11 Rules for Safe Handling of Hazardous Materials, Essay Example

Safety in the work environment is an imperative part of the operation of any system of mechanical engineering to ensure that no workers get hurt and that the job gets done adequately. If there is an existing safety hazard, it must immediately be addressed so that nobody is put in harm’s way while trying to do their job.

Air conditioning and refrigeration are an essential component to the engine room on Navy ships. This may include chillers and condensers. However, when operating the mechanics of these operations, it is important to have a system of safety to guide and protect workers when carrying out their duties. There is always the risk of safety hazards which may include but are not limited to that of energy sources, hazardous functions, hazardous operations, hazardous components, as well as hazardous materials.

Safety Hazard Check List

• Energy Sources
• Hazardous Functions
• Hazardous Operations
• Hazardous Components
• Hazardous Materials

The following material covers minimum requirements and is not intended to be a comprehensive guide to job safety. Some conditions greatly increase the chance for accidents in any working environment, including crowded work areas, blocked passageways, overloaded platforms and hoists, inadequate support for scaffolds, elevators without proper guards, damaged tools or power cords, poor ventilation or lighting, defective or worn protective equipment and clothing, improper storage or use of chemicals, and unsafe use of flammable materials. Some behaviors also boost the odds of accident and injury, such as inattention, creating sparks or flames near flammable materials, creating toxic fumes in unventilated areas, riding equipment not designed for personnel, removing guards from machinery, stacking materials poorly, and neglecting to wear protective clothing. Horsing around and working when tired are other common causes of accidents.

Energy Sources

Sources of energy must be addressed with extreme safety precautions to prevent hazards such as electrical burns from the energy sources. Electricity OSHA requires compliance with the 1971 National Electric Code in most cases.

Below are some commonsense guidelines for electrical safety that are applicable to the ACR industry:

• Check electrical equipment before using. Equipment must be grounded. Don’t use equipment with frayed cords or damaged insulation.
• Never operate electrical equipment when standing in wet or damp areas.
• Electric cords must be the three-wire type. Do not hang cords from nails or wires. Splices must be soldered and adequately insulated.
• Keep electrical wires off the ground. Never run over wires with equipment.
• Plug receptacles must be the approved, concealed-contact type.
• Exposed metal parts of electrical tools that do not carry current must be grounded. (Grainger)

Hazardous Functions

Any form of construction can be dangerous, and workers and management are obliged to cooperate to ensure a safe workplace. The employer must maintain a log and summary of all reportable injuries and illnesses for each work site. Reportable events are those that result in fatality, hospitalization, lost workdays, medical treatment, job transfer or termination, or loss of consciousness. Incidents must be entered in the log within six days of the date the employer learns of them. (Bourne)

Tool safety is essential. First, always wear safety glasses or goggles when using any striking tools. Check that the handle is securely attached before using a hammer. Never pound one hammer with another. Use the correct sized hammer for the job. Throw out a hammer or chisel with dents, cracks, chips, or mushrooming. Electric tools must have double insulation, proper grounding, or a ground-fault circuit interrupter. Dead-man switches, which require constant pressure on the trigger to operate, are required for electric tools at construction sites. (OSHA)

Housekeeping Good housekeeping reduces hazards and increases efficiency by allowing work to flow smoothly and reducing searches for tools or materials. The Occupational Safety Health Administration or (OSHA) requires that job sites be orderly and clear of debris and recognized hazards. (OSHA)

OSHA requires that:

• material storage and waste disposal yards are convenient but out of the way;
• traffic lanes permit efficient movement;
• hazardous materials are stored in proper containers and away from the work area;
• obstacles and uneven ground are clear of trash, piles of fill, and other obstacles; and
• ropes, electric cords, and tools from the working area are kept as clear as possible during construction.

Proper lifting and carrying procedures can prevent falls, back injuries, and hernias. Before carrying something heavy, make sure the route is clear of obstructions and has good footing. Wipe off oil or grease. Wear gloves if necessary. Get a firm grip on the object, being wary of splinters, nails, and other hazards. Then lift it with the knees, keeping the back straight and vertical. Set the object down the same way it was lifted, with the knees and not the hack. Make sure fingers and toes are clear before setting down the object. When carrying a long object on shoulders, lower the front end to get a clear view of the path. Use special care when turning. It is required to ask for help when needed. (OSHA)

Openings in floors may have standard railings or be covered with planks or steel plate. Do not cover floor openings with plastic as this will hide the danger. Ladder way openings require standard railings except at the entrance. Passage through the entrance must be guarded by a swinging gate or the path can be offset so a worker cannot walk directly into the opening. (OSHA)

Hazardous Operations

The concept of mechanical refrigeration is achieved by the continuous movement of circulating, evaporating and condensing within a closed system. Any cooling system must meet certain basic operating conditions, including:

• The system must be dry and uncontaminated.
• The compressor (in a vapor-compression system) or generator (in an absorption system) must remain within safe and efficient temperature, pressure, and electrical limits.
• All moving parts that require lubrication must receive enough oil under the proper pressure.
• No liquid refrigerant can enter the compressor through the suction line.
• The evaporator must receive enough liquid refrigerants.
• The piping cannot cause excessive pressure reduction.
• The devices for disposing of heat must function well.

Hazardous Components

Air conditioning and refrigeration systems rely on several types of controls. Some controls serve multiple functions, and several types of controls can be housed in a single component, especially with solid-state controls. (Harbin)

These controls are described here:

• Capacity controls determine how much refrigerant the compressor pumps to the condenser.
• Operating controls regulate electric current to the compressor motor.
• Refrigerant controls, or metering devices regulate the flow of refrigerant through the system.
• Safety controls prevent the system from operating when it might harm people, equipment, or facilities.

Other components that help control system operation, such as two-temperature valves and pressure limiters. Faulty controls can cause almost any sort of problem in a cooling system, bat the complicated nature of modem controls can interfere with trouble shooting. If a control problem is suspected, try to bypass the control rad watch the result. If the bypass corrects the problem, then the problem has probably been isolated. Another simple troubleshooting technique is to replace the questionable control with one that is good. (Harbin)

Goals of a control system are to:

• establish design conditions (pressure and temperature);
• restore conditions quickly when they deviate;
• ensure safety for building occupants, products, and mechanical equipment; and
• ensure economical operation.

In a closed-loop control system, the controller senses a variable and changes it when necessary.

Compressors need protection from any foreseeable source of trouble. Compressors are designed to pump compressible vapor; pumping uncompressible liquid can break pistons or valves. Thus, all compressors need flood back safety devices to prevent liquid refrigerant from entering through the suction line.

To prevent motors from running during conditions that endanger the motor, compressor, or other components, designers use a high-pressure cut-out, a low-pressure cut-out, internal relief valve, motor thermostat, and an oil safety switch. These switches are called “limits” because they prevent the system from operating outside safe limits. Smaller systems usually have a smaller group of limits. (Harbin)

Installation and repair of comfort-cooling and refrigeration machinery can be hazardous, and employees must wear and use OSHA-approved safety equipment. Wear steel toes to prevent foot injury. Do not use lifelines or lanyards for any purpose except employee safeguarding.

Air Pack Employees must he trained to use respiratory protective equipment. The protective devices must be appropriate to the danger and the nature of the work requirements and inspected daily before use. One good protective measure is an air pack—a small, self-contained breathing apparatus for use in areas that may become contaminated with dangerous gas, such as ammonia and high concentrations of halocarbon refrigerants. The mask covers the head to protect the eyes, nose, and face, and receives bottled air through a hose. A common type of air pack—the mine safety apparatus—provides “pressure-demand” air supply. (Harbin)

Helmets must be worn in areas where head injuries are possible due to flying or falling objects, impact, or electrical shock or burns. Eye and face protection are required whenever there is a danger of injury. Employees working with torches must wear appropriate filters and safety goggles. Goggles are a good safety measure when soldering, brazing, grinding, using hammer and chisel, and working with refrigerants. Always wear goggles when working with ammonia systems. Gloves are a smart precaution, especially when soldering, brazing, grinding, or handling other hot metal. Gloves are also useful when using a hammer and chisel, or working around leaking refrigerants or in cold areas. (OSHA)

Hazardous Materials

Flammable liquids pose a tire and explosion danger. It is required to store gasoline in approved cans away from any possible fire, sparks, or mechanical hazard. Pour gasoline with an approved gooseneck filler. Keep the spout in contact with the metal opening to the tank to prevent sparks caused by static electricity. Do not smoke while filling. Never fill a machine while it is running. (Bourne)

It is important to be aware of the following concerns related to hazardous materials.

Condenser: Most air cooled refrigeration systems are designed so that the refrigerant will condense at a temperature about 25 to 30 degrees above the ambient air temperature around the condenser. Most water cooled systems are designed for 75° to 95° entering condenser water temperature, with 85° being the design temperature. (Air Conditioning & Refrigeration Guide, 2010)

Heat-exchanging pipes: serpentine or coiled set of pipes outside the unit

Hot gas discharge line: This tube connects the compressor with the condenser. After the compressor has discharged the high-pressure, high-temperature refrigerant gas, the hot gas discharge line carries it to the condenser Refrigerant – liquid that evaporates inside the refrigerator to create the cold temperatures

Suction line: This is the tube between the evaporator and the compressor. After the liquid has absorbed the heat, the suction line carries the refrigerant to the compressor. At this point, the refrigerant is a superheated gas.

Evaporator: This device helps with the heat exchanging. The evaporator boils the liquid refrigerant at a low temperature, which causes the refrigerant to absorb heat

Expansion Valve: Within the refrigeration system, “the expansion valve is located at the end of the liquid line, before the evaporator. The high-pressure liquid reaches the expansion valve, having come from the condenser. The valve then reduces the pressure of the refrigerant as it passes through the orifice, which is located inside the valve. On reducing the pressure, the temperature of the refrigerant also decreases to a level below the surrounding air. This low-pressure, low-temperature liquid is then pumped in to the evaporator” (Honeywell Control Systems Ltd, 2004)

Works Cited

Air Conditioning & Refrigeration Guide. (2010). The Refrigeration Cycle. Retrieved 2 16, 2011, from Air Conditioning & Refrigeration Guide: http://www.air-conditioning-and-refrigeration-guide.com/refrigeration-cycle.html

Bourne. 11 Rules for Safe Handling of Hazardous Materials. April 2012. 10 July 2015 <http://safetydailyadvisor.blr.com/2012/04/11-rules-for-safe-handling-of-hazardous-materials/>.

Grainger. Electrical Safety. 2015. 10 July 2015 <http://www.grainger.com/content/qt-electrical-safety-266>.

Harbin, Mark. Refrigerant Safety 101. July 2006. 10 July 2015 <http://www.facilitiesnet.com/hvac/article/Refrigerant-Safety-101-Facility-Management-HVAC-Feature–4833#>.

Honeywell Control Systems Ltd. (2004). THE REFRIGERATION SYSTEM. Retrieved 2 16, 2011, from Honeywell Control Systems Ltd.: http://www.europe.honeywell.com/70_refrigeration_control/EN5B-0024UK07%20R0505.pdf

OSHA. Occupational Safety and Health Standards. 2015. 10 July 2015 <https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9777>.

Petchers, N. (2003). Combined heating, cooling, and power handbook . New York: Fairmont Press.

Refrigeration Basics. (2010). Refrigeration Basics. Retrieved 2 16, 2011, from Refrigeration Training: http://www.refrigerationbasics.com/1024×768/rb2.htm