CHEMICAL DATA NOTEBOOK SERIES #56: ISOPROPYL ALCOHOL
HAZARDOUS MATERIALS
Isopropyl alcohol is a flammable, toxic, irritating, volatile, clear, colorless liquid with a sharp odor. It is often found in the medicine cabinet, where it is known as rubbing alcohol. It also is an important commercial chemical used in the manufacture of antifreeze, cosmetics, dyes, lacquers, pharmaceuticals, perfumes, soaps, window cleaners, and many other chemicals. The correct chemical name for isopropyl alcohol is isopropanol.
PROPERTIES
Isopropyl alcohol has a flash point of 53°F, a flammable range of 2.3 percent to 12.7 percent in air, and an ignition temperature of 750°F. It has a specific gravity of 0.785, a molecular weight of 60, and a vapor density of 2.07. It boils at 180°F, freezes at — 127°F, and is very soluble in water. Its molecular formula is C3H7OH.
HAZARDS
The principle hazard of isopropyl alcohol is its flammability. A flash point of 53°F means that when its temperature is 53°F or higher and it is exposed to the atmosphere, it will generate vapors sufficient to form an ignitable mixture near its surface or near its open container. Consider any open container of isopropyl alcohol that is in an environment or work area at room temperature (approximately 70°F) a severe fire hazard. Perhaps it is its familiarity as rubbing alcohol that causes users to ignore its fire hazards. Doctors and nurses also may neglect its hazards since they often use it to wipe oft the skin before injecting a needle or to clean around a wound.
A flammable range of 2. 3 percent to 12.7 percent is not exceedingly wide, but the lower flammable limit is easily reached in a spill. If the spill occurs outside, the temperatures of the liquid and the objects it contacts are below 53°F, and the ambient temperature is also below 53°F, there is no immediate danger of explosion because not enough vapors are being liberated to reach 2.3 percent in air. However, if the liquid, any object it contacts, or the ambient temperature rises to 53°F or above, the situation immediately becomes dangerous.
Its relatively low ignition temperature of 750°F is easily reached by all common ignition sources, including all sources of flame, sparks, electrical resistance, static discharge, and any other phenomenon capable of raising the temperature of even a tiny amount of the vapor to 750°F. This means that a mere hot piece of metal (750°F or higher) can cause the vapors to ignite. It is important to eliminate all sources of ignition —not only in the immediate area but in any area to which the vapors might flow.
The vapors will flow, traveling along low spots in the terrain and downhill. Remember that flammable and combustible liquids do not burn, but rather their vapors do. A vapor density of 2.07 means that isopropyl alcohol vapors are more than twice as heavy as air, so they always will be found near the floor of a room or near the ground if outside (if there is no strong air movement present ). If the liquid is hot, the vapors may rise temporarily before cooling and falling. These vapors may flow a long way and tend to accumulate in low spots or enclosed spaces.
Isopropyl alcohol has a low-tomoderate degree of toxicity. Its TLVTWA (threshold limit value-time weighted average) is 400 ppm (parts per million in air), its STEL (shortterm exposure limit) is 500 ppm, and its IDLH (immediately dangerous to life and health) is 12,000 ppm.
Ingestion of the product will cause drowsiness, headaches, vomiting, diarrhea, unconsciousness, and even death. Prolonged exposure to isopropyl alcohol vapors will cause eye, nose, and throat irritation. High concentrations become very hazardous, resulting in drowsiness, intoxication, and possibly a coma. Even 800 ppm, although not a very’ high concentration and well below the IDLH, can cause discomfort. Higher levels may lead to narcosis, and longer periods of exposure may cause death. Contact of the liquid with the skin can lead to irritation due to the defatting action of isopropyl alcohol.
NONFIRE SCENARIO
In the event of a large release, notify the proper environmental authorities. Consider their advice throughout the incident in order to minimize damage to the environment. Consult other professionals, including the manufacturer of the released material, the shipping company, and the consignee (the recipient).
Human life is the primary consideration, and actions required to maintain the safety of humans take precedence. Therefore, first consider evacuating the danger area. Once the threat to human life has been eliminated, seek expert advice on possible mitigation alternatives. Keep in mind that after the incident your mitigation procedures will be carefully reviewed for their effects on the environment.
Approach the incident scene from upwind. Secure it from unauthorized personnel and all ignition sources. Place personnel and equipment for safe redeployment in case a change in wind direction creates a new danger zone. At this point decide whether aggressive action by emergency responders is necessary. If there is no threat to life, the environment, systems, or property, you may decide to not get involved (beyond securing the area and seeking expert advice) or simply to monitor the situation and allow the flammable vapors to disperse.
If the container is leaking vapors and not liquid, disperse the vapors by applying water spray or fog. A wooden plug or some other type of plugging or patching material can stop the flow of vapors. The situation may not be as dangerous as with some other leaking materials, but use caution not to produce a spark or any other possible ignition source that could cause an explosion. Personnel working on the leak require respiratory protection.
If the container is leaking liquid that can be caught in some other container, use this containment technique even if the second container is not secure (not able to be closed and sealed). In some rare cases, it may be possible to pump the released liquid from the second container back into the leaking container until a secure container is found. This is only a short-term solution, since the isopropyl alcohol still will be leaking and flammable vapors will continue to enter the atmosphere. Make sure the pump and any other equipment used do not generate sparks or have hot surfaces.
If the released isopropyl alcohol cannot be captured in another container, consider constructing a containment pond or digging a pit to hold the liquid. Construct the pond by pushing soil, sand, clay, or other absorbent materials into dikes around the spill. Proper equipment and operators are necessary to dig a pit. Again, make sure all equipment and machinery used do not become an ignition source for the isopropyl alcohol vapors. A containment pit is preferable, since it usually has a smaller surface area exposed to the atmosphere. The smaller the exposed area, the slower the evaporation rate of any liquid exposed to the air. It also will be easier to cover the smaller surface area of the pit than that of the larger pond.
Once the isopropyl alcohol is captured in the pit or pond, slow the evolution of vapors by applying an alcohol-type firefighting foam. The foam may break down over time and have to be replenished; it may add to the volume of liquid in the pit or pond. The pit or pond also may be covered by a sheet of compatible rubber, plastic, or some other material to slow the isopropyl alcohol vapor production. Use standby hoselines to disperse leaking vapors by applying spray or fog into the air. Use this technique until the manufacturer, shipper, or consignee can salvage the isopropyl alcohol.
If the pit or pond is big enough to hold more liquid, add water to the isopropyl alcohol to dilute it, which effectively raises its flash point and slows the production of vapors. If you add enough water, you can raise the flash point to a temperature above that of the liquid and its surroundings. This removes the immediate threat of explosion if an ignition source is present, since the diluted isopropyl alcohol no longer will be generating vapors sufficient to form an ignitable mixture with the air near its surface. However, some vapors will be generated, and if ambient conditions produce enough energy, the diluted isopropyl alcohol may be raised to its new flash point, renewing the original danger.
Once the isopropyl alcohol has been pumped from the containment pond or pit, the remaining liquid may be absorbed with ash, cement powder, clay, sand, soil, or other materials. These materials, now contaminated, must be treated as you would the liquid. The same applies to any soil that environmental authorities determine must be removed after the incident. Flammable (explosive) vapors will continue to be released from these materials until all the isopropyl alcohol has evaporated. They must be disposed of in accordance with federal, state, and local regulations.
Make every effort to prevent isopropyl alcohol from entering a sewer or waterway. If it enters a sewer and remains at a temperature above 53°F, the sewer will begin to fill with explosive vapors. At any point along the sewer line where the vapors exist in concentration between 2.3 percent and 12.7 percent in air (the flammable range) and an ignition source also exists capable of producing temperatures of 750°F or higher, an explosion will occur, which then will flash back to the source of the explosive vapors. The extent of the explosion and the degree of damage will be determined by how far down the line the vapors moved before igniting. The danger will be lessened if there is an appreciable amount of water present in the sewer and it is moving rapidly. Isopropyl alcohol is very soluble in water and dilution will raise the flash point of the resulting solution. However, unless the volume of water in the sewer is large in relation to the amount of isopropyl alcohol entering the sewer, the flash point will not be raised significantly and the danger will not be lessened greatly.
IDENTIFICATION NUMBERS AND RATINGS
CAS
(Chemical Abstract Services)
67-63-0
STCC
(Standard Transportation Commodity Code)
4909205
RTECS
(Registry of Toxic Effects of Chemical Substances)
NT8050000
UN/NA
(United Nations/North America)
1219
DOT
(U.S. Department of Transportation)
Flammable Liquid
NFPA 704 Rating
1-3-0
IMO
(International Maritime Organization)
3.2, Flammable Liquid
If isopropyl alcohol enters a waterway, consider the following: What is the amount of isopropyl alcohol entering the waterway? Is the waterway a small pond or a large lake? Is it a very small stream with little flow of water or a large river? Is the water moving rapidly or is it stationary?
Since isopropyl alcohol is very soluble in water, the “best case” scenario would be where the volume of isopropyl alcohol is small in relation to the volume of water. The resulting dilution would raise the flash point of the solution far above the temperature of the water and, therefore, above the danger point. Another “best case” scenario is where the volume of isopropyl alcohol entering the waterway is small and the volume of water is moderate but fast-moving. This situation also will cause rapid dilution of the isopropyl alcohol.
In slow-moving and low-volume streams, it may be possible to divert the flow of water into a low-lying impoundment area. Once contained, aeration techniques such as sparging and air stripping can be used. Once the water is declared safe it can be released back into the waterway.
As soon as isopropyl alcohol enters a waterway, notify all downstream users. The environmental experts will constantly monitor the water’s purity and determine when it is safe to use again.
FIRE SCENARIO
If a container of isopropyl alcohol is not burning but is threatened by flame or radiated heat from the fire, apply cooling water from as great a distance as possible with unmanned appliances. The distance from the container and the size of the evacuation area will be determined by the size of the container and the volume of isopropyl alcohol involved. Handle an incident involving isopropyl alcohol just as you would most other flammable liquid incidents, keeping in mind the product’s water solubility. This property is typical of flammable alcohols but not of flammable hydrocarbons, and it can be used as a mitigation technique.
Exercise care whenever a container of liquid is exposed to heat. Of course the danger is intensified when that liquid is flammable. As the temperature of the container rises, heat is conducted to the liquid, which in turn rises in temperature. As the liquid gets hotter, its vapor pressure rises. This means evaporation of the liquid increases in speed, and more vapors are produced and trapped in a container of constant size. As the temperature of the liquid climbs, so does the pressure of the vapors above the liquid. This pressure will increase until a safety relief device (if present) operates to lower the pressure within the container. This relief of pressure means that the vapors are vented to the atmosphere and probably will be ignited. If the pressure within the container drops below the operating pressure of the device (assuming it is a spring-loaded valve or similar device), the venting to the atmosphere will cease. If the venting is continuous, do not extinguish the burning isopropyl alcohol vapors. If you do, the isopropyl alcohol vapors will continue to rush from the tank, and when reignition occurs (and it will) it will do so explosively. Extinguish the flame from the vent only if you can stop the flow of vapors immediately afterward.
If the pressure rise within the container is too fast for the pressure-relief device to handle or if there is no pressure-relief device on the container. the internal pressure will rise until it surpasses the design strength of the container, and the container will burst. This catastrophic rupture will be accompanied by a pressure-relief explosion. The explosion will coincide with the release of the burning isopropyl alcohol vapors as a large fireball, followed by flaming liquid (the liquid is not really burning, but its vapors are). This is a BLEVE, or boiling-liquid, expanding-vapor explosion. The death and destruction caused by this explosion are limited only by the size of the container, the amount of isopropyl alcohol involved, and the people and property impinged on by the blast force and flame.
SYNONYMS
Alcojel
Alcosolve
Avantin
Avantine
Chromar
Combi-schutz
dimethyl carbinol
Hartsol
2-hydroxypropanol
Imsol A
isohol
isopropanol
IPA
Lutosol
1-methylethyl alcohol
petrohol
Pro
2-propanol
n-propan-2-ol
propan-2-ol
Propol
sec-propanol
2-propyl alcohol
rubbing alcohol
Spectra
Sterisol Hand Disinfectant
Takinecol
If isopropyl alcohol has been released as a liquid and has been ignited, extinguishment techniques depend on the amount released; weather conditions (especially wind); and the environment, property, systems, and terrain surrounding the spill. Isopropyl alcohol may be extinguished with alcohol foam, carbon dioxide, dry chemical, or water spray or fog, depending on the above conditions. If burning isopropyl alcohol is contained and the container (tank, pit, or pond ) has sufficient capacity, you can add water to dilute the product, increasing the flash point above the temperature of the liquid (and cooling the liquid). This is much more difficult to do than in the nonfire scenario, because in this case the temperature of the isopropyl alcohol will be very high due to the heat of its radiated flames.
Emergency responders must use caution after extinguishing the flames. Reignition can occur if liquid isopropyl alcohol contacts any objects that may have been heated by the fire whose temperatures remain above the product’s ignition temperature.
PROTECTIVE CLOTHING AND EQUIPMENT
Use protective clothing and equipment that prevents contact of the material with the skin or eyes. This includes any material impervious to isopropyl alcohol that will not absorb it. Nitrile rubber gloves and boots, chemical splashproof goggles, and face shields may be sufficient. Some manufacturers say chlorobutyl rubber, neoprene, nitrile rubber, olyethylene, and Viton are compatible materials. Use respiratory’ protection in the form of positive-pressure, self-contained breathing apparatus.
FIRST AID
For inhalation of isopropyl alcohol vapors, move the victim to fresh air and keep calm and warm. If the victim’s breathing has stopped or has become labored, administer artificial respiration (be aware that such action might expose the first-aid giver to the material in the victim’s lungs and/or vomit). Seek immediate medical attention.
For eye contact, flush the eyes immediately for at least 15 minutes, occasionally lifting the eyelids. Seek immediate medical attention.
For skin contact, remove contaminated clothing and wash the affected body areas w ith large amounts of soap and water. Medical attention may be required.
For ingestion, immediately make a conscious victim drink a strong solution of salt water and induce vomiting. Never try to make an unconscious person drink or vomit. Seek immediate medical attention.
