O2 Cleaning: Some Harsh Chemical Realities

O2 Cleaning: Some Harsh Chemical Realities
by
Larry “Harris” Taylor, Ph.D.

There is no question that material used for oxygen service must be oxygen cleaned. (See Compressed Gas Association (CGA) and National Fire Protection Association (NFPA) references, below). The potential for disaster associated with the increased flammability of all materials in an oxygen rich atmosphere necessitates that all potential combustible material be removed. There is a variety of oxygen cleaning protocols that address this necessity. The specific procedure utilized will depend upon the chemical nature of the potential contaminant, the amount of material to be removed, the physical location and composition of the O2distribution system, the cost of materials and safeguards, and the experience of the technician who does the cleaning. Typical cleaning methods include steam cleaning, vapor degreasing, solvent washing, alkaline (base or caustic) immersion, acid cleaning, mechanical cleaning (wire brushes, etc.) and purging. Many of these procedures pose a significant chemical health hazard. This article reviews these hazards and suggests some safeguards to minimize the risk.
Steam/Hot Water Cleaning
Steam cleaning is the most chemically benign procedure. In general, the object to be cleaned is either submerged in a vat of hot water or subjected to a stream of steam. The combination of heat, agitation or pressure of the flowing fluid removes common dirt, oils, greases and soaps, After cleaning, any remaining water soluble detergent is removed with a vigorous warm water rinse and dried under a stream of oil-free air or nitrogen.
The detergents commonly used in steam cleaning are considered to be mild skin irritants. Precautions during use include protection of the skin, particularly the eyes, by using protective clothing and safety glasses. If mixing of bulk solid detergents is involved, then respiratory filters should be worn to avoid inhaling the powder. If skin is contaminated, the detergent can generally be removed with a cool water rinse. The most likely injury is thermal burns caused by handling warm or hot material. Wearing appropriate garments and handling the cleaned components with safety tongs best prevent skin contamination and injury.
Caustic Cleaning
Caustic agents (chemical bases such as sodium or potassium hydroxide) are used to remove heavy or stubborn surface contamination. The cleaning chemicals are removed with multiple, vigorous water rinses. Strong bases will rapidly attack and degrade aluminum and aluminum alloys. These agents are extremely destructive to body tissues and may cause severe chemical burns. Inhalation can be fatal.
Prevention of injury involves working in well-ventilated areas, using approved containers, wearing safety glasses, protective clothing and rubber gloves. In case of skin or eye contact, wash affected area with running water for a minimum of 15 minutes. If the eyes are involved, hold the eyelids open to insure adequate irrigation. The eyes are particularly vulnerable to injury by chemical bases; eye contact should be considered a medial emergency. If inhaled, remove victim to fresh air, give artificial respiration, if needed. (If breathing is labored, supplement breathing with oxygen). Seek immediate emergency medical care.
Acid Cleaning
Acids are used to remove oxides, light rust, and light oils. Phosphoric acid can be used for all metals. Hydrochloric acid is generally reserved for carbon and low alloy steels. It should not be used with stainless steel. Chromic acid and or nitric acid based agents are recommended for aluminum, copper, and their alloys. Acid cleaning techniques should not be used unless the manufacturer of device being cleaned has specified this procedure be employed. Following their use, acids are removed by rinsing with copious amounts of clean, running water. This rinse is critical! Diver injury has resulted from inhaling residual hydrochloric acid fumes in a “cleaned” scuba cylinder.
Concentrated acids may be lethal, if inhaled or swallowed. However, the most common injury is tissue destruction (chemical burns) of mucous membranes in the upper respiratory tract, eyes and skin. The best prevention is mechanical isolation: work in a well-ventilated space, use only materials that are acid compatible, wear safety glasses, rubber gloves, and protective clothing. In case of contact, wash the affected area at least 15 minutes with copious amounts of cool running water. If the eyes are involved, separate the eyelids to insure adequate flushing. If the acid has been inhaled, move to fresh air; provide artificial ventilation (if needed; oxygen supplemented if breathing is labored). Seek immediate medical attention. Wash contaminated clothing before reuse and discard contaminated foot ware.
OXIDIZING AGENTS: Chromic acid is commonly found in glass cleaning solutions. As such, it should be stored separate from any organic solvents or acids. (For example, chromic and acetic acid stored together is a common explosive hazard found chemical storage areas.) Use only as specified by manufacturer or vendor of the process utilized in cleaning procedures. Along this same line, a number of years ago, a very gifted chemistry student, faced with cleaning a rather nasty, solid mass in some lab glassware, figured that if a mixture of chromic acid and sulfuric acid (common commercial glass cleaning solution), a better cleaner could be obtained by mixing potassium permanganate (a strong oxidizer) and sulfuric acid. While this is theoretically solid thinking, the problem is that potassium permanganate and sulfuric acid give rise to a highly explosive and easily detonated mixture. An appearance of a rapidly expanding purple gas cloud is often the last thing seen when this mixture is made. In this particular incident, the student survived the explosion. Left a trail of bloody palm prints along the lab wall as, blinded, he felt his way to the safety shower. He walked away, but with permanent disfigurement from the combination of glass lacerations and acid burns. The point of this little story is that mixing cleaning agents is NOT a good idea AND that in chemistry (as in diving and all life activities), it is often that which is unknown that poses the greatest risk.
ORGANIC SOLVENTS: Organic solvents such as carbon tetrachloride, chloroform, methylene chloride (dichloromethane), refrigerant 11 (trichlorofluoromethane), refrigerant 113 (trichlorotrifluoethane), perchloroethylene, 1,1,1-trichloroethane (methylchloroform) or trichloroethylene are often employed in industry as degreasers. These reagents commonly also contain corrosive inhibitors and/or chemical stabilizers to prevent decomposition of the chlorinated chemicals.
These are powerful solvents. They will dissolve most greases and oils. This is why they have been employed in the dry cleaning operations. In addition they will dissolve or leach material from many common plastics. Users of these solvents need to check compatibility of containers and object being cleaned with these materials.
These solvents are harmful if swallowed, inhaled or absorbed through the skin. Their vapors are irritating, especially to the eyes and mucous membranes of the upper respiratory tract. Direct skin contact is quite destructive to tissue. Carbon tetrachloride and trichlorethylene are particularly toxic. Inhaling the common solvent 1,1,1-trichloroethane can lead to distorted perceptions of reality, hallucinations, behavioral instability, diarrhea and headache. Consumption of alcohol may increase the toxic effects of this class of solvents.
All chlorinated solvents pose a health risk to humans. Once absorbed or inhaled, they will accumulate in the liver and kidneys. Often, there are central nervous system and cardiovascular impairment side effects. Eventually, enough material will accumulate and organs will cease to function. (As a practicing organic chemist, my rule of thumb is “If I can smell it, the chemical is going to my liver (body’s primary detoxification center), but if it has a chloro in the name, it may never leave my body.”) Some of these compounds (dichloromethane, in particular) will decompose in the body to form carbon monoxide. Many of the chlorinated hydrocarbon solvents have been demonstrated to be carcinogenic. Those not formally labeled carcinogenic are generally believed to be so. Most, particularly 1,1,1-trichloroethane have been demonstrated to be mutagenic. If spilled on leather shoes, the trapped solvent can create blisters and other skin lesions on the foot.
Many of these chlorinated solvents have been used in fire extinguishing agents. However, when heated, these materials can decompose to such nasty compounds as carbon monoxide, hydrochloric acid, hydrofluoric acid, and phosgene (a very powerful chemical warfare agent used for its ability to attack lung tissue). Since these life threatening products of decomposition can also be formed in many common chemical reactions, chlorinated solvents should not be stored near heat sources, strong oxidizing agents, strong acids, strong bases, or near aluminum, magnesium, potassium, or sodium metals. Some of these chlorinated solvents are flammable when combined with an oxidizer, so it is critical that all such solvents be entirely removed before exposure to oxygen enriched atmospheres. There have been spectacular explosions resulting from the ignition of chlorinated solvents in oxygen systems!
Aluminum is a porous metal. Thus, use of chlorinated solvents in cleaning aluminum scuba cylinders will result in some solvent being absorbed into the walls of the cylinder. Toxic chlorinated solvent and by products will then be slowly released into the gas contained within the cylinder. I am aware of no data that examines this risk to the diver if such solvents are used for scuba cylinders, but I would NOT want to be part of the alpha test group. In addition, many of these solvents slowly form hydrochloric acid that is known to attack and degrade aluminum metal. If using chlorinated solvents, it is wise to check with the cylinder or regulator manufacturer to check for compatibility.
If chlorinated solvents must be used, then several safeguards should be employed to insure the health and safety of those exposed. Such solvents should only be used in well-ventilated areas. The user should be protected with adequate clothing, eyeglasses and gloves. Since these solvents dissolve or pass through most common glove materials, the preferred material for gloves is Viton. (These gloves are very expensive, but much cheaper than a liver transplant!)
In case of skin contact, flush exposed area with copious amounts of water for a minimum of 15 minutes. Assure adequate flushing of the eye by manually holding the eyelids open. If the solvent has been inhaled, move to fresh air; provide artificial ventilation (if needed: oxygen supplemented if breathing is labored). Seek immediate medical attention. If swallowed, rinse mouth with water (if victim is conscious) and seek immediate medical attention.
The used solvent also poses a health hazard. These materials are water insoluble and should not be poured down the drain. Proper disposal usually involves a commercial vendor who specialized in handling waste materials. Most often these solvents are re-distilled for recycling, but total destruction typically involves extreme high temperature ignition.
Since these materials are commonly listed by a variety of environmental protection enforcement agencies as hazardous, they are subject to a number of regulations and disposal procedures. Violation of these laws can be extremely damaging to the environment and most expensive for the offender. Those using these materials should consult local and regional authorities for guidelines.
Inspection Hazards
One method of inspecting the cleaned component for residual contamination is observation of the part under ultraviolet (“black” or UV) light. This method only works for materials that fluoresce (emit light when excited by UV light). Many contaminants and most residual solvents will NOT fluoresce. So, inspection under UV light should not be the sole criteria for acceptance of O2 clean status. Users of UV light should be aware that this light could damage the skin (sunburn is a result of ultraviolet light from the sun) and the eyes. Even if not looking directly into the light source, reflected UV light can cause permanent damage to the eyes by burning the retina. Whenever the UV inspection light is used, the inspector should be wearing glasses specifically designed to stop UV radiation. Users should not look directly into the light source.
The OSHA Specter
In 1971 the Occupational Safety and Health Act (OSHA) became law. This act is without a doubt the most comprehensive health and safety legislation in the history of the world. This act mandates that EVERY employer in the United States provide a working environment that is “free” from recognized hazards. This set of regulations has teeth: employers found in violation of OSHA standards are subject to extensive fines (may be assessed daily until compliance is documented) and imprisonment. In November of 1983, the Hazard Communication Standard (HCS) extended the chemical regulations, which had been aimed primarily at the chemical manufacturing industry. This is a generic document that regulates ALL hazardous chemicals used by ANY employer in the United States. This law, commonly referred to as “Right To Know” mandates the following:
1. Chemical manufacturers must evaluate the hazards of all chemical products they produce.
2. Users of chemicals MUST provide their employees with information on chemical hazards using a formal chemical hazard communication program. (Many have adopted a so-called “Chemical Hygiene Program.”)
3. This hazard communication program must include hazardous labels, Material Safety Data Sheets (MSDS), warning signs and employee training.
Unless state laws are more stringent, the federal Right To Know legislation applies to ALL users of chemicals in the United States. With time, OSHA will be “visiting” all users of chemicals to insure compliance with federal OSHA chemical safety standards.
Translation: For compliance with federal OSHA regulations, every employer must make available to his employees: a set of written instructions which identify hazardous materials, the manufacturing safety data sheets for all chemicals used on the premises, warning labels on containers, safety warning signs in areas where hazardous materials are used and proper training in the safe handling of hazardous materials. Finally, the employer must be able to document compliance to OSHA.
Beyond OSHA
In addition, users of hazardous chemicals must make certain that their method of disposal of harsh chemical materials is appropriate. Remember, hazardous waste poured down the drain or allowed to evaporate into the air will eventually contaminate the water in which you or your children will dive. The Environmental Protection Agency (EPA) may regulate by local ordinance or guidelines the safe disposal of chemical waste (which may include removal by a commercial vendor).
Those filling oxygen cylinders should be aware that there are numerous regulations concerning the transfilling of oxygen cylinders used for human respiration. It is possible the Federal Drug Administration (FDA) could consider oxygen cylinders used for decompression to be regulated by their Compressed Medical Gases Guidelines. This may include licensing of the transfilling station. Lastly, those filling oxygen cylinders should be aware that several oxygen cylinders used in-water have violently ruptured during filling. As a result, the CGA has specifically recommended that oxygen cylinders NOT BE USED UNDERWATER.
Conclusion:
The extreme risk of fire and explosion associated with oxygen enriched atmospheres mandates oxygen cleaning. The cleaning process, however, has its own set of risks: handling and disposing of hazardous chemicals. Understanding the nature of the problem, as with all risks in diving, can minimize these risks. Wise people providing oxygen-cleaning services will consult chemical hygiene and legal authorities to minimize all risks associated with the process.

Source: http://www.mindspring.com/~divegeek/oxclean.htm

Wine is becoming increasingly popular in Manila and other cities in the Philippines. Wine lovers in Manila travel to the north to visit Clark, Pampanga to shop for good and rate vintage wines at good duty-free prices. The most frequently visited liquor shop in Manila and wine shop in Pampanga is Clark Wine Center. This highly recommended wine shop located outside Manila near Angeles City, Pampanga in North Luzon is known for offering a great selection of fine vintage wine that is good quality and good value for money also.

This well-known wine shop is a famous shopping destination for wine enthusiasts in Manila and wine lovers from other cities in Asia including Hong Kong, Macau, Shanghai, Beijing, Seoul, Osaka and Tokyo.

Famous Philippines wine supplier known for its line of fine vintage wines, Yats Wine Cellars was established in 2000 to address the requirement of a growing population of wine enthusiasts in the Philippines. This 5-star wine shop caters to the discerning client who requires these qualities in their wines: (1) excellent value, (2) large selection of labels and vintages to choose from and (3) wines properly aged for full enjoyment.

Public wine tastings are held from time to time in Clark and sometimes in Manila. Tickets range from p500 to p1500 for these themed events that are professionally run –no wine merchants sponsorship, pushy salesmen or tacky banners to ruin the evening. Each ticket contains a certain number of stubs that can be redeemed for a tasting pour of a wine among those on a line-up which often contains wines that are quite old and expensive.

http://www.ClarkWineCenter.com

Getting to this wine shop in Pampanga Angeles City Clark Freeport Zone Philippines from Manila
Getting to the Clark Wine Center wine shop from Manila is quite simple: after entering Clark Freeport from Dau and Angeles City, proceed straight along the main highway M A Roxas. Clark Wine Center is the stand-along white building on the right, at the corner A Bonifacio Ave. From the Clark International Airport DMIA, ask the taxi to drive towards the entrance of Clark going to Angeles City. From Mimosa, just proceed towards the exit of Clark and this wine shop is on the opposite side of the main road M A Roxas.

Best place to buy wine in Clark Pampanga outside Manila near Subic and Angeles City Philippines is Clark Wine Center.

Click here to contact Clark Wine Center in Clark Pampanga for inquiries and orders.

Clark Wine Center
Bldg 6460 Clark Observatory Building
Manuel A. Roxas Highway corner A Bonifacio Ave,
Angeles Clark Freeport Zone, Pampanga 2023
0922-870-5173 0917-826-8790 (ask for Ana Fe)

Wine@Yats-International.com

YATS Wine Cellars
Manila Sales Office
3003C East Tower, Phil Stock Exchange Center,
Exchange Rd Ortigas Metro Manila, Philippines 1605
(632) 637-5019 0917-520-4393 ask for Rea or Chay

Wedding couples looking for wedding reception venues and beach wedding venues can log on to this Philippines Wedding Venue web site for free information and assistance:

http://www.PhilippinesWeddingVenue.com

While in Clark, it might be a good idea to enjoy an evening of wine-and-dine in the fine dining Yats Restaurant and Wine Bar that features an award winning 2700-line wine list. Highly recommended fine dining restaurant in Manila for special occasion is Yats Restaurant & Wine Lounge located in the famous Mimosa Leisure Estate in Clark Pampanga. Situated near this popular restaurant in Clark is the Mimosa Golf Course as well as the Mimosa Clark Casino. This top rated restaurant near Angeles City Pampanga in Clark Philippines is frequently used for private parties and corporate functions such as board meetings and other gatherings. It is located in Mimosa Leisure Estate of Clark Freeport Zone. For more information, visit http://www.YatsRestaurant.com

YATS Leisure Philippines is a developer and operator of clubs, resorts and high-class restaurants and wine shops in Clark Angeles Philippines http://www.YatsLeisure.com

Looking for famous tourists spots, places to visit and see, relax and unwind in Clark, Pampanga, Philippines? You may want to check out these sites also:

http://www.LondonPubClark.com

Besides good restaurants to wine and dine near Manila, Subic or in Angeles City Pampanga, Clark Philippines, those requiring assistance for hotel and resort bookings in Clark, Pampanga, Philippines may log on to http://www.HotelClarkPhilippines.com for more information and reservations.

The lifestyle in Clark Pampanga is quite unique. For more information about shopping, sports, golf, leisure, hotel accommodation, where to see and visit, what to do, where to wine and dine and good places to hang out, relax, have a drink with friends, child-friendly establishments, log on to
http://www.ClarkPhilippines.com

Wine lovers looking for a special bottle or something that is of great value and special discounts might log on to this web site to shop for fine vintage wines
http://www.YatsWineCellars.com

Those visitors who plan to relax and unwind in Angeles City, Subic, Pampanga, Clark Philippines might make an effort to book a room at the famous beach and lake resort Clearwater Resort & Country Club. This famous hotel in Clark Pampanga is frequently visited by families with children looking for a good place in Clark to see, a good holiday destination for the family to relax and unwind in the beautiful outdoor facilities. For more information, log on to www.ClearwaterPhilippines.com