confined spaces can include:
Poor air quality: There may be an insufficient amount of oxygen for the worker to breathe. The atmosphere might contain a poisonous substance that could make the worker ill or even cause the worker to lose consciousness. Natural ventilation alone will often not be sufficient to maintain breathable quality air.
Chemical exposures due to skin contact or ingestion as well as inhalation of 'bad' air.
Fire Hazard: There may be an explosive/flammable atmosphere due to flammable liquids and gases and combustible dusts which if ignited would lead to fire or explosion.
Process-related hazards such as residual chemicals, release of contents of a supply line.
Noise.
Safety hazards such as moving parts of equipment, structural hazards, entanglement, slips, falls.
Radiation.
Temperature extremes including atmospheric and surface.
Shifting or collapse of bulk material.
Barrier failure resulting in a flood or release of free-flowing solid.
Uncontrolled energy including electrical shock.
Visibility.
Biological hazards.
What should be done when preparing to enter the confined space?
The important thing to remember is that each time a worker plans to enter any work space, the worker should determine if that work space is considered a confined space. Be sure the confined space hazard assessment and control program has been followed.
The next question to ask is - Is it absolutely necessary that the work be carried out inside the confined space? In many cases where there have been deaths in confined spaces, the work could have been done outside the confined space!
Before entering any confined space, a trained and experienced person should identify and evaluate all the existing and potential hazards within the confined space. Evaluate activities both inside and outside the confined space.
Air quality testing: The air within the confined space should be tested from outside of the confined space before entry into the confined space. Care should be taken to ensure that air is tested throughout the confined space - side-to-side and top to bottom. A trained worker using detection equipment which has remote probes and sampling lines should do the air quality testing. Always ensure the testing equipment is properly calibrated and maintained.
How are hazards controlled in confined spaces?
The traditional hazard control methods found in regular worksites can be effective in a confined space. These include engineering controls, administrative controls and personal protective equipment. Engineering controls are designed to remove the hazard while administrative controls and personal protective equipment try to minimize the contact with the hazard.
However, often because of the nature of the confined space and depending on the hazard, special precautions not normally required in a regular worksite may also need to be taken. The engineering control commonly used in confined spaces is mechanical ventilation. The Entry Permit system is an example of an administrative control used in confined spaces. Personal protective equipment (respirators, gloves, ear plugs) is commonly used in confined spaces as well.
How is air quality maintained?
Natural ventilation (natural air currents) is usually not reliable and not sufficient to maintain the air quality. Mechanical ventilation (blowers, fans) is usually necessary to maintain air quality.
If mechanical ventilation is provided, there should be a warning system in place to immediately notify the worker in the event of a hazard or a failure in the ventilation equipment.
Care should be taken to make sure the air being provided by the ventilation system to the confined space is 'clean' throughout the entire space.
Ease of air movement throughout the confined space should be considered because of the danger of pockets of toxic gases still remaining even with the use of mechanical ventilation.
Do not substitute oxygen for fresh air. Increasing the oxygen content will significantly increase the risk of fire and explosion.
The use of mechanical ventilation should be noted on the entry permit
Ensure air being removed from the confined space is exhausted away from workers on the outside.
What are other safety precautions?
Many other situations or hazards may be present in a confined space. Be sure that all hazards are controlled including:
Any liquids or free-flowing solids are removed from the confined space to eliminate the risk of drowning or suffocation.
All pipes should be physically disconnected or isolation blanks bolted in place. Closing valves is not sufficient.
A barrier is present to prevent any liquids or free-flowing solids from entering the confined space.
The opening for entry into and exit from the confined space must be large enough to allow the passage of a person using protective equipment.
Case Study:City Water Worker Dies When Overcome by Natural Gas Vapors in a Confined Space in Ohio
INTRODUCTION:
On July 1, 1985, an industrial meter reader employed by a mid-sized city in Ohio began his workday as usual at 7:30 a.m. He did not return to the garage at quitting time (4:00 p.m.) and was found face down in a meter vault at 6:45 p.m.
OVERVIEW OF EMPLOYER'S SAFETY PROGRAM
This city has a population of 235,000 an employs approximately 2,500 permanent and temporary workers. There are six major departments, one of which is the Department of Public Service. The Department of Public Service has several bureaus, including the Public Utilities Bureau. The Public Utilities Bureau has four divisions: Utility Services, Water Supply, Water Pollution Control, and Water Distribution. The victim was employed by the Water Distribution Division. This division employs 145 full-time and up to 25 seasonal workers. There are six industrial meter readers, two of which are assigned to reding meters at any one time. (Meter readers work individually.)
A deputy to the mayor is the designated safety officer and 90 percent of his time is spent handling labor relations and the remainder of his time is spent dealing with safety-related issues.
A deputy to the mayor is the designated safety officer and 90 percent of his time is spent handling labor relations and the remainder of his time is spent dealing with safety-related issues.
SYNOPSIS OF EVENTS
On July 1, 1985, route assignments were received by the meter readers at 7:30 a.m. The victim (a 42-year-old meter reader) was assigned 76 accounts to be read that day. The victim had traded the original route assigned for a route with which he was unfamiliar. Industrial meters may be located in basements, at ground level, or in meter vaults and any one route may include all of these meter locations. The victim did not return to the garage at the usual quitting time of 4 p.m. This is not unusual because workers are occasionally late. At 5 p.m. when the victim still had not returned and he did not respond to dispatch calls, the police were notified. At 6:45 p.m. a passerby reported that the meter reader was down in a manhole and a fire rescue unit was dispatched to the accident site. The victim was found face down in the vault. The vault had approximately 4 1/2 inches of water in it. Resuscitation efforts were unsuccessful and the victim was pronounced dead at 9:31 p.m.
The victim had read 33 out of the 76 assigned meters when he reached the accident site. His supervisor felt that this should have taken until approximately 1:30 p.m. The victim was familiar with this vault, having seen it at the time of installation; however, this was the first reading of this newly installed meter. The vault was installed in May 1985 and was inspected for compliance with city regulations at that time. During this inspection, it was noted that the manhole cover did not have holes required for sufficient ventilation. The manhole cover was to be checked for compliance at this meter reading. No holes were present in the cover. According to the employee's supervisor, the victim may have had difficulty in removing the cover because the hook used to pull the lid open was straightened out and a sledge hammer was lying next to the manhole.
The vault (a two-piece, precast concrete structure---15 feet by 9 feet by 8 feet) contains large water lines and an industrial water meter. No other utility services used this vault. An investigation of the vault was undertaken by the local coroner's office. The investigation revealed a faint odor of natural gas. The local gas company was notified about a possible leak. It was later determined that a leak was present in a nearby line and the gas was then turned off. After the vault was determined safe for entry, the interior of the vault was inspected; however, no signs were present that indicated that the victim may have slipped or fallen. Since natural gas was suspected in this accident, the vault was further tested. On July 3, 1985, the gas line was turned on and the vault tested. The atmosphere in the vault was periodically tested. It was eventually determined that oxygen (17 percent), methan (15 percent), and carbon monoxide (<600 parts per million) were present. On July 10, 1985, the gas line was excavated by hand. A leak was found at a coupling approximately 34 inches from the vault.
The victim had read 33 out of the 76 assigned meters when he reached the accident site. His supervisor felt that this should have taken until approximately 1:30 p.m. The victim was familiar with this vault, having seen it at the time of installation; however, this was the first reading of this newly installed meter. The vault was installed in May 1985 and was inspected for compliance with city regulations at that time. During this inspection, it was noted that the manhole cover did not have holes required for sufficient ventilation. The manhole cover was to be checked for compliance at this meter reading. No holes were present in the cover. According to the employee's supervisor, the victim may have had difficulty in removing the cover because the hook used to pull the lid open was straightened out and a sledge hammer was lying next to the manhole.
The vault (a two-piece, precast concrete structure---15 feet by 9 feet by 8 feet) contains large water lines and an industrial water meter. No other utility services used this vault. An investigation of the vault was undertaken by the local coroner's office. The investigation revealed a faint odor of natural gas. The local gas company was notified about a possible leak. It was later determined that a leak was present in a nearby line and the gas was then turned off. After the vault was determined safe for entry, the interior of the vault was inspected; however, no signs were present that indicated that the victim may have slipped or fallen. Since natural gas was suspected in this accident, the vault was further tested. On July 3, 1985, the gas line was turned on and the vault tested. The atmosphere in the vault was periodically tested. It was eventually determined that oxygen (17 percent), methan (15 percent), and carbon monoxide (<600 parts per million) were present. On July 10, 1985, the gas line was excavated by hand. A leak was found at a coupling approximately 34 inches from the vault.
CAUSE OF DEATH
According to the coroner/pathologist, the cause of death was cardiovascular collapse due to the acute myocardial ischemia due to inhalation of toxic fumes: "methane and carbon monoxide."
RECOMMENDATIONS/DISCUSSION
Recommendation #1: The city should develop and implement a comprehensive safety program. The Division of Water Distribution should have a documented safety program that identifies safe work practices to be followed. This program should include recognition of potential hazards.
Discussion: The city has no safety program and no written safety policy exists. Additionally, the Divison of Water Distribution does not have a written safety policy or manual. Safety training is the responsibility of supervisory personnel and is limited to on-the-job training. The Division of Water Distribution is in the process of starting a new safety program for all employees consisting of four hours of initial training and a monthly, one-hour follow-up. This course needs to be supplemented by a written safety manual.
Discussion: The city has no safety program and no written safety policy exists. Additionally, the Divison of Water Distribution does not have a written safety policy or manual. Safety training is the responsibility of supervisory personnel and is limited to on-the-job training. The Division of Water Distribution is in the process of starting a new safety program for all employees consisting of four hours of initial training and a monthly, one-hour follow-up. This course needs to be supplemented by a written safety manual.
REFERENCE
- Confined Spaces. National Institute for Occupational Safety and Health (NIOSH) Workplace Safety and Health Topic.
- Preventing Occupational Fatalities in Confined Spaces. U.S. Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 86-110, (January 1986).
- Confined Spaces Advisor. OSHA. Provides an interactive expert help for the Permit-Required Confined Spaces Standard (29 CFR 1910.146). Assists users in identifying confined spaces and deal with permit-required confined spaces.
